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1. le E fQ cs 3 Gey CRE LEE ER E LH Hi T Pee be ee P ir 2 d GER ETT um 2 pe tn m Pala d ch H lu inm EH BE LL mie j LEE Es Sex EON D ie ag E z E NES 5 d E i Eu EID LE aru HE EE SH miu s ie EE quos Bv B TES EE Zi SL E Bu Avoid Touching Gold Fingers gt gt WARNING ELECTROSTATIC SENSITIVE DEVICE STATIC PROTECTION REQUIRED MAINTAIN ANTI STATIC CONDITIONS FOR HANDLING AND INSTALLATION P1 P2 I O Port Select Jumpers pcRTA User Manual 5 Chapter 1 Installatio n IBM PC ISA EISA Expansion Bus I O Port Map 200 3FF Hex 01234 56789 200 Game Controller BH rr 220 230 Reserved 3270 PC Network Card 380 BiSymComm2 38F 3A0 Bisync Comm 1 SAF 3B0 LPT 1 3BF 3 0 EGAVGAVdeo SCF 3DO CGA Video 3DF 3E0 COM 3 3EF COM 1 3FF 01234 5 6 7 8 9 ABCDEF pcRTA User Manu
2. pcRTA User Manual 288 Amplitude Response Control Panel xi Noise Signal Generator Automatic On Off Pink Noise Gen Output Level 4 dBm gt Vins Input Source rl Line Input MultiMic Select Enable Enable Mic2 V Enable y Enable Mics Multiples _ Normalized Fiat M Chapter 11 Car Audio Applications You can use the internal generator in pcRTA or an external source such as a CD or tape with pink noise on it Using the internal pink noise source is highly recommended because it is very precise repeatable Using any other pink noise source can give misleading results Test disks may not have true pink noise on them they may have just a close approximation If you want to verify the precision of any pink noise source you can measure it with pcRTA To measure an external source plug it into the Line Input Set the Input Source on the Control Panel to Line Input Set the Detector on the Control Panel to Leq with an averaging time of at least 5 00 Seconds Longer average times will yield more accurate results When you run a test with these settings you should see a flat line across the screen The flatter the line the more precise Detector Type of Data e the pink noise source Fast Dynamic Range dBspl 2 2 curd 2 If you must use an external pink
3. Hide Tool Bar Hide Curve Box 25 63 W0 160 250 400 630 th 20 ms 50 60 t5 200 500 500 wos Run Stop Test Del Gen On Off Ins Curve Library F2 System Options Control Panel Tool Box Artwork View Data Area Graph Setup F4 Notes Comments N Microphone Setup INI VI Graph Design F9 System Options F10 System Options Floating Fixed Left E Fixed Right Multi Mode gt Fixed Top Fixed Bottom Cursor Control Bitmap Selection Blink Rate Now select System Options from the Edit menu Set the Artwork View to Data Area and the Window Update to Multi Mode Click pcRTA User Manual 319 11 Car Audio Applications eee ee ee ae di It is important to understand that the window loca mak tions and sizes in this file were set on a VGA screen resolution of 640x480 If your computer is running in a SuperVGA mode 800x600 1024x768 or higher the graphs will use a smaller portion of the screen The figures on this page illustrate the same GDS file at three different screen resolutions 45 as 25 40 63 100 160 250 400 630 1k 1k6 25 4k 6k3 10k 16k Line Graph 20 31 5 50 80 125 200 315 500 800 1k25 2k 3k15 5k 8k 12k5 20k I Cursor j VGA 640x480 Display poRTA Amplitude dB EXAMPLE1 DB File Processing Utilities View Window
4. GenLevel 2 5 GenNoise Pink AveTime 5 0 Sec v Cursor ERE ee Start pcR TA impedanceZ da 009 wl 125PM The analyzer reaches a maximum of around 5k 10k Ohms when reading an open circuit Library Untitled z Shorted Cable Test Open Circuit Test Shorted Cable Test rom gt Press the Curve Library on the Tool Bar urveName 4 CurveName 5 gt Click the circle marker ON in entry 2 ees Click the square marker OFF in entry 1 Curve ame d gt Change the name of entry 2 to Shorted CurveName 9 CurveName10 Cable Test even sme nt gt Click OK to exit and save your changes Now we will test a short circuit and save that curve in entry number 2 Copy Move Curve Delete Curve Delete All Edit Data Show Info Take another measurement and rescale gt Press Run Test on the Tool Bar gt Press Scale Auto after a few seconds pcRTA User Manual 59 Chapter 3 Tutorial M pcRTA Impedance Z EXAMPLE3 Z Impedance Graph BAIE File Edit Processing Utilities View Window Help 81 edance Response EE le Panel rm Setup Curve Library Up oom
5. Bandpass in Free Field os 100 100 95 95 90 90 85 85 80 80 75 75 70 70 65 Hz 50 100 200 500 1k 2k 5k 10k 2065 Bandpass in Closed Field digi 100 100 95 95 90 90 85 85 80 80 75 75 70 70 65 Hz 50 100 200 500 1k 2k 5k 10k 2065 These graphs show the response curves of a bandpass cabinet free field and inside the car Note the extreme SPL boost at 50Hz on the closed field response This is typical of bandpass cabinets in cars 300 pcRTA User Manual 11 Car Audio Applications Now go to the Processing menu of the pcRTA software and select Divide Divide the reference free field curve by the comparison closed field curve The result is the transfer function of the vehicle This is the change in response that any speaker of the same volume as the reference will exhibit when placed in this particular vehicle It includes the closed field pressurization and the standing waves that are present in the vehicle s acoustic environment This transfer function can be saved for Divide Curves Result A B future reference when designing sys Library HIJAAK DB tems for the same type of vehicle To Evan Curve Ent Dperand A see the response of any woofer cabi npe AERE net with the same volume of speakers in this particular vehicle simply mea nt Curve Enty pan sure the cabinet a free field environ El ment and then multiply t
6. pcRTA User Manual 2 General System Features 18 pcRTA User Manual 2 General System Features 2 1 Main Screen Overview The main screen as shown below has main window which displays the various graphs and charts The main window can be zoomed and scrolled by using the scroll bars tool bar menu bar and minimize maximize buttons At the top of the screen the menu bar and title bar are displayed The menu bar shows command menus which may be pulled down The title bar will display the current measurement mode and library name in the center A moveable floating window is also shown below This is the Tool Bar This window can be moved anywhere on the screen and can also be closed and reopened It provides special features or direct access to menu commands commonly used throughout the program The lower areas of the graph also respond to double clicks of the mouse If the mouse is double clicked over the Curve Legend the curve library dialog box will appear The control panel will appear if the System area is double clicked and the Note editor will be activated if a note line is double clicked Title Bar Menu Bar Ps Minimize Maximize Close M pcRTA 4 UNTITLED DB buttons Tool Bar File Edit Processing Utilities View Window Help Graph Artwork Board Scroll Bars 4k 6 1
7. 1 Cursor A Start QJ Exploring Perta_v2 TER Amplitude dB 14 dm M 519PM pcRTA User Manual Microphone Setup x Microphone Input 1 Edi Clear Author Date Model 4 Serial sis dB m Response Errors dB FullHz 0 00 20 Hz Load Mic Data File MDF Ea File Name Directories sn201181 mdf sn201182 mdf sn201183 mdf sn201184 mdf pcrta 3 db export LI na C List Files of Type Drives MicD ataFiles mdf c new c J Microphone Setup x Microphone Input 1 j Edit Clear Author Date Model M53 dBspl Serial dBm pcRTA User Manual Response Errors dB 63Hz 027 Chapter 1 Installation This dialog box shows the current param eters assigned to the input The parameters at this time will be blank or zero To load an MDF press the Load Mic Data File button Another dialog box will appear to select the file You should now look at your LinearX micro phone and note the serial number There should be a matching SNnnnnnn MDF file in the pcRTA path Highlight this file and then press OK The system will then read the file and derive the necessary parameters When completed the setup parameter fields will be filled in as shown in the dialog box b
8. 2 Shorted Cable Test DataType Ohme 3 Spealer Tests GenNoise Pink GenLeve 27 FullBand Flat RTABands Flat TestMode 4 Wire AvrgTime 50 Sec Display 31band pcRTA 1 00 EXAMPLE3 7 0 wg Aug 30 1994 Tue 2 42 am Subtracted Result pcRTA 2 EXAMPLE3 Z File Edit Processing s View Help Impedance Response Ohm Ohm 1000 soo Curve Legend System Notes and Comments 16 3 2 Result DataType Ohms GenHoise Pink GenLevel 27 FullBand Flat RTABands Flat Testhiode 4 Wi AvrgTime 5 0 Sec Display 31band pcRTA 1 00 EXAMPLES Z D AO Odd Aug 30 1994 160 pcRTA User Manual 6 Processing Menu 6 7 Curve Averaging It is sometimes desirable to be able to average multiple measurements to come up with a single representative curve This processing feature can mathemati cally average up to 20 curves and store the data in a separate Curve Library entry or on top of one of the data curves being averaged If you do nothave multiple microphones this utility can perform essentially the same function with a single mic and taking multiple measurements at different locations A common use for this utility is generating a true power response curve from multiple curves taken at different off axis angles around a transduce
9. 9 20 90 i lam car number 1 DataType dBepl 2 This is another test GenHoise Pink FE Control FE Curve Library FE Scale E Auto Scal E Down gt In Zoom Out Zoom Amir Ri GenLevel 39 8 FullBand Flat RTABands Flat InputSre Linein AvrgTim e 10 0 Sec Display 21band n 10096 Zoom Level pcRTA User Manual 219 8 View Menu 220 8 2 1X 2X 4X 8X These four menu options can be used to set a specific magnification level directly They are largely self explanatory 1X is 10096 2X is 20096 AX is 400 and 8X is 80096 The 1X command can also be activated from the Tool Bar using the ZoomFull button or by pressing ALT 1 on the keyboard The 2X 4X and 8X levels can be activated by pressing ALT 2 ALT 4 and ALT 8 on the keyboard 1X 100 Zoom Level pcRTA Amplitude dB TEST3 DB File Edit Processing Utilities View Sound Pressure Level m 100 20 tk Curve Legend Notes and Comments LE 2 ri another test System DERTA 00 TESTS DD EE ETE T 4X 400 Zoom Level pcRTA Amplitude dB TEST3 DB File Edit Processing Utilities View 2X 200 Zoom Level
10. 4 2 Cursor Bar Graph Curve 1 Band 20k E Data 37 8 dB pcRTA User Manual 191 Chapter 7 Utilities Menu 192 pcRTA User Manual Chapter 7 Utilities Menu 7 9 True Sound Quality Scoring This utility provides a special automated algorithm for producing comparison score reflecting the true sound quality of a car audio system This routine was developed by LinearX during August of 1996 to solve some of the present problems associated with existing car audio scoring formulas There are two principal problems which this scoring system resolves 1 the score will more accurately reflect the true sound quality ofthe system and 2 there are no hard threshold ranges which cause scoring variability Itis well known that car audio systems scored under existing methods can have a wide range of system frequency response while all may be producing nearly identical scores This is due to the 3dB band pair minor deviation requirement Many systems using these older scoring formulas could have response charac teristics with substantial differences in level between the low and high fre quency ends of the spectrum While the actual difference between any band pair may be less than 3dB producing a relatively high score the overall system frequency response is extremely poor In spite of these systems producing a seemingly high score there was very little correlation between the score and actual real listening
11. 11 Car Audio Applications 290 Setting Up For Measurements The first step is to connect a noise source to the system If you are going to use the internal Pink Noise source you will need to find a place to patch into the system Usually you can just disconnect the head unit and plug the pcRTA into the cable that leads to the rear of the car Make sure that the total cable length from the pcRTA to the first piece of electronics in the system is no longer than 100 feet The next step is to set up the microphone The microphone should be placed in the approximate position of the driver s head The mic stand should be a cylinder with the smallest possible diameter Any flat surface near the microphone will cause a reflection at some high frequency When running cables into and out of the vehicle you should use a part of the window door or trunk that has a rubber seal on it This will provide some measure of padding to prevent damage to the cables NOTE Care should be taken to start with a low level of output from the internal noise source because it is very easy to send a full level signal into the amplifier s This could be dangerous to loudspeakers and human ears pcRTA User Manual 11 Car Audio Applications 11 2 Measuring SPL There are two major types of car audio competitors those that want the highest fidelity of sound reproduction sound quality and those that want to create the loude
12. 186 Note If your printer driver has spool ing enabled DO NOT start another test until the previous score has been completely printed The print spooler consumes much of the CPU time and this will cause errors in the time dependent testing algorithms Disabling print spooling is another means to eliminate this potential problem Parameters to Set before Testing Begins The microphone input source to be used during the testing is set in the control panel prior to the start of the scoring session Also the MDF file for the microphone to be used must be already loaded into the system prior to testing to provide accurate SPL calibration If you will be using the pcRTA internal Pink Noise Generator than you may also wish to set the generator level to an appropriate value However a CD tape etc can also be used with Pink Noise or music as the source for the car stereo system Most of the other control panel parameters will be automatically set by the scoring utility The scoring system uses the Text Chart display mode The single value for the full range SPL will be displayed pcRTA User Manual Outlaw SPL Scoring Documentation Testing Controls _ Print Each Graph Lib Name Test Number 1 LibCurve 1 Event Title Western Bass Olympics Contestant Max Volume Mic 1 Mic 2 Mic 3 Mic 4 Lineln Seconds 15 SPL Test Produce SPL Score Outlaw SPL Sco
13. Push when done Event Title My Contest A Contestant SPL Mar Tes Adjust your system for 90dB in Full Band Produce IASCA Score Mic 2 Mic t Mic A Lineln equence Stop Testing Exit Help 63 100 160 250 400 630 1k 1k6 2k5 4k 6k3 10k 16k 80 125 200 315 500 800 1k25 2k 3k15 5k 8k 12k5 20k Rest Line Graph _ Cursor c E pcRTA User Manual 327 11 Car Audio Applications Have the competitor restart the pink noise track on the CD and press the RTA Response Test button IASCA Scoring RTA Response Documentation Testing Controls Test button Print Each Graph zr Name IASCA001 die Test Number 1 Lib Curve 1 Contestant SPL Max Test 2 a z Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln Restart Sequence Stop Testing The pcRTA now takes 10 second average of the pink noise in the car At first the Bar Graph will update quickly and then it will freeze for 2 seconds while the pcRTA is taking measurements The graph will be updated 4 more times 2 seconds apart After ten seconds the testis finished The RTA score appears in the text box below the Contestant field If desired the test can be run again by pressing the RTA Response Test button again Now if you are doing Sound Q on this competitor press the SPL Max Test button IASCA Scoring Documentation Testing Control
14. tame Line Multiple Titles Helvetica Bold 11 0 gt Single Readout Helvetica Regular zig 1 Oct Multiple Readout Helvetica Bold 14 0 ER EE gm Graph Setup Parameters Bar Graph Settings Line Graph Settings Parameter Value Parameter Value Scale Top Value Scale Top Value dB Div D dB Div Absolute Type Absolute Major Minor Div 8 5 Major Minor Div 8 5 Graph Bars Dot Rainbow Length of Hash Dot 30 10 Full Rng Band Display Off Full Rng Band Display Off 1 3 Octave On 1 3 Octave On 1 Octave Off 1 Octave Off Single Band Off Single Band Off Amplitude Reference Curves l Text Chart Settings Noise Contours All Parameters SMPTE N Curve SMPTE X Curve Surround Curve Level dB pcRTA User Manual 273 10 Cinema Applications 10 7 Reverb Time RT60 Measurement 274 Reverb Time RT measurements characterize the reverberant properties of an acoustic space The graphs of RT display the amount of time it takes for acoustic energy to decay by a preset amount in dB at each frequency The process of measuring reverberation consists of generating a stimulus noise for a length of time sufficient to excite any reverberant modes in the space The stimulus is then cut off and the analyzer detects when the noise has decayed by a finite amount such as 60dB RT60 The pcRTA has built in reference curves for measuring RT Measuring
15. Amplitude dB TEST3 DB File Edit Processing Utilities Help 8X 800 Zoom Level pcRTA Amplitude dB TEST3 DB File Edit Processing Utilities View pcRTA User Manual 8 View Menu 8 3 Redraw Screen This menu option can be used to redraw the main graph window t is sometimes necessary to refresh the window manually when making changes to the data curves or font selections The command is largely self explanatory This command can also be activated from the Tool Bar using the Rdrw Scrn button or by pressing CTRL R R on the keyboard pcRTA User Manual 221 8 View Menu 8 4 Scale Up Scale Auto Scale Down 222 Scale Up The Scale Up menu option increases the value at the top of the graph scale by one major division Note this is moving the scale up so the data being displayed moves down The exact amount of the increase will depend on the type of scale and or the dB per division For log scales such as impedance the increase will conform to a 1 2 5 sequence The screen will be automatically redrawn after the operation This command can also be activated from the Tool Bar using the Scale Up button or by pressing CTRL UP 1 on the keyboard Scale Auto The Scale Auto menu option is used to allow the system to automatically adjust the scale When pressed the program scans the data in the curves
16. Sound Pressure Level pcRTA User Manual 309 11 Car Audio Applications These graphs illustrate what you would see with four mics set to measure in the Average mode The data from the four mics is averaged in real time and displayed as a single curve The upper graph is the average with only the left channel of the sound system turned on and the lower graph is the average with only the right channel turned on 310 pcRTA User Manual 11 Car Audio Applications If you have only one microphone you will need to average the measurements manually Once you have several curves measured go to the Process menu and select Averaging Click on all the curves you want to average and select an empty entry for the result curve The results will be the same as the graphs on the previous page however with four mics the average can be observed in real time This is very handy when adjusting an equalizer Curve Averaging Library Untitled db Select Curves to Average 1 Car Curve 1 2 Car Curve 2 3 Car Curve 3 4 Car Curve 4 5 Average of Curves 1 Thru 4 5 CurveName 7 CurveName 7 Library Curve Entry for Result d 5 Average of
17. Score 37 1 E 5 7 Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln ane Restart Sequence Stop Testing pcRTA User Manual 11 Car Audio Applications 286 pcRTA User Manual 11 Car Audio Applications 11 1 Measuring System Response This section of the manual assumes that the installation is complete All components ofthe system should be in place and functioning before you begin system measurements There are many different ways to think about the installation of a system in a car The most important consideration is what you want the end result to be Some people want to reproduce exactly what the mixing engineer heard in the control room when the recording was made Others want the car to vibrate the pavement as much as possible Some may try to achieve a happy medium between these two extremes When your goalis to realistically reproduce the orginal recording you will want to spend most of your time working towards a flat frequency response with good balance between the left and right channel When dynamic music is being played such as classical or jazz the noise floor of the system becomes very critical Special attention should be paid to road noise and the noise of the system with no music playing If you want to win a high SPL competition you will want to create a curve with most of it s energy in the low frequencies because you can take advantage of the
18. 6 Processing Menu 6 2 Invert Curve In some cases it is necessary to invert a curve This can be useful for equalizing systems and for other purposes The process of inverting a curve is the result of dividing a reference level by the curve data This reference level can be chosen by the user and controls where the curve will be positioned The dialog box for this processing operation is shown below An edit box is provided to enter the reference level The units shown for the value will change depending on the type of data The curve entry to be inverted is selected in the list box To invert a curve select the curve to be inverted in the list box Next enter the reference level for the inversion and press OK If you wish to exit without inverting press CANCEL Whether or not the data is actually dB or linear units is unimportant The data will still be inverted properly for either type of curve units An example of this operation is shown in the graphs on the following page Invert Curve Library Untitled db Reference Level 17 00 dB Library Rive Entry to Invert 4 CurveName 4 pcRTA User Manual 151 6 Processing Menu Original Curve Curve inverted at 20dB 152 pcRTA Amplitude dB EXAMPLE1 DB File Edit Processing Utilities View Help 20 EU 100 GenNoise Pink GenLevek 69 6 FullBand ANSFB RTABands ANSFB InputSrc Mic 2 AvrgTime 1 0 Sec Dis
19. Bar Graph ev Sound Pressure Level me 0 0 8 85 as 25 40 63 100 160 250 400 639 1k 1 amp 205 4k 6k3 10k 16k 20 50 80 425 200 315 500 800 1k25 2k 3k15 5k Bk 12k5 20k Line Giaph Super VGA 800x600 Display XAMPLET DB If your screen resolution is Te ER porcas in higher than VGA 640x480 Sound Pressure Level you will probably want to drag the corners of the win dows out to fill the screen Once you have the screen set up the way you like it save your settings in a GDS file so that you can recall them any time Super VGA 1024x768 Display 320 pcRTA User Manual Control Panel icon File Manager Terminal Use Print Manager Button Chapter 11 Car Audio Applications When running the scoring routines in pcRTA itis critical thatthere are no screen saver programs running and that the print spooling options are disabled These options tie up the CPU during tests and can cause invalid readings from pcRTA In Windows 3 x go to the Main window and open Control Panel Double click on the Desktop icon and click on the Screen Saver Name drop down list Select None and click OK Now double click on the Printers icon Turn off the Use Print Manager option and click Close In Windows 95 use the Settings button on the Start bar to open Control Panel Notepad Print MS DOS
20. White Noise 10 sec s3 Q SPUA 5 CurveName 5 9116 CurveN lame First hide the Curve Box Go to the View menu and click on Hide Curve Box ReDraw R Le Click here to h ScaleDown Dn hide the Curve Box Hide ToolBar T Hide Curve Box pcRTA User Manual 235 10 Cinema Applications 236 M pcRTA Amplitude dB EXAMPLE1 DB Ele Edit Processing View Window Help FT Text Chart Line Graph T Bar Graph FullRing 0 2d8 BETES Line Graph Maximize Button Sound Pressure Level Tool Bar nn 40 63 1k 4k 6k3 10k 16k 500 1k25 35 5 8k Your screen should now look like the figure above The Line Graph will be used to display the data for frequency response measurements in this text Click on the Line Graph Maximize button Your screen should Fullang 0 408 F sem C look like this 1 Pink Noise 01sec ave 2 Pink Noise 10 sec ave amp Whie Noise 10 sec ave 7 m E pcRTA User Manual 10 Cinema Applications Connecting to the pcRTA You will be u
21. J Cursor The IASCA Scoring dialog box opens Click on Start Testing IASCA Scoring Documentation _ Print Each Graph Lib 1 5 001 Level Setting Test Test Number Lib Curve Testing Controls ERES a MK Stak esting Produce IASCA Score Nic 2 Nic 3 Mic 4 Lineln IASCA Scoring Dialog Box pcRTA User Manual 323 11 Car Audio Applications Restart Sequence Button Yes button 324 Note that the Start Testing button now says Stop Testing IASCA Scoring Documentation Testing Controls _ Print Each Graph Lib Name 1 5 001 mac Test Number Lib Curve Event Title p Contestant SPLMer Test 2 z 5 Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln When starting a new competition you will want to use the Restart Sequence button This button should only be used once before anyone has been scored If the sequence is restarted during a competition some of the scores of previous competitors will be erased and replaced with new ones Click the Restart Sequence button IASCA Scoring Documentation Testing Controls A message box will pop up asking if you really want to restart the sequence Click the Yes button pcRTA User Manual 11 Car Audio Applications Now enter the name of the competition To do this click the mouse inside the area that says
22. LU 2c Show Info To select another curve for display click on the oval to the right of the curve number This will set that curve to save the data from the next test and to display on the graph To name a curve click inside the curve name edit box and type in the new name Click OK to close the Curve Library dialog box and save any changes you have made pcRTA User Manual 247 10 Cinema Applications STEP 3 Load A Chain Control Panel Settings and Graph Display Settings ZAE GototheFilemenuandselect Load Graph Display Set A dialog box Processing Utilities Ve titled Load Graph Display Set File opens New Open Sounc Save S Load the file CINE ACH GDS This file will set all of the characteris saveas tics of the display Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Click OK to close the dialog box Load Graph Display Set File File Name Directories cotormn2 aus perta blkwhtO1 gds ex cine ach gds cine bch gds cine nc gds cine rt gds color 1 gds colormn2 gds List Files of Type Graph Display Set Files gds El Go to the File menu and select Load Control Panel Set dialog box titled Load Control Panel Set File opens New Open Save 75 SaveAs Load the file CINE ACH CPS This file will set all of the pa
23. 120 to 20 eals Fixed 60 to 20 10 00 7 gt Fixed 80 to 0 Fixed 100 to 20 FullBand gt Fixed 1201040 Input Source 4 Flat Generator x ANSI Testing Mode MultiMic Select Dose Enable Mici nis DR y Enabie ands ie _ Enable Flat Limit 5 _ Enable Mic ANSI Measurement Data Enable Mic eee ree Ave Multiplex ANSI Filter GTC Relative gt Now we are ready to take another measurement Let the analyzer make a couple of updates to the screen and then turn off the test gt Press the Run Test button in the Tool Bar and wait 10 30 seconds gt Press the Stop Test button in the Tool Bar pcRTA User Manual Chapter 3 Tutorial The bar graph display now appears as shown below Unlike the Pink Noise which had equal energy per log frequency White Noise has equal energy per linear frequency This produces an RTA response which increases 10dB per decade of increasing frequency or 1dB per 1 3 octave band This results in the upward staircase effect shown here Since the RTA bands are slightly lower than before we can move the scale down to show the lower bands M pcRTA Amplitude dB EXAMPLE2 DB Bar Graph File Edi Processing Utilities View Window Help Amplitude Response ET gt Press the Scale Down but ton in the Tool Bar twice The full range bar is
24. BEBE 2 Load Control Panel Set File File Name Directories cAperta cine ach cps 1 setupl cps List Files of Type Control Panel Set Files cps pcRTA User Manual 269 10 Cinema Applications The Line Graph should look like the one shown here The data curve on this graph would pass the NC 20 criteria but would not meet NC 15 pcRTA Amplitude dB MIKEOFC DB Line Graph File Edit Processing Utilities View Window Help FullAng 46 0dB e Sound Pressure Level Pg ggg MIT TT II LAI eee LH HP FF ar NY RE f T LIL You are now ready to take an NC measurement 270 pcRTA User Manual Run Test Button AE Control ponet Graph Setup E Curve LI Library Chapter 10 Cinema Applications General procedure for Noise Criteria Measurements The settings you have loaded include 10 second averaging time and a four mic multiplexing arangement This means that the pcRTA will collect measurements from Mic Input 1 for 10 seconds then display the average of all measurements taken during that time and store that data in curve entry number 1 The process then repeats at Mic Input 2 storing the data in curve entry 2 When all four mic inputs h
25. 19 s so gt Beds s 100 s so Bend Display Type Absolute Relative 1 3 Octave Type Absolute gt Relative 1 30ctave 1 Octave 1 Octave Major Minor Div 5 Single Band Major Minor Div 4 5 Single Band Graph Bars EI Tr Rainbow 1 gj Length of Hash Dot 30 10 mil Referens Curves s Bar Line Graphe Noise Contours SMPTE N Curve SMPTE X Curves Surround Curve Level 4 Text Chart Display Readout Boxes FontSelections TypeFace Style Size Color 1i Single Title fa i amp g _ Dox Backsround utile Tites Hermes 7 MIS Single Readout J Helvetica Regular 212 9 p Lol Multiple Readout Helvetica Bold 14 0 Graph Setup Parameters Bar Graph Settings Line Graph Settings Parameter Value Parameter Value Scale Top Value Scale Top Value dB Div E dB Div 4 Type Absolute Type Absolute Major Minor Div 4 5 Major Minor Div 4 5 Graph Bars Dot Rainbow Length of Hash Dot 30 10 Full Rng Band Display Off Full Rng Band Display Off 1 3 Octave On 1 3 Octave On 1 Octave Off 1 Octave Off Single Band Off Single Band Off Amplitude Reference Curves l Text Chart Settings Noise Contours All Parameters SMPTE N Curve SMPTE X Curve Surround Curve pcRTA User Manual 10 Ci
26. 233 10 2 General Setup rerit niet PE sce daire 235 10 3 MIGTOPNONBS senkin SEE 239 10 4 A Chain Alignment 245 10 5 B Chain Alignment 256 10 6 Noise Criteria NC 266 10 7 Reverb Time RT60 Measurement 274 Chapter 11 Car Audio Applications 285 11 1 Measuring System Response 287 11 2 Measuring SPL issue 291 11 3 Vehicle ACOUSIICS cater nae eta ee uen be dece 295 11 4 Measuring Transfer Function 298 11 5 Measuring Road Noise 304 11 6 Measuring Electrical Noise 305 11 7 Adjusting With an Equalizer 306 11 8 Spatial Averaging 308 11 9 Measuring Impedance 313 11 10 Scoring 5 317 333 Appendix A pcRTA Analyzer Specifications 335 Appendix B pcRTA Connector Box Interface 339 Appendix C M50 Series Microphone Specifications 341 Appendix D Keyboard Shortcuts Quick Reference 343 Index em Hi vi pcRTA User Manual Installation pcRTA User Manual Chapter 1
27. Save Control Panel Set Load Control Panel Set PET EER 1 dialog box with the title Save Amplitude dB File opens Type in the name you want to give the file and click OK Save Amplitude dB File You now have anew DE amplitude curve li weet brary with 20 blank E entries ready to re example2 db ceive data hijaak db iasca001 db iasca002 db mike1 db mike2 db Cancel mike3 db List Files of Type Amplitude dB Files Read Only 246 pcRTA User Manual STEP 2 Curve Library Button Curve Scale Up Seale ES 2o Ef 350 2 8 Chapter 10 Cinema Applications Select and name a curve to receive the measured A Chain data Click on the Curve Library button on the Tool Bar The Curve Library dialog box opens In the figure below curve 1 is currently selected for saving the data and displaying it Before each measurement another curve must be selected in the Curve Library as the data curve or the previous test will be overwritten Curve Library Editing Curve Name Edit Box Library Untitled db CurveName 1 CurveName 2 CurveName 3 CurveName 4 CurveName 5 CurveName CurveName 7 CurveName 8 CurveName 9 CurveName10 Q 11 Copy Curve Move Curve Delete Curve Delete All m Co C3 E C3 Edit Data
28. fiii dni nd 88888588 municate with the RW 232 equalizer The equalizer must be connected to one of the PC s serial ports The type of UART in the PC is also displayed If a particular serial port is not present or unavailable in the E med 9 Start Link Hec Optimize PC certain selections may be grayed out You must choose the same serial port here 204 as is physically connected to the EQ Note If you are using the PAC interface for the pcRTA you will need an additional serial port for the EQ Start Link Button Once the serial port selection has been made this button should be clicked to initialize communication with the EQ A search of all possible RW 232 ID device address values is performed to locate any EQ s attached to the serial port When a suitable EQ is found the Device Address Model and Brand fields will be filled in with the unit s data Additionally the current EQ settings will be read from the unit and used to update the band levels and filter selections The EQ unit is now ready for operation and the other buttons at the bottom of the dialog box will be activated EQ Controls HighPass LowPass Memory Channel and Band Levels These dialog box elements mirror the settin
29. pcRTA User Manual Drives You now have anew amplitude curve li brary with 20 blank entries ready to re ceive data 257 10 Cinema Applications STEP 2 Curve Library Button 258 Select and name curve to receive the measured B Chain data Click on the Curve Library button on the Tool Bar The Curve Library dialog box opens In the figure below curve 1 is currently selected for saving the data and displaying it Before each measurement another curve must be selected in the Curve Library as the data curve or the previous test will be overwritten C Lil Editi Chive urve Library cating Name Library Untitled db Edit Box CurveName 1 CurveName 2 CurveName 3 CurveName 4 CurveName 5 CurveName CurveName 7 CurveName 8 CurveName 9 CurveName10 Q CurveNamel1 Copy Curve Move Curve Delete Curve Delete All c oco m sh C _ 1211101910100 Edit Data 2c Show Info To select another curve for display click on the oval to the right of the curve number This will set that curve to save the data from the next test and to display on the graph To name a curve click inside the curve name edit box and type in the new name Click OK to close the Curve Library dialog box and save any changes you have made pcRTA User Manual 10 Cinema Applications STEP 3 Load B C
30. _ dB 2 0 00 Start 0 000 Stop 0 000 _ dB 3 0 00 Start 0 000 Stop 0 000 Offset Adjustments For many types of environmental acoustical noise measurements an adjustment offset is applied to the data for various portions of time Three different offset periods can be defined using the features in this group box The features and descriptions of each offset period are identical The check box is used to enable disable the offset and the value of the offset is entered in the edit box which follows The next two edit boxes specify the starting and ending times for which the offset is to be applied For example a starting time of 0 0 means the offset will be applied from the start of the run and a value of 1 5 means that the offset will begin 1 5 time units after the run is started An ending time of 3 2 means that the offset will be dropped after 3 2 time units from the beginning of the run 110 OK The OK button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and save any changes you have made in the dialog box Cancel The CANCEL button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and abort any changes you have made in the dialog box Help The Help button is common to most of the dialog boxes throughout the program Use this button when you wish to open the help system and receive informat
31. example1 db example2 db hijaak db iasca001 db iasca002 db mike1 db mike2 db mike3 db List Files of Type Directories Ic ApcrtaXdb Amplitude dB Files db pcRTA User Manual You now have a new amplitude curve li brary with 20 blank entries ready to re ceive data 267 10 Cinema Applications STEP 2 Curve Library Button Control Graph IL Setup SEA Nee e se M 3125125 Ja N es 3 268 Select and name curve to receive the measured data Click on the Curve Library button on the Tool Bar The Curve Library dialog box opens In the figure below curve 1 is currently selected for saving the data and displaying it Before each measurement another curve must be selected as the data curve or the previous test will be overwritten Curve Name Curve Library Editing Edit Box Library Untitled db Copy Curve 1 CurveName 1 2 CurveName 2 Move Curve Q CurveName 3 4 CurveName 4 Delete Curve 5 0 CurveName 5 6 CurveName 6 Delete 7 CurveName 7 8 CurveName 8 Edit Data CurveName 9 10 CurveName10 Show Info 11 CurveNamel1 To select another curve for display click on the oval to the right of the curve number This will set that curve to save the data from the next test and to display on the graph To name a
32. i gt e Input iid Select 20Hz BPF RMS dB pe Select Mic2 e 25Hz BPF RMS dB 32Hz RMS dB AutoRange Gain 20Hz BPF RMS dB Generator Select DAC Attenuator Square Wave Generator 22 pcRTA User Manual 2 General System Features 2 4 Tool Bar The Tool Bar provides several buttons which duplicate commands also provided on the menu bar These commands mainly concern the display and updating of information shown in the main window and are provided here for quick access These commands are used repeatedly throughout the use of the program In adddition other specialized comands are provided on the Tool Bar for controlling measurement process Ui window Help Zoomin The View menu provides a command to both display and remove the Tool Bar The second to the lastline at the bottom of the menu will toggle between Show Tool 2 Bar and Hide Tool Bar The accelerator key CTRL T T can also be used to activate the command sus Scale Up Up The Edit System Options dialog provides a um ScaleAuto A FR m set of radio buttons for selecting fixed posi Scale Down gt Floating Full Graph tions for the Tool Bar or allowing it to float nra i Bela un and to be dragged around by the user The Show Curve Box C L iara Window Update figure below shows the Tool Bar in the Fixed Nei ee
33. ing Controls group box provides 4 buttons for conducting various tests involved with the scoring cycle Each can be operated individually or repeated as necessary They are generally executed in order from top to bottom for each contestant The first test is for adjusting the level for the actual RTA measurement Press the Level Setting Test and adjust your car audio system for 90dB in the Full band If you are using the pcRTA as the noise source the generator level will be that which was set in the control panel before the scoring ses sion began When done press the button again to stop the adjustment cycle The next test is the actual measurement of the frequency response RTA Press RTA Response Test button after you have turned on your pink noise source if external The system will perform a 10 second high pre cision average The last test is for maximum SPL Press the SPL Max Test button and the analyzer will measure the maximum SPL over a 10 sec ond period with peak hold The standard test uses a compact disk with predeter mined program material 197 Chapter 7 Utilities Menu The graph display will show the full RTA response in addition to the Full range level However only the Full range band data is retained This test is unlimited with respect to maximum SPL and points are based on the Full band SPL over 100dB When using an M51 mic the maximum SPL level which can be measured is 150dB and when using the M
34. pcRTA User Manual 119 5 Edit Menu Reverb Time Graph Reverb Time Graph This graph displays the time required in each band to fall Scale Control to the selected RT20 0 or RT60 Value at Top Log Time Log Cycles z Scale Control Linear Time The Value at Top text box is used to display the reverb time scale value at the top of the grid Because of the Major Minor 5 nature of log grids this parameter cannot be edited directly but must be changed using the increment decre Length Hash 7 Dot EI ment buttons The vertical scale may be log or linear 120 depending on the selection from the control panel In the log mode the increment and decrement buttons are used to change the value in a 1 2 5 sequence The Cycles list box provides selection for the total number of vertical log cycles In the linear mode the number of seconds per division is produced automatically since the bottom of the scale must be zero Major Minor Divisions These two parameters determine the number of major and minor divisions when a linear vertical scale is used Length of Hash Dot The graph grids contain small hash marks and dots which are used to indicate the minor divisions between major divisions These parameters control the length of the hash and dot markers If both lengths are set to zero than the minor divisions are drawn as solid lines The line lengths are entered in mils 1 10
35. It is not necessary to add the extension yourself the pcRTA software will add the correct extension automatically If you do type in an extension make sure itis correct so you will be able to recognize the file in the future as a specific library file Library files by default are located in one of the four data subdirectories NDB Z RT or NA depending on the library type However you can save and load files from other paths if desired To save a file quickly without having to go to the menu use the accelerator key CTRL S S This will update the library in memory to disk providing the library file name has already been set pcRTA User Manual 67 4 File Menu 4 4 SaveAs File The SaveAs File menu option saves the library data file in memory to disk and prompts you to enter the new file name pcRTA library files have the extension DB Z RT or NA to indicate that they are library data files It is not necessary to add the extension yourself the pcRTA software will add the correct extension automatically If you do type in an extension make sure itis the correct type so you will be able to recognize the file in the future as a library data file Library files by default are located in one of the four data subdirectories DB Z RT or NA depending on the library type However you can save and load files from other paths if desired Save Amplitude dB File x File Name example1 db ic perta
36. Pink Noise Gen Output Level 88 dBm Yims Automatic On Off This check box controls whether or not the generator output will be turned on automatically whenever a measurement is in progress When this box is checked the Gen On button in the tool bar will automatically be depressed whenever the Run Test button is depressed Noise Signal Selection This list box provides selection for Pink Noise White Noise and square waves at the 31 ISO standard center frequencies The period cycle time of the noise spectrums are 2 0 seconds and the accuracy of the square wave frequencies is typically 0 5 Output Level Edit Box The desired output level from the generator Line Output is entered and shown here The value is in dBm OdBm 0 775Vrms Regardless of the type of output signal the system correctly outputs this level in dBm Due to the nature of linear DAC attenuators the resolution of the setting will depend on the value At high values such as OdBm the resolution is very fine At low values such as 50dBm the resolution will be coarse However by closing the dialog box and reopening it the exact value used will be displayed The minimum output value is approximately 62dBm and the maximum value will depend on the particular signal Typical values are pink noise 2 6dBm white noise 8 6dBm and square wave 9 6dBm AY Output Level Increment Decrement Buttons These buttons will change the displayed output leve
37. Scaling factor unit 149 Scoring routines 317 Screen saver 210 321 Scroll bars 19 Search 228 Selected printer 73 Serial number 15 229 Serial port 207 208 210 211 Short circuit 59 Show curve box 27 Show info 86 Show tool 23 Show Hide 223 224 Sine wave 292 Slit loss equalizer 250 Slow response 292 SMPTE 260 Snake 237 Solid color 144 Spatial averaging 241 295 307 308 Speaker 52 Specifications 335 SPL 51 SPLresponse 37 Square graph marker 46 Square wave 48 Standing waves in vehicles 308 in vehicles 295 small rooms 101 Starting and stopping measurements 43 Index Statistical graphs 21 Statistics Occupational Noise 128 Stimulus time 102 Stop test 24 79 Subdirectories 21 66 Subtract curves 159 Sum multiple measurements 163 Super VGA 320 System options 145 265 319 System statistics 229 T Terminate 76 Testing mode 94 Text chart 123 Text chart display 105 115 TGA 173 TIF 173 Time out 103 Title bar 19 Tool bar description 23 show hide 223 319 Transfer function measuring 298 of acoustic environments 299 of passive crossovers 302 saving 301 Transfer to notes 86 Transferring graphics 173 True RMS detector 292 TrueType 3 TrueType fonts 3 Tutorial 37 Type of data 52 93 Type of library 65 Typeface 143 144 U UART 209 Units 149 Untitled 65 USAC scoring 181 193 V Vector images 173 Vector type fonts 144 VGA 320 Video graphics 3 Video system resolution 223 224 W
38. The Probability Distribution Noise Analysis Mode graph also displays curves for each band butit uses the left and right arrows to select the bands because data is displayed across the Y axis up and down M pcRTA Amplitude dB TEST3 DB _ 2 File Edit Processing Utilities View Window Help ff Line Graph Sound Pressure Level s 1 This is a sample curve 2 This is another test pcRTA User Manual 2 General System Features The 3D Frequency Perspective and 3D Time Perspective Noise Analysis Mode graphs include a Z axis along with the typical X and Y axes These graphs utilize the up and down keyboard arrows to move along the Z axis The shape of the cursor and it s blink rate are controlled from the System Options dialog under the Edit menu The figure below shows the cursor displaying the data of curve 1 M pcRTA Amplitude dB TEST3 DB Elle Edit Processing Utilities View Window M Line Graph Sound Pressure Level Curve Legend System Notes and Comments s 1 This is a sample curve Input Mic 1 2 This is another test Range Auto DataType SPL Abs Detector Leq 0 50 GenLevel 25 GenNoise Pink FullBand Sum RTABands Flat PRTA 1 995 TeST3 0B Mar 29 1999 Mon 6 01 pm v C
39. This process is called optimization For more information see the Utilities chapter 306 pcRTA User Manual 11 Car Audio Applications Adjusting for Flatness Set the volume of the system to a moderate level around 90dB SPL on the full range band of the pcRTA Turn off the right channel of the system by using the balance control or disconnecting the signal Adjust the equalizer on the left channel for a smooth flat response from 20Hz on up to 20kHz Frequencies below 200Hz require special attention because of the unique demands of the acoustic environment of vehicles as discussed in an earlier section Save the curve now for use when tuning the right channel of the system Turn off the left channel of the system and turn on the right channel Using the saved curve from the left channel as a reference adjust the right channel until the left and right channels are as close to identical as possible It will require different settings on the equalizer s left and right channels to make the two channels match on the pcRTA display Now turn on the left and right channels together Adjust the equalizer for a flat response again making the same relative changes on both channels For example if you move the left channel s 1kHz band down 3dB from OdB to 3dB and the right channel s 1kHz band is at 2dB move the right channel s 1kHz band down also to 5dB This will maintain the relative flatness between the left and righ
40. This check box controls whether or not the generator output will be turned on automatically whenever a measurement is in progress When this box is checked the Gen On button in the tool bar will automatically be depressed whenever the Run Test button is depressed In most NA measurements the internal generator is not used Noise Signal Selection This list box provides selection for Pink Noise White Noise and square waves at the 31 ISO standard center frequencies The period cycle time of the noise spectrums are 2 0 seconds and the accuracy of the square wave frequencies is typically 0 5 Output Level Edit Box The desired output level from the generator Line Output is entered and shown here The value is in dBm OdBm 0 775Vrms Regardless of the type of output signal the system correctly outputs this level in dBm Due to the nature of linear DAC attenuators the resolution of the setting will depend on the value At high values such as OdBm the resolution is very fine At low values such as 50dBm the resolution will be coarse However by closing the dialog box and reopening it the exact value used will be displayed The minimum output value is approximately 62dBm and the maximum value will depend on the particular signal Typical values are pink noise 2 6dBm white noise 8 6dBm and square wave 9 6dBm Output Level Increment Decrement Buttons These buttons will change the displayed output level value by 0 1dBm If the le
41. To retrieve a previous score go to the Edit menu and open the Curve Library pcRTA User Manual 329 11 Car Audio Applications The Curve Library dialog box opens Click on the Data button on the curve that you need le Mani Run Stop Test Del Gen On Off Ins Curve Library F2 Control Panel Graph Setup F4 Notes Comments Microphone Setup Graph Design F9 System Options F10 70 Click on the Show Info button Curve Library Editing Library Data button Charles Lamarca Matt Billmeier Troy Babcock Stuart Allum Earl Wills Troy Milner Mark Eldridge Show Info button The Curve Information dialog box opens This is the IASCA score that is saved in memory for this competitor 330 pcRTA User Manual 11 Car Audio Applications Click on the Transfer to Notes button Click OK Click OK again The competitor s score is now displayed in the Notes and Comments field of the graphs To print go to the File menu and select Print Transfer to Notes button Curve Information Library IASCA001 DB Curve SPL Test 0 0dBspl Score 0 0 Points RTA Test Score 37 2 Points ie B Total SPL amp RTA Results Score 37 2 Points If you need to continue scoring simply start the scoring routine again The software will automatically start at the last curve entry and will not overwrit
42. Utilities Menu Measuring ISA Bus Clock Speed Note Before running the calibration rou tine always allow your computer to warm up and stabilize for at least 15 minutes This will provide the best accuracy 216 About the Calibration Process The top area of the dialog box displays the parameters which are stored within the analyzer E2PROM The lower area shows other additional results of the calibration process When the calibration begins a message box will appear that displays the tests currently being performed If any test fails an error message box will appear The pcRTA uses the bus clock of the computer for many purposes Each computer may have a different bus clock speed The calibration routine measures the clock speed along with extensive testing and alignment of the analyzer circuitry All of the parameter fields shown in the dialog box are largely self explanatory and require no intervention on the part of the user They are provided for diagnostic information if tests fail However user adjustment of absolute level is provided in the top edit box for the OSC square wave level if necessary The absolute levels are measured based on the 5V logic power supply of the computer This voltage is controlled quite tightly and no adjustment is normally required If you wish to adjust this level you must measure the full RMS square wave output voltage with a true RMS meter The value is then entered in dBm OdB
43. a single reference microphone for frequency response correction in the range from 10Hz to 40kHz This correction is applied to the measured response by the pcRTA during measurements This technique results in a microphone response accuracy of 1dB from 10Hz to 40kHZ Each LinearX microphone is provided with a calibration file on a 3 5 floppy known as an MDF Microphone Data File The pcRTA system uses MDF s to obtain the necessary sensitivity and response curve information about a given microphone The MDF consists of an ASCII text file with 552 data points arranged in four columns index frequency magnitude and phase The open format of this file allows the user to easily edit an existing MDF or create their own MDF for mics made by other manufacturers Itis very important that the MDF files for each microphone are loaded correctly and that the microphones are connected to the proper inputs If this is not done correctly it can introduce errors in the measurements pcRTA User Manual 239 10 Cinema Applications 240 Microphone Mounting When choosing a mounting method for the mics it is important to keep reflecting surfaces to a minimum Some mic clips have flat surfaces which can cause measurement artifacts in the high frequencies The best possible shape to have near the mic is a small cylinder because the reflections are directed away from the mic capsule One technique that has been used successfully to redu
44. the noise is caught at different levels when the measurement is stopped It should be clear that accurate low frequency levels cannot be measured using short averaging times Longer averaging times are necessary gt Press the Stop Test button in the Tool Bar to stop measuring We will now change the averaging time to a much longer value Also we will place this new data into a different curve entry so that the previous data will not be lost First we will change the data curve To bring up the Curve Library edit dialog box again this time use the button on the Tool Bar gt Press the Curve Library button in the Tool Bar Library UNTITLED DB Graph Data Pink Noise 10 sec ave Now we will change the name of entry 2 and change Pink Noise 0 1sec ave ara Rte poop or the markers to make entry 2 the data entry and the Cavale only entry for graph display CurveName 5 CurveName CurveName 7 gt Edit the 2 name to Pink Noise 10 sec ave CurveName 9 gt Click the circle on entry 2 CurveNamet1 gt Click the square on entry 2 gt Click the square on entry 1 Your dialog box should look the same as shown here on the left gt Press OK to exit pcRTA User Manual 43 Chapter 3 When the screen is redrawn the graph will be filled by bars This is because the current data in entry number two is initially set to OdB which places all bars at the
45. 163 pcRTA User Manual Table of Contents Chapter 7 Utilities Menu 7 1 Export ASCII Data 7 2 Import ASCII Data 7 3 Clipboard Export JA Graphics Export ioter tenetis 7 5 IASCA Scoring 7 6 USAG SCONNG nette 7 7 Outlaw SPL Scoring 7 8 Drag Racing Scoring 7 9 True Sound Quality Scoring 7 10 Programmable EQ PA 422 7 11 Programmable EQ 232 7 12 PAG Interface rte eerte er 7 13 Analyzer Calibration Chapter 8 View Menu 8 1 Zoom In Zoom Out B2 DX eis me oceu id 8 3 Redraw SGreen iecit exceed 8 4 Scale Up Scale Auto Scale Down 8 5 Show Hide Tool Bar 8 6 Show Hide Curve Chapter 9 Help Menu 9 1 GOntenlts ete antec tec enisi eene ins 9 cues tune pcRTA User Manual Table of Contents Chapter 10 Cinema Applications 231 10 1 een
46. 4 Lineln Help Show Info This function button opens the Curve In formation dialog box which shows gen eral text information about the curve entry Unlike the Library Notes Comments fields which provide text information on a library basis this dialog box provides for text to be stored for each curve entry Each time a measurement is taken the system auto matically writes text into these fields which record the settings and date time of the analyzer when the measurement was taken However the user can edit and change these text strings to reflect other informa tion about the measurement as the user desires Pressing Ok will keep your changes while pressing Cancel will abort any infor mation changes Transfer to Notes Pressing this button will automatically trans fer the text from these curve information lines into the Notes Comments lines of the library for display on the graph charts OK The OK button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and save any changes you have made in the dialog box The Help button is common to most of the dialog boxes throughout the program Use this button when you wish to open the help system and receive information about this specific dialog box and its controls or parameters 86 pcRTA User Manual 5 4 Control Panel Amplitude Chapter 5 Edit Menu This Control Pane
47. Appearance Settings RECETTE mites minutes Printers Folder Add Remove Programs Keyboard and Fax 322 Print to the following port eri eo x AdiPot HP DeskJet 600 New Driver Timeout settings Notselected I5 seconds Transmission ety 45 seconds Setup Spool Settings _ Part Settings CET bi suppor to trie pint Diebe bidirectional support ton thre printer I ont num Now double click on the Printers Screen Saver Drop Down List folder Double click on the printer that you will be using Click on the Details tab Select Print di rectly to the printer and then dick OK Click OK again Details Tab Print Directly to Printer Button pcRTA User Manual 11 Car Audio Applications Go to the Utilities menu and select Scoring drop down menu appears Select IASCA File Edit Processing Text Ch 10 LL 0 0 View Window Help Export ASCII Data IASCA Scoring Import ASCII Data Clipboard Export Graphics Export ressure Level Programmable EQ USAC Interface CMAA Analyzer Calibration OutLaw SPL dB Drag Race True Sound Quality a6 25 40 63 100 160 250 400 630 1k 1k6 2k5 4k Gk3 10k 16k 20 31 5 50 80 125 200 315 500 800 1k25 2k 3k15 5k 8k 12k5 20k Line Graph gt
48. Cinema Applications Notes for Reverb Time Measurement continued In some rooms it may not be possible to achieve the low noise floor necessary to take true RT60 measurements down to the 20Hz band and up to the 20kHz band Since most RT60 specifications are listed only from 125Hz to 8kHz you can measure in the RT60 mode and ignore timeouts in the low and high frequencies below 125Hz and above 8kHz pcRTA ReverbTime RT RT TEST RT Reverb Time Graph 2 File Edit Processing Utilities View Window Help 2 fand Xn Rd E Reverberation Time zewsor3 o p i mum The curve shown here has good RT60 data within the 125Hz 3kHz region while the very low and very high frequencies timed out during the measurement Itis common to see a higher noise floor in the low frequency region which caused this result in the measurement 282 pcRTA User Manual Required System Output for RT60 Measurement Required System Output for RT40 Measurement Required System Output for RT20 Measurement Measured Noise Floor Chapter 10 Cinema Applications Notes for Reverb Time Measurement continued If you want to measure Reverb Time at all frequencies without timeouts you need to consider the size of the room the background noise level and the output capability of the sound system In the control panel you can choose a
49. Curves 1 Thru 4 B pcRTA User Manual 311 11 Car Audio Applications 312 pcRTA User Manual 11 Car Audio Applications 11 9 Measuring Impedance There are two different types of impedance measurement available in the pcRTA They are 2 wire and 4 wire The 2 wire method uses only the Line Output of the pcRTA It requires only one cable with two leads connected to the device to be tested The accuracy of measurements taken with the 2 wire depend on the user subtracting the short circuit impedance of the cable from the measured curve The 4 wire method uses the Line Output and the Line Input of the pcRTA It requires two cables with two leads each connected to the device to be tested The measurements that are taken with this method do not require any processing All examples in this section were measured with the 4 wire method The impedance measurement capability can be used on individual speakers as shown in these graphs The first is an 8 Ohm woofer with a Fo resonant frequency of about 30Hz The general shape of the curve is the characteristic one seen on nearly all loudspeakers with a narrow peak or hump at the low end and an upward slope at the high end Impedance Response E LL 01 100 200 pcRTA User Manual 313 11 Car Audio Applications 314 20 Hz Impedance Response The next graph shows the impedance response of a 4
50. Event Title Erase the old name and type in the name of the competition IASCA Scoring Event Title field Testing Controls _ Print Each Graph Lib Name 1 5 001 2 Level Setting Test st Number 1 Lib Curve miss Even tie RTA Response Test Contestant SPL Max Test z z Produce IASCA Score Mic 1 Input button Mic 1 Mic 2 Mic 3 Mic 4 Lineln Restart Sequence Stop Testing The pcRTA has the ability to use any of the four mic inputs or the Line Input as sources for the scoring This allows for multiple lanes to be measured with one pcRTA For single lane testing the Mic 1 input should always be selected Verify that this is true You are now ready to start scoring The preceding steps should only need to be done once at the beginning of a competition Click the Print Each Graph button if you want printouts of each competitor s results Print Each Graph button Documentation Testing Controls Print Each Graph i Name 1 5 001 Level Setting Test Test Number Lib Curve a Contestant SPL Mox Test 5 p Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln Restart Sequence Stop Testing pcRTA User Manual 325 11 Car Audio Applications Enter the competitor s name in the area marked Contestant IASCA Scoring Documentation Print Each Graph Lib Name IASCA001 Test Number TR Lib Curve a Con
51. Fixed 100 to 20 Full Band gt Fixed 120 to 40 Flat ANSI Testing Mode Sum Continuous RTA Bands ine Gu xm Flat Bel miel ANSI Measurement Data ANSI Filter Absolute gt Relative Ste pcRTA User Manual The generator box should be set for Auto PinkNoise and 0 0dBm The band response selections should be marked FLAT on both The type of measurement will be marked dBm Select the averaging time for 0 10 seconds For the input source select GENERATOR The last group box Testing Mode should have CONTINU OUS checked After you have matched these settings press OK to retain your changes and exit gt Click the OK button to exit the dialog box and keep your changes 41 Chapter 3 Tutorial We are now ready to take a measurement The top button on the Tool Bar is labeled Run Test gt Press the Run Test button in the Tool Bar Note There are also two other means provided to activate this button 1 the DELETE key on the keyboard and 2 the RightMouse button The analyzer is now running You should also note that the second button Gen On is now depressed This is the result of the generator Auto function enabled on the control menu previously You may or may not be able to see any actual bar display on the graph at this time The scale may be too high or low to see the data The Scale Auto function can now be used to locate the bars gt Press the Sca
52. Full band If you are using the pcRTA as the noise source the generator level will be that which was set in the control panel before the scoring ses sion began When done press the button again to stop the adjustment cycle The next test is the actual measurement of the frequency response RTA Press RTA Response Test button after you have turned on your pink noise source if external The system will perform a 10 second high pre cision average The last test is for maximum SPL Press the SPL Max Test button and the analyzer will measure the maximum SPL over a 10 sec ond period with peak hold The standard IASCA test uses a compact disk with prede termined program material 179 Chapter 7 Utilities Menu IASCA Scoring E Testing Controls Level Setting Test RTA Response Test SPL Max Test N Documentation _ Print Each Graph Lib Name IASCA001 Test Number 2 libCuve 2 Event Title The Big Sound Off Contestant Bill Fold SPL Score 138 8 Mic 1 gt Mic 2 gt Mic 3 gt Mic 4 gt Lineln Restart Sequence Stop Testing Help The graph display will show the full RTA response in addition to the Full range level However only the Full range band data is retained This test is unlimited with respect to maximum SPL and points are based on the Full band SPL When using an M51 mic the maximum SPL level which can be mea sured is 150dB and when using
53. Input Impedance pcRTA User Manual Appendix Appendix B pcRTA Connector Box Interface 2 lbs 7 x 2 1 75 inches DB 15 Female 1 4 Inch female jack 2 unbalanced 500 Ohms 1 4 Inch female jack 2 unbalanced 100k Ohms 3 pin XLR female 3 unbalanced 1 Shield 2 Signal 3 10VDC 100k Ohms 339 Appendix 340 pcRTA User Manual Appendix Appendix C M50 Series Microphone Specifications Note All specifications subject to change without notice Common Specifications Element Type Electret Condensor Preamp Line Driver SMT active preamp Uncorrected Freq Response 5dB 20Hz 20kHz Corrected Freq Response 1dB 10Hz 40kHz Output Impedance format 150 Ohms unbalanced Temperature Range OC to 40 Temp Coefficient 1kHz 0 01dB C DC Supply Voltage 9 11 Vdc DC Supply Current 50mA Max Electrical Connector Switchcraft TB3M Construction and Finish Aluminum Black Anodized Weight 1 oz 28 grams Length diameter 4 25 inches 0 52 inch Pinout 1 Shield 2 Signal 3 VDC Model Specific Parameters pcRTA User Manual 341 Appendix 342 pcRTA User Manual Appendix D Keyboard Shortcuts Quick Reference pcRTA User Manual Save File F2 Control Panel F3 Print Graph Exit Program Run Stop Test Gen On Off Curve Library Graph Setup Graph Design System Options Zoom In Zoom Out Zoom 1X Zoom 2X Zoom 4X Zoom 8X Redraw Screen Scale Up Scale Auto Scale Down Show Hide Too
54. MDF file which has been loaded will not be included in the measured Full Band level When set to SUM the Full Band will measure the total RMS sum of all of the 1 3 octave bands This selection only includes frequency content between 20Hz 20kHz and will follow the filtering selected for the RTA bands and not the Full band In this mode the correction curve provided by any MDF file which has been loaded will be included in the measured Full Band level RTA Bands Response This group box provides two selections Flat and ANSI The RTA bands refer to the 31 1 3 octave bands displayed across the graphs These bands can be controlled as a group separately from the full range band When set to FLAT the RTA bands will measure an unweighted response and ignores the setting of the weighting filter shown below When set to ANSI the RTA bands will measure a weighted response as specified by the weighting filter selected below pcRTA User Manual 91 5 Edit Menu ANSI Filter Full Band This list box provides six selections Flat ANSI A ANSEB ANSI C ANSI D Flat and ANSI E The Flat selection provides the ability to use the extra gain ANSI block for measuring extremely low signal levels Sum The response of the ANSI weighting filters is shown below Filters RTA Bands were originally developed to simulate human hearing at various SPL levels Flat ranging from low A to high C The D and E filters were d
55. Manager Prompt Windows ATM Control Setup Panel Paintbrush PIF Editor Printers icon Printers Default Printer NEC Silentwriter 1097 v2013 109 on LPT1 Installed Printers er 1097 v2013 109 NEC Silentwriter2 90 on LPT1 PostScript Micrografx on LPT1 PostScript Printer on LPT1 PROPRINT on LPT1 Set As Default Printer Ll Use Print Manager pcRTA User Manual Screen Saver Name drop down list Desktop icon Control Pane C Settings Fonts Ports Desktop Keyboard na B omo Printers International Date Time Enhanced Drivers Fax Sound A Mouse Changes the Windows screen colors Desktop Pattern Applications Fast Alt Tab Switching Delay Minutes Wallpaper File Icons Tile Spacing EJ wrap Title f Sizing Grid Granularity Slow Fast Cursor Blink Rate Border Width el 321 11 Car Audio Applications Double click on the Display icon Click on the Screen Saver tab and then select None on the Screen Saver drop down list Click OK Display icon Add Remove Date Time Hardware Programs E Keyboard Fax 6 Multimedia Network Background Screen Saver
56. Method ods are provided 2 wire and 4 wire The 2 wire 2 Wire LineOut mode only uses the Line Output The 4 wire mode the Line Output and Line Input 4 Wire LineOut Lineln x rd The 4 wire mode is more accurate and useful for R measuring low impedance and removes the cable Cancel Help resistance from the measurement The wiring methods for both modes is shown below 1 4 INCH PLUG LINE IN i 0 SHIELDED CABLE TEST CLIPS SHIELDED CABLE y 1 4 INCH PLUG LINE OUT lt SHIELDED CABLE pcRTA User Manual 97 5 Edit Menu Noise Generator Noise Generator This group box controls whether or not the generator output will be turned on automatically whenever a measurement is in progress When this box Manual is checked the Gen On button in the tool bar will automatically be depressed whenever the Run Test button is depressed When the manual box is checked the generator must be turned on by the user Automatic Averaging Time CE The noise signal for this test mode is fixed at Pink Noise and the level is preset to maximum output Averaging Time There are several selections provided in this list box The pcRTA performs highly accurate true RMS averaging over time periods from 0 05 to 50 seconds For typical measurements an averaging time of 10 seconds produces excellent results for Pink Noise Shorter averagi
57. Sept 24 1990 AlFightsReceved LINEAR Star Linea Aopicatione E Adobe PageMaker 6 5 IP lien A pcRTA User Manual 1 Installation 1 6 Calibration After starting the software the Calibration procedure must first be run to align the analyzer to your particular computer The uses the bus clock ofthe computer for many purposes Each computer may have different bus clock speed The Calibration routine measures the clock speed along with extensive testing and alignment of the analyzer circuitry Another very useful feature of the Calibration process is to verify correct operation of the analyzer and computer This provides a good check to ensure that there is not a port I O address conflict with another card in the system If any of the tests fail or fail randomly on occasion this is usually an indication of corrupted data being read written to the analyzer through the bus This indicates the need for changing the P1 P2 jumpers to assign a different port address for the analyzer Go to the Utilities Menu and then select Analyzer Calibration M pcRTA Amplitude dB TEST1 DB Bar Graph File Edit Processing MIE Window Help 1 Export ASCII Data Import ASCIIData lressure Level o dBspt CE Clipboard Export RTA o E Scoring 5 5 10 15 20 o 1 New Curve 1 Input LineOut 2 The Smooth Curve Range
58. Set Print P Exit Q The Load Graph Display Set File dialog box opens Select the GDS file scoring gds by double clicking the file name Load Graph Display Set File File Name Directories hp600c gds e iascatst gds internet gds aes nal gds i expo Double Click perch gd H na Drives scoring qds page ge List Files of Type Graph Display Set Files gds 318 pcRTA User Manual 11 Car Audio Applications EE NER 1 Yourscreenwilllooksomething Teaco CEE LA like this Sound Pressure Level m 09 D ata lun CurveNameT5 Ts Next hide the Curve Box and CurveNamel amp Gen m z 17 0 Cuvetame17 the Tool Bar Go to the View Caveameld Ern at menu select Hide T Setup ss a Box Go to the View menu again po QT and select Hide Tool Bar SE A Hee ES bow Line Graph TAB m ae Out _ Cursor E zom 5 Graph fis O CurveNamel5 16 O CurveName16 17 O 17 hs O 18 Scale Up Up 19 0 CurveNamel9 Scale Auto Scale Down Dn 4
59. Testing Controls Each Lib Name USACOO01 Test Number Lib Curve a Adjust your system for 904 in Full Band Mic 4 metn SPL Max Test Event Title The World of Car Audio Contestant car number 1 Response Test Produce USAC Score The next test is for adjusting the level for the actual RTA measurement Press the Level Setting Test and adjust your car audio sys tem for 90dB in the Full band If you are using the pcRTA as the noise source the generator level will be that which was set in the control panel before the scoring session began When done press the button again to stop the adjustment cycle Thelasttestis the actual measurement of the frequency response RTA Press RTA Re sponse Test button after you have turned on your pink noise source if external The system will perform a 30 second high precision average pcRTA User Manual 183 Chapter 7 Utilities Menu The graph display will show the full RTA response in addition to the Full range level However only the Full range band data is retained This test is unlimited with respect to maximum SPL and points are based on the Full band SPL over 100dB When using an M51 mic the maximum SPL level which can be measured is 150dB and when using the M52 mic the maximum SPL is 170dB After the test is finished you can repeat any of the
60. There are several data fields shown in the dialog box These data fields reflect the information read from the MDF file The Response Errors list box shows the errors developed from the frequency response data provided in the MDF file The inverse of these values will be subtracted from the measurements to produce corrected data The microphone response data within the MDF file represents the true response based on a high resolution swept sine wave measurement It is not merely 1 3 octave band data The scanning process reads this data and constructs a full frequency response curve from 10Hz 40kHz regardless of the frequency range covered in the MDF data Interpolation and extrapo lation is automatically used as needed Using this response curve a weighting function representing the 2nd order bandpass response of the RTA band filters is multiplied and the result integrated on a log frequency basis for each frequency band Individual error corrections for each band are then produced relative to a pink noise spectrum 134 pcRTA User Manual 5 Edit Menu Installing Multiple Microphones If you have multiple mics to install simply repeat the same process for the other inputs as well Since each input is configured for a specific mic you will need to keep track of which mics have been setup for which inputs The mics should always be used on the inputs for which they have been configured This provides for very high
61. a measurement of the input voltage When set to SPL the MDF data is used to produce a true SPL reading Sensitivity offset and microphone response correction is applied as dic tated in the loaded MDF mic setup The pcRTA can measure very accurate SPL levels with virtually any mic if correct MDF data is loaded pcRTA User Manual Chapter 3 Tutorial When you have finished setting up the control panel press OK to exit the dialog box gt Press OK to exit and save your changes Now test your output to see if it is too high or too low gt Press the GenOn button in the Tool Bar If the level is very low press the Control Panel button and increase the level 10dB higher to 30dBm gt Press Control Panel in the Tool Bar gt Adjust generator level to 30dBm gt Press OK to exit and save your changes If the level is still too soft you can repeat the process of increasing the generator level until itis ata comfortable audible level If you get up to OdBm and the level is still too low then you need to increase the volume control on the amplifier It is set too low Once you have a reasonable test level press the RunTest button gt Press the Run Test button in the Tool Bar The data will probably be off the top of the graph because the data is now SPL units rather than dBm Use Scale Auto to let the system find the proper scale for you gt Press the Scale Auto button in the Tool Bar Now you should see the bars mo
62. a negative value like 20dB will move the curve down 0 dB is no change If you are entering a linear scaling factor ratio its value must always be positive Entering 10 0 would move the curve up and entering 0 10 would move the curve down Entering 1 00 is no change Whether or not the data is actually in dB or linear units is unimportant The data will still be scaled properly for either type of scaling factor units or curve units An example of this operation is shown in the graphs on the following page Scale Curve Library Untitled db dB Ratio gt Linear Ratio 500 000m Library Curve Entry to Scale ns pcRTA User Manual 149 6 Processing Menu Original Curve Curve scaled down 15dB 150 pcRTA Amplitude dB TEST1 DB File Edit Processing Utilities View Help GurveLegend System GenLevek 69 6 FullBand ANS B RTABands ANSKFB InputSrc Mic 2 AvrgTime 1 0 Sec Display 31band TESTI DB LLL M Aug 29 1994 Notes Comments pcRTA Amplitude dB TEST1 DB File Edit Processing Utilities View Help EH Scale Ex Auto Scale Down Zoom In Zoom Out Zoom Full DataT ype dBm GenNoise Pink GenLevel 69 6 FullBand ANSFB RTABands ANSHB InputSrc Mic 2 AvrgTime 1 0 Sec Display 31band PORTA 1 00 TESTI DB B pcRTA User Manual
63. above tests again if necessary When completed press the Produce USAC Score button and the data will be written to the note fields in the screen and printed if you have selected that option as well For the next contestant enter in the new contestant name and repeat the process pcRTA Amplitude dB USAC0001 DB File Edit Processing Utilities View Help Sound Pressure Level EI Control baie Panel 1 1 number 1 DataType dBs pl x i ility x GenNoise Pink SEL Test 109 9dBspl Score 9 9 Points GenLevek 39 8 Test Score 4 0 Points max 20 FullBand Flat 6486 996 12dB Errors 1 2 3 RTABands Flat 6dB 31 5 a0 gt InputSre Lineln 9dB 25 31 5 AvrgTime 10 0 Sec 12dB 20 25 20k Display 31band Total SPL amp RTA Results Score 13 9 Points pcRTA 1 00 USAC0001 Re Aug 30 1994 Tue 7 16 am 184 pcRTA User Manual Chapter 7 Utilities Menu 7 7 Outlaw SPL Scoring This utility provides a special automated algorithm for producing comparison score for maximum SPL The maximum number of points for the SPL portion is unlimited and is simply the SPL value 100dB The measurement microphone must be positioned in the driver s seat at roughly ear level pointed toward the dash Use of microphone stand 26 inches high above the center of the seat is recommended All windows doors sun roofs and trunk must be closed The engine must b
64. and an amplifier It is not necessary for the test cabinet to have an extremely flat response because it will be used as a relative reference only The test cabinet should however have about the same volume of speakers as the final installation This will assure accuracy of the low frequency pressurization This technique will not provide much valuable information at the higher frequencies because you cannot place the midrange drivers and tweeters where they will be in the final installation For this reason you may elect to use just a woofer cabinet and concentrate on the frequencies below 200Hz You must first measure the reference cabinet in a free field environment The recommended method is to take a ground plane measurement This means to place the reference cabinet on the ground and the microphone on the ground 1 meter away Using a low output level about 1 Watt measure the speaker with pink noise Save the response curve as a reference Reference Cabinet Microphone Ground Plane Measurement pcRTA User Manual 299 11 Car Audio Applications Next place the reference cabinet inside the vehicle closed field and measure it again with the same pink noise signal at the same level Save the response curve for comparison
65. averaging time to 10 0 Seconds gt Press the OK button to exit and keep your changes pcRTA User Manual Chapter 3 Tutorial gt Press the RightMouse button to take a measurement It will now take 10 seconds for the display to be updated but after each update the display will barely change The measurement is very stable and accurate One thing you may wish to try is moving the mic around at different positions in front of the speaker Try on axis and off axis You will notice that the resulting curves look very different at mid and high frequencies This is due to the directional response of the speaker at different frequencies and room environment conditions Where you place a microphone is crucial to the response curve that is produced Different positions will produce different curves To save this new library data the library name will be changed to EXAMPLE2 Select File SaveAs from the menu gt Enter EXAMPLE2 DB in the file dialog box and press OK M pcRTA Amplitude dB EXAMPLE2 DB File Edit Processing Utilities View Window Help M Bar Graph Sound Pressure Level n tt ten Ful 25 63 100 160 250 400 630 ik 25 dk 6B 10k 20 315 50 80 125 200 315 500 800 105 3ki5 Sk 8 125 20k GenNoise Pink FullBand Flat RTABands Flat ees eee A Start pc TA Amplitude dB dE lug 122PM pcRTA User Manual 55 Chapte
66. averaging with selectable periods from 50 mS to 50 Sec The display update period will be equal to the Leq period When using the pcRTA to measure frequency response with pink noise stimulus the Leq detector should be used with a minimum averaging time of 2 seconds This will provide accurate and stable levels within 0 1dB across all bands Note Only Leq linear averaging can be used for the multi mic input selection pcRTA User Manual Full Band Flat ANSI Sum Flat ANSI RTA Bands ANSI Filter Chapter 5 Edit Menu Full Band Response This group box provides three selections Flat ANSI and Sum The full band is the band displayed at the left of the graph and represents a full range frequency response rather than a 1 3 octave RTA band response This band can be controlled separately from the 1 3 octave bands When set to FLAT the Full Band will measure an unweighted response and ignores the setting of the weighting filter shown below This selection includes frequency content below 20Hz and above 20kHz In this mode the correction curve provided by any MDF file which has been loaded will not be included in the measured Full Band level When set to ANSI the Full Band will measure a weighted response as specified by the weighting filter selected below This selection includes frequency content below 20Hz and above 20kHz as allowed by the selected ANSI filter In this mode the correction curve provided by any
67. be used to help flatten the low frequency rolloff of a cabinet The extent of the effect depends on the size of the passenger compartment and how much leakage there is Leakage is the amount of pressure which escapes to the outside and is caused by the sheet metal of the body flexing and other leaks such as open windows and holes The volume cone area of the speakers used to pressurize the space will also have an effect on the amount of low frequency boost A large cone area will create more boost than a small one This is true whether you are using a single very large speaker or a number of smaller speakers This graph shows the response change caused by 11018 space with 20in of leakage using a single 15 speaker This curve does not include any changes caused by standing waves Low Frequency Pressurization dipl asl 15 12 12 9 9 6 6 3 3 3 3 79 Hz 50 100 200 500 lk 2k 5k 10k 20k pcRTA User Manual 11 Car Audio Applications External Noise Noise from outside the vehicle s compartment has negative effect on the listening experience Road noise and engine noise can become a very signifi cant part of the sound inside the vehicle This noise can be reduced greatly by the use of dampening materials in the doors and on the surfaces of the passenger compartment Electrical Noise Noise
68. currently being displayed and determines the necessary top scale value This function is very useful for quickly locating the position of curves which are currently not visible on the graph The screen will be automatically redrawn after the operation This command can also be activated from the Tool Bar using the Scale Auto button or by pressing CTRL A A on the keyboard Scale Down The Scale Down menu option decreases the value at the top of the graph scale by one major division Note this is moving the scale down so the data being displayed moves up The exact amount of the decrease will depend on the type of scale and or the dB per division For log scales such as impedance the increase will conform to a 1 2 5 sequence The screen will be automatically redrawn after the operation The screen will be automatically redrawn after the operation This button can also be activated by pressing CTRL DOWN on the keyboard pcRTA User Manual 8 View Menu 8 5 Show Hide Tool Bar The Show Hide Tool Bar menu option is used to control the display of the Tool Bar This bar is a floating window which provides quick access to commonly used functions The menu text will toggle between Show and Hide to display the current available and relevant operation The position of the window is persistent which means that the bar will appear at its last position when the show command is again used The accelerator key CTRL T
69. curve click inside the curve name edit box and type in the new name Click OK to close the Curve Library dialog box and save any changes you have made pcRTA User Manual 10 Cinema Applications STEP 3 Load Noise Criteria Control Panel Settings and Graph Display Settings mp Go to the File menu and select Load Graph Display Set A dialog box Edit Processing Utilities vie titled Load Graph Display Set File opens New Sounc Load the file CINE_NC GDS This file will set all of the characteristics SaveAs of the display Save Graph Display Set y Click to close the dialog box Save Control Panel Set Load Control Panel Set Load Graph Display Set File File Name Directories cAperta bikwht01 gds Gex cine_ach gds cine bch gds cine nc gds cine rt gds color01 gds colormn2 gds List Files of Type Graph Display Set Files gds Edit Processing Utilities Go to the File menu and select Load Control Panel Set A dialog box New ne Sound _ titled Load Control Panel Set File opens Save 75 SaveAs Load the file CINE NC CPS This file will set all of the parameters of Save Graph Display Set the control panel Load Graph Display Set VE Save Control Panel Set Click to close the dialog box Print P Ext
70. db examplel db example2 db iasca001 db iasca002 db perryad db scoring db skyskan db test1 db List Files of Type Amplitude dB Files Directories CX c CX perta db Drives c new c m N Cancel 68 pcRTA User Manual Chapter 4 File Menu 4 5 Save Graph Display Set Save Graph Display Set File ET File Name blkwht01 gds cine ach gds cine bch gds cine nc gds cine 9 color01 gds contest gds contest gds List Files of Type Drives Graph Display Set Files gds c new c The Save Graph Display Set menu option saves the current settings for the display graphs to a file on disk and prompts you to enter select the file name for the file These files have an extension of GDS Itis not necessary to add the extension yourself the pcRTA software will add the correct extension automati cally If you do type in an extension make sure it is the correct type so you will be able to recognize the file in the future as a Graph DisplaySet data file Graph DisplaySet files store the colors line styles fonts position and scale information currently in use by the program This allows you to save your current display settings and later reload them to restore the previous settings all at one time This is much faster than editing all of the numerous colors and fonts one at a time By default GDS files are located in the main PCRTA subdirectory How
71. degree of control over many of the artwork elements including fonts and color selections Frame Selections Grid Selections Main Background Mils Grid Background Mils Large Frame Line Grid Frame Line Small Frame Line Major Division Line 15 Note Guide Line Minor Division Line EJ 5 Line Color Style Selections 15 Reference Curves 15 Solid Surface Lines 15 Font Selections TypeFace Style Size Color Frame Title Bar Regular 12 0 Parameter Title Bar Helvetica Bold 18 0 Parameter Values Tahoma Regular 13 0 Notes Comments Regular 10 0 Graph Title Helvetica Bold 24 0 Graph Frequency Regular 11 0 Graph Scale Regular 12 0 esp 9 pcRTA User Manual 139 5 Edit Menu Color Buttons In many locations of the dialog box small rectangular color patches are shown These are actually active buttons and will respond to a mouse click When the mouse is clicked on one of these color buttons a color selection Font Selections dialog box will appear to select change the color Frame Title Bar Font Buttons Parameter Title Bar In the lower left hand corner of the dialog box a vertical array ofrectangular Parameter Values buttons is provided Pressing one of these buttons will open font selection dialog box for changing the font parameters A separate color Notes Comments p
72. for the background behind the bar grid Major Division Line we 15 Note If your system uses 256 colors or less palette color then choosing black background is Minor Division Line Exi 5 ommended In color limited systems the anima tion process may not be able to correctly represent the selected color Grid Frame Line This parameter refers to the border of the inner grid of the graph The color pad is used to select the color and the edit box is used to enter the line width in mils 1 1000 of an inch Major Div Line This parameter refers to the major division lines usedin the graph grid The color pad is used to select the color and the first edit box is used to enter the line width in mils 1 1000 of an inch The second edit box is used to set the number of major divisions and must be greater than 0 Minor Div Line This parameter refers to the minor division lines used in the graph grid The color pad is used to select the color and the first edit box is used to enter the line width in mils 1 1000 of an inch The second edit box is used to set the number of minor divisions and must be greater than pcRTA User Manual 141 5 Edit Menu 142 Line Color Style Selections Solid Surface Lines 15 Line Color Style Selection Parameters This group of fields control parameters which affect the color and line style of curve data reference curves and
73. from DOS if your Windows directory is in your system path or you may install the program from Windows directly Installation from Windows If your Windows system is already up and running follow these instructions for installation Place the distribution disk 1 into your floppy drive A or B E Choose RUN from the Start Menu Type in A SETUP or B SETUP and press OK Bi Follow the instructions given by the installer program Installation from DOS If your Windows directory is in your system path and you are currently in DOS then follow these instructions for installation Place the distribution disk 1 into your floppy drive A or B Bi Type in A SETUP B SETUP and press ENTER Bi Follow the instructions given by the installer program If Windows does not load then start Windows as you normally would and use the method outlined above The installer will automatically create a new folder and place the icon for pcRTA in that folder The installer will not modify your AUTOEXEC BAT CONFIG SYS or WIN INI files Also no files are placed in your Windows Windows System directories All files installed will be placed into the pcRTA directory path pcRTA User Manual Chapter 1 Installation 1 3 Hardware Installation IMPORTANT Your pcRTA analyzer card has several parts that are static sensitive and can be damaged by the static electricity that may have built up in your body The best way to assure tha
74. from the ignition system and electro mechanical devices such as heater fans can be extremely annoying even at very low levels These noises are usually present only when some part of the system is improperly grounded Calculation vs Measurement While itis possible to estimate the effects of standing waves and closed field low frequency pressurization mathematically the results would be only an approxi mation Accurate calculation of these effects would require so much raw data about the vehicle that it would not be practical Also there is no way to predict the amount of external noise and electrical noise you will observe The fastest easiest and most accurate way to account for all factors in the vehicle s environment is to measure them Standing waves and closed field pressurization can be measured together as a single transfer function Trouble shooting noise problems is much easier when you can check your progress against a reference measurement pcRTA User Manual 297 11 Car Audio Applications 11 4 Measuring Transfer Function 298 What is Transfer Function Transfer function is the ratio of two measurements It can be determined by dividing one measurement by another Commonly the transfer function of a device is simply the output divided by the input Crossovers equalizers amps speakers wires and acoustic environments all have transfer functions Some of these devices have transfer functions which can b
75. is available The intent is to pick up at least some of the sound from the speaker Library EXAMPLET DB Graph Data SPL Test 0 1 ave 1 Pink Noise 0 1sec ave 2 Pink Noise 10 sec ave 3 White Noise 10 sec ave 4 250Hz square wave 1 sec 6 CurveName 6 7 CurveName 7 8 CurveName 8 9 CurveName 9 10 CurveName10 11 CurveNamel1 0 pcRTA User Manual We will continue with the previous library The first step is to set the data curve For this first SPL measurement the data will be placed in entry 5 gt DoubleClick mouse over Curve Legend area gt Click the circle data marker on in entry number 5 gt Click the square graph marker off in entry number 4 and any others Edit the name of entry 5 to SPL Test 0 1 sec ave gt Press the OK button to exit and keep your changes 51 Chapter 3 Tutorial Amplitude Response Control Panel x Noise Signal Generator Automatic On Off Pink Noise zl Gen Output Level ww dBm Vims Input Source MultiMic Select Enable Mict Enebe Enable Mioi Enable Mic Ave Multipiex _ Nonnatized The control panel now must be setup for the measurement Since this is the first time you are using the pcRTA with an amplifier the proper signal level needed will have to be determined experimentally If you have not already c
76. its distributors and dealers shall not be responsible under any circumstances for providing information on or corrections to errors and omissions discovered at any time in the product whether or not they are aware of the errors or omissions LinearX does not recommend the use of this product in applications in which errors or omissions could result in loss of life injury or other significant loss This license agreement shall be governed by the laws of the state of Oregon and shall inure to the benefit of LinearX its successors administrators heirs and assigns or third party licensors E United States Federal Government Restrictions If this software is acquired by or on behalf of the U S Federal government or its agencies this provision applies Use duplication or disclosure of this software is subject to restrictions set forth in the appropriate FAR 52 227 19 and DFAR 252 227 7013 documents as applicable The software is commercial computer software and is licensed only with Restricted Rights Other Federal restrictions may also apply This manual was produced on a Pentium 166 PC with Windows 95 using Adobe PageMaker 6 5 Adobe Illustrator 8 0 Adobe Photoshop 5 0 and HyperSnap DX 3 13 for screen captures Digitally printed directly to Xerox Docutech 6135 LinearX Systems Inc 9500 SW Tualatin Sherwood Rd Tualatin OR 97062 8586 USA TEL 503 612 9565 503 612 9344 EMAIL info linearx com WEB www linearx com Copyr
77. library entries and can also be printed after each test cycle automatically IASCA Scoring Documentation Testing Controls Print Each Graph Lib Name IASCA001 ESTETTES Test Number 2 LibCurve 2 BEI The Big Sound Off BIA Response Test Tas Contestan SPI c4 2 Bici Mic 2 Mic 3 gt Linein Restart Sequence Start Testing pcRTA User Manual 177 Chapter 7 Utilities Menu IASCA Scoring Documentation Testing Controls _ Print Each Graph Lib Name IASCA001 Te Test Number 2 LibCurve 2 Event Title The Big Sound Off Contestant Joe Blow SPL Test As shown in the dialog box here there is a check box which controls printing of the test results This box should be either checked or unchecked as required before the scoring session begins 5 A 3 Produce JASCA Score Mic Mic 2 Mic 3 Mic t lineln Note that a special text box is provided below the contestant name field where vari Restart Sequence 178 ous instructions and the scores will appear Note If your printer driver has spooling en abled DO NOT start another test until the previous score has been completely printed The print spooler consumes much of the CPU time and this will cause errors in the time dependent testing algor
78. looking for 2 Click the index entry you want and then click Display About pcRT Add Curves Al Amplitude Graph Display Amplitude Graph Setup Analyzer Block Diagram Analyzer Calibration Analyzer Specifications Appendix ASCII Data Block Diagram BMP Calibration Display Frit pcRTA User Manual 9 9 3 About pcRTA The About pcRTA menu option will open a dialog box containing various system statistics information from the analyzer hardware as well as your registration data The system statistics are largely self explanatory by their names and values Some of this information may be asked for when you call for technical support The analyzer data box gives your 1 O port address the ISA bus clock speed in your computer the serial number of your board revision level the production date and the last calibration date About pcRTA xi Yer 1 995 Sept 24 1998 System Information C opyright 1998 All rights reserved Date Mar 12 1999 DOS Ver 7 10 Author C Strahm July 20 1994 Time Fri 1 40 pm WIN Ver 3 95 LinearX Systems Inc abit eins n in pacs ds ode Enhance ree D EMS NonFrame Video Color 16b C Registration Infomation We ees see soe Mem 66 582 260 Video Vert 768 Company linearx Block 16 711 680 Ver Person mike Drv D 637 108 224 TrueType YES pcRTA Analyzer Hardware Data B
79. noise source oul Fixed 60 to 20 you can use the relative measurement mode 5 gt Fixed 80 to 0 to compensate for any problems in the re Fired te 20 sponse of the source To do this store the ull Band Fixed 120 to 40 Flat measurement of the pink noise source in one EnH of the curve library entries Go to the Control Cont MEN PANES Panel and set the Measurement Data to Rela HMS Cycle Limit tive Click on the list box in the Measurement d ion of the Control Panel and sel ANSI MAD Data section of the Control Panel and select ANSI Filter Absolute gt Relative the library entry that contains your measure ment of the external pink noise source This curve becomes the reference for any measure ments taken while in the relative mode Click OK 1 This is a sample 4 pcRTA User Manual The measurements taken under these conditions will respond as if the external pink noise source is flat even if it isn t Keep in mind that these measurements do not relate to absolute SPL values but are related to the original signal level of the external pink noise source An alternative to using the relative measurement mode is to divide the measured curve that you want to correct by the stored measurement of the external pink noise source This will remove any variations in frequency response that were present in the external pink noise source 289
80. not correct or not recognized by the application you will need to use one of the Graphics Export formats Clipboard Viewer Oy x File Edit Display Help Sound Pressure Level 1 Pink Noise 0 1sec ave Input MultiMic 2 Pink Noise 10 sec ave Range Auto 3 White Noise 10 sec ave DataType SPL Abs 4 250Hz square wave 1 sec Detector Leg 0 05 GenLevel 0 0 GenNoise Pink FullBand Flat IRTABands ANSI C pcRTA 1 995 EXAMPLE1 DB Mar 8 1999 430pm 172 pcRTA User Manual Chapter 7 Utilities Menu 7 4 Graphics Export The Graphics Export menu option will open a dialog box for choosing various options for exporting graphics from the program This utility provides the most versatile and powerful means of transferring graphics from the pcRTA system to other desktop publishing programs Raster Images Raster images are bitmap representations of the artwork They are formed by rows of pixels They can be color or black amp white The resolution of the image is fixed at the time it is created While raster images are probably the most portable form of graphic representation they are very bulky and inefficient for high quality resolution The following industry standard raster formats are supported BMP Windows BitMap Format GIF Graphics Interchange File JPG Joint Photo Experts Group PCT Macintosh Picture Format PCX ZSoft Picture Format TGA Targa Picture Format TIF Tagged Image File Format When using
81. of the characteristics of the display Click OK to close the dialog box Load Graph Display Set File File Name Directories bikwht01 gds cx cine ach gds cine bch gds cine nc gds cine rt gds color 1 gds colormn2 gds List Files of Type Graph Display Set Files gds Go to the File menu and select Load Control Panel Set A dialog box titled Load Control Panel Set File opens Load the file CINE RT CPS This file will set all of the parameters of the control panel Click OK to close the dialog box Load Control Panel Set File File Name Directories cine_ach cps cx mikel cps setupl cps List Files of Type Control Panel Set Files cps 277 10 Cinema Applications The Line Graph should look like the one shown here There are no data curves on this graph only the grid and the RT curves overlay Reverberation Time gt You are now ready to start measuring Reverb Time 278 pcRTA User Manual 10 Cinema Applications General procedure for Reverb Time Measurements The settings you have loaded include 5 second stimulus time and 5 second time out This means that the pcRTA will generate pink noise for 5 seconds and then collect measurements for 5 seconds It will then display a grap
82. ofthecurrently loaded library The settings in the Control Panel have no effect and all control panel parameters are controlled internally by the routine Setup Help Cancel pcRTA User Manual 189 Chapter 7 Utilities Menu Drag Racing Testing Controls Start Drag Race Clear Display Tree Test Display Tree Print Graph Contestant Names Name of Contestant 1 Name of Contestant 2 Automatic RollUp RollDn 20 100 Hz Response Limit 190 Parameters to Set before Testing Begins The MDF files for the two microphones to be used must be already loaded into the system on Mic Inputs 1 amp 2 prior to testing to provide accurate SPL calibration For this routine the Noise Generator is not used and is forced off automatically The user should also press the Setup button and enter any specific parameters as required for the configuration As for the graph setup you will probably want to set up the bar graph display with the desired range dB div and the number of major divisions The tree display will have this same range In most cases the Line Graph window will probably not be important Starting a Session After the desired settings for the Control Panel and Graph Setup have been made select the Utilities Scoring Drag Racing selection from the main menu Enter or edit any changes necessary for the base port locations bits
83. other analyzers per forming phase correction as well 0 0 0 0 0 0 0 0 0 0 0 It is typical for the response curve to be normalized to a level of OdB at 1kHz 136 pcRTA User Manual 5 Edit Menu 5 14 MDF Convert Select file to convert to Random file x File Name sn201181 mdf sn201182 mdf sn201183 mdf sn201184 mdf List Files of Type MicD ataFiles mdf C3 c new c The MDF Convert option provides the means to convert the default on axis MDF microphone response files into their equivalent random pressure re sponse files By default all MDF files produced by LinearX are calibrated for on axis free field response This type of calibration is utilized when the mic is directly on axis with the sound source However for reverberant field measure ments or for other applications where the sound source is not localized a random pressure measurement is typically performed In this case the mic is generally pointed upwards and the calibration data is referenced to a 90 degree off axis type measurement After selecting the MDF Convert menu option you will be prompted to choose the MDF file you wish to convert The default path is the program sub directory where the MDF files are typically located The source MDF file will be of the form 5Nnnnnnn MDF where nnnnnn is the 6 digit serial number of the mic The converted output file will be place
84. pressing CTRL A A on the keyboard Scale Down The Scale Down button decreases the value at the top of the graph scale by one major division Note this is moving the scale down so the data being displayed moves up The exact amount of the decrease will depend on the type of scale and or the dB per division For log scales such as impedance the increase will conform to a 1 2 5 sequence The screen will be automatically redrawn after the operation This button can also be activated by pressing CTRL DOWN 4 on the keyboard pcRTA User Manual 25 2 General System Features Control Panel Graph di Setup E 26 Zoom In The Zoom In button will cause the graph window to be zoomed in by increasing the magnification The magnification steps are 141 yeilding a doubling of the magnification for every two increments of zoom factor The maximum zoom factor is 800 This button can also be activated by pressing CTRL PLUS on the keyboard Zoom Out The Zoom Out button will cause the graph window to be zoomed out by decreasing the magnification The magnification steps are 71 yeilding half the magnification for every two decrements of zoom factor The minimum zoom factor is 100 which is full view This button can also be activated by pressing CTRL MINUS on the keyboard Zoom Full The Zoom Full button will cause the graph window to be zoomed out to full size This is the 100 mag
85. quality True Sound Quality Scoring Documentation Testing Controls _ Print Each Graph Lib Name 75000001 Level Setting Test Test 3 Lib Curve 3 gt Mio gt Mis o 4 o Lingin Hestart Sequence Start Testing SEC Help pcRTA User Manual 193 Chapter 7 Utilities Menu 194 The second problem has to do with the repeatability of the scoring process itself In the old scoring formulas if a band pair is less than 3dB no point is deducted and a difference of greater than 3dB causes a whole point deduction Any particular measurement of a given system can produce a number of band pair differences which are right on the edge of the threshold For example the difference between a given band pair may be 2 9dB on one measurement During another measurement of the same system the difference on the same band pair may be 3 1dB Even though the measurement changed by only 0 2dB the score changes by one whole point It is very possible that there may be several band pairs a system which are right on the edge of the 3dB threshold This can cause the score to change by several points during repeated measurements due to the various band pairs toggling at the 3dB thresholds The TSQ formula solves both of these serious problems but also goes further Many of the old scoring formulas use bands from 25Hz to 20kHz in the scoring computat
86. room is fully saturated Output Level Edit Box The desired output level from the generator Line Output is entered and shown here The value is in dBm 0dBm 0 775Vrms Due to the nature of linear DAC attenuators the resolution of the setting will depend on the value At high values such as OdBm the resolution is very fine At low values such as 50dBm the resolution will be coarse However by closing the dialog box and reopening it the exact value used will be displayed The minimum output value is approximately 62dBm and the maximum value will depend on the particular signal Typical values are pink noise 2 6dBm white noise 8 6dBm and square wave 9 6dBm AY Output Level Increment Decrement Buttons These buttons will change the displayed output level value by 0 1dBm If the level reaches the maximum or minimum capable values the level will not change These buttons are type a matic and can be held down to continuously step the value Input Source There are several selections provided in this list box which control the input source selection for the analyzer measurement Most of the selections are clear and reflect the external connectors on the pcRTA connector box The Generator selection allows direct measurement of the signal noise generator This selection will follow the programmed output level but is always ON regardless of the Gen On button pcRTA User Manual 5 Edit Menu RT Test Limit RT Te
87. runtime and SPL Top value Next you may wish to select different types of display options given in the lower region of the dialog box The tree display can be tested first by pressing the Test Display Tree button Drag Racing Setup Setup Parameters CH 1 1 0 Port Base Adr Hex CH 2 1 0 Port Base Adr Tree Display Resolution Bits Drag Race Time Period Sec Top of SPL Scale Tree db Start Demo Display Count Down Speed Med Fast Slow Race Mode 5 Dot Display Winner Display Mode Flash Ramp Chase pcRTA User Manual Chapter 7 Utilities Menu When ready simply press the Start Drag Race button to begin the contest When the run is completed the winner will be indicated with a modulated display If there is a tie caused by identical tree levels then both displays will be modulated The modulated display will continue until terminated by the operator by pressing the button again The run can also be aborted at any time by pressing the button Ifi pcRTA Amplitude dB DRAGRACE DB File Edit Processing Utilities View Window Help iff Bar Graph dBspl Sound Pressure Level Testing Controls Start Drag Race LEEREN CNN Clear Display Tree Test Display Tree Print Graph Contestant Names Name of Contestant 1 Name of Contestant 2 LI 217 _ Automatic RollUp RollDn 20 100 Hz Response Limit
88. status CurveName10 box reflects the setting of the square mark CurveNamel1 ers Data Curve Status This box will display the word Data if the currently selected highlighted curve en try is selected as the data curve entry This status box reflects the setting of the circle markers There can only be one entry selected as the data curve This is where the data from the next measurement will be placed Name Editing Box This box is used to edit enter the name for a curve entry Whenever a curve entry in the list box is highlighted focused the name is automatically copied to the name editing box If you wish to edit the name simply click your mouse in this box and begin editing To save your changes simply click the mouse back into the main list box and the text from the editing box will be copied to the list box This function can also be initiated by pressing the N key while a curve entry name is highlighted focused Curve List Box The large list box displays the curve entry names within the library All library types have 20 curve entries Each entry in the list can be highlighted focused by using the mouse and scroll bar or by using the cursor keys on the keyboard Each entry also has a square and circle marker which is used to select and indicate the curve s status for graphing and data selection 82 pcRTA User Manual 5 Edit Menu Graphing Indicators Square Markers Each curve ent
89. the PAC unit Battery Voltage displays the actual measured battery voltage inside the PAC unit External Voltage displays the actual measured DC voltage inside the PAC unit produced from the external power source This could be either from the AC line or from the 12VDC auto power connector Power Source This group box contains two readouts which display the origin of the operating power It shows if the unit is running off the internal battery or if the unit is running off external power AC line or 12VDC auto Oh 214 Exit Help The Exit button is used to close the dialog box and the Help button is used to open the Windows help system and display help information on this dialog box pcRTA User Manual Chapter 7 Utilities Menu 7 13 Analyzer Calibration This utility is used to align the analyzer to your particular computer It also serves as a good test to verify that your system and the analyzer is working correctly port address conflicts usually produce failed tests here If this occurs change the P1 P2 jumpers to assign a different port address The calibration utility can be run at any time and must be run at least once on a newly installed computer or if the analyzer is moved to a different computer From then on re calibration should not be necessary unless substantial temperature changes occur or other hardware modifications to the computer have been made To start
90. the same crossover with an 8 ohm speaker load NOTE When measuring the out put of a power amplifier be very careful not to exceed the maxi mum input voltage ofthe pcRTA Voltages in excess of 5 8VRMS will DESTROY the electronics Connect the Line Out of pcRTA to the input of the amplifier If you are using an amplifier that is known to have flat frequency response connect the Line In of pcRTA to the speaker terminals Theresulting measured curve will be the transfer function of the crossover This is the voltage in putto the speaker after the cross over pcRTA User Manual 11 Car Audio Applications If you suspect that your power amplifier does not have a flat frequency response you should measure the output of the amplifier Set the amplifier s gain control to a low setting Connect the pcRTA s Line Out to the amplifier s input and the Line In to the amplifier s output The resulting curve will be the transfer function of the amplifier If you find that the amplifier does not have a flatfrequency response divide the measured curve of the amp by the measured curve of the crossover to correct for the error introduced by the amplifier NOTE It is important to observe the maximum input voltage of the pcRTA NEVER allow the voltage at the Line Input to exceed 5 8VRMS or severe damage will result pcRTA User Manual 303 11 Car Audio Applications 11 5 Measuring Road Noise 304 Roa
91. the two frequency and time 3D graphs Full controlis provided for viewing the graphs from all possible sides which adjustable start and end time ranges dB Scale Control The Value at Top text box is used to display the vertical dB scale value at the top of the grid The increment and decrement buttons can be used to change the value in steps of dB Div The dB Div list box provides a wide selection of possible resolutions for the major divi sions Time Scale Control The three radio buttons provide time base unit selec tions of seconds S minutes M and hours H The two edit boxes control the start and ending time limits for the graph display grid These four parameters determine the number of major and minor divisions for both the vertical and horizontal axis Wire frame Solid surface Forward Reverse View The wire frame selection will draw the 3D plots using only lines while the solid surface selection will draw the plots using polygon surfaces The forward and reverse selections allow you to view the 3D plot from either side pcRTA User Manual 127 5 Edit Menu Statistics Occupational Noise This group box provides control over the generation of Statistics Occupational Noise the last column value in the Statistical Analysis chart 1507 gt OSHA gt DOD gt Other For ISO OSHA DOD selections the threshold values predefined and fixed Using the Thres dB Q Facto
92. these should not be selected at the same IRQ as the COM port Network cards sound cards etc may all use IRQ s as well and if you choose the same IRQ for more than one device a conflict will result causing corrupted communication You may need to determine first where the com port IRQ in your computer is currently set by inspecting the jumpers on the motherboard or I O card If you have other cards installed as well you may need to do the same for them It is very important that no IRQ conflicts exist with the COM port When you have made your selections press the OK button If you have made changes Windows will ask you if you wish to restart at this time Restarting Windows is necessary before the changes will take effect UART Chips and your Computer Speed The PAC interface is designed to operate at high baud rates Because of this it is possible for overrun errors to occur depending on the speed of your computer and the type of UART Universal Asynchronous Receiver Transmit ter chip contained in your serial port hardware There are two types of UART chips the 16450 8250 and the 16550 The 16450 type partis older and only has a 2 byte buffer The 16550 is newer and has a 16 byte buffer If your computer cannot read the bytes coming in from the PAC before the UART buffer fills up then an overrun error occurs With the 16550 UART the larger 16 byte buffer allows more time for the CPU in the computer to read the bytes before an over
93. this mode the software must be set to update both windows at the same time Go to the Edit menu and click on System Options F10 Set the Window Update to Multi Mode Eile Processing ties View windo Run Stop Test Del Gen Ins Curve Library F2 Control Panel Graph Setup F4 Notes Comments Microphone Setup Fg F10 Graph Design System Options System Options pcRTA User Manual System Options x Tool Box Artwork View Floating Full Graph Fixed Left Data Area Fixed Right Fixed Top Fixed Bottom Cursor Control Bitmap Selection Blink Rate 1 Right Mouse Button Analyzer Control Multi Mode Button 265 10 Cinema Applications 10 6 Noise Criteria NC Measurement 266 Noise floor measurements characterize the steady state background noise level in an acoustic space The pcRTA has built in reference curve overlays for NC responses The microphone that you use will affect your ability to measure low noise environments For applications in which you only need to verify that the house meets the NC 35 criteria or higher the M51 mic will suffice If you need to measure as low as NC 15 you will need the M53 low noise microphone Noise measurements may be taken from one microphone at a time to eliminate the electronic switching noise present in all multiplexed systems This should only be a concern when using
94. to be used for the rectangular boxes which are used to display the text readouts Box Frame Line Each readout box has a border which can be controlled with this param eter The color pad is used to select the color and the edit box is used to enter the line width in mils 1 1000 of an inch Data Display Buttons These controls handle the display of data on the Text Chart The three radio buttons provide selection for either 1 3 octave 1 octave or single band display If single band display is selected the band to be displayed is chosen in the list box below In 1 3 Octave mode there will be 32 boxes in the chart with data from each of the 32 bands displayed in them In 1 Octave mode there are 11 boxes In Single Band mode only one box is displayed unless the MultiMic input mode is selected and set for multiplex mode then 4 boxes are displayed one for each mic input pcRTA User Manual 5 Edit Menu 5 9 Graph Setup Impedance This dialog box provides control over the appearace of the graph in the impedance mode There is only a single line graph for the impedance mode Impedance Graph Setup Ea Scale Control Value at Top Cycles Length of Half Div Dots pcRTA User Manual Scale Control The text box displays the value at the top of the graph Since the impedance graph is a log log grid the top value follows a 1 2 5 sequence The increment and decr
95. to function properly To check and or edit the serial port configuration go to the Start Menu Settings and double click on the Control Panel icon Now double click on the System icon Under the Device Manager tab double click the Ports amp LPT item There will Properties Refresh Remove Pint be a listing for each COM port that exists on the computer is usually used for the mouse Choose an unused port for operation with the PAC and double click on that port Then click the Port Settings tab The parameters shown under the Port Settings tab for Bits per second Parity etc are not important These values are used by Windows for printing but the PAC routines control these parameters directly and will be adjusted as needed automati cally Click on the Resources tab Two parameters are now shown Interrupt Request and Input Output Range The Use automatic settings box should be checked Windows uses default settings for the COM ports which will work in most cases The Interrupt Request MUST be set correctly and this selection must match the IRQ jumper setting of the COM port card For IRQ 4 is normal and for COM2 IRQ 3 is normal There are no rigid industry standards for the IRQ settings for COM3 and use pcRTA User Manual Serial Port ADR COM 1 COM 2 COM 3 COM 4 Chapter 7 Utilities Menu Also if you have other cards in your computer which use interrupts IRQ s
96. top of the current scale We now need to change the control panel for an averaging time of 10 seconds We will use the Tool Bar again Tutorial Noise Signal Generator Detector Type of Data Automatic On Off Peak dBm gt SPL Pink Noise Dynamic Range dBm Gen Output Level Auto 120 to 20 al Fm gt SCT Fixed 80 to 0 Fixed 100 to 20 Input Source ES Urn 200 ae Generator Testing Mode MultiMic Select RE Vi Enable RTA Bands a 0 _ Enable Mic amp Flat Limit dps e ANSI Measurement Data _ Enable Mic ee _ PCM ee 5 neuve M pcRTA Amplitude dB EXAMPLE2 DB Bar Graph File Edt Processing Utilities View Window Help gt Press the Control Panel button in the Tool Bar gt Change the averaging time to 10 0 Seconds gt Press OK to exit and retain your changes Now we can take another measurement gt Press the Run Test button in the Tool Bar You will not see an immediate effect but every 10 seconds the screen will be updated with new data After about 30 seconds stop the test gt Press the Stop Test button in the Tool Bar The bars now show a very flat response Typically less than Amplitude Response 0 5dB across the entire range The pcRTA performs highly accurate true RMS averaging pcRTA 1 995 De ZAM PLEO 20 26 1995 MEET o
97. values and updated if the value is higher When the measurement is stopped the last values are retained Cycle Limit provides a finite number of measurement cycles Each cycle is one averaging time period If 3 cycles are selected with an averaging time of 10 seconds the measurement will last 30 seconds after which the Run Test button will be automatically turned off and the last data retained Measurement Data This group box allows you to select the kind of measured data whether it be Absolute or Relative Absolute data simply means that the values displayed on the graph and stored in the library for the current data curve entry will be the true dBm or dBspl values measured by the analyzer This is the normal operating mode Relative data means that the displayed and stored values for the data curve will be the difference in dB between the actual measurements and the previously measured values in a selected curve entry of the curve library The Relative mode is very useful when you wish to show the changes between the current measurements being taken in real time and a previously stored curve This essentially normalizes all new data to dB if it has the same values as the previously stored relative curve The Relative curve to be used is selected in the list box below the two mode selection buttons This list box is disabled when the Absolute mode is in use pcRTA User Manual 5 Edit Menu cmt _ OK The OK
98. wiring of the adaptors is shown in the figure below Pin 1 MALE XLR PLUG Shield Common Pin 3 Not Used 0 SHIELDED CABLE Signal A Center Conductor NOTE Nothing should be tied to pin 3 of the XLR Pin 3 carries the 10VDC power supply for the microphones Connecting this pin to anything other than a LinearX microphone can result in severe damage to the pcRTA The units of measure on the Control Panel must be set to dBm so that the microphone calibration files do not affect the measurements The Input Source must be set to MultiMic with only mics 1 and 2 enabled for measurement The Multiplex button must be pressed instead of the Average button so that will display two separate curves rather than one average curve of the two inputs These control panel settings are contained in the Control Panel Settings file CINE AC2 CPS When the MultiMic mode is selected the data curves will always be in the first four curve entries of the curve library Data from Mic 1 will be stored in curve 1 Mic 2 in curve 2 and so on If you have measurement data in the first four curve entries that you want to save move the data to another curve entry or create a new library Press the Start Test button on the Tool Bar The Line Graph should have two nearly identical lines on it one for each mic You can now adjust the optics and slit loss eq s while observing the changes on both channels at the same time See the next page f
99. words with equal signs followed by a parameter The key words must be the same as shown here but they are not case sensitive Most of the first five lines are self explanatory and can contain any information you desire for documenta tion purposes The dBspl is the acoustic reference level used to produce the dBm electrical reference output level from the microphone These two param eters define the sensitivity of the microphone The next line reflects the number of response data points given in the file Any number of points can be used but there should be at least three points in the range of MDF Microphone Data File Format 10Hz to 40kHz For example simple re Author LinearX Systems Inc no correction Date Jul 13 1994 Wed 1 43AM SPONSE Curves 8 S Model M51 could consist of merely three data points at Serial 123456 100Hz 1kHz and 10kHz all with Odb dBspl 94 00 710 2 The next line must be included to hold the oints 552 Index Freq Hz column titles Index Freq etc 10 15 M i p The response data points consist of rows with pli four data columns The first column is the 10 78 point index then the frequency of the point the amplitude error in dB and last the phase error in degrees The last line of the file is simply End The phase data is not used by the pcRTA and can be a column of zeros It is described and included here simply as a complete format which may be used by
100. 00 Over Charging 5V Bus Voltage 19 200 Fast Charging s Battery Vollage 28 800 Slow Charging Ent 38 400 Discharging ciu cai EEE 57 600 E i Power Source Automatic Link at StartUp Battery External pcRTA User Manual 207 Chapter 7 Utilities Menu System Properties General Device Manager Hardware Profiles Performance View devices by type C View devices by connection 188 Computer 8 2 CDROM 9 9 Disk drives tz Display adapters H 6 Floppy disk controllers 4 Hard disk controllers 9 8 Keyboard 2 Monitor H A Mouse 59 89 Network adapters 8 9 Other devices Ports COM amp LPT B E Communications Port COM1 E Communications Port COM2 Printer Port LPT1 c3 4 con ll Communications Port COM2 Properties 2 x General Port Settings Driver Resources O Communications Port COM2 Resource settings Conflicting device list No conflicts 208 Windows Serial Port Configuration ixi Window s provides the drivers for communication with serial ports The correct settings must be established for the serial port to be used If you have never used this serial port before for other pur poses it may or may not be setup correctly It is good idea to verify the settings before attempting to use the PAC The IRQ selection must be correct for the port
101. 00 of an inch pcRTA User Manual Decay Time Graph Chapter 5 Edit Menu Decay Time Graph Scale Control This graph displays the actual decay vs time in each ofthe Value at Top dB Div bands The decay plots have many curves since there is a set of 32 possible curves for each displayed library s 2 s entry The Decay Band Display group box provides Horz Time Scale 5 control over these individual bands and how they are displayed Major Div Ver Hor Scale Control Minor Div Ver Hor 5 5 The text box shows the value at the top of the grid The Decay Band Display v IS I IN 500 _ 630 800 1000 1250 1500 2000 2500 3150 4000 5000 6300 8000 10k 12k5 16k 20k All On All oft increment and decrement buttons can be used to change the value in steps of dB Div The dB Div list box provides a wide selection of possible resolutions for the major divisions The Horizontal Time Scale edit box sets the maximum range of the horizontal time axis in seconds The beginning value at the left of the axis is always zero Major Minor Divisions These four parameters determine the number of major and minor divisions for both the vertical and horizontal axis Decay Band Display Each of the 32 check boxes in the upper array of the group box enable or disable the display of individual bands The two buttons All On and All Off can be used to change all the bands sta
102. 0k 125 20k I a lili pcR TA Amplitude dB leg ulis 1207 PM Double Click Double Click Double Click Data Cursor for Curve Library for Control Panel for Note Editing Status Bar pcRTA User Manual 19 2 General System Features Graph Formats Conventional RTAs typically have very limited display capability Generally the display takes the form of discrete steps displayed by LEDs The pcRTA has a wide variety of powerful display modes and graphics capabilities The user is not merely limited to the conventional bar type readout Line graphs as well as precision text readouts are also available Resolution is provided on a pixel continuous basis not as discrete coarse steps Moreover full control is provided for the scale factor graph divisions and displayed dynamic range Curve Libraries and Multi Curve Display Traditional RTAs have always had the limitation of single measurement display The pcRTA provides multi curve display as well as unlimited storage All measurements are placed as entries into a curve library Each library stores up to 20 measurements and any number of libraries can be saved as disk files Multiple curve entries from a library can be displayed simultaneously together on the same graph This provides for easy comparison of measurements without having to switch back and forth from one curve to another Library TEST1 DB 1 0 0 NewCuvetti n The Smo
103. 20 The measurement microphone must be positioned in the driver s seat at roughly ear level pointed toward the dash Use of a microphone stand 26 inches high above the center of the seat is recommended All windows doors sun roofs and trunk must be closed The engine must be off during testing This utility is designed to perform repeated tests each time allowing the user to enter a contestant name while saving each measurement into a curve library entry automatically A library called USACnnnn is automatically created and the entry numbers incremented 1 through 20 as the tests are performed The result curves for each contestant are permanently saved in the library entries and can also be printed after each test cycle automatically USAC Scoring Documentation Testing Controls Print Each Graph Lib Name USAC0001 GPL Max Test Test Number 1 Lib EV The World of Car Audio Lord Saiting Contestant am car number 1 RTA Response Test R F A 7 Produce USAG Score Mic 2 Mic Mic _ Restart Sequence M pcRTA User Manual 181 Chapter 7 Utilities Menu 182 USAC Scoring Documentation Testing Controls _ Print Each Graph eae mures Test Number 1 LibCuve 1 LE As shown in the dialog box here there is a check box which controls printing of the test results This box should be eithe
104. 3 38 Calibration Date Jan 21 1999 Thr 5 17 pm Production Date Sep 1996 Fri 1 55 pm AutoRange Gain 3 dB AutoRange Gain 4 48 RMS Scale Factor RMS Scale Offset dB FullHz 1 478 FullHz 19 5 20Hz 1 474 20Hz 25 1 25Hz 1 475 25Hz 25 2 31 5Hz 1 470 31 5Hz 24 4 ANSI A Filter Gain dB ANSI B Filter Gain dB ANSI C Filter Gain 48 ANSI D Filter Gain 48 783 ANSI E Filter Gain dB 40Hz 1 472 50Hz 1 469 50Hz 25 3 63Hz 1 470 63Hz 25 1 RMS Rates 48 5 Pink Noise Flatness dB 0 00 DAC Atten White Noise Flatness dB 0 00 Line Output ANSI A Curve Level dB 0 00 0 00 Linelnpu ANSI B Curve Level dB 0 00 0 00 Mic 1 Input ANSI C Curve Level dB 0 00 Mic 2 Input ANSI D Curve Level 4 0 00 0 00 Mic 3 Input ANSI E Curve Level dB 0 00 0 00 Mic 4 Input Run Calibration Exit Help 12 pcRTA User Manual Chapter 1 Installation Mee ico oe a should look similar to the one shown here at the bottom of the page You can then press Exit to remove the dialog box 76 The system calibration can be run again at anytime in the future as desired by the user Under most conditions it will not be necessary to run this unless the pcRTA card is moved to another computer In this case the calibration must be run again at least once to al
105. 3 D graph lines Curve Color and Line Controls These parameters control the appearance of the data curve lines displayed on the grid They are selected and assigned by curve library entry through the list box shown here above The controls following the list box display the color line width and line style for the selected curve After selecting a curve the attributes will be updated and displayed for that curve These parameters can be changed as desired for each curve Note the Windows 3 1 GDI only supports solid line styles of specific line widths Dot or Dash type line styles will appear on the screen as only 1 pixel wide However if you are printing to a PostScript printer they will be printed correctly with the full line width pcRTA User Manual 5 Edit Menu Font Selections TypeFace Style Size Color Frame Title Bar Regular 12 0 Parameter Title Bar Helvetica Bold 18 0 Parameter Values Regular 13 0 Notes Comments Regular 10 0 Graph Title Helvetica Bold 24 0 Graph Frequency Regular 11 0 Graph Scale Regular 12 0 Font Selections This array of parameters is used to control the appearance and selection of fonts used in the graphs Most of the parameters are self explanatory and the text items are displayed on the selection buttons themselves The first column provides an array of buttons which display the text items whic
106. 35 Appendix Auto Ranging Gain Gain Blocks Gain Range ANSI Weighting Filters Filter Types Design Standard Criteria ANSI Weighting Filter Response 4 to 80dB in 20dB steps A B C D E ANSI 51 42 1986 ASA 64 1986 IEC 537 1976 ASA 51 575 601 1972 pe ne E JANSI B Z7 7 ta der 336 pcRTA User Manual Appendix Band Filters Fractional Band 1 3 Octave Dynamic Range gt 120dB Detection Method Linear RMS Exponential RMS Averaging Time Selectable 50mS to 50 seconds Filter Topology Multiple Feedback Loop MFL Filter Order Class 4 Pole 2nd Order Bandpass Class II Design Criteria ANSI 51 11 1986 ASA 65 1986 Type and Sub Type ANSI 1 D er Band Response dB io P 1 0 TE 0 5 5 10 10 15 15 i IN avi 10 Freq 50 100 500 1k Hz 5k 10k 40k pcRTA User Manual 337 Appendix 338 pcRTA User Manual Physical Weight Length width height Connector Interface Line Output Connector Type Conductors format Output Impedance Line Input Connector Type Conductors format Input Impedance Mic Inputs Connector Type Conductors format Pinout
107. 5 1000 dB Div dB Div gi 10 000 1000 7 40 1600 Major Div Vert Horz Major Div Vert Horz 50 v 2000 Minor Div 5 25 2m inor Div Vert Horz inor Div Vert Horz v 80 v 3150 Cumulative Distribution Graph 3D Perspective Graphs v 100 4000 dB Scale dB Scale Time Scale 125 5000 Value at Top dB Div Value at Top S vi 160 6300 200 v 8000 10 59 9 12 Major Div Vert Horz 8 dB Div 24 000 315 v 12k5 Minor Div Vert Horz 5 5 Major Div Vot Horz e 400 16k vi 500 w 20k Statistics ccupational Noise Minor Div Vert Horz 5 5 150 gt OSHA gt DOD gt Other All On All Off der Wire frame Forward View Thres dB Q Factor Solid Surface Reverse View v Rainbow Colors M Cancel Help pcRTA User Manual 123 5 Edit Menu Amplitude Time Graph dB Scale Value at Top s 100 v dB Div Major Div Vert Horz Minor Div Vert Horz 5 5 Time Scale 5 M Time Scale Control Amplitude Time Graph This graph displays amplitude measured in each band vs time There are a large number of possible curves in the plot since each library entry displayed can contain up to 32 curves dB Scale Control The Value at Top text box is used to display the vertical dB scale value at the top of the grid The increment and decrement butt
108. 52 mic the maximum SPL is 170dB After the test is finished you can repeat any of the above tests again if necessary When completed press the Produce Score button and the data will be written to the note fields in the screen and printed if you have selected that option as well For the next contestant enter in the new contestant name and repeat the process Ifi pcRTA Amplitude dB TSQ00001 db Bar Graph File Edit Processing Utilities View Window Sound Pressure Level Rangec 60 620 DataType SPL Abs Detector Leq 0 50 GenLevel 2 5 GenNoise Pink FullBand Surn RTABands Flat 198 pcRTA User Manual Chapter 7 Utilities Menu 7 10 Programmable PA 422 The PA 422 interface is a serial port protocol standard which is used by several different audio manufacturers for their programmable signal processing equip ment This routine was characterized with the MicroAudio 2 2CQ and White 4700 2 1 3 octave stereo equalizer units While the PA 422 spec defines the protocol of communication most PA 422 equalizers will generally still require specific configuration due to their unique parameter tables Please contact LinearX for support of other equalizer brands or models This dialog box provides the means to remotely control many of the functions of 1 3 octave equalizers and also provides automatic control and optimization of the equalizer bands to achieve a predetermined target response curve Manu
109. 88 102 106 microphone sensitivity 133 136 type of data 93 108 Decay time 101 Decay time graph 121 Delete all 84 Delete curve 84 DELETE key 24 79 Detector 109 292 Directional response 55 Display modes 20 Distribution disk 4 Dithered 75 Divide curves 155 DMA 5 DOS 4 Dot matrix 75 Double click 19 Double click zones 45 DPI 173 Dynamic range 109 E Edit curve data 85 Edit mic data 133 EEPROM 12 Electrical noise 297 305 EPS 173 Equalizer graphic 306 programmable 199 203 Example 37 Exit 76 pcRTA User Manual Index Exiting 65 Export ASCII data 167 graphics 173 text 167 External equipment 37 Extrapolation 169 F Fastresponse 292 Features 37 Film 245 Floating window curve box 224 tool bar 223 Focused 28 82 Font buttons global graph design 140 text chart display 115 Font selection global graph design 143 text chart display 115 Font style 143 Frame selection parameters 140 Full band 89 G GDI 142 GDS file See also Graph display set for VGA Super VGA 320 Gen off 80 24 80 Generator amplitude mode 88 description 22 on off 80 tool bar button 24 Generator response 37 Index GIF 173 Graph bars 112 Graph design 139 Graph display settings a chain alignment 248 b chain alignment 259 description 233 318 loading 70 318 noise criteria 269 reverb time 277 saving 69 Graph formats 20 Graph setup amplitude 111 impedance 117 noise analysis 123 reverb time 119 tool bar butt
110. Auto I Etc Mt CM DataType SPL Abs Detector Leq 0 50 GenLevel 0 1 GenNoise Pink FullBand Sum _ _ RTABands Flat SS Saas 4 gt Cursor d Start QJ Exploring Perta_v2 im pcRTA Amplitude dB JA 5 18PM pcRTA User Manual 11 Chapter 1 Installation Note Before running the calibration routine always allow your computer to warm up for at least 15 minutes This will provide best accuracy The calibration dialog box is shown below The top area displays the parameters which are stored within the analyzer EEPROM The lower area shows other additional results of the calibration process Press the Run Calibration button to start the operation A message box will appear that displays the tests currently being performed The full calibration process takes about 4 minutes If all of the tests pass the utility will give a final message beep at the end and then write the new data to the EEPROM of the analyzer If any test fails an error message box will appear If this happens try running the calibration again If the problem persists it probably indicates a conflict with another card and the jumpers should be changed Analyzer Data 05 Sqw dBm Port Bus Clock MHz 8 3435 Pink Noise dBm Computer Calculation Speed Index White Noise dBm Serial Number 153435 Revision AutoRange Gain 1 dB 1
111. E RT CPS Reverb Control Panel Generator Testing Mode RT Test Limit Stimulus Time Continuous s RT20 Cycle 1 RT40 dBm Input Source TimeOut ho ES Control Panel Parameters Parameter Value Gen Stimulus Time 5 Sec Gen Output Level 20 00 dBm Testing Mode Cycle 1 Input Source Miclnput 1 RT Test Limit RT60 TimeOut 5 Sec 280 pcRTA User Manual 10 Cinema Applications Notes for Reverb Time Measurement continued Here are the Graph Setup settings saved in the Graph Display Set file CINE RT GDS Reverberation Graph Setup x Reverb Time Graph Decay Band Display Scale Control Full 630 Value at Top Log Cycles 20 800 2 25 1000 Log Time Linear Time 40 1600 Major Minor Div 8 5 50 res _ 63 _ 250 Length Hash Dot 15 80 3150 100 4000 Decay Time Graph 125 _ 5000 Scale Control 160 6300 Value at Top dB Div 25 2 s DET ullae Horz Time Scale S 400 16k 1500 20k Major Div Ver Hor 8 Al On Au ort Minor Div 5 5 j Rainbow Colors Reverb Reference Curve Room Vol 70000 00 cuFt Graph Setup Parameters Parameter Value RT Value at Top RT Log Cycles RT Major Minor Div RT Length Hash Dot Decay Time Graph Decay Band Display pcRTA User Manual 281 10
112. GenLevel 39 5 FullBand Flat RTABands ANSHE InputSrc Lineln AvrgTime 1 0 Sec Display 31band TEST3 DB p EI Aug 90 1994 Tue 3 10 am Scale Down Zoom In Zoom Out Ber Full Rdrw J 5 pcRTA User Manual 6 Processing Menu 6 8 Curve Summation It is sometimes desirable to be able to sum multiple measurements to come up with a single total equivalent curve This processing feature can mathematically RMS sum up to 20 curves and store the data in a separate Curve Library entry or on top of one of the data curves being summed This operation can be used to sum separate sectional measurements of a multi way crossover based system Since this is an RMS summation the result represents non correlated signal combination which may or may not be true Since RTA measurements are noise they do not include phase information This function is very similar to averaging with the exception that the result is not divided by the total number of curves It is pure RMS summation of the curve data The large list box shown below provides for multiple selection of curves in the library Click your mouse on a curve name to toggle its selection as a curve to be summed The smaller list box is used to select the location for the result lapi be the same as one of the Library Untitled db data curves used to construct the sum However the origi Select Curves to Sum
113. In Curve Legend system Notes and Comments ET 2 Shorted Cable Test Method 4 Wire DataType Ohms Zoom TestMode Cont Full GenLevel 2 5 GenNoise Pink m Rdrw AveTime 5 0 Sec Sem EEE z afl vi Cursor MStar 60 127 If you are using a 2 wire configuration you will probably be measuring around 1 3 ohms of resistance depending on your cable length For a 4 wire configuration the curve will be in the 0 2 0 3 Ohm range These are typical results for short circuit measurements Now we will measure a speaker Connect a transducer to the test clips We will save this data in entry number 3 gt Press the Curve Library on the Tool Bar gt Click the circle marker ON in entry 3 gt Click the square marker OFF in entry 2 gt Change the name of entry 3 to Speaker Test gt Click OK to exit and save your changes Take another measurement and rescale gt Press Run Test on the Tool Bar gt Press Scale Auto after a few seconds pcRTA User Manual Chapter 3 Tutorial The impedance response of the transducer Library Untitled z should look something like the curve shown Speaker Tess below Your speaker is not the same so the pen Circuit Test Shorted Cable Test Speaker Tests CurveName 4 CurveName 5 CurveName 6 CurveName 7 CurveName 8 CurveName 9 CurveName10 CurveNamel1 z c
114. Installation 2 pcRTA User Manual 1 Installation 1 1 System Requirements The pcRTA program can be installed in any 386 or higher PC compatible computer operating the Windows 3 1 graphical operating system Since pcRTA is an engineering type program extensive use of floating point calcula tions are required For this reason the use of a 80x87 math coprocessor is strongly recommended 486 DX CPUs have the coprocessor built in and 486 SX systems do not The difference in the speed of calculations is typically an order of magnitude faster with a coprocessor Also high speed video animation techniques are used to display and update information to the graphs on the screen in real time The use of a Windows Accelerator type video graphics card will greatly improve video performance For best overall performance it is recommeded that a 486 system or higher be used Windows is a graphical operating system and places larger demands on the CPU for both data processing and video operation The following is a list of the recommended minimum system configuration E 486DX CPU or higher with math coprocessor Bl MS Windows 3 1 ll 8 MB RAM minimum Bl VGA 640x480 video or higher accelerator type card preferred Bl Adobe or TrueType fonts pcRTA User Manual 3 Chapter 1 Installation 1 2 Software Installation The software installation program is in itself a Windows application You can begin the installation
115. JC 4000 New on LETT n to change the printer port selection This is shown below Cancel Configure From the Printer Select dialog box you may also use the Configure button to fully configure the currently selected printer When this button is pressed another series of dialog boxes will appear specific to the particular printer selected Printer and Port These dialog boxes are supplied by the Windows system Consult your Windows manual for more information on printer setup Also you may wish to consult your printer manual for other details about your specific printer and how to configure its options pcRTA User Manual 75 4 File Menu 4 10 Exit Program The Exit menu option is used to terminate the program When this option is selected the system checks to see if any changes have been made since the library data was last saved If changes have been made then a dialog box will appear with three options for exiting the program If the current library name is Untitled you will always receive this message Use the YES button if you wish to save the library and another dialog box will appear to allow you to enter a new file name if the current name is Untitled If the current name is valid the file will be updated The program will exit after saving the file Use the NO button if you do not wish to save the current library as a file or do not wish to update the existing file on disk The program wi
116. MDF s to provide the necessary sensitivity and response curve information about a given microphone If you purchased M50 series mics with the analyzer MDF files were provided with them These must now be loaded into the software The MDF files should be in the pcRTA subdirectory for your particular microphone s serial number s if you followed the instructions during the installation of the pcRTA software The pcRTA analyzer has five inputs four Mic Inputs and 1 Line Input Each of these inputs can be configured for an individual mic MDF file Since every microphone has unique characteristics which differ from others the mic which is setup for a specific input should always be used with that particular input Go to the Edit Menu choose Microphone Setup and a specific input such as Mic Input 1 A dialog box will open as shown on the next page ff pcRTA Amplitude dB TEST1 DB Bar Graph Eile Processing Utilities View Window Help Run Stop Test Del GenOn 0f Sound Pressure Level dBspl 0 Curve Library F2 peRTA Control Panel 5 Graph Setup F4 Notes Comments Microphone Setup EEN gt Mic Input 2 Mic Input 3 Mic Input 4 Line Input A o 50 90 315 800 k 3k5 5k Sk 125 20k Curve Notes and Comments a 1 New Curve 1 Input LineOut 2 The Smooth Curve Range Auto DataType SPL Abs Detector Leg 0 50 GenLevel 0 1 GenNoise Pink FullBand Sum PE RTABands Flat SS
117. Maker you must use the WMF Placeable format and not the WMF Standard Both WMF formats contain full RGB color information The EPS formats can also be used for this purpose and contain a preview raster image built into the vector files The two EPS formats are more tightly controlled and defined for B amp W and CMYK color Use the CMYK EPS format for 4 color separations If you wish to use a graphics illustration program such as Adobe Illustrator Micrografx Designer or CorelDraw for editing the artwork use the Al or formats However many programs handle vector files in strange ways and a variety of problems with text often result Most require additional work in the graphics program itself to modify the images back to their correct form For best results use the AI format and Adobe Illustrator This is also directly transportable to the Macintosh environment as well The AI format technically requires Adobe fonts If you have assigned TrueType fonts in the program to some text items you will receive a warning message when you open the Al file in Adobe Illustrator of an unknown font However you can easily reassign the font as needed in Illustrator Other graphics programs ignore the font name information altogether Vector formats provide the most powerful editing abilities and the highest quality resolution Unfortunately they also produce the most trouble and have a nasty habit of locating any and all bugs in other applicati
118. Mict RTA Bands Geis _ Enable Flat MELDE LL _ Enable Mic ANSI Measurement Data 1 Enable Mic E ANSI Filter Absolute Relative ie Chapter 3 Tutorial The next step is to setup the control panel for the exact measurement we wish to perform gt Go to the Edit Menu and select Control Panel Amplitude Response Control Panel x Noise Signal Generator Automatic On Off Pink Noise xl Gen Output Level dBm Input Source Generator zl MultiMic Select Enable Mict Enable Mic2 Enable Mic3 Enable Mic Ave Multiplex fSonnafized BEES A similar looking dialog box should be displayed as shown here on the left Your parameter fields may not be in exactly the same initial condition This dialog box is the heart of the pcRTA system It is the primary control over the analyzer board We will not go into all of its detail here For this test we wish to measure the pink noise generator directly The dialog box displayed at the bottom of the page shows the required settings Change the control settings as needed on your dialog box until they match the control settings shown here gt Match your control settings to the ones shown below Detector Type of Data Peak dBm 2 5 Lost Dynamic Range dBm en Auto 120 to 20 Fixed 60 to 20 Fixed 80 to 0
119. Ohm metal dome tweeter It has an Fo of about 2 3kHz The resonant frequency hump is difficult to pick out because it s magnitude is only about 1 2 Ohm higher than the nominal impedance This is a very common type of curve seen on tweeters pcRTA User Manual 11 Car Audio Applications Impedance Respons ime NEE This graph shows the impedance response of a three way system with a passive crossover It was measured at the input to the passive crossover circuits This type of measurement is useful for determining whether the amplifier will see an impedance at any frequency that could cause it to go into protection It will also alert you to possible wrong connections and short or open circuits The graphs on the following page show the impedance response of a 2nd order passive lowpass circuit first into an 8 Ohm resistor and then into an 8 Ohm woofer pcRTA User Manual 315 11 Car Audio Applications mpedance Respons mpedance Respon ons 316 pcRTA User Manual 11 Car Audio Applications 11 10 Scoring Routines This section is a judge s guide to using the car audio competition scoring routines The IASCA routine will be used as an example but you should be able to use this guide with all of the scoring routines The scoring routines in the pcRTA are based on the curre
120. PCRT A Precision Noise Analyzer 32 Band True RMS Real Time Analyzer with 4 Channel Microphone Multiplexer Version 2 00 Software August 20 1999 Manual February 16 2000 n T MICROSOFT WINDOWS COMPATIBLE LINEARX License Agreement and Limited Warranty E Acceptance Carefully read all of the following terms and conditions of this agreement before opening and using the contents of this package The opening of this package indicates your acceptance of the terms and conditions of this license agreement If you are not willing to accept the terms and conditions of this agreement then you should return the entire product with the package seal unbroken to the place of purchase for a full refund of the purchase price E Copyright Ownership Both the program and the documentation are protected under applicable copyright laws LinearX is the holder of this copyright Your right to use the program and the documentation are limited to the terms and conditions described herein Use of the software unless pursuant to the terms and conditions of this license or as otherwise authorized by law is an infringement of the copyright B Limited Non Exclusive License You may a use the enclosed program on a single computer b physically transfer the program from one computer to another provided that the program is used on only one computer at a time and that you remove any copies of the program
121. RT60 can be somewhat problematic because it requires that the sound system be capable of producing a signal that is at least 60dB higher than the noise floor For this reason the pcRTA includes the ability to measure to the less demanding limits of RT40 and RT20 Once the measurement is made using RT40 or RT20 you can extrapolate the data to represent RT60 by scaling the curves If the noise floor is only a problem at low frequencies you can take an RT60 measurement and allow the analyzer to time out at the low frequencies where the data is not needed for verification of the cinema This is explained in greater detail in the notes section RT measurements are taken from one microphone at a time The mics cannot be multiplexed in the RT measurement mode To get an accurate RT60 curve for a room it is necessary to take at least two measurements from each microphone and then average all of the curves pcRTA User Manual STEP 1 Open new Reverberation Mode curve library Chapter 10 Cinema Applications Go to the File menu and choose New then choose Reverberation The program creates a new reverb time library with the name Untitled db Save S SaveAs Amplitude Impedance Reverberation Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Print P To give ita different name go to the File menu and choose Sa
122. T can also be used to activate the command If you change your video hardware and reduce your video system resolution the tool bar may disappear To findit simply hide the bar and then show it again The position will be updated to the new video limits pcRTA User Manual 223 8 View Menu 8 6 Show Hide Curve Box The Show Hide Curve Box menu option is used to control the display of the Curve Box This box is a floating window which provides quick access to the Curve Library The menu text will toggle between Show and Hide to display the current available and relevant operation The position of the window is persistent which means that the box will appear at its last position when the show command is again used The accelerator key CTRL C C can also be used to activate the command If you change your video hardware and reduce your video system resolution the Curve Box may disappear To find it simply hide the box and then show it again The position will be updated to the new video limits Curve Library EXAMPLE1 DB Pink Noise 0 1sec ave Pink Noise 10 sec ave White Noise 10 sec ave 250Hz square wave 1 sec amp 3 Multiplied amp 3 Divided 224 pcRTA User Manual Help Menu Chapter Contents Search About pcRTA pcRTA User Manual 9 226 pcRTA User Manual 9 9 1 Contents The Con
123. Test Produce TASCA Score Start Testing 1 IASCA Scoring Documentation Pint Each Graph Lib Name IASCA001 Test Number 2 LibCuve 2 Event Title The Big Sound Off Testing Controls Push when done RTA Response Test SPL Max Test Linein Adjust your system for 904 in Full Band Produce JASCA Score IASCA Scoring 1 Documentation _ Print Each Graph Lib Name IASCA001 Test Number 2 LibCurve 2 Event Title The Big Sound Off Contestant Bill Fold Score 12 0 Mic 1 Mic 2 Mic 3 Mic 4 Lineln Testing Controls Level Setting Test Response Test Produce IASCA Score Restart Sequence Stop Testing Exit Help pcRTA User Manual Chapter 7 Utilities Menu To begin a scoring session press the Start Testing button and then enter the event name The first step in each of the scoring cycles is to enter the contestant name The Testing Controls group box provides 4 buttons for conducting various tests in volved with the scoring cycle Each can be operated individually or repeated as neces sary They are generally executed in order from top to bottom for each contestant The first test is for adjusting the level for the actual RTA measurement Press the Level Setting Test and adjust your car audio system for 90dB in the
124. Tite Bat Regular 19 0 J Frame Line i 35 Multiple Titles Helvetica Bold 11 0 Ron ll Regular 7120 19022 v ELLE 10 ffun x Multiple Readout Helvetica Bod 14 0 ERI zi Cancel Scale Top Value dB Div Type Major Minor Div Graph Bars Full Rng Band Display 1 3 Octave 1 Octave Single Band Graph Setup Parameters Bar Graph Settings Line Graph Settings Parameter Value parameter Value a Absolute 8 5 Dot Rainbow Off On Off Off Scale Top Value dB Div Type Major Minor Div Length of Hash Dot Full Rng Band Display 1 3 Octave 1 Octave Single Band Amplitude Reference Curves Absolute 8 5 30 10 Off On Off Off Text Chart Settings Parameter Value Parameter Value Single Title Font Size 19 0 Single Readout Font Size 212 0 All Other Font Settings Box Background Color pcRTA User Manual As Desired As Desired 1 3 Octave 1 Octave Single Band Band to Display Off Off On Full Hz 263 10 Cinema Applications Click here to display Text Chart Notes for B chain Alignment continued With the settings you have loaded you can switch to a text chart view of the full band SPL using the Window menu or the CTRL TAB keys Click 1 Text Chart on the Window menu or press CTRL TAB until the text chart appears as the focused window mm NOTE The CTRL TAB method will only work w
125. Top position Cursor Control Bitmap Selection Blink Rate Target 2 0 1 Right Mouse Button Analyzer Control Note Video resolutions below 800 x 600 Super VGA can cause some ofthe Tool Bar buttonsto disappear because the screen does not have enough room to display all of them M Amplitude dB TEST3 DB 15 Help 5 Mew Window He HN i se Esse even een mn e s Sound Pressure Level SOUNCIFrESSUrTE despl som Pla 5 IL Curve Legend ul 25 40 100 160 250 400 630 dk Gk3 10k 16k 20 315 50 125 200 315 500 800 1k25 2k Sk Sk 12k5 20k System Notes and Comments PRTA 1 995 JEST3 D8 EX wi Cursor Bar Graph Mcuve tll l Data 78048 pcRTA User Manual 23 2 General System Features 24 RightMouse Button or DELETE key INSERT key F3 F2 F4 Up A iDn Run Test The Run Test button will change to Stop Test after it has been pressed This button functions as a push on push off and toggles between these two states When it is pushed in the analyzer is conducting a measurement and placing the data into the currently selected curve entry marked f
126. Weighted 91 107 White noise 46 WIN INI 4 Window update 265 319 Windows help system 227 Wiring connectors 51 WMF 173 X XLRs 8 Z Zoom 1X 2X 4AX 8X 220 factor 26 219 full 26 220 in 26 219 26 219 pcRTA User Manual
127. a surround sound systems The information is presented in a way that allows the installer service technician to perform a specific procedure without reading the entire text in detail Every effort has been made to minimize the time spent reading the manual The information is generic meaning that it should be useful no matter which cinema processor is being used Some of the steps shown for each type of measurement will not need to be completed each time a measurement is made For example each procedure shows the process of creating a new curve library Since each curve library can hold 20 data curves the amplitude measurements A Chain alignment B Chain alignment Noise Criteria could all be saved to a single amplitude library This would eliminate the first step in most of the procedures Reverb Time measure ments require a separate library Organization The sections of this chapter that deal with the various types of measurements have a common structure The first part of each section shows the setup of the software Next there is a generalized procedure for measurement and adjust ment Finally each section contains some notes about issues that pertain to that type of measurement and how the settings in the software will affect the results Control Panel Settings and Graph Display Settings Given the broad range of applications that pcRTA can perform it is not surprising that there are many many features and functions in the softwa
128. a fast averaging time When using a longer averaging time 10 seconds or more you can measure each of the four microphones automatically and without leaving the measure ment position You can then average the curves from each location to produce a measurement that represents the background noise of the entire room Measuring noise is also an important first step to making Reverb Time measurements This will be explained in greater detail in the RT section of this chapter pcRTA User Manual STEP 1 Open new AMPLITUDE MODE curve library Save S SaveAs Print P Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Chapter 10 Cinema Applications Go to the File menu and choose New then choose Amplitude The program creates a new amplitude library with the name Untitled db Impedance Reverberation Noise Analysis choose SaveAs B IN Edit Processing Utilities View Windc To give it a different name go to the File menu and pcRTA Amplitud Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set EETEER AN dialog box with the title Save Amplitude dB File opens Type in the name you want to give the file and click OK Save Amplitude dB File File Name untitled db
129. accuracy in SPL measurements Note If you ever forget which mics are setup for which inputs just check the Microphone Setup dialog boxfor the inputs The parameter fields include a serial number that shows what file was loaded for that input Using the same MDF on Multiple Inputs If you have a single microphone and wish to use it on different inputs you can of course setup the same MDF on more than one input There is really no difference between any of the inputs but if you would like to use the same mic on more than one input this can be done Creating MDF files for other Microphones In order to setup other brands of microphones you will need to construct your own MDF fileforthat microphone The MDF formatis a simple ASCII file which can be created with any standard text editor or word processing program The MDF file structure is described on the following page It should also be noted that the system allows you to setup a mic on the Line Input This will probably be the input source for a third party mic since an external preamp will likely be used As an alternative a special XLR connector could also be wired to drop the 10V pin 3 line of a mic input Many other mics preamps would not necessarily use this voltage pcRTA User Manual 135 5 Edit Menu MDF File Structure The listing below shows an example of the lines in an file The first line must start with MDF The next seven lines are key
130. ad is also provided for changing the color directly Graph Title Graph Frequency Graph Scale Frame Selection Parameters This group of fields control parameters which affect the Frame Selections overall design of the graphs or charts Main Background Mils Main Background Large Frame Line EM This color pad allows selection of the color to be used for the background of the graph Small Frame Line ES Note Guide Line Large Frame Line The main boarder around the graph is the large frame line The color pad is used to select the color and the edit box is used to enter the line width in mils 1 1000 of an inch Small Frame Line The inner portion of the graph is divided into different areas with a smaller frame line The color pad is used to select the color and the edit box is used to enter the line width in mils 1 1000 of an inch Note Guide Line The note area has eight possible text lines This parameter controls the characteristics of the lines used to underline these text notes The color pad is used to select the color and the edit box is used to enter the line width in mils 1 1000 of an inch 140 pcRTA User Manual 5 Edit Menu Grid Selection Parameters This group of fields control parameters which Eni affect the grid data display area of the graphs Grid Background Hils Grid Background BOUE cde 25 This color pad allows selection of the color to be used
131. al Installing the Analyzer PC Board Chapter 1 Installation To install the card first turn the power switch of your computer OFF Remove the cover or enclosure of your computer s chassis to access the slot area ofthe mother board Insert the card into one of the empty bus slots The pcRTA analyzer is an 8 bit card and can be used in any standard ISA 8 bit 16 bit EISA or VESA slot Analyzer VLSI CONTROLLER Computer pcRTA User Manual Motherboard Cd Fr ca SIMM DRAM ARRAY The PC board is a full length card so you will need to have a clear space available for the board over its entire length On many newer systems there can be large obstructions such as the CPU located on the mother board which may not allow for full length access in some of the available slots If this is the case you may need to re arrange existing cards to provide for a clear open full length slot Most system cards such as video serial LPT port disk controllers etc do not require full length Make sure the tail end of the pcRTA card is held in the proper card guide for the slot Replace the cover of your computer and turn your computer power switch ON Note Power Supply Considerations The pcRTA contains substantial analog pro cessing circuitry This circuitry uses approx 200mA from the 12Vo
132. al control of the EQ is also possible as well as manual operation of the pcRTA analyzer Programmable EQ 422 Serial Port ADR UART Device Address Manufacturer Type Memory Channel com COM 2 02F8h 16550 a Curve Entry for T Highpass Lowpass COM 3 03E8h 03E 8h 7 Theater 7 Theater Response 2 M ot x COM 4 02E8h N A Zero Bands EK af d d f fi nf ff zl 24243 Ei ed sd ed Ea J HAA Pansessgog995988288982 J942xaaga535868 Start zi Run Recall Program Optimize Exit pcRTA User Manual 199 Chapter 7 Utilities Menu Programmable 422 Serial Port ADR Device Address Manufacturer Type COM 1 03F8h 16450 bd COM 2 02 8 16550 Library Curve Entry for Target 03E8h N7A CMM CE Zero All Bands Memory Channel Highpass rp pp s e s e er s S m n p E E T s P e e I EEREEEEEEEEEEEEEREEREEEEEEEREEEEI 2 5 95 5 Sd Start Link Run RTA Recall Program Optimize Exit Default x x Lowpass 7 Theater Response m Off zi Of Serial Port Sel
133. alue Gen Auto On Off Off Input Source Full Band Response Sum Dynamic Range RTA Bands Resp Flat Testing Mode ANSI Filter Flat Measurement Type of Data SPL Detector Leq S Averaging Time 0 50 Sec 294 Mic Input 1 Gen Output Level N A MultiMic Select N A Fixed Highest Peak Hold Data Absolute pcRTA User Manual 11 Car Audio Applications 11 3 Vehicle Acoustics The goal of this discussion is to point out the major aspects of vehicle acoustics Later sections will show you how to measure them with the pcRTA The acoustic space inside a vehicle is one of the most difficult and demanding environments in which to install a sound system The small size of the space and the varying reflective and absorptive surfaces within it create many problems when optimizing a system for sound quality On the other hand the small size makes it possible to create Sound Pressure Levels SPL atlow frequencies that would require much more power and many more speakers in a larger space Standing Waves When designing a car audio system you musttake into consideration the effect of standing waves Sometimes known as modes they are a major problem in car audio situations Whenever there is sound in an enclosed environment there will be standing waves within that environment Standing waves occur at frequencies whose wavelengths correspond to twice the distance between the walls of the space In cars standing wav
134. ame 9 CurveName10 Show Info CurveNamel1 gt Press the Control Panel button on the Tool Bar The impedance control panel is much simpler than the amplitude control panel There are far less parameters to set For this example set the generator to automatic the averaging time to 5 seconds and the testing mode to continuous Impedance Control Panel x Noise Generator Automatic Manual Averaging Time Cycle Limit arm l Impedance Test Method 2 Wire LineOut Testing Mode Continous Peak Hold 58 If you have constructed a 2 wire cable select that option If you are using a 4 wire cable select that option gt Make your selections gt Click OK to exit and save your changes Now press the Run Test button to take a measurement It will take about 5 seconds for the screen to be updated The scale range may not be correct so use Scale Auto to find the curve gt Press Run Test in the Tool Bar gt Press Scale Auto in the tool Bar pcRTA User Manual Chapter 3 Tutorial M pcRTA Impedance Z EXAMPLE3 Z Impedance Graph File Edit Processing Utilities View Window 18 x Ee kx Bg Impedance Response a ge 25 Ij Control m Panel En Graph Setup Curve ET es m B lt Seal Eg
135. anual Chapter 7 Utilities Menu 7 3 Clipboard Export The Clipboard Export menu option will transfer the graphics from the pcRTA main window to the MS Window s clipboard system This can be a handy feature when you wish to Paste a graphics item from this program into another MS Windows application directly However other applications may or may not be able to handle all of the GDI elements used by the pcRTA graphics images If you experience problems try using one of the Graphics Export formats instead Clipboard E Fi Before the process begins a dialog box will open to confirm that you wish to transfer the graphics of the window Press Ok to i i Copy Graphics to Clipboard tr nsier the graphics E Fax The transfer takes only a few seconds When 5 Games 2 completed you can view the contents of the 9 Intemet Tools gt clipboard by using the Clipboard Viewer in the 5 Multimedia Start Programs Accessories folder shown here 23 System Tools gt E3 Calculator Sa Character Map Clipboard Viewer 129 Dial Up Networking 33 Direct Cable Connection _ HyperTerminal Imaging 47 Notepad e Online Registration 00 Paint Phone Dialer Y WordPad pcRTA User Manual 171 Chapter 7 Utilities Menu A sample of the clipboard viewer is shown below with a graph image from the pcRTA system If you paste the item into your other application and the image is
136. ary curves in a variety of different formats Fully adjustable scale factors 1 Octave resolution and dynamic range are provided including control Graph Bars Ej Bar Rainbow zl Full Hz zl 112 Single Band over the number of major and minor divisions Scale Top Value dB Div Scale Type The edit box is used to set the scale value at the top of the grid The increment and decrement buttons can be used to change the value in steps of dB Div The dB Div list box provides a wide selection of possible resolutions for the major divisions The type parameter controls how the scale will be drawn In the Absolute mode the scale is drawn normally with the largest value at the top progressing to the smallest value at the bottom In the Relative mode the center of the scale range is marked with the absolute value but the scale values given above or below this are derived as relative offsets from this center value Major Minor Divisions These parameters refer to the number of major and minor division lines used in the vertical graph grid Graph Bars These parameters control the appearance of the actual bars However this data is only used if a single library data curve is selected for display For multiple curve display the colors assigned in the Global Graph Design will be used for the bars as a set The list box provides a variety of different display options for the bars Data Display Format These controls handle the d
137. at box TIF Tagged Image File Format Graphics File Format Resolution DPI Color Format Compression This list box is where the specific file format is chosen For raster images set 720 No gt Yes this parameter first before choosing color or compression Total Image Pixel Width Total Image Pixel Height Resolution DPI Image Bits per Pixel Use the two stepper buttons to increase UnCompressed Image Size Bytes e 3 456 000 Or decrease this value The value will be changed in units of 8 Color Format Cancel Help The possible color choices are B amp W s 16 Color 256 Color 16M Color 16 Gray 256 Gray Depending on the file format not all color choices may be available Compression Some of the raster file formats have optional compression If so you will be able to choose either compressed or uncompressed For other file formats this selection will be chosen for you Image Specification List The group box at the bottom of the dialog box displays four parameter lines These are only relevant to raster images and not vector images The first two parameters display the total pixel width and height The bits per pixel is controlled by the color mode and the last line provides the total image size in bytes With high color resolution such as 16 million colors the image size can become very large even at moderately low DPI values You must have enough virtual memory f
138. ave been measured the test will stop If you start the test again the data in curves 1 4 will be overwritten Click the Run Test button on the Tool Bar to begin Wait for the pcRTA to complete the measurement cycle total of 40 seconds The Run Test button changes to the Stop Test button when a test is running but the software will not allow you to interrupt the test The data from the test is stored in the Curve Library in entries 1 through 4 corresponding to mic inputs 1 through 4 If you wish you can use the Averaging Process to produce a single averaged noise curve from the four stored curves pcRTA User Manual 271 10 Cinema Applications Notes for Noise Criteria Measurements Here are the Control Panel settings saved in the Control Panel Set file CINE NC CPS Amplitude Response Control Panel x Noise Signal Generator Detector Type of Data _ Automatic On Off Peak dBm SPL Pink Noise M Dynamic Range dB spl ow Legs 2 Fixed 60 to 20 E Gen Output Level Auto 120 to 20 dBm Yims Fixed 80 to 0 Fixed 100 to 20 Full Band Fixed 120 to 40 Input Source Flat Mic Input 1 ANSI Testing Mode MultiMic Select m Peak Hold Enable RTA Bands XV Enable Mic Flat y Enable Mic3 ANSI Measurement Data V Enable Mic nn cn Moines ANSI Filter Absolute tn No
139. be a flat line in the 90dB range When the target curve and data curve have been setup the Optimize button is clicked to begin the process The pcRTA will perform a measurement using the current existing control panel parameters and then compare this data to the target curve data The EQ band values will be adjusted to minimize the difference between the new RTA data and the target The process may iterate several times until a suitable match is obtained or until no further improvement can be produced This occurs when one or more bands are driven to the top or bottom of their maximum range It should be noted that a suitable averaging time should be employed to yield stable measurements atlow frequencies Typically a 2 10 second Ave Time will produce good results If you wish to take manual RTA measurement the Run RTA button can be used for this purpose Clicking the button will start stop the manual RTA measure ment When the EQ operations are completed press the End Link button to terminate the communication The Exit button will then be activated pcRTA User Manual 201 Chapter 7 Utilities Menu 202 pcRTA User Manual Chapter 7 Utilities Menu 7 11 Programmable EQ RW 232 The RW 232 interface is a serial port protocol standard which is used by RANE and possibly other audio manufacturers for their programmable signal process ing equipment This routine was characterized with the RANE RPE 228 1 3 octave stereo equal
140. box which provides control over the appearance of the graphs Each measurement mode has it s own graph setup dialog with different parameters that can be adjusted The F2 key on the keyboard can also be used to activate this button pcRTA User Manual 2 General System Features Curve Library The Curve Library button brings up the editing dialog box for the curve entries in the library After this button is pressed a dialog box will appear The F4 key on the keyboard can also be used to activate this button Scale Up The Scale Up button increases the value at the top of the graph scale by one major division Note this is moving the scale up so the data being displayed moves down The exact amount of the increase will depend on the type of scale and or the dB per division For log scales such as impedance the increase will conform to a 1 2 5 sequence The screen will be automatically redrawn after the operation This button can also be activated by pressing CTRL UP 1 on the keyboard Scale Auto The Scale Auto button is used to allow the system to automatically adjust the scale When pressed the program scans the data in the curves currently being displayed and determines the necessary top scale value This function is very useful for quickly locating the position of curves which are currently not visible on the graph The screen will be automatically redrawn after the operation This button can also be activated by
141. btracted from the measured data For example to raise a measurement by 10dB 10 would be entered here as the dB error value Also these input corrections are of course only applied when the SPL mode is in use and not in the dBm mode The dBspl and dBm values are used to pro duce a general offset which is applied equally to all of the bands The actual values for the individual parameters dBspl dBm are not really important since only the difference between these two is used to scale the bands For example 90dBspl 40dBm is equivalent to 70dBspl 60dBm etc Both will raise the readoutlevel by 130dB The difference between the two is the important value The name and identification fields are also provided here for editing These should be modified with new labels or names which will be meaningful to the user as reference purposes to identify what the new or modified data repre sents Pressing Ok will keep your changes while pressing Cancel will abort any data changes pcRTA User Manual 133 5 Edit Menu Microphone Setup Microphone Input 1 Edit EX Response Errors dB Full Hz 0 40 mc Author LinearX Systems Inc 25 Hz 0 60 Date Dec 11 1997 Thr 4 53PM 31 5 Hz 0 23 Model M53 dBspi 34 00 Serial Mem Clear This button will clear the information cur rently assigned to the input and initialize all parameters to zero Data Fields
142. button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and save any changes you have made in the dialog box Cancel The CANCEL button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and abort any changes you have made in the dialog box Help The Help button is common to most of the dialog boxes throughout the program Use this button when you wish to open the help system and receive information about this specific dialog box and its controls or parameters pcRTA User Manual 95 5 Edit Menu 96 pcRTA User Manual 5 Edit Menu 5 5 Control Panel Impedance This Control Panel menu option will be provided when the current library type and measurement mode is Impedance This control panel handles virtually all aspects of the analyzer and software for standard impedance measurements x This menu option can also be activated from the tool bar and the DoubleClick zone in the graph area under System Impedance Control Panel Noise Generator Testing Mode Automatic Continous The example here shows the various elements of Manual Peak Hold the Control Panel dialog box The dialog box is separated into several different regions Each Averaging Time Cycle Limit region controls similar associated parameters cms For measuring impedance two different test meth Impedance Test
143. by TypeFace TypeStyle TypeSize Century Schoolbook TypeColor Copperplate31bc abcdefghi jkImnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890l 8 _ jal Strikeout the mouse this dialog box will appear to select the desired font This dialog box allows selection of the typeface size style and color to be used for the font Only vector type fonts will appear in the list These are generally TrueType or Adobe fonts A sample of the type as it will appear is provided in another window just below The type of font is also shown in a text box at the top Is Cancel ue Choosing a font and its size is completely up to the user It is certainly possible to select a font and or its size that is too large for the available space in the graphics However with a little experimen tation you will quickly see whatis possible and what will actually work The program positions text items automatically either left right or center justified depending on the particular item By changing the size of a font you can easily see how the program will justify the text 144 pcRTA User Manual 5 Edit Menu 9 16 System Options This dialog box provides several selections to control various system wide features and parameters Tool Box The Tool Box type and position can be selected using the radio Tasik Atak Viii buttons in this group bo
144. ce early reflections at high frequencies is to mount the microphone inside a hollow tube or pipe with a diameter slightly larger than the mic This provides an extension that does not significantly impact the acoustic signature of the microphone s body Care must be taken not to obstruct the capsule in any way The microphones should be pointed at the ceiling because of the non directional nature of the source and the reverberant quality of the larger rooms that are typical of cinemas This type of mounting requires the MDF files to be converted from the on axis type to the random pressure field type as discussed in later paragraphs Speaker s On Axis Pressure Field On axis vs Pressure Field pcRTA User Manual 10 Cinema Applications Microphone Placement Microphones should not be placed directly on the center lines of the cinema The mics should be in an asymmetrical pattern They should also be at least 6 inches above the top of the seats to avoid any grazing effects According to ANSI SMPTE 202M 1991 Itis recommended that measurements be made at a normal seated ear height between 1 0 m and 1 2 m 3 3 ft and 4 0 ft but not closer than 150 mm 6 in from the top of a seat and not closer than 1 5 m 4 9 ft to any wall and 5 0 m 16 4 ft from the loudspeaker s Microphone positions employed in a spatial average shall be distributed among a range of positions in lateral and transverse direc
145. communications link between the pcRTA software and a pcRTA analyzer card located in the PAC unit The PAC unit communicates over a serial port with your computer which eliminates the requirement of mounting the analyzer card in your computer Defective Win3 x and Win95 Serial Port Drivers Many if not all versions of the Window s COMM DRV serial port drivers produced with date codes of 1993 or higher have a CTS handshaking bug in them We have found this to be true as well of the initial releases of Windows 95 Because of this problem we have provided a correct serial port driver COMM31 DRV which the pcRTA installer version 1 76 or higher can install automatically into your Windows system Because many modem control programs have also taken this approach it is impossible to know if the current driver in your system has this bug or not We suggest you choose the replacement option provided by the installer to eliminate any possibility of your current driver being defective If your present driver has this bug and you do not choose the replacement option you will receive a CTS Timeout error message during linking to the PAC Serial Port ADR System Status COM 1 Link Status NotActive OFF COM 2 Rate COM 3 CPURev N A pcRTAPor Hex Baud Rate Battery Status edidere um Ex 2VBusVoltage 9 600 Fully Charged 5 5VBusVoltage 14 4
146. consuming Make your measurements in zones around the listening position s Small changes in the position of the microphone will provide averaging at high frequencies For low frequencies the mic must be moved several feet to provide averaging Also itis best to use long averaging times when you are striving for high accuracy in your measurements Spatial Averaging driver s seat Spatial Averaging both front seats 308 pcRTA User Manual 11 Car Audio Applications The measurements shown here were taken at four positions across the car in the front seat as shown in the lower diagram on the previous page The mics were placed at head level The following two graphs show four curves one from each of the four separate mic positions These graphs illustrate what you would see with four mics set to measure in the Multiplex mode Each mic is displayed separately and the data is saved separately in the first four curve entries This can also be done with a single microphone by moving it to each position to take four separate measurements The first graph was taken with the left channel of the sound system turned on and the right channel turned off Sound Pressure Level The second graph was taken with the left channel off and the right channel on
147. curve entry and press OK If you wish to exit without performing the operation press CANCEL Whether or not the data is actually dB or linear units is unimportant The data will still be added properly for either type of curve units An example of this operation is shown in the graphs on the following page Add Curves Result A B Library Untitled db Library Curve Entry Operand A 3 CurveN ame 3 Library Curve Entry Operand B 4 CurveName 4 Library Curve Entry Result 5 CurveName 5 pcRTA User Manual 157 6 Processing Menu Original Curves A B Addition Result 158 pcRTA Amplitude dB EXAMPLE1 DB Edit Processing Utilities View Help Curve Legend peer Notes anc Comments 1 PnkHoise 01sec ave DataType dBm 3 White Hoise 10 sec ave GenNoise Pink GenLevek 69 6 FullBand ANSFB RTABands ANSKFB InputSrc Mic 2 AyrgTime 1 0 Sec Display 31band PA MPL EI DB 22220 1994 pcRTA Amplitude dB EXAMPLE1 DB File Edit Processing Utilities View Help GenNoise Pink GenLevek 69 6 FullBand ANSFB RTABands AHSEB InputSrc Mic 2 AwrgTime 1 0 Sec Display 31band Aug 30 1994 pcRTA User Manual 6 Processing Menu 6 6 Subtract Curves This operation will produce a new curve by subtracting one curve from another curve This method provides simple subtraction The curves may be either dB
148. d into the same sub directory and have a new name of the form SRnnnnnn MDF where the SN has been replaced by SR meaning random calibration This makes it easy to tell the original on axis MDF file from the new random MDF file of the same serial number If you are using multiple microphones for spatial averaging you will need to convert the MDF file for each microphone to be used Directories After you have converted the MDF file s as needed you can load these in the usual manner via the Microphone Setup Load MDF File menu option You will of course want to load the SR MDF file name s rather than the SN file name s C3 export C3 na Ca rt Drives The MDF Convert option can only be used with MDF files generated for LinearX micro phones The convert routine checks the model name M31 M51 M52 M53 and appropriately applies the correct transfer function to produce the new random calibration data This function will not work for MDF files created by the user to represent other 3rd party micro phones pcRTA User Manual 137 5 Edit Menu 138 pcRTA User Manual 5 Edit Menu 9 15 Global Graph Design This dialog box provides many controls which determine the global character istics of all graphs used throughout the program The features and parameters setin this dialog box will be applied to all graphs As with all of the display graphs the user has a high
149. d noise is the background noise level caused by the tires against the road the air flowing over the car and mechanical noises from the engine and drive train These noises must be measured while the vehicle is being driven To measure road noise inside the vehicle you will need a portable computer and the PACA Portable Analyzer Chassis 4 slot from LinearX The is a slot card holder which interfaces with the serial port on PC compatible computers It requires AC power which can be generated with an invertor connected to the vehicle s battery Characterizing Road Noise You can localize the source of various road noises by moving the microphone to different locations in the vehicle while it is being driven If you save the measurements with a note about where each was taken you can compare them to measurements after adding dampening materials to the passenger compartment With an RTA you can get an idea not only of where the noise is but what is causing it If you see a peak in the high frequencies it might be wind coming through a leak in the weatherstripping A constant low frequency peak is probably caused by the drive train and the tires moving on the pavement A mid low peak that changes in frequency when you rev up the engine is probably mechanical engine noise pcRTA User Manual 11 Car Audio Applications 11 6 Measuring Electrical Noise Electrical noise is the background noise level caused by the e
150. de selection of possible resolutions for the major divisions The type parameter controls how the scale will be drawn In the Absolute mode the scale is drawn normally with the largest value at the top progressing to the smallest value at the bottom In the Relative mode the center of the scale range is marked with the absolute value but the scale values given above or below this are derived as relative offsets from this center value Major Minor Divisions These parameters refer to the major and minor division lines used in the vertical graph grid Length of Hash Dot The graph grids contain small hash marks and dots which are used to indicate the minor divisions between major divisions These parameters control the length of the hash and dot markers If both lengths are set to zero than the minor divisions are drawn as solid lines The line lengths are entered in mils 1 1000 of an inch Data Display Format These controls handle the display of data on the graphs The Full Range check box controls the display of the Full Range Band on the graph When checked the full range band is displayed When not checked only the RTA bands will be displayed in the grid and the Full Range level will appear in the upper left hand corner of the graph as a text value This only affects 1 3 octave or 1 octave multi band display The next three radio buttons provide selection for either 1 3 octave 1 octave or single band display If single band display
151. deviate by more than 3dB 6dB 9dB or 12dB from the median level Testing Procedure There are two tests defined which constitute the objective portion of the sound quality judging RTA and SPL The maximum number of points for the SPL portion is unlimited and the RTA portion is 40 The measurement microphone must be positioned in the driver s seat at roughly ear level pointed toward the dash Use of a microphone stand 26 inches high above the center of the seat is recommended All windows doors sun roofs and trunk must be closed The engine must be off during testing This utility is designed to perform repeated tests each time allowing the user to enter a contestant name while saving each measurement into a curve library entry automatically A library called TSQnnnnn is automatically created and the entry numbers incremented 1 through 20 as the tests are performed The result curves for each contestant are permanently saved in the library entries and can also be printed after each test cycle automatically pcRTA User Manual 195 Chapter 7 Utilities Menu True Sound Quality Scoring x lt AS shown in the dialog box here there isa Documentation Testing Controls check box which controls printing of the test results This box should be either checked or unchecked as required before the scoring session begins _ Print Each Graph Lib Name 75000001 a Level Setting Test Test Number La Lib Curve asm P
152. dex BMP 173 Bus clock speed 11 216 C weighting 261 Cable resistance 57 Calibration date 229 description 215 during installation 11 microphone 14 131 239 process 216 running 12 with PAC unit 211 Circle data marker 46 Clipboard export 171 Clipboard viewer 171 Clock speed 11 CMYK color 176 Color buttons 115 140 Color pad 141 Color patches 140 Color selection 115 140 144 COM port 208 210 Combing 308 COMM DRV 207 Comment lines 129 Compression 174 CONFIG SYS 4 Connections 254 Connector box 8 Contents 227 Continuous 94 Control panel amplitude 87 impedance 97 noise analysis 105 reverb time 101 tool bar button 24 Control panel settings a chain alignment 248 b chain alignment 259 description 233 loading 72 measuring the generator 41 noise criteria 269 reverb time 277 saving 71 Conversions 159 Coprocessor 3 Copy curve 84 CorelDraw 176 CPS file See Control panel settings Crossover 163 Cumulative distribution graph 126 Curve averaging 161 Curve box description 27 hiding 235 319 show hide 224 Curve color 142 Curve legend 19 81 Curve library description 20 dialog 81 multimic entries 254 tool bar button 25 Curve list curve box 28 curve library 82 Curve summation 163 Cycle limit 94 D DAC attenuator 22 DAT file 170 Data area 319 Data cursor 31 pcRTA User Manual Data curve 28 82 Data curve indicators 29 83 Data file format 168 DB15 pininterface 8 dBm generator output
153. df eerta sn201181 mdf Aes 201182 mdf perta sn201183 mdf db sn201184 mdf a CJ export Lj na zi List Files of Type Drives MicDataFiles md LrrcNENEN 242 Go to the Edit menu and choose Microphone Setup then choose MDF Convert dialog box opens with the title Select OnAxis file to convert to Random MDF file This box allows you to browse for the MDF file you wish to convert The default path is the program sub directory where the files are typically located The source MDF file will be of the form SNnnnnnn MDF where nnnnnnis the six digit serial number of the mic The converted output file will be placed into the same sub directory and have a new name of the form SRnnnnnn MDF where the SN has been replaced by SR meaning random calibration This makes it easy to tell the original on axis MDF file from the new random MDF file of the same serial number After you have converted the MDF file s you can load them into the mic inputs as shown on the next page The MDF Convert option can only be used with MDF files generated for LinearX microphones The convert routine checks the model name M31 M51 M52 M53 and appropriately applies the correct transfer function to produce the new random pressure field calibration data This function will not work for MDF files created by the user to represent other 3rd party microphones pcRTA User Manual m pcRTA Am
154. e any of the previous scores unless the Restart Sequence button is used pcRTA User Manual 331 11 Car Audio Applications 332 pcRTA User Manual pcRTA User Manual Appendix 334 pcRTA User Manual Appendix Appendix pcRTA Analyzer Specifications Note All specifications subject to change without notice Physical Format Size Connector Interface Power Requirements DC Voltages DC Currents Microphone Supply Total Power no mics Noise Generator Noise Spectrums Digital Sequencer Cycle Time Pink Noise Filter Maximum Output Output Impedance Output Attenuator Square Wave Generator Output Frequencies Frequency Accuracy Maximum Output Output Impedance Output Attenuator Input Sources Types Maximum Input Level Input Impedance Full Band Frequency Response Full Band Noise Floor 20Hz 1 3 oct Band Noise Floor 20kHz 1 3 oct band Noise Floor pcRTA User Manual ISA 8 bit PC slot card 13 2 x 4 inches DB 15 Male 12V 12V 5V 200mA 200mA 230mA 10Vdc 50mA 6 Watts White Pink 19 bit MLS 2 0 seconds 6 stage 0 5dB 10Hz 40kHz 2 6dBm Pink 8 6dBm White 500 Ohms 12 bit DAC 31 20Hz 20kHz ISO centers 0 5 9 6dBm RMS 500 Ohms 12 bit DAC Mic 1 Mic2 Mic 3 Mic 4 Lineln 20dBm 100k Ohms 3dB 0 6Hz 150kHz 91dBm shorted input 130dBm shorted input 110dBm shorted input 3
155. e 171 PC board 5 PCRTA INI file 65 76 PCT 173 PCX 173 Peak detector 292 Peak hold 94 Peak response 292 Persistent 223 224 Pink noise 22 288 Port address 5 215 Portable analyzer chassis 207 Portrait 73 PostScript printer 142 Power response 161 Power supply 7 Preamps 16 Print 73 Print spooling 321 Printer configuration 73 Printer port selection 75 Printing options 74 Probability distribution graph 125 Processing operations 20 149 Production date 229 Program group 4 Programmable equalizer 199 203 306 Q Quark XPress 176 R RAM minimum 3 Random pressure field 137 240 242 Raster images 173 RCA plugs 8 Redraw screen 26 221 pcRTA User Manual Reference curve 266 reverb time 122 Reference level 151 Registration data 229 Relative measurement 289 Relative mode 94 112 113 Resonant frequency 314 Response errors 134 Response time 292 Restart sequence 324 Result curve 161 Reverb time control panel 101 graph setup 119 measurement 274 Reverb time graph 120 Reverberant field 137 Reverberation 21 Revision level 229 RGB color 176 RightMouse button 24 RMS detector 22 Road noise 304 RT20 274 RT40 274 RT60 274 284 RTA bands 91 Run test 24 79 5 Scale auto 25 curve 149 down 25 factor 73 74 type 112 113 up 25 pcRTA User Manual Index Scale control bargraph 112 decay time 121 impedance 117 noise analysis 124 128 reverb time 120 text chart 113 Scaling a curve 149
156. e battery inside the PAC3 unit This data is updated each time the link is activated or when the dialog box is re displayed Note These indicators apply only to the PAC3 If you have a PAC4 the Battery Status will always indicate Fully Charged with ChrgAmps at 0 000 when the link is active Fully Charged means that the battery is at full charge This corresponds to the Battery Charge LED on the control panel of PAC in the OFF condition Over Charging means that the battery is currently having its charge topped off by a controlled over charging cycle This corresponds to the Battery Charge LED on the control panel of PAC in the ON condition Fast Charging means that the battery is currently in the bulk charge cycle This corresponds to the Battery Charge LED on the control panel of PAC in the Flashing Fast condition Slow Charging means that the battery is currently in the conditioning charge cycle This corresponds to the Battery Charge LED on the control panel of PAC in the Flashing Slow condition In this state the battery voltage is very low and must first be brought up to areasonable voltage before fast charging is possible If the charger never comes out of this state on an old battery then the battery probably needs to be replaced Discharging means that the battery is currently being discharged by the operation of the unit from battery power The ChrgAmps text box shows the current in amps being used to charge the batter
157. e ignored such as large gauge speaker wire and high quality amplifiers Measuring the transfer function of a passive crossover can be very useful when designing a system It will show you if your crossover is working correctly and what the crossover is doing to the signals fed to it Knowing the transfer function of the acoustic environment of the vehicle is extremely helpful when designing woofer enclosures With a measured curve of a vehicle s transfer function you can accurately predict the response of a cabinet in a vehicle before you actually install it This can save enormous amounts of time and money If you know that the frequency response being fed to a device is flat you can just measure the output of the device to determine it s transfer function The difference that the device causes is then directly measured If the response being fed to a device is not flat then that response must be saved for later use in a division process to determine the transfer function through the device Transfer Function Transfer Function of Equalizer of Crossover Pink Noise Source Equalizer Crossover Transfer Function of Equalizer and Crossover Measurement at Input of Equalizer Divided by Measurement at Output of Crossover pcRTA User Manual 11 Car Audio Applications Transfer Function of Acoustic Environments To measure the transfer function of the acoustic environment inside the vehicle you will need a test cabinet
158. e of the necessary conversions internally This can be a very useful operation for a variety of applications such as combining two response curves into one Also EQ or weighting functions can be divided from one and another curve The dialog box for this processing operation is shown below Three list boxes are shown for the selection of the two operand entries and the location of the result You can set the name for the result curve before or after this operation in the usual manner using the Curve Library edit dialog box To divide curves select the operand A and B curve entries in the two top list boxes Next select the result curve entry and press OK If you wish to exit without performing the operation press CANCEL Whether or not the data is actually dB or linear units is unimportant The data will still be divided properly for either type of curve units An example of this operation is shown in the graphs on the following page Divide Curves Result A B Library Untitled db Library Curve Entry Operand A 3 CurveN ame 3 Library Curve Entry Operand B 4 CurveName 4 Library Curve Entry Result 5 CurveName 5 pcRTA User Manual 155 6 Processing Menu 156 Original Curves A B Divided Result pcRTA Amplitude dB EXAMPLE1 DB BA File Edit Processing Utilities View Help Curve Legend peer Notes anc Comments 1 PnkHoise 01sec ave DataType dBm 3 W
159. e off during testing This utility is designed to perform repeated tests each time allowing the user to enter a contestant name while saving each measurement into a curve library entry automatically A library called OUTLAWnn is automatically created and the entry numbers incremented 1 through 20 as the tests are performed The result curves for each contestant are permanently saved in the library entries and can also be printed after each test cycle automatically Outlaw SPL Scoring Documentation Testing Controls _ Print Each Graph Lib Name OUTLAWO1 S ds 15 Test Number 17 Lib Curve 1 1 SPL Max lest PT 5 scoe Mici Mic 2 Mio 3 Mic imein Semen Start Testing Help pcRTA User Manual 185 Chapter 7 Utilities Menu As shown in the dialog box here Documentation Testing Controls Print Each Graph Test Number Lan Lib Curve 3111 there a check box which controls printing of the test results This box should be either checked or un Event Title SPL Contestant Produce SPL Score Mic 3 Mic imei checked as required before the scoring session begins Note that a special text box is pro Restart Sequence vided below the contestant name field where instructions will appear Start Testing p t
160. e status of a marker simply move your mouse over the marker and press the left mouse button Graph markers squares will toggle Off On and the data markers circles will change if a different curve is picked pcRTA User Manual 39 Chapter 3 Tutorial To edit the name of a curve simply click the mouse anywhere on the name line and the name text will be copied into the white edit box shown above Then click your mouse in the edit box and change the name gt Select CurveName 1 into the edit box gt Change the name to Pink Noise 0 1sec Ave gt Click the 1st curve line area to update the list box Your dialog box should now look something like the one shown here Editing the names and se controlling the curve entry markers is very easy Graph Data Pink Noise 0 1sec Ave Cov Curvo FSG NEEL SNE OOOO To keep your changes you must exit the dialog box 3 0 0 tea N pressing n ul CANCEL would abort any Delete Curve 5 CurveName 5 anges you ave made 7 Cuveane 7 CurveName 8 Note Most dialog boxes throughout the program CurveName 9 in b h he b OK O O CurveName10 ave three main buttons shown at the bottom OK Shom tnta 11 Cavelamett CANCEL and HELP If you wish to keep the changes you have made in a dialog box you must press OK to exit If you wish to abort the changes press CANCEL to exit The HELP button wi
161. e text only graphs Ifi pcRTA NoiseAnalysis NA SAMPLE1 NA BEE File Edit Processing Utilities View Window Help f Amplitude Time Graph 15124 Tools Run Test E Curve Legend System Notes and Input LineOut Range Auto Measure Leq 15 GenLevel 0 0 GenNoise Pink FullBand Flat RTABands Flat vi Cursor Amplitude vs Time Curve 5 Band Full Time 4 400Sec Data 66 0 dB Cursor Status Graph Curve 1 3 Data Cursor On Off Type Number Octave Readout Readout Band pcRTA User Manual 31 2 General System Features 32 When the cursor is first displayed it will be undefined In other words it will not necessarily be on any curves that are currently displayed and the data fields in the cursor status bar may be blank The figure belowillustrates this condition Once the cursor is visible you must press either PgUp or PgDn on your keyboard to place the cursor onto a curve thatis currently displayed Once there the arrow keys will move the cursor across the graph one data point at a time while displaying the data in the cursor status bar The Amplitude vs Time and Cumulative Distribution Noise Analysis Mode and the Decay Time Reverberation Mode graph types will display multiple curves showing each frequency band for a single library entry These graphs use the up and down keyboard arrows to select the desired band within each entry
162. eans of very high precision display in 0 1dB resolution The values are displayed directly and do not have to be interpreted from the position of bars or curves on a grid The single band mode is also very useful for reading the screen from a far distance In this mode any band can be selected for single display As with all of the display graphs the user has a high degree of control over many of the artwork elements including fonts and color selections The group box shown here displays the various parameters for the text chart display Color Buttons In many locations of the dialog box small rectangular color patches are shown These are actually active buttons and will respond to a mouse click When the mouse is clicked on one of these color pads a color selection dialog box will appear to select or change the color Font Buttons In the lower left hand corner of the dialog box a vertical array of rectangular buttons is provided Pressing one of these buttons will bring up a font selection dialog box for changing the font parameters A separate color pad is also provided for changing the color directly pcRTA User Manual 115 5 Edit Menu Text Chart Display Font Selections TypeFace Style Size Color Readout Boxes Single Title a Muliple Tiles Pane ee m Single Readout coti Multiple Readout SingleBand 116 Box Background This color pad allows selection of the color
163. ection The group box in the upper left hand corner displays the possible selection for the serial COM port to be used to communicate with the PA 422 equalizer The equalizer must be connected to one of the PC s serial ports The type of UART in the PC is also displayed If a particular serial port is not present or unavailable in the PC certain selections may be grayed out You must choose the same serial port here as is physically connected to the EQ Note If you are using the PAC interface for the pcRTA you will need an additional serial port for the EQ Start Link Button Once the serial port selection has been made this button should be clicked to initialize communication with the EQ A search of all possible PA 422 ID device address values is performed to locate any EQ s attached to the serial port When a suitable EQ is found the Device Address Model and Brand fields will be filled in with the unit s data Additionally the current EQ settings will be read from the unit and used to update the band levels and filter selections The EQ unit is now ready for operation and the other buttons at the bottom of the dialog box will be activated EQ Controls HighPass LowPass Memory Channel and Band Levels These dialog box elements mirror the settings of the EQ unit To manually program any of these settings to the EQ simply modify the desired band levels or selections and click the Program button This updates the EQ unit
164. ector on the pcRTA analyzer Under normal use with the connector box you will probably never need to wire into this connector directly However this schematic is provided for special applications which some customers may require DB 15 Male Connector Pin Out Mic4 Vdc Line Input Mic4 Input Line Output Mic3 Vdc Gnd Mic3 Input Gnd Mic2 Vdc Gnd Mic2 Input Gnd Mic1 Gnd Mic1 Input pcRTA User Manual 9 Chapter 1 Installation 1 5 Starting the pcRTA Software PORTAHep peRTA READ 4 TXT Version 20 peRTA VERSION T RTE 10 Once the installation program has been completed a new folder LinearX Applications will be shown on your Windows desktop The folder may be minimized in which case it will appear as an icon in the taskber at the bottom of your screen To start pcRTA first maximize the folder if needed and then double click on the pcRTA icon The program will then begin to load and the initialization process will begin While the initialization process is un derway the cursor will appear as an hourglass When completed the cur sor will return to an arrow After the cursor has returned to an arrow the main graph screen will be drawn and the previous library file will be automatically loaded Minc TA Edt Processing Utilties View window Help Um ne iu PCRTA res a Version 1 995 Cepin 144 1447
165. elow To keep your changes you must now exit the dialog box by pressing OK Installing Multiple Microphones 15 Chapter 1 Installation 16 If you have multiple mics to install simply repeat the same process for the other inputs as well Since each input is configured for a specific mic you will need to keep track of which mics have been setup for which inputs The mics should always be used on the inputs for which they have been configured This provides for very high accuracy in SPL measurements Note If you ever forget which mics are setup for which inputs just check the Microphone Setup dialog box for the inputs The parameter fields include a serial number that shows what file was loaded for that input Using the same MDF on Multiple Inputs If you have a single microphone and wish to use it on different inputs you can of course setup the same MDF on more than one input There is really no difference between any of the inputs but if you would like to use the same mic on more than one input this can be done Using Microphones other than M50 Series In order to setup other brands of microphones you will need to construct your own MDF file for that microphone The MDF formatis a simple ASCII file which can be created with any standard text editor or word processing program This is covered in the Edit Menu Chapter under Microphone Setup It should also be noted that the system allows you to setup a mic on the Li
166. em only provides selection of one data curve at a time in the library these multiple data curves are pre assigned into special library entry positions Mic 1 data is placed into entry 1 and Mic 2 data is placed into entry 2 etc The total averaging time will be multiplied by the number of mics in use plus about 1 2 second per mic for settling time The minimum screen update time in Multimic mode is approxi mately 2 seconds When the Normalized check box is on the mic levels will be normalized to the Full Range band level of Mic 1 For this reason Mic 1 must always be enabled for normalized measurements The Full Range bands can of course have either Flat A B C D orEANSI weighting applied With Normalization the Full Range band level of each enabled microphone will be identical to the Full Range band level of Mic 1 pcRTA User Manual 89 5 Edit Menu 90 Detector Detector This group box provides four selections for the time weighting or time averaging of the measured data The detector values follow the require ments of ANSI S1 4 1983 etc The Peak selection provides the fastest measured response and provides nominally 10 display updates per second The Fast selection is an exponential time average of 125mS and also provides 10 display updates per second The Slow selection is an exponential time average of 1000mS and provides 10 display updates second The Leq selection provides linear RMS time
167. ement buttons can be used to change the value in the 1 2 5 steps The list box provides selection of the number of vertical cycles Length of Half Division Dots The graph grid contains small hash marks or dots which are used to indicate the minor divisions between major divisions This parameter controls the length of the dot markers If the length is set to zero than the minor divisions are drawn as solid lines The line lengths are entered in mils 1 1000 of an inch 117 5 Edit Menu 118 pcRTA User Manual 5 Edit Menu 5 10 Graph Setup Reverb Time This dialog box provides control over the appearace of the graphs in the reverb mode There are two line graphs for the reverb mode Reverb Time and Decay Time Reverb Time Graph Decay Band Display Scale Control v Ful _ 630 Value at Top Log Cycles _ 20 800 ail 25 wm E J 31 _ 1250 gt Log Time Linear Time 40 1600 Major Minor Div 8 5 El 4 Length Hash Dot _ 80 _ 3150 1100 4000 Decay Time Graph 125 5000 Scale Control 160 6300 Value at dB Div _ 200 8000 s 29 JE pp315 12k5 Horz Time Scale 5 _ 400 16k 500 20k M All On Au off Minor Div Ver Hor 5 5 vi fas Reverb Reference Curve Theater Room Vol 1000 00 cuFt gt
168. en long cables are used between the computer and PAC unit For typical applications where the serial port cable is 10ft or less using 57 600 should be no problem If longer cables are needed and errors occur during general operation then it may be necessary to choose a lower baud rate Start Link Automatic Link The Start Link button is used to manually open and close the communication link between the computer and PAC When the link is active the text in the button will change to End Link When the button is pressed with the link active the link will be closed Therefore this button is used to manually toggle the link ON and 212 OFF The Automatic Link check box provides the means to allow the software to establish the link automatically each time the software is started Using this feature eliminates the need of using this dialog box each time to open the link The software automatically closes the link upon exit In order to use this feature you must have the PAC unit connected and with power ON before starting the software When the link is activated or deactivated the PAC unit will produce a confirmation beep to acknowledge the status change pcRTA User Manual Battery Status X Fully Charged Over Charging Fast Charging Slow Charging Discharging ChrgAmps Chapter 7 Utilities Menu Battery Status This group box contains a number of readouts which display the current status of th
169. es typically occur between 50Hz and 200Hz depending on the size of the vehicle It is important to understand that there are several modes standing waves in any car and when these modes are combined they can cause large peaks or dips in the frequency response curve This is because the standing waves will be at different phase angles When two waves at the same frequency and equal phase combine they increase the SPL at that frequency When two waves at the same frequency and opposite phase combine they decrease the SPL at that frequency Standing waves are very apparent when measuring at a single point in space As the point of measurement is changed the peaks and dips caused by the standing waves will appear at different frequencies across the spectrum For this reason it is recommended that measurements be taken at several different points in space and then averaged This technique is called spatial averaging and is explained in greater detail in a later section pcRTA User Manual 295 11 Car Audio Applications 296 Low Frequency Pressurization Another major factor affecting low frequency response in vehicles is the pressurization caused by the speakers being in an enclosed environment When a volume of air is sealed it will have an effect on the low frequency response of speakers in that space The effect of this sealed environment is a dramatic boost of sound at the lowest frequencies This rising response can
170. ethod recommended for resolutions of 1024x768 or higher is to place a small copy of the text chart with full band SPL displayed in the corner of the screen while having a larger line or bar graph covering most of the rest of the screen pcRTA User Manual STEP 1 Open new AMPLITUDE MODE curve library Chapter 10 Cinema Applications Go to the File menu and choose New then choose Amplitude The program creates a new amplitude library with the name Untitled db Edit Processing Utilities Impedance Reverberation Noise Analysis View Winde Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set New Iu Edit Processing Utilities View Windc To give it different name go to the File menu and choose SaveAs pcRTA Amplitud SaveAs Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set CETTE dialog box with the title Save Amplitude dB File opens Type in the name you want to give the file and click OK File Name Save Amplitude dB File Directories untitled db c pcrta db examplel example2 hijaak db db db jiasca001 db iasca002 db mikel db mike2 db mike3 db perta List Files of Type Amplitude dB Files db c ap Read Only
171. ethod for both purposes or a 4 wire method which sends the signal out on one pair and measures the voltage with the other pair of wires The advantage of the 4 wire method is that the cable resistance is not in LINE INC Y SHIELOED CABLE TEST CLIPS cluded in the measurement This pro duces better accuracy at low imped de 04 bete ance This may also be necessaryifthe cable length is relatively long 1 4 INCH PLUG You will need to construct at least one TEST CLIPS of these two cable arrangements Al E 9 ligator clips are best for clipping on to the terminals of various devices pcRTA User Manual 57 Chapter 3 To start an impedance measurement an impedance library must be gt Select File New from the menu and then Impedance The first test will be a simple open circuit test We will change the name gt Press the Curve Library button on the Tool Bar gt Change the name of entry 1 to Open Circuit gt Click OK to exit and save your changes Now we will need to set up the impedance control Tutorial opened or created of entry number 1 accordingly Library Untitled z Graph Data Open Circuit Test Test Cv eaves CurveName 2 Move Curve CurveName 3 CurveName 4 Delete Curve CurveName 5 CurveName 6 Delete All CurveName 7 CurveName 8 Edit Data CurveN
172. eveloped for ANSI special acoustic testing relating to aircraft noise All filters are designed for a gain equal to OdB at 1kHz ANSI Filter ANSI Weighting Filter Response 20 Frequency 100 92 pcRTA User Manual Type of Data dBm SPL Dynamic Range dBm Auto 120 to 20 Fixed 60 to 20 Fixed 80 to 0 Fixed 100 to 20 Fixed 120 to 40 Chapter 5 Edit Menu Type of Data There are two possible choices dBm and SPL The Type of Data parameter is very important When set to dBm the analyzer measures the simple voltage level of the selected input source OdBm 0 775Vrms Even ifthe inputis a microphone the MDF data isnotused The reading is exactly ameasurement of the input source voltage When set to SPL the MDF data is used to produce a true SPL reading Sensitivity offset and microphone response correction is applied as dictated in the loaded MDF mic setup The pcRTA can measure very accurate SPL levels with virtually any mic if correct MDF data is loaded When the input is either the Line Output or Generator both settings will produce the same data values since there are no MDF configurations applied to these sources Dynamic Range Control This group box allows you to select the dynamic range of the analyzer inputs In most cases the AutoRange selection can be used and the analyzer w
173. ever you can save and load files from other paths if desired Directories CX c E3 perta C3 db 2 export 2 na Cancel pcRTA User Manual 69 4 File Menu 4 6 Load Graph Display Set The Load Graph Display Set menu option loads a GDS file from disk which restores the graph display settings to the values in the GDS file These files have an extension of GDS After the Graph DisplaySet file is loaded the screen will be redrawn with the new display values Graph DisplaySet files store the colors line styles fonts position and scale information currently in use by the program This allows you to save your current display settings and later reload them to restore the previous settings all at one time This is much faster than editing all of the numerous colors and fonts one at a time By default GDS files are located in the main PCRTA subdirectory How ever you can save and load files from other paths if desired Load Graph Display Set File x blkwhtO1 C ec cine ach gds t cine bch gds perta cine nc gds db cine rt gds 1 export LI na contest Sa rt contest2 gds List Files of Drives Graph Display Set Files gds c new c 70 pcRTA User Manual Chapter 4 File Menu 4 7 Save Control Panel Set The Save Control Panel Set menu option saves the current settings for the control
174. from the computer from which the program is being transferred c make copies of the program solely for backup or archival purposes You must reproduce and include the copyright notice and label any backup copy You may not a distribute copies of the program or the documentation to others b lease rent grant sublicenses or other rights to the program c provide use of the program in a computer service business network time sharing multiple CPU or multiple users arrangement without the prior written consent of LinearX d translate or otherwise alter the program or related documentation without the prior written consent of LinearX Terms Your license to use the program and the documentation will automatically terminate if you fail to comply with the terms of this agreement Your license erminates in the event that you receive a license for an updated version of the product that replaces this product If a license expiration date is printed on your documentation or provided through other means such as a time limited electronic or software key your license expires on the day as shown in the documen ation or on the day that the electronic or software key expires If this license is terminated you agree to destroy all copies of the program and documentation E Limited Warranty LinearX warrants to the original licensee that the disk s and or electronic key s on which the program is recorded will be free from defects in materials and workmanshi
175. gnals or noise over a period of time and also produces a number of standard statistical graphs This mode produces measurements of L Iles EQ Lip 10 790 pcRTA User Manual 21 2 General System Features 2 3 Analyzer Block Diagram An equivalent block diagram for the pcRTA analyzer is shown below The various functions are shown in the gray blocks with signal flow indicated by arrows along the circuit paths The generator system provides three basic types of output white noise pink noise and a square wave oscillator The most commonly used signal is pink noise but the other types are provided as well for special applica tions The output of the generators is fed into a DAC attenuator for controlling the output level and is then routed to the Line Output with a source impedance of 500 Ohms The input source to the analyzer can be one of 7 different signals The five external inputs the Line Output or the direct Generator signal Auto ranging gain is applied and the signal is fed to the ANSI filter array Independent source selection for the full range band and 1 3 octave RTA bands is provided Each of the bands contains a logging RMS detector which converts the RMS signal energy in each band into the equivalent dB level Each dB output is then selected and fed into the analog to digital convertor and read by the software pcRTA Equivalent Block Diagram Full Select Full Range RMS dB Band
176. gs of the EQ unit To manually program any of these settings to the EQ simply modify the desired band levels or selections and click the Program button This updates the EQ unit to match those settings To read the current settings of the EQ unit and recall the settings of a particular memory location or channel first select the desired memory and channel and click the Recall button The operating parameters of the EQ will cause the dialog box controls to match those values For more information on the EQ parameters and their meaning or operation please consult the EQ manufacturer s documentation pcRTA User Manual Chapter 7 Utilities Menu Automatic Optimization of Response The pcRTA can be used to automatically adjust the EQ band levels to match the response measurement to a previously defined target curve entry In order to perform this function you must have previously setup an appropriate target curve in one of the library entries The curve entry to be used as the target is selected in the Library Curve Entry for Target list box This could be a flat line or any other shape desired Note The data curve entry must NOT be the same as the target curve or new measurement data will overwrite your target response It is also important to understand that the absolute target level must be in the same range as the expected measured RTA data For example if the measured SPL response is in the 90dB range a target that is a flat
177. h are controlled Pressing one of the buttons will open a font selection dialog box The TypeFace column shows the typeface currently assigned to each text item The Style column shows the font style currently assigned to each text item The Size column shows the font size in points currently assigned to each text item The Color column shows the font color currently assigned to each text item These color pads can also be used to change the color pcRTA User Manual 143 5 Edit Menu Color Selection Ea _ Color 65536 Colors Red Jm 00 02 Green am B rss Blue lo Black lt 21 White Ex Cancel Color Selection When a color padis clicked by the mouse this dialog box will appear to select new color Full support for true 24 bit color is provided along with convenient handling of dithered or solid palette color At the top of the dialog box a large sample is shown of the currently selected color Below this the number of currently available colors in the system is given This is controlled by your video system The check box for Solid Color controls the use of dithered colors The three scroll bars below are used to mix the primary Red Green Blue components If your system has more than 256 colors all colors will be solid regardless of the check box Font Selection Font Selection gt T When a font selection button is clicked
178. h curve library It should also be noted that the editing box can also be activated one a single line basis by using the DoubleClick zone in the Note region of the graph Comment Lines 1 8 Each of the eight lines provide approximately 40 60 characters of space for text comment strings Depending on the size and type of font used the actual display space may be different Itis up to the user to determine how much text can be placed on a line before the line length may overrun the available display space Multiple Note Comment Editing Line 1 LL Line 8 pcRTA User Manual 129 5 Edit Menu 130 pcRTA User Manual 5 Edit Menu 5 13 Microphone Setup The pcRTA system uses a Microphone Data Format MDF to provide the necessary sensitivity and response curve information about a given micro phone The data contained in the MDF file contains all relevant information about the microphone s electrical acoustical performance and other very useful documentation information This menu function loads the MDF data into the software If you purchased M50 series mics with the analyzer MDF files were provided with them The MDF files should be in the pcRTA subdirectory for your particular microphone s serial number s if you followed the instructions during the installation of the pcRTA software The pcRTA analyzer has five inputs four Mic Inputs and 1 Line Input Each of these inpu
179. h an Equalizer Equalizers The ideal equalizers for tuning with pcRTA will be stereo or two separate mono 1 3 octave units meaning that they have two sets of 31 adjustments Most equalizers of this type have their bands centered at the same frequencies as pcRTA which makes adjustment very easy If your equalizer has less than 31 bands you can still measure and adjust it with pcRTA Another feature to look for in an equalizer is the graphic style of adjustment This simply means that the unit has linear sliders instead of rotary knobs When you make an adjustment on such a unit it leaves a graphic representation of the frequency response change being added by the equalizer This is much more intuitive than several rows of round knobs Stereo 1 3 Octave Graphic Equalizer Programmable Equalizers In recent years equalizers have been developed that can be adjusted by a computer These equalizers typically do not have any controls on the front panel with the occasional exception of a few buttons which allow for adjust ment if no computer is present These equalizers can be automatically programmed by pcRTA while measurements are being taken so that pcRTA actually adjusts the eq to achieve the operator s ideal target response
180. h as in the case of Noise Analysis the screen saver may pop in to blank the screen with some Screen Saver mw ar other moving image While the screen saver is re Bassiord Grange Walt zi minutes working the CPU must also be handling the incoming data from the pcRTA in the PAC unit Shut off monitor saving features of monitor 9 minutes This can be too much processing for the CPU to d handle and an overrun may occur If you are taking a long term measurement it is best to 30 Sj minutes disable the screen saver from popping in during EEE _ the course of the measurement Baud Rate 9 600 gt 14 400 gt 19 200 gt 28 800 gt 38 400 57 600 210 Selecting the Baud Rate Probably the best way to approach this parameter is to select the top baud rate of 57 600 as an initial value and see if errors occur If errors occur at this speed try the next lower speed and repeat the testing If errors persist continue reducing the baud rate If errors are still present at 9600 baud then it is very possible that something is wrong with the IRQ setup for the COM port and or that a conflict exists with some other card in the computer This problem will have to be investigated and corrected before the serial port will operate correctly pcRTA User Manual Serial Port ADR COM 1 COM 2 COM 3 COM 4 Chapter 7 U
181. h of time vs frequency and a graph of decay rate amplitude vs time This will only happen once unless you hit Run Test again Run Test Button Click the Run Test button on the Tool Bar to begin Wait for the pcRTA to complete it s measurement cycle 10 seconds The Run Test button changes to the Stop Test button while the test is running but the pcRTA will not allow you to interrupt this type of test Control Panel Button eer D Go to the Curve Library and select the next curve in the list to receive data Run the test again with the Mic 1 Input selected EB Scale Go to the Curve Library and select the next curve in the list to receive data Go to the Control Panel and change the Input Source to Mic 2 Input Repeat the test twice for mic 2 py EE ev Curve Library Button Continue through all four microphones and save the data from each mic to a different curve entry When you are finished use the Averaging Process to produce a single averaged RT curve from the two sets of curves taken at four different positions S You may wish to use the Scale process to change an RT40 or RT20 curve to represent an RT60 indication Use a linear ratio of 1 5 to convert RT40 to RT60 and a linear ratio of 3 0 to convert RT20 to RT60 pcRTA User Manual 279 10 Cinema Applications Notes for Reverb Time Measurement Here are the Control Panel settings saved in the Control Panel Set file CIN
182. hain Control Panel Settings and Graph Display Settings New Open Save 75 SaveAs Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Hi Edit Processing Utilities New Open Save 75 SaveAs Save Graph Display Set Load Graph Display Set Save Control Panel Set Print P Exit Q ETET pcRTA User Manual Go to the File menu and select Load Graph Display Set A dialog box titled Load Graph Display Set File opens Load the file CINE_BCH GDS This file will set all of the characteris tics of the display Click OK to close the dialog box Load Graph Display Set File File Name Directories cAperta bikwht01 gds Ce cine_ach gds cine bch gds cine nc gds cine rt gds color 1 gds colormn2 gds List Files of Type Graph Display Set Files gds Go to the File menu and select Load Control Panel Set A dialog box titled Load Control Panel Set File opens Load the file CINE BCH CPS This file will set all of the parameters of the control panel Click OK to close the dialo box Load Control Panel Set File 8 P File Name Directories cAperta cine ach cps ec mikel cps setupl cps List Files of Type Control Panel Set Files cps 259 10 Cine
183. he analyzer to the PAC unit is equivalent to moving the analyzer to a different computer where the bus clocks may not be the same Serial Port Select This group box contains buttons for selecting the serial port to which the PAC unit is connected This group box is only enabled when the PAC link is NOT active The selection cannot be changed while the link is active and can only be changed when NIAE the link is OFF gt gt 2 Note If you choose a wrong COM port where another device such as the mouse is already connected when you press the Activate Link button the mouse may malfunction requiring a re boot to restore mouse operation pcRTA User Manual 211 Chapter 7 Utilities Menu Automatic Link at StartUp Baud Rate 9 600 14 400 19 200 28 800 38 400 57 600 Baud Rate Select This group box contains buttons for selecting the speed of communication over the serial port to the PAC unit This group box is only enabled when the PAC link is NOT active The selection cannot be changed while the link is active and can only be changed when the link is OFF The PAC unit has a built in feature of AutoBaud detection and will automatically lock on to the baud rate chosen here No jumper or switch changes in the PAC unit are required It is best to always use the highest baud rate of 57 600 unless other circumstances do not permit this Generally the only problem with using high baud rates occurs wh
184. he measured curve by the previously saved transfer Library Curve Entry Result function curve 3 Transfer Function of Car The graph below shows the transfer function that resulted from the two bandpass cabinet measurements shown on the previous page Transfer Function dep 15 15 10 10 5 5 o 0 5 5 10 10 15 15 50 100 200 500 1k 2k 5k 10k 2020 pcRTA User Manual 301 11 Car Audio Applications Transfer Function of Passive Crossovers To measure the transfer function of a passive crossover you need a power amplifier and the speaker s that the crossover will be attached to Passive crossovers should be measured with the speaker load The speaker presents reactive load meaning that the impedance of the speaker changes depending on frequency When measured with a resistive load you will see the thoerectically perfect response from the textbook as Sound Pressure Level 302 demonstrated in the top graph Because speakers are not purely resistive loads this type of mea surement is not very useful The bottom graph shows
185. hen the graph window is maximized 6 Control ay Un E Cascade Arrange Icons Maximize i Minimize DCRTA Amplitude dB EXAMPLE1 DB Text Chart id 1 Text Chart File Edit Pr ssing Utilities w Window Help 2 Bar Graph ETE Ser T n IEEE Line Graph 264 dBspl FullHz You will now see a full screen Text Chart as shown above This graph is displaying the C Weighted full band SPL in large digits Now you can resize the Text Chart to a small window in the corner and view the line graph as a large window taking up most of the screen This allows you to see the full band SPL and the real time response curve simulta neously This mode is recommended for higher video resolutions and large screen monitors See the figure on the next page pcRTA User Manual peRTA Amplitude dB EXAMPLE1 DB File Edit Processing Utilities View Window Help Chapter 10 Cinema Applications Control Ex Graph Curve Scale 9 Scale Fa Scale Zoom Zoom MERE Up EEE c Qut Zoom Full Sem ors ES Line Graph Sound Pressure Level Cursor Text Chart To use
186. hite Hoise 10 sec ave GenNoise Pink GenLevek 69 6 FullBand ANSFB RTABands ANSKFB InputSrc Mic 2 AvrgTime 1 0 Sec Display 3 band PA MPL EI DB 22220 1994 E pcRTA Amplitude dB EXAMPLE1 DB File Edit Processing Utilities View Help ontrol Panel Curve Curve Legend System Notes and Comments 6 1 amp 3 Divided DataT ype d Bm GenNoise Pink GenLevel 69 6 FullBand ANSFB RTABands ANSKB hnputSrc Mic 2 AvrgTime 1 0 Sec Display 31 band PKA MPL ET DB ig 20 1904 Tue 2 24 am pcRTA User Manual 6 Processing Menu 6 5 Add Curves This operation will produce a new curve by adding one curve to another curve This method provides simple addition and not RMS For RMS use the Summation operation The curves may be either dB or linear units The software will automatically take care of the necessary conversions internally This can be a very useful operation for variety of applications such as adding impedance curves The dialog box for this processing operation is shown below Three list boxes are shown for the selection of the two operand entries and the location of the result You can set the name for the result curve before or after this operation in the usual manner using the Curve Library edit dialog box To add curves select operand A and B curve entries in the two top list boxes Next select the result
187. ifferent regions Each region controls similar associated parameters Measuring reverberation can only be performed in relatively large rooms typically greater than 50 000 cubic feet 1 500 cubic meters This would be a room larger than 50ftx 50ft with a 20ft ceiling Small rooms do nothave enough surface area and volume to produce high diffusion In small rooms all that can be measured are standing wave patterns The process of measuring reverberation consists of detecting when the stimulus noise has decayed by a finite amount such as 60dB RT60 The problem in some roomsis that the background noise level may be quite high This prevents the decay time from being measured for typical RT60 values Using less demanding limits of RT40 or even RT20 can help solve the problem Reverb Control Panel x Generator Testing Mode RT Test Limit Stimulus Time Continuous RT20 Lise RT40 ycle EH s on Input Source TimeOut pcRTA User Manual 101 5 Edit Menu Generator Stimulus Time 2 dBm IL 20 00 Input Source 102 Stimulus Time This list box has several selections which can be used to control the length of the stimulus time The stimulus time is the amount of time that the generator will be turned on to produce an output and saturate the room being tested For very large rooms and auditoriums several seconds of stimulus time may be required before the
188. ight 1999 LinearX Systems Inc All rights reserved All other Trademarks are the property of their respective owners Table of Contents Chapter 1 Installation 1 1 1 System Requirements essent 3 1 2 Software Installation 4 1 3 Hardware Installation 5 1 4 Interface Cable and Connector 8 1 5 Starting the pcRTA Software 10 DES erro 11 1 7 Microphone 14 Chapter 2 General System Features 17 2 1 Main Screen Overview 19 2 2 Measurement Modes 21 2 3 Analyzer Block Diagram sese 22 2 4 TOOL gt ERR RES Un 23 2 5 CUVE BOX c 27 2 6 DATA CUISOM 31 Chapter 3 Tutorial 35 3 1 E 37 3 2 Example 1 Measuring the Generator Response 39 3 3 Example 2 Measuring SPL Response 51 3 4 Example 3 Measuring 57 Chapter 4 File Menu 63 CMENIIIe 65 4 2 Open Flle x tette 66 433 Save 67 44 Saves File 68 4 5 Save Graph Display Set 69 4 6 Load Graph Dis
189. ighting filter selected below Type of Data There are two possible choices dBm and SPL The Type of Data parameter is very important When set to dBm the analyzer measures the simple voltage level of the selected input source 0dBm 0 775Vrms Even if the input is a microphone the MDF data is not used The reading is exactly a measurement of the input source voltage When set to SPL the MDF data is used to produce a true SPL reading Sensitivity offset and microphone response correction is applied as dic tated in the loaded MDF mic setup The pcRTA can measure very accurate SPL levels with virtually any mic if correct MDF data is loaded When the input is either the Line Output or Generator both settings will produce the same data values since there are no MDF configurations applied to these sources Run Time There are three radio buttons for selection of the base time unit as seconds minutes or hours The edit box allows you to enter the numeric value of the total run time pcRTA User Manual Input Source Hiclnput 1 Detector Peak Fast Slow Leq 1S Chapter 5 Edit Menu Input Source There are several selections provided in this list box which control the input source selection for the analyzer measurement Most ofthe selections are clear and reflect the external connectors on the pcRTA connector box The Generator selection allows direct measurement of the signal noise genera tor This selec
190. ign the system to the new computer Analyzer Calibration x Analyzer EPROM Data OSC Sqw dBm Port Bus Clock MHz 3 6864 Pink Noise dBm Computer Calculation Speed Index 8 276 White Noise dBm 8 8 Serial Number 153435 Revision AutoRange Gain 1 dB 19 38 Calibration Date Feb 23 1999 Tue 12 09 pm Gam 2 UB Production Date Sep 6 1996 Fri 1 55 pm AutoR ange Gain 4 RMS Scale Factor RMS Scale Offset dB AutoR ange Gain 4 4 Fullizz 1 433 FE 18 4 E 8 z ullHz 1 ullHz 18 ANSI A Filter Gain dB 0 07 20Hz 1 424 20Hz 24 2 ANSI B Filter Gain dB 25Hz 1 428 25Hz 24 3 ANSI C Filter Gain dB 31 5Hz 1 428 31 5Hz 23 5 ANSI D Filter Gain dB ANSI E Filter Gain dB 40Hz 1 430 40Hz 24 2 50Hz 1 432 50Hz 24 4 63Hz 1 432 63Hz 24 2 RMS Rates dB S Pink Noise Flatness dB 0 44 DAC Atten Passed FullHz 138 4 White Noise Flatness dB 0 52 Line Output ANSI A Curve Level dB 0 27 0 10 Line Input 51 5Hz 100 ANSI B Curve Level dB 0 22 0 06 Mic 1 Input 40Hz 115 ANSI C Curve Level 48 0 13 0 05 Mic 2 Input 50Hz 124 ANSI D Curve Level dB 0 45 0 32 Mic 3 Input S3Hz 120 ANSI E Curve Level dB 0 66 0 04 Mic 4 Input pcRTA User Manual 13 1 Installation 1 7 Microphone Setup The pcRTA system uses Mic Data Files
191. ignments Note the new bar colors M pcRTA Amplitude dB EXAMPLE2 DB Bar Graph il File Edit Processing Utilities View Window Help Amplitude Response 1 Pink Noise D 1sec ave 2 Pink Noise 10 sec ave FullBand Flat RTABands Flat pcRTA 1 995 2 08 a Feb 26 1999 5 56pm vi Cursor Bar Graph Curve 2 Band 630 Data 16 8 dB ols pcRTA User Manual 45 Chapter 3 For the next measurement curve entry number 3 will be used gt DoubleClick mouse over Curve Legend area gt Click the circle data marker on in entry number 3 gt Click the square graph marker off in entry numbers 1 amp 2 Edit the name of entry 3 to White Noise 10 sec ave gt Press the OK button to exit and keep your changes Tutorial Library UNTITLED DB Graph Data white Noise 10 sec ave Pink Noise 0 1 ave Pink Noise 10 sec ave CurveName 4 CurveName 5 CurveName CurveName 7 CurveName 8 CurveName 9 CurveName10 CurveName11 46 Now we need to change the control panel for generator signal of White Noise gt DoubleClick mouse over System area gt Select White Noise for the generator gt Press the OK button to exit Noise Signal Generator Detector Type of Data V Automatic On Off Peak dBm SPL Fast Dynamic Range dBm
192. ill automatically select the proper gain based on the amplitude of the input signal AutoRanging will produce an occasional pause in the measurements when the input signal amplitude changes dramatically The Fixed Range selections allow you to manually lock the analyzer in a particular signal range No AutoRanging will be performed If the input signal exceeds the selected range an OVER LOAD indicator will flash on the graph This means you will need to increase the range setting or inaccurate measurements will result pcRTA User Manual 93 5 Edit Menu Testing Mode Continuous Peak Hold Cycle Limit 5 Testing Mode There are three basic types of testing modes which can be selected when taking measurements Continuous Peak Hold and Cycle Limit The edit box below is used to enter the number of measurement cycles to execute when the Cycle Limit mode is chosen Absolute 1 CurveN ame 1 Relative d Continuous means that the measurements will continue as long as the Run Testbutton in the Tool Baris depressed When the Stop Testbutton is pressed the last measurement data will be retained 94 Peak Hold means that only the largest or peak values measured will be retained after the measurement is stopped When a measurement is started by depressing the Run Test button in the Tool Bar the data is initialized At the end of each averaging time period the new data is compared with the previous
193. important The data will still be multiplied properly for either type of curve units An example of this operation is shown in the graphs on the following page Multiply Curves Result A B Library Untitled db Library Curve Entry Operand 3 CurveN ame 3 Library Curve Entry Operand B 4 CurveName 4 Library Curve Entry Result 5 CurveName 5 pcRTA User Manual 153 6 Processing Menu Original Curves A B Multiplied Result 154 pcRTA Amplitude dB EXAMPLE1 DB Edit Processing Utilities View Help Curve Legend peer Notes anc Comments 1 Pink Hoise 04sec ave 3 White Hoise 10 sec ave GenLevek 69 6 FullBand ANSFB RTABands AHS B InputSrc Mic 2 AyrgTime 1 0 Sec Display 31band PA MPL EI DB ig 290 1994 pcRTA Amplitude dB EXAMPLE1 DB File Edit Processing Utilities View Help Amplitude Re 5 1 amp 3 Multiplied DataType dBm GenHoise Pink GenLevek 69 6 FullBand ANSFB RTABands ANSKFB InputSrc Mic 2 AvrgTime 1 0 Sec Display 31band peRTA100 pampe o Aug 30 1994 Tue 2 19 am pcRTA User Manual 6 Processing Menu 6 4 Divide Curves This operation will produce a new curve by dividing one curve by another curve Dividing two curves is equivalent to subtracting their magnitudes in dB The curves may be either dB or linear units The software will automatically take car
194. inor divisions to be shown on the graph The scoring routine will use these values and will only adjust the top SPL value of the scale as needed 196 pcRTA User Manual True Sound Quality Scoring Documentation Print Each Graph Lib Name 5000001 Test Number 3 libCuve 3 Contestants Se Mic 2 Mic 3 Mic 4 Linein Hestart Sequence Testing Controls Leyel Setting Test RTA Response Test SPL Test Produce Score True Sound Quality Scoring 251 Documentation Punt Each Graph Lib Name 15000001 Test Number 3 LibCuve 3 Event Title Best Sound Wins Contestant Adjust your system for 904 in Full Band Mic Mic 2 Mic Mic 4 Testing Controls I Push when done RTA Response Test SPL Test Produce Score True Sound Quality Scoring Documentation _ Print Each Graph Lib Name 15000001 Test Number 3 libCuve 3 Event Title Best Sound Wins Contestant Speaker Tweak RTA Score 11 Mic 1 Mic 2 Mic 3 Mic 4 Lineln Testing Controls Level Setting Test RTA Response Test Produce Score pcRTA User Manual Chapter 7 Utilities Menu Starting a Session To begin a scoring session press the Start Testing button and then enter the event name The first step in each of the scoring cycles is to enter the contestant name The Test
195. ion The pink noise source generally used for scoring is generated from a CD The CD process cannot record frequen cies above 20kHz A bandpass filter centered at 20kHz has one half of its effective pass band above 20kHz Any measurement using pink noise from a CD will show about a 2dB loss in the 20kHz band solely from the CD DSP processing itself For this reason the TSQ scoring formula does not use the 20kHz band Many of the competitors utilize 1 3 octave graphic equalizers with 28 bands ranging from 31 5Hz to 16kHz To match this equalization range the TSQ formula also only uses low frequency bands down to 31 5Hz Scoring Formula The TSQ scoring formula is straight forward and easy to compute Essentially the response of the system is scored based on its relative flatness or reproduction quality The scoring computation steps are 1 Find the median level Add the dB levels of the 28 bands from 31 5Hz to 16kHz and divide by 28 2 Find the total deviation Add the 28 absolute value differences between each of the band s level and the median level pcRTA User Manual Chapter 7 Utilities Menu 3 Find the total score Score is equal to 40 minus the total deviation divided by 6 Round to whole number For the maximum SPL test simply subtract 100 from the maximum SPL reached and round to the nearest whole number For user information purposes the computed median level is displayed along with a list of the bands which
196. ion about this specific dialog box and its controls or parameters pcRTA User Manual 5 8 Graph Setup Amplitude Chapter 5 Edit Menu This dialog box provides control over the appearace of the graphs in the amplitude mode There are three graphs used in the amplitude mode Bar Graph Line Graph and Text Chart Amplitude Graph Setup x Bar Graph Display Scale Top Value dB Div Full Range Band Display Type Absolute Relative 1 3 Octave A s E 1 Octave Major Minor Div 5 Sivas Band Graph IN Line Graph Display Scale Top Value dB Div v Full Range Band Display Type Absolute Relative 1 3 Octave 1 Octave Major Minor Div 5 Single Band Length of Hash Dot Amplitude Reference Curves Bar Line Graphs Noise Contours SMPTE SMPTE X Curves Surround Curve Level 4 oo Text Chart Display Readout Boxes Font Selections TypeFace Style Size Color Background Single Tite Multiple Titles a Multiple Readout pe Line 35 SingleB and 1 Oct pcRTA User Manual 111 5 Edit Menu Bar Graph Display Scale Top Value dB Div eoe so gt Type Absolute Relative Major Minor Div 5 _ Bar Graph Display aranmo The bar graph display provides the traditional method of RTA 1 30cteve data display This graph can display multiple libr
197. is selected the band to be displayed is chosen in the list box below pcRTA User Manual 113 5 Edit Menu Amplitude Reference Curves Bar Line Graphs Noise Contours SMPTE N Curve _ SMPTE X Curves Surround Curve Level dB 114 Reference Curves This group box contains selections for various reference curves Reference curves are lines drawn on the Bar and Line graphs which allow you to compare your measurements directly with those of standard reference or alignment curves Whether or not the curves actually appear on the grid will depend on the current position of the scale and the values of the reference curve For example if the reference curve has values in the OdB range and the current scale is in the 100dB range the reference curve will not be visible since it would be far below the graph pcRTA User Manual 5 Edit Menu Text Chart Display Readout Boxes Font Selections TypeFace Style Size Color Box Background Single Title Times Regular Multiple Ties cy aw Single Readout pcr Multiple Readout us Text Chart Display The text chart display is used in the amplitude measurement mode to display the data in a text format Each text readout is provided in a rectangular box with a title The number of boxes will depend on the graphics display mode 1 3 octave 1 octave or single band The text chart mode provides a m
198. isplay of data on the graphs The Full Range check box controls the display of the Full Range Band on the graph When checked the full range band is displayed When not checked only the RTA bands will be displayed in the grid and the Full Range level will appear in the upper left hand corner of the graph as a text value This only affects 1 3 octave or 1 octave multi band display The next three radio buttons provide selection for either 1 3 octave 1 octave or single band display If single band display is selected the band to be displayed is chosen in the list box below pcRTA User Manual 5 Edit Menu Line Graph Display Line Graph Display Scale Top Value dB Die FullRange line graph display provides an improved method of data Band Display vi d E Lj 2 64171 Gee display over the traditional RTA bar graph display This graph one s 10ctave can display multiple library curves in a clearly visible fashion Single Band 4 Lena of Hash Dota Jo Fully adjustable scale factors resolution and dynamic range j are provided including control over the number of major and minor divisions Many different grid designs are also possible Scale Top Value dB Div Scale Type The edit box is used to set the scale value at the top of the grid The increment and decrement buttons can be used to change the value in steps of dB Div The dB Div list box provides a wi
199. ithms Disabling print spooling is another means to eliminate this potential problem Parameters to Set before Testing Begins The microphone input source to be used during the testing is set in the control panel prior to the start of the scoring session Also the MDF file for the microphone to be used must be already loaded into the system prior to testing to provide accurate SPL calibration During the testing you can select different input sources which allow for multiple testing stations to be utilized If you will be using the pcRTA internal Pink Noise Generator you may also wish to set the generator level to an appropriate value However IASCA testing generally uses a CD with Pink Noise as the source for the car stereo system Most of the other control panel parameters will be automatically set by the scoring utility The scoring system uses the Bar Graph display mode You do have the option to select the dB value per division and the number of major and minor divisions to be shown on the graph The scoring routine will use these values and will only adjust the top SPL value of the scale as needed Starting a Session pcRTA User Manual IASCA Scoring 1 Documentation Print Each Graph Lib Name IASCA001 Test Number 2 libCuve 2 Event Title The Big Sound Off Contestant Mic 2 Mic 4 Linein Restart Sequence Testing Controls Level Setting Test BIA Response Test SPI
200. itled db CurveName 1 CurveName 2 CurveName 3 CurveName 4 CurveName 5 CurveName CurveName 7 CurveName 8 CurveName 9 CurveName10 Q 11 Copy Curve Move Curve Delete Curve Delete All Edit Data Show Info Co C3 C3 C3 C3 EJ C3 EI other curve for display click on the oval to the right of the curve number This will set that curve to save the data from the next test and to display on the graph To name a curve click inside the curve name edit box and type in the new name Click OK to close the Curve Library dialog box and save any changes you have made pcRTA User Manual 10 Cinema Applications STEP 3 Load Reverb Time Control Panel Settings and Graph Display Settings Edit Processing Utilities New Open Sounc Save 75 SaveAs Save Graph Display Set Save Control Panel Set Load Control Panel Set Edit Processing Utilities New Sound Save 75 Nu SaveAs Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Print P Exit ial Le TT 2 pcRTA User Manual Goto the Eile menu and select Load Graph Display Set A dialog box titled Load Graph Display Set File opens Load the file CINE RT GDS This file will set all
201. izer units This dialog box provides the means to remotely control many of the functions of 1 3 octave equalizers and also provides automatic control and optimization of the equalizer bands to achieve a predetermined target response curve Manual control of the EQ is also possible as well as manual operation of the pcRTA analyzer Programmable EQ RW 232 Serial Port ADR UART Device Address Manufacturer Type Memory Channel COM 2 02F8h D Curve Entry for Highpass Lowpass Off Off Y gt COM 4 02E8h Ee Eu Zero All mx E ou 2 2 ERPERERFEBEBPEEBERFERIEREBSREEIEEEREBE 1 off mf f dd ded fid efe f di f fid d f ef d fi CE REE ae a Panzesogg9598829888 J9 25aags556868 Start Link Run Recall Program pcRTA User Manual 203 Chapter 7 Utilities Menu Programmable EQ 232 Serial Port ADR UART Device Address Manufacturer Type Memory Channel Serial Port Selection The group box in the upper left hand COM 2 02F8h Library Curve Entry for Target corner displays the possible selection for Highpass Lowpass LEE COM 3 03E8h Theater Response _ COM 4 CNZA I fon m s the serial COM port to be used to com eee
202. l Bar Show Hide Curve Box Appendix 343 Appendix 344 pcRTA User Manual Index pcRTA User Manual Index Il pcRTA User Manual Index Index Symbols 66 66 RT 66 Z 66 2 Wire 57 313 24 bit 144 256 colors 141 3D Perspective graphs 127 4 Wire 57 313 80x87 3 A A chain alignment 245 About pcRTA 229 Absolute mode 94 112 Accelerator key control panel 24 curve box 27 generator on off 24 quick reference 343 redraw screen 26 run stop test 24 42 save file 50 tool bar 23 Acoustic environment 298 299 Acoustic reference level 136 Add curves 157 Address conflict 215 Adobe ATM 3 Adobe fonts 144 Adobe Illustrator 176 Al 173 Alligator clips 57 Amplifier 51 pcRTA User Manual Amplitude control panel 87 graph setup 111 measurement mode 21 Analyzer calibration 215 Analyzer hardware 229 Animation 3 141 ANSI filter array 22 ANSI weighting filters 92 107 Artwork view 319 ASCII data 167 AUTOEXEC BAT 4 Autoranging 109 Average detector 292 Average multiple measurements process 161 spatial averaging 308 Averaging time amplitude measurement 90 changing 43 impedance measurement 98 minimum 292 multimic mode 89 pink noise measurement 289 Azimuth adjustment 245 253 B B chain alignment 256 Background noise 101 304 Band display decay time graph 121 noise analysis 128 Bandwidth 293 Bar graph display 112 Baud rate 210 212 Black White 75 Block diagram 22 In
203. l menu option will be provided when the current library type and measurement mode is Amplitude This is the largest control panel in the system and handles virtually all aspects of the analyzer and software for standard amplitude measurements This menu option can also be activated from the tool bar and the DoubleClick zone in the graph area under System The example below shows the various elements of the Control Panel dialog box The dialog box is separated into several different regions Each region controls similar associated parameters Amplitude Response Control Panel Noise Signal Generator Automatic On Off Pink Noise Gen Output Level dBm gt Vrms Input Source Mic Input 2 HultiMic Select Enable ict y Enable Mic _ Enebe Mic3 _ nable Mic gt Bre Detector Full Band gt Flat gt ANSI Sum RTA Bands Flat gt ANSI Type of Data dBm gt SPL Dynamic Range dBm gt Auto 120 to 20 Fixed 60 to 20 gt Fixed 80 to 0 gt Fixed 100 to 20 gt Fixed 120 to 40 Testing Mode Continuous Peak Hold gt Cycle Limit ANSI Filter Measurement Data Absolute gt Relative 1 CurveName 1 pcRTA User Manual 87 5 Edit Menu Noise Signal Generator Automatic On Off
204. l parameters will be reset to the values saved in the CPS file Control Panel Set files store all of the parameters for all types of control panels currently in use by the program This allows you to save your current measurement setups and later reload them to restore the previous settings all at one time This is much faster than editing all of the numerous analyzer parameters one at a time By default CPS files are located in the main PCRTA subdirectory However you can save and load files from other paths if desired Load Control Panel Set File x E cine ac2 cps Gy c cine ach cps t cine bch cps os cine nc cps cine rt cps Eg export dbdrag cps LI na 29 List Files of Type Drives Control Panel Set Files cps new c 72 pcRTA User Manual 4 9 Print Chapter 4 File Menu The Print menu option opens a dialog box for printing control From here the artwork generated in pcRTA can be printed to any output device currently supported in your Windows system The graphs used in pcRTA have art boards of 10 inches wide by 8 inches high These are the full size dimensions Printing at a scale factor of 10096 will generally require landscape orientation on 8 x 11 letter size paper For portrait printing use a reduced scale factor such as 809 or less Printer Configuration This box displays the configuration for the currently selected printer When you start a p
205. l value by 0 1dBm If the level reaches the maximum or minimum capable values the level will not change These buttons are type a matic and can be held down to continuously step the value pcRTA User Manual 5 Edit Menu Input Source Input Source There are several selections provided in this list box which control the Mic Input 2 input source selection for the analyzer measurement Most of the selections are clear and reflect the external connectors on the pcRTA Select connector box Enable Enable Mic The Generator selection allows direct measurement ofthe signal noise Wicd generator This selection will follow the programmed output level but El 4 is always ON regardless of the Gen On button bMutipiex ri The MultiMic selection performs two different kinds of multiple microphone measurement Average and Multiplex When this selec tion is chosen the group box below is enabled The microphone enable check boxes control which microphones will be included in the multimic measurement This can be any combination of mic inputs from 1 through 4 In the Average mode the enabled mic inputs will be RMS averaged into a single data curve The total averaging time will be multiplied by the number of mics in use In the Multiplex mode the enabled mic inputs will produce individual data curves one for each enabled mic Since the syst
206. le Auto button in the Tool Bar After the screen is redrawn you should now see the bars moving on the graph The display should appear similar to the one shown here The bars are moving in rela lum File Edit Processing Utilities View Window Help 1 tively rapid fashion The Amplitude Response at the far left shows the over all full range response level and will be bouncing around the OdBm level The other 31 bars show the energy in each 1 3 octave band at a level about 17dB below the full range The lower bands are in con stant motion and do not maintain asmooth level This is due to the short averaging time of 0 1sec Cursor x 42 hs pcRTA User Manual Chapter 3 Tutorial To stop the display simply press the Stop Test button gt Press the Stop Test button in the Tool Bar The display freezes The bars maintain the last data when the measurement was stopped and the data is already stored in the curve library entry You can press the Run Test button again to reactivate the measurement process Try this a couple of times to get the feel of starting and stopping measurements gt Press the Run Stop Test button in the Tool Bar a few times You will probably have noticed that the bars freeze in a different position each time This is due to the random nature of noise With a short averaging time
207. lectrical energy generated by the car s engine and other electrical devices This type of noiseis only present while the engine is running or while one of the other devices is running To measure electrical noise connect the output of the power amplifier to the Line Input of the pcRTA Measure the system noise with the engine off by turning the volume all the way up with no signal Use a long averaging time atleast 5 Seconds This is the background noise or noise floor of the electronic components in the system CAUTION NEVER allow the voltage at the Line Input to exceed 5 8VRMS or severe damage will result Start the engine and take another measurement You can use the relative mode or divide the measured curve by the stored curve of the noise floor Any difference observed is the noise caused by the engine s electrical system It is usually very easy to determine which device is causing the noise because the noise will have a frequency which corresponds to the frequency of the device For instance if the noise has a higher frequency when you rev up the engine it is ignition noise If the noise changes when you change the heater fan from low to high it is noise from the fan Electrical noises in cars are usually due to improper grounding schemes in the stereo installation The solutions for these problems is beyond the scope of this manual pcRTA User Manual 305 11 Car Audio Applications 11 7 Adjusting Wit
208. line at OdB would be impossible The optimizer would attempt to reduce the band levels by 90dB clearly out of the adjustment range of 12dB bands The correct target would be a flat line in the 90dB range When the target curve and data curve have been setup the Optimize button is clicked to begin the process The pcRTA will perform a measurement using the current existing control panel parameters and then compare this data to the target curve data The EQ band values will be adjusted to minimize the difference between the new RTA data and the target The process may iterate several times until a suitable match is obtained or until no further improvement can be produced This occurs when one or more bands are driven to the top or bottom of their maximum range It should be noted that a suitable averaging time should be employed to yield stable measurements atlow frequencies Typically a 2 10 second Ave Time will produce good results If you wish to take manual RTA measurement the Run RTA button can be used for this purpose Clicking the button will start stop the manual RTA measure ment When the EQ operations are completed press the End Link button to terminate the communication The Exit button will then be activated pcRTA User Manual 205 Chapter 7 Utilities Menu 206 pcRTA User Manual Chapter 7 Utilities Menu 7 12 PAC Interface The PAC Portable Analyzer Chassis interface allows you to setup and establish the
209. ll bring up context sensitive help about the dialog box gt Click the OK button to exit the dialog box and keep your changes Looking at the lower left corner of the graph note that an area called Curve Legend is shown The name of curve entry number 1 is shown here along with a colored line in front Note also that this line has a small dot placed on it The dot means that this entry is the data curve 75 eu 25 945 40 50 6 90 100 125 160 200 20 syst curve legend area lists the curves that are being displayed and 1 Pink 0 15e ave bats also indicates what colors are assigned to the curves or bars It also GenNoi Geneve indicates which curve is marked to hold the next measurement and FullBanc gives the names of the curve entries This fully automatic annotation Si mw system provides very helpful information when viewing the graphs Display or printing the graphs for record keeping purposes 40 pcRTA User Manual Amplitude Response Control Panel x Noise Signal Generator Detector Type of Data Automatic On Off Peak dBm SPL 31 5 Hz SaWave Dynamic Range dBspl low Gen Output Level 4 Leats Auto 120to 20 0 50 i gt SRE v Fixed 80to 0 Fixed 100 to 20 EEE Fixed 120 to 40 Input Source Flat ase eae tie Line Input ANSI Testing Mode MultiMic Select m Continous Peak Hold y Enable
210. ll exit after pressing this button The PCRTA INI file is always updated with the current system configuration data when the program is terminated Use the CANCEL button if you wish to abort the exiting process You will be returned to the pcRTA system after this button is pressed M pcRTA Amplitude dB TEST1 DB Bar Graph BAIE nl File Edit Processing Utilities View Window Help Sound Pressure Level 0 d Control ale Panel Ex Graph pcRTA Message ke Curve Library E EXAMPLE1 DB has been changed Scale EE ES Scale Auto Save library file No Cancel Ihisiatest _ 1 New Curve 1 Input LineOut Range Auto DataType SPL Abs Detector Leq 0 50 GenLevel 0 1 GenNoise Pink FullBand Sum RTABands Flat N selec at 075 lugens Fa a Deme Start QJ Exploring Pcita v2 Jani pcRTA Amplitude dB dem nl 5 16 PM 76 pcRTA User Manual Edit Menu Run Stop Test Del Gen On Off Ins Curve Library F2 Control Panel Graph Setup F4 Notes Comments Microphone Setup 4 Graph Design System Options F10 pcRTA User Manual 5 Edit Menu 78 pcRTA User Manual 5 Edit Menu 5 1 Run Stop Test Choosing this menu option will start a measurement This menu selection toggles the analyzer measurement to sta
211. low frequency pressurization effect that occurs in small acoustic spaces to generate higher SPL scores Whether you want a ground pounding bass generator or an audiophile dream vehicle the measurement process includes the same basic steps For system measurements the process is simple Make noise with the system and measure it with pcRTA With the real time measurements being displayed on the screen you can adjust the electrical components and or the acoustic environment and watch the changes appear as you make them pcRTA User Manual 287 11 Car Audio Applications The ocean produces natural pink noise White noise is the sound you hear from the electronic The most common noise source used is Pink Noise You may be asking What is Pink Noise and Why Should Use It The simple answer is that pink noise will produce a flat line on the pcRTA when averaged over time Pink noise is equal energy vs log frequency and white noise is equal energy vs linear frequency The pcRTA displays log frequency so a pink noise signal produces aflat line while a white noise signal produces a line that rises with Pink Noise frequency E 3 pun ES 5 e oe 2 x system when music is These graphs show what pink noise and white noise look like on the pcRTA screen components in a sound playing E 2 E un 2 2 E
212. lt computer supplies Some computer power supplies have very limited 12Volt current If you have other heavy analog processing cards Sound Blaster multimedia etc in your system they will also consume 12Volt current If your computer fails to re start try removing one of these other analog cards You may be exceeding the maximum available current for the 12volt supply Chapter 1 Installation 1 4 Interface Cable and Connector Box All connections to the pcRTA are provided through a DB15 pin interface cable and connector box The connector box has four female XLRs for the microphone inputs 1 2 3 4 and two 1 4 inch jacks for the Line Input and Line Output circuits All circuits are unbalanced lines Depending on your application you may need additional adapters and or connectors of a different type In the case of Hi Fi equipment conversion of the 1 4 jacks to RCA plugs will be common These adapters and connectors can be purchased at most electronic supply stores or Hi Fi shops The XLR mic inputs provide a DC voltage on pin 3 of approx 10V for powering the M51 microphones If you need to extend the microphone cables standard 3 pin XLR microphone cable may be used MICROPHONE INPUTS LINE IN 60 MIC 1 MIC 2 MIC 3 MIC 4 LINE OUT pcRTA User Manual Chapter 1 Installation Pin Out for DB15 connector The following diagram shows the pin out for the DB15 conn
213. m 0 775Vrms You do not need to change or adjust this 9 6dBm level unless you have the proper equipment and are confident that your measurements are very accurate pcRTA User Manual View Menu pcRTA User Manual 1X Alt 1 2X Alt 2 4x Alt 4 Bx Alt 8 BeDraw R Scale Up Up Scale Auto A ScaleDown Dn ToolBar T Show Curve Box C Chapter 8 View Menu 218 pcRTA User Manual 8 View Menu 8 1 Zoom In Zoom Out The Zoom In and Zoom Out menu options can be used to control the magnification factor of the large window The minimum zoom level is 100 which is full view and the maximum zoom level is 800 These commands also be activated from the Tool Bar using the Zoom In and Zoom Out buttons The zoom magnification increment decrement is 14196 and 7196 respectively These values were chosen to produce a doubling or halving of the magnifica tion level for every two clicks These menu items can also be activated by pressing the Zoom buttons on the Tool Bar or CTRL PLUS and CTRL MINUS on the keyboard pcRTA Amplitude dB TEST3 DB Be File Edit Processing Utilities View Help Sound Pressure Level cH FII 85 L Bi 80 N 76 TN 400 Zoom Level T pcRTA Amplitude dB TEST3 DB GE File Edit Processing Utilities View Help
214. ma Applications The Line Graph should look like the one shown here pcRTA Amplitude dB Untitled DB Line Graph gt 2 gt File Edit Processing Utilities View Window Help I Control Graph Curve Zoom Zoom 9A Rdrw Panel Libray 0 E Full 8 Sem FullRng 0 0dB dBspl 80 sp There are no data curves on this graph only the grid and the SMPTE X curves overlay You will see three high frequency rolloff curves in the high end of the SMPTE X reference curve These curves reflect the fact that the high frequency roll off characteristics change for different room sizes The reference curves correspond to rooms with 30 seats 500 seats and 2000 seats 260 pcRTA User Manual Run Test Button Control d Graph UL Setup Library Scale Up Scale Ex Auto Scale i Down Zoom In Zoom Out Zoom Full SA Rdrw Sem Chapter 10 Cinema Applications General procedure for B chain Alignment The settings you have loaded include a 10 second averaging time This means that the pcRTA will collect measurements for 10 seconds and then display the average of all measurements taken during that time The process then repeats with all new data The curve will only change once every 10 seconds For coarse adjustments you could use a faster averaging time This way the effects of your adjustme
215. mplitude Response Control Panel Noise Signal Generator Automatic On Off Pink Noise zl Gen Output Level CIEL M dBm Vrms Input Source Line Input MultiMic Select Enable Miot Enable Mic Enable Enable Ave Multiples _ Noimalized v v v Detector Peak Fast Slow Leafs Full Band Flat ANSI Sum Flat Chapter 10 Cinema Applications Type of Data dBm SPL Dynamic Range dB spl Auto 120 to 20 Fixed 60 to 20 Fixed 80to 0 Fixed 100 to 20 Fixed 120 to 40 ANSI ANSI Filter Testing Mode Continuous Peak Hold Cycle Limit Measurement Data Absolute Relative ttem Control Panel Parameters Parameter Value Parameter Value Gen Auto On Off Off Gen Output Level N A Input Source MultiMic Select N A Detector Leq s Averaging Time Full Band N A pcRTA User Manual Line Input 1 00 Sec RTA Bands ANSI Filter Type of Data Dynamic Range Testing Mode Measurement Data Flat N A SPL Auto Continuous Absolute 251 10 Cinema Applications 252 Notes for A chain Alignment continued Here are the Graph Setup settings saved in the Graph Display Set file CINE ACH GDS Amplitude Graph Setup x Bar Graph Display Line Graph Display Scale Top Value dB Div _1 Full Range Scale Top Value dB Div _1 Full Range
216. n again To use this function first highlight select the entry to be moved before pressing the button Then press the Move Curve button Next highlight select the entry position to move the curve to If you wish to abort the command simply press the button again Delete Curve This function button is used to erase a curve from one entry position Both the data and the curve name will be erased To use this function first highlight select the entry to be deleted before pressing the button Then press the Delete Curve button Delete All This function button is used to erase all curves from the library Both the data and the curve name will be erased for all entries To use this function just press the Delete All button 84 pcRTA User Manual 5 Edit Menu Edit Data Library Untitled db This function button opens another dialog CurveName 1 box which allows the user to manually CurveName 1 B enter edit the actual data in the 32 bands ee Prior to pressing the button the user should CurveName 4 highlight the curve entry for which the data CurveNamo 5 is to edited The dialog box is self explana CurveName 6 Copy Curve Move Curve Delete Curve Delete All CurveName 7 tory with each band value displayed in its Edi Das ibis own editing field For dB data the values CurveName10 may be either positive negative or zero Ha Show Info CurveNamel1 For impedance and time data
217. nal data will be overwritten 1 CurveName 1 when the operation is com 2 CurveName 2 pleted 3 CurveName 3 4 CurveName 4 6 Civilians 5 An example of this opera CurveName tion is shown in the graphs 7 CurveName 7 on the following page Library Curve Entry for Result 19 CurveNamel9 N pcRTA User Manual 163 6 Processing Menu Original Curves A B Summation Result 164 pcRTA Amplitude dB TEST3 DB File Edit Processing Utilities View Help GurveLegend System DataType dBspl GenHoise Pink GenLevel 395 FullBand Flat Notes anc Comments 1 car number 1 2 This is another test RTABands ANSKE InputSrc Lineln AvrgTime 1 0 Sec Display 31band TEST3 DB Arg 90 1994 4 TEST3 DB File Edit Processing Utilities View Help E m Full Rdiw Sern 6 Summation of 1 amp 2 GenlNoise Pink GenLevel 39 5 FullBand Flat RTABands AHSKE InputSrc Lineln AvrgTime 1 0 Sec Display 31band pcRTA 1 00 TEST3 DB e Aug 30 1994 Tue 3 10 am pcRTA User Manual Utilities Menu Export ASCII Data Import ASCII Data Clipboard Export Graphics Export Scoring Programmable EQ gt Interface Analyzer Calibration pcRTA User Manual Chapter 7 Utilities Menu 166 pcRTA User Ma
218. nalized ANSI C x 1 CurveName 1 E Control Panel Parameters Parameter Value Parameter Value Gen Auto On Off Off RTA Bands Resp Flat Gen Output Level N A ANSI Filter ANSI C Input Source Mic Input 1 Type of Data SPL MultiMic Select N A Dynamic Range Auto Detector Leq s Testing Mode Continuous Averaging Time 10 0 Sec Measurement Data Absolute Full Band Response ANSI 272 pcRTA User Manual 10 Cinema Applications Notes for Noise Criteria Measurements continued Here are the Graph Setup settings saved in the Graph Display Set file CINE NC GDS Amplitude Graph Setup x Bar Graph Display Line Graph Display Scale Top Value dB Div Full Range Scale Top Value dB Div Full Range 2 s Band Display 800 Ea 100 Band Display Type Absolute Relative 1 30ctave Type Absolute Relative 1 3 Octave 1 Octave 1 Octave Major Minor Div 8 5 Single Band Div 8 5 Single Band Graph Bars Dot Rainbow zl Full Hz Length of Hash Dot 30 10 Full Hz Ej Amplitude Reference Curves Bar Line Graphs V Noise Contours SMPTE N Curve SMPTE X Curves Surround Curve Level dB 0 0 Text Chart Display Font Selections TypeFace Style Size Color Readout Boxes Box Backi d Single Title Arial Regular 190
219. ne Input This will probably be the input source for a third party mic since an external preamp will likely be used As an alternative a special XLR connector could also be wired to drop the 10V pin 3 line of a mic input Many other mics preamps would not necessarily use this voltage pcRTA User Manual General System Features M pcRTA Amplitude dB UNTITLED DB Fie Edit Processing Utilities View Window Help ities Sound Pressure Level View Help ATAR 1207M 5 Full 20 2k Curve Legend eRTA 109 4 z E dem 6 em 100Hr E dem FulHz File Edit Processing dem sk He E 200 em 125Hr 3 dem 20Hz 1 New Curve 1 pcRTA 1 00 TESTI DB Aug 23 1994 Tue 10 44 pm Amplitude dB TEST1 DB ilities View Help dm Ek 3H ek He d m ickHr dBmizksHz d em tek He ES dBm tkHe dem ik2sHe d amp m iksHr dom 2ksHz d m aki SH En ES Em E E EE dm 150He 200Hz dem 2soHr dBm 31 sHr dem 400Hz Ez Ed E E dem 25Hz dBm 31 5Hr dem 40Hz dem S0Hz dem est GenNoise Pink GenLevel 00 FullBand Flat RTABands Flat InputSrc LineOut AvrgTime 0 1 Sec Display 31band
220. neOut which control the input source selection and testing 4 Wire LineOut Lineln mode Two different test methods are provided 2 wire and 4 wire The 2 wire mode only uses the Line Output and the 4 wire mode uses the Line Output and Line Input Ns INTE OK The OK button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and save any changes you have made in the dialog box Cancel The CANCEL button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and abort any changes you have made in the dialog box Help The Help button is common to most of the dialog boxes throughout the program Use this button when you wish to open the help system and receive information about this specific dialog box and its controls or parameters pcRTA User Manual 99 5 Edit Menu 100 pcRTA User Manual 5 Edit Menu 5 6 Control Panel Reverb Time This Control Panel menu option will be provided when the current library type and measurement mode is Reverberation This control panel handles virtually all aspects of the analyzer and software for reverb time measurements This menu option can also be activated from the tool bar and the DoubleClick zone in the graph area under System The example below shows the various elements of the Control Panel dialog box The dialog box is separated into several d
221. nema Applications Notes for A chain Alignment continued If you do not have an oscilloscope or want to avoid taking it up to the projection booth you can set the azimuth by adding the right and left signal electrically and observing the high frequency response The signals should have a series resistance added to avoid damaging the processor s output circuitry The diagram below shows the connection method for this technique 2kQ From Processor Left Output To pcRTA Line Input 2kQ From Processor Right Output The graph will display a single curve which is a composite of the left and right channels The azimuth is adjusted for minimum loss in the high frequency region This setup uses the standard CPS and GDS files used for the A chain alignment Note It is important to check that the optical head is perpendicular to the surface of the film after adjustment It is possible to get a false good reading when the azimuth adjustment is very skewed When it is near perpendicular however there will be only one best response position pcRTA User Manual 253 10 Cinema Applications 254 Notes for A chain Alignment continued Itis possible using the pcRTA to view both the left and right channels of the optical preamp simultaneously for easier adjustment of the optics and slit loss eq The procedure requires the user to build two adaptors to attach the leftand rightsignals to the Mic 1 and Mic 2 inputs on the pcRTA The
222. ng times can be used for less accurate but quicker measurement Testing Mode There are three basic types of testing modes which can be selected when Continous taking measurements Continuous Peak Hold and Cycle Limit The edit Peak Hold box below is used to enter the number of measurement cycles to execute when the Cycle Limit mode is chosen Testing Mode Cycle Limit 5 Continuous means that the measurements will continue as long as the Run Test button in the Tool Bar is depressed When the Stop Test button is pressed the last measurement data will be retained Peak Hold means that only the largest or peak values measured will be retained after the measurement is stopped When a measurement is started by depressing the Run Test button in the Tool Bar the data is initialized At the end of each averaging time period the new data is compared with the previous values and updated if the value is higher When the measurement is stopped the last values are retained Cycle Limit provides a finite number of measurement cycles Each cycle is one averaging time period If 3 cycles are selected with an averaging time of 10 seconds the measurement will last 30 seconds after which the Run Test button will be automatically turned off and the last data retained 98 pcRTA User Manual 5 Edit Menu Impedance Test Method Impedance Test Method There two selections provided this group box 2 Wire Li
223. nification factor and will display all of the artwork in the window This button can also be activated by pressing ALT 1 on the keyboard Redraw Screen The Redraw Screen button will cause the graph window to be redrawn This is sometimes useful or necessary when manual changes have been made to the artwork notes and data or if fonts and colors have been changed This button can also be activated by pressing CTRL R R on the keyboard pcRTA User Manual Chapter 2 General System Features 2 5 Curve Box The Curve Box provides quick access to the entries in the Curve Library It duplicates much of the functionality of the Curve Library edit dialog box The Curve Box controls the selection of curves for display on the graphs as well as the data entry selection and editing of curve entry names The example below shows the various elements of the Curve Box Each of the key features are detailed The View menu provides a command to both display and remove the Curve Box The last line at e Mai the bottom of the menu will toggle between Show Curve Box and Hide Curve Box The accelerator key CTRL C C can also be used to activate the command Library Name Graphing Status Data Curve Status Name Editing Box Data Indicators Curve Library EXAMPLE 1 DB Graphing Indicators 250Hz square wave 1 sec 1 amp 3 Multiplied 1 amp 3 Divided Curve List Box pcRTA User Manual 27 2 Gene
224. now off the top of the grid but all of the 1 3 octave bands are vis ible on the grid As this graph demonstrates there is exactly a 30dB differ ence between the 20Hz band and the 20kHz band These frequency bands are three de cades apart o GenLevel 00 GenNoise Pink FullBand Flat RTABands Flat 1 Cursor a pcRTA User Manual is 47 Chapter 3 Tutorial For the last test we will measure the spectrum of a 250Hz square wave Curve entry number 4 will be used to hold the data gt DoubleClick mouse over Curve Legend area gt Click the circle data marker on in entry number 4 gt Click the square graph marker off in entry number 3 gt Edit the name of entry 4 to 250Hz square wave 1 sec ave gt Press the OK button to exit and keep your changes Now we need to change the control panel for a generator signal of 250Hz We will also change the averaging time to 1 0 seconds Since we are not measuring random signal such as noise shorter averaging times can be used Graph Data 250Hz square wave 1 sec Copy Curve Pink Noise O 1sec ave Pink Noise 10 sec ave Move Curve White Noise 10 sec ave gt DoubleClick mouse over System area Select 250Hz SqWave for the generator ee gt Select 1 0 Sec
225. nput 1 Author Date Model M53 dBspl Serial dBm Response Errors dB 63Hz 0 27 Mic Data Edit x Microphone Input 1 Date Dec 11 1997 Thr 4 53PM Serial 201181 dBm 15 51 Full 040 0 100 2 026 630Hz 0 08 AkHz 0 17 20Hz 1 06 125Hz 0 18 800Hz 0 01 5kHz 0 48 25Hz 0 61 150Hz 022 1kHz 0 01 6k3Hz 0 77 31 5Hz 0 23 200Hz 0 24 1K25Hz 0 07 8kHz 0 93 40Hz 0 00 250Hz 027 1k6Hz 0 01 10kHz 1 22 50Hz 012 026 2kHz 0 27 12k5Hz 1 80 amp 3Hz 0 28 0 20 2k5Hz 0 20 16kHz 2 26 025 500Hz 015 3k15Hz 0 11 20kHz 0 79 Chapter 5 Edit Menu Edit This button opens another dialog box which allows the user to manually enter edit the actual mic line input error data used inter nally by the system to calibrate SPL levels This function can be used to create a custom calibration or offsetfor special purposes or to modify the corrections produced from the import of an MDF file If MDF editing is the intended purpose the MDF file must first be imported prior to editing the data Note This function does not create MDF files which are entirely different It is important to remember that the values entered here represent error values and are su
226. ns and options provided which are pertinent to the type of data being measured All of this is handled automatically by the program and requires no intervention on the part of the user pcRTA Amplitude dB TEST1 DB Bar Graph The type of data to be measured the measurement mode Edit Processing Utiities View Window Help is chosen by the type of library which is opened or created This is performed using the File menu option and choosing EET Ex the desired type of library in the New or Open operations Save 5 Beverberation Saves udi p Noise Analysis TUNE To change the type of data being measured simply open a Load Graph Display Set Save Control Panel Set Load Control Panel Set Print Exit P different library type All required menus and dialog boxes will be automatically loaded for the new mode Amplitude Mode simply refers to the usual dBm or dBspl data measured by all RTAs This is the general purpose mode of the analyzer for taking normal RTA measurements Impedance Mode is provided for general speaker or passive crossover measurements This gives a 31 point response curve for the impedance characteristics of a transducer or component The data is given in ohms Reverberation Mode or ReverbTime is a measure of how sound decays in a closed environment The data is given in seconds Noise Analysis Mode provides the ability to record and or average si
227. nt rules from each of the sanctioning bodies If the rules change the software is changed to reflect the new rules Updates of the software are available on the World Wide Web at the LinearX home page LinearX Web Address http www linearx com home htm Figures are used extensively in this section so that you will know what the software should look like at each step Note This section assumes that the pcRTA has been installed and the micro phone calibration files are properly assigned to the input s to be used pcRTA User Manual 317 11 Car Audio Applications There are many graphic elements of the pcRTA software that can be adjusted or manipulated by the user To duplicate the look of a particular graphics setup can be challenging For this reason we have incorporated the Graph Display Set GDS files feature GDS files keep track of all colors fonts window locations and window sizes Using these files you can recall the exact look that you saved previously and there are some generic files included with the software pcRTA Amp GX Edit Processing Utilities The first step in this section New will be to load the GDS file Open called scoring gds To load the GDS file go to the File menu and select Load Graph Dis play Set de 0dB So SaveAs Load Graph Display Set Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel
228. nts to the system become visible more quickly At the low frequencies you will have trouble using faster averaging so this technique is mainly useful for the mid and high frequencies The fine adjustments should be done with 10 second averaging or longer for the highest accuracy Click the Run Test button on the Tool Bar to begin The Run Test button changes to the Stop Test button while a test is running You can leave the test running as long as required to set the channel gains and adjust the equalizers The typical adjustment process calls for setting the gain of each channel to 85db C weighted and then adjusting the eq for a flat response The software settings that are loaded provide C weighting on the full band readout and no weighting on the RTA response readout See the Notes section for information about switching the display between full band SPL text chart display and RTA response line graph or bar graph Before adjusting the equalization on each channel it is a good idea to check for a similar response from each channel and for even coverage throughout the room If one channel has a drastically different response it may have a blown driver or crossover problem Checking the response at each mic individually will indicate any problems with severe standing waves at one mic position This can cause misrepresentative readings when averaging four mics and the microphone should be moved When you are finished adjusting each channel of
229. nual 7 1 Export ASCII Data Chapter 7 Utilities Menu The Export ASCII Data menu option will open a dialog box for exporting the curve as an ASCII text file The frequency range is 20Hz 20kHz and the number of data points is 31 Select Library Entry This list box contains the names of the curves currently present in the system Select the desired curve to export here ASCII Data Export Library Curve Entry to Export Select Library Entry 5 1 amp 3 Multiplied Reverberation Data Sever Time Decay Time Noise Analysis Data Pusplitude ve Tune Class intervals g s Cancel pcRTA User Manual After you have made your selections press the Ok button Another dialog box will open to set the file name and path where you wish the file to be placed The default path is the PCRTA EXPORT subdirectory but another may be chosen as desired The default file extension is DAT for data Export Data File x File Name Directories es dn amptime dat class dat class2 dat db dat na 1 dat na 2 dat na 3 dat na 4 dat List Files of Type Export Files dat 2 new c gt eyes 3 perta yj export Drives Dem 167 Chapter 7 Utilities Menu 168 Data File Format The ASCII text data file format is essentially a spread sheet type format It consists of a header line with the column heading text and an array of te
230. ny number of seconds and a variety of different display types are provided During the measurement run the analyzer updates the display once per second The display tree is driven in a fasion to produce an equivalent display DiagiHacng range matching that of the Bar Graph window This means that the top light is equal to the top of the scale and the bottom light is equal to the bottom of the scale The Scale top value is set in the dialog box prior to beginning the run The number of major divisions and the dB value per Testing Controls Em division is controlled via the normal Graph Setup dialog box The use of Clear Display Tree these features enable display range to be created producing Test Display Tree degree of resolution or range for the tree light display Also the Text Chart window can be used to view the Full Range band levels of each of Gran the two mic channels in precise dB values wide vareity and unlimited RUN SE number of display combinations are possible Name of Contestant 1 Additionally a test pattern is provided to check the lights in the tree for Name of Contestant 2 non functioning bulbs or other problems prior to use The test 1 85 1 pattern can be aborted at any time to freeze the display for evaluation Automatic RollUp RollDn 20 100 Hz Response Limit Themeasurement data is written into the first and second library entries
231. o choose the maximum range for the horizontal axis Major Minor Divisions These four parameters determine the number of major and minor divisions for both the vertical and horizontal axis pcRTA User Manual 125 5 Edit Menu Cumulative Distribution Graph dB Scale Value at Top dB Div 190 Major Div Vert Horz Minor Div Vert Horz 5 Ea Cumulative Distribution Graph This graph displays the cumulative probability mea sured for each band There are a large number of possible curves in the plot since each library entry displayed can contain up to 32 curves dB Scale Control The Value at Top text box is used to display the vertical dB scale value at the top of the grid The increment and decrement buttons can be used to change the value in steps of dB Div The dB Div list box provides a wide selection of possible resolutions for the major divi sions Major Minor Divisions These four parameters determine the number of major and minor divisions for both the vertical and horizontal axis 126 pcRTA User Manual 3D Perspective Graphs dB Scale Time Scale Value at Top gt S M H SEU son dB Div 50 24000 Major Div Vert Horz Minor Div Vert Horz 5 5 gt Wire frame Forward View Solid Surface gt Reverse View Major Minor Divisions Chapter 5 Edit Menu 3D Perspective Graphs This group box provides display control for
232. ol Bar is depressed When the Stop Test button is pressed the last measurement data will be retained Cycle Limit provides a finite number of measurement cycles Each cycle is one averaging time period If 3 cycles are selected with an averaging time of 10 seconds the measurement will last 30 seconds after which the Run Test button will be automatically turned off and the last data retained pcRTA User Manual 103 5 Edit Menu 104 OK The OK button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and save any changes you have made in the dialog box Cancel The CANCEL button is common to most of the dialog boxes throughout the program Use this button when you wish to Exit and abort any changes you have made in the dialog box Help The Help button is common to most of the dialog boxes throughout the program Use this button when you wish to open the help system and receive information about this specific dialog box and its controls or parameters pcRTA User Manual 5 Edit Menu 5 7 Control Panel Noise Analysis This Control Panel menu option will be provided when the current library type and measurement mode is Noise Analysis This is the largest control panel in the system and handles virtually all aspects of the analyzer and software for complex noise analysis measurements The Noise Analysis mode provides recording ofthe meas
233. on 24 Graphic equalizer 306 Graphics accelerator card 3 display 115 export 173 Graphics file format 174 Graphing indicators 83 Graphing status 28 82 Graphs 20 Gray halftones 75 Grid background 141 H Harmonics 49 Help 38 Help buttons 38 Help system 227 Hide curve box 27 Hide tool bar 23 VI port 5 215 IASCA 317 IASCA scoring 177 323 Impedance control panel 97 graph setup 117 measurement mode 21 measuring 57 313 Impedance test method 99 Import ASCII data 169 text 169 Importing 170 Input source amplitude 89 noise analysis 109 reverb time 102 Input Output range 208 Inputs 14 INSERT key 24 80 Installation 4 Interface cable 8 Internal generator 289 Interpolation 169 Interrupt request 208 Invert curve 151 IRQ 5 208 ISA 7 ISA bus clock 229 J JPG 173 Jumpers 5 K Keyboard shortcuts 343 pcRTA User Manual L Landscape 73 Laser printers 75 Leq response 292 Library entries 39 Library name 82 Line graph amplitude 113 cinema applications 236 impedance 117 noise analysis 123 reverb time 119 Line graph display 113 Line input car audio scoring 325 cinema snake 237 connector box 8 impedance measurement 97 313 maximum input voltage 305 pink noise measurement 289 specifications 339 transfer function 303 with correction 16 133 Line output cinema snake 237 impedance measurement 97 313 on off 80 output level 88 102 106 Linear units 149 LMS 57 Load mic data file 132 Low freq
234. on s import filters However with a little experimentation and testing you should be able to determine which formats and applications will achieve the desired results pcRTA User Manual Chapter 7 Utilities Menu 7 5 IASCA Scoring This utility provides a special automated algorithm for producing a comparison score according to the International Auto Sound Challenge Association IASCA This is arevised scoring routine based on the new standard effective Jan 1 1997 Further information about the judging and test setups can be obtained directly from IASCA There are two tests defined which constitute the objective portion of the sound quality judging SPL and RTA The maximum number of points for the SPL portion is unlimited the RTA portion is 20 The measurement microphone must be positioned in the driver s seat at roughly ear level pointed toward the dash Use of a microphone stand 26 inches high above the center of the seat is recommended All windows doors sun roofs and trunk must be closed The engine must be off during RTA testing but may be running during SPL testing This utility is designed to perform repeated tests each time allowing the user to enter a contestant name while saving each measurement into a curve library entry automatically A library called IASCAnnn is automatically created and the entry numbers incremented as the tests are performed The result curves for each contestant are permanently saved in the
235. onds for the averaging time it Data urveName severi Dre gt Press the OK button to exit We are ready to take another measurement Since the measurement time is now only 1 second you can stop the measurement a couple of seconds after starting it Noise Signal Generator Detector Type of Data vi Automatic On Off Peak dBm SPL gt Press the Run Test button Dynamic Range dBm 125HzSqwave Slow Auto 120 to 20 in the Tool Bar and wait a Fue 60020 couple seconds Fixed 80 to 0 Fixed 100to 20 CS Full Band Fixed 120 to 40 Flat M gt Press the Stop Test button s zi as Testing Mode in the Tool Bar MultiMic Select Sum eq continous Enable Mic RTA Bands Peak Hold _ Enable Mie Cycle Limit _ m usd uo ANSI Measurement Data eu nee ANSI Filter Absolute gt Relative 48 pcRTA User Manual Chapter 3 Tutorial The new data will be back higher in level so the scale needs adjustment You can either use the Scale Up twice or use the Scale Auto button to let the software find the scale automatically gt Press the Scale Up button in the Tool Bar twice While the full range bar shows a level of 0 dBm the 250Hz bar is about 1 dB lower This is because the full range bar is measuring the RMS level of the actual full square wave while the 250Hz band show
236. onnected the pcRTA to your amplifier do so now Also connect power amp to the speaker and the microphone to one of the mic inputs of the pcRTA It will be assumed you are using Mic 1 To prevent driving the amplifier and speaker at a level too high we will Detector Type of Data dBm SPL begin by setting the generator at Fast fairly low level Most power amplifi Slow CHER re ers have a volume control and it Leafs Em should be setata typical normal level 0 10 z Re for starting purposes Later you Fixed 100 to 20 wish to change the generator level Full Band Fixed 120 to 40 from the pcRTA or change the vol Flat ume control of the amplifier ANSI Testing Mode ee gt Set the generator for PinkNoise Bands gt Set the output level for 40dBm Flat Looe Lias gt Set the Data Type for SPL ANSI Measurement Data gt Set the Averaging for 0 1 Sec ANSI Filter Absolute gt Relative gt Set the Input Source for Mic 1 INF The remaining settings should be the METTE same from example number 1 If they are not set your parameters to match the values shown here 52 The Type of Data parameter is very important When set to dBm the analyzer measures the simple voltage level of the selected input OdBm 0 775Vrms Even if the input is a microphone the MDF data is not used The reading is exactly
237. ons can be used to change the value in steps of dB Div The dB Div list box provides a wide selection of possible resolutions for the major divi sions The three radio buttons provide time base unit selections of seconds S minutes M and hours The two edit boxes control the start and ending time limits for the graph display grid Major Minor Divisions These four parameters determine the number of major and minor divisions for both the vertical and horizontal axis 124 pcRTA User Manual Probability Distribution Graph dB Scale Percent Scale dB Interval Value at Top Pim ange dB Div Major Div Vert Horz Minor Div 5 5 Percent Scale Control Chapter 5 Edit Menu Probability Distribution Graph This graph displays the probability in of a given dB value occuring in the selected class intervals This graph can have many curves since there is a set of 32 possible curves for each displayed library entry dB Scale Control The Value at Top text box is used to display the vertical dB scale value at the top of the grid The increment and decrement buttons can be used to change the value in steps of dB Div The dB Div list box provides a wide selection of possible resolutions for the major divi sions The upper list box provides a wide range of selections for the class interval The pcRTA has a maximum class resolution of 0 25dB The lower list box allows you t
238. operation of the program are introduced there and will be helpful for this tutorial pcRTA User Manual 37 Chapter 3 Tutorial 38 Starting the Program If you have not already started the program do so now This can be done by double clicking on the pcRTA icon When the program has finished initializing itself go to the File menu pick New and Amplitude On Line Help The pcRTA software provides extensive on line help which is available throughout the program Help can be accessed in two different ways 1 Go to the Help menu and open it directly 2 Press one of the help buttons shown in a dialog box Pressing a help button in a dialog box will bring up context sensitive help about that specific dialog box and its options pcRTA User Manual Chapter 3 Tutorial 3 2 Example 1 Measuring the Generator Response In this example we will be performing a measurement of the signal noise generator itself This is really nothing more than a simple self test of the system No external equipment is required If you have not already selected a new amplitude library then do so now Go to the File menu and select New Amplitude This will create a new amplitude library and set the measurement mode for amplitude The first step in taking a measurement is selecting where you wish the data to be placed Remember the system uses a library to store curves The data from a measurement is placed into one of the twenty library ent
239. or data When the button is out the measurement has stopped There are also two other means provided to activate this button 1 the DELETE key on the keyboard and 2 the RightMouse button Either of these controls can be used to toggle the state of the Run Stop Test button Using the RightMouse button is very convenient for remote control purposes Gen On The Generator On button will change to Generator Off after it has been pressed This button functions as a push on push off and toggles between these two states Whenitis pushedin the generatoris producing an output signal at the Line Output When the button is out the generator output is turned off The INSERT key on the keyboard can also be used to control this button Note this button does not affect the Direct Generator input source selection which is always active The generator button and function will also be activated automatically by the use of the RunTestbutton Some control panels provide for automatic generator On Off control when running a measurement test Control Panel The Control Panel button brings up the control panel for the analyzer under the current measurement mode After this button is pressed a dialog box will appear to set one or more parameters in the control panel The control panels differ for each type of measurement mode The F3 key on the keyboard can also be used to activate this button Graph Setup The Graph Setup button brings up the editing dialog
240. or linear units The software will automatically take care of the necessary conversions internally This can be a very useful operation for a variety of applications such as subtracting impedance curves The dialog box for this processing operation is shown below Three list boxes are shown for the selection of the two operand entries and the location of the result You can set the name for the result curve before or after this operation in the usual manner using the Curve Library edit dialog box To subtract curves select the operand A and B curve entries in the two top list boxes Next select the result curve entry and press OK If you wish to exit without performing the operation press CANCEL Whether or not the data is actually dB or linear units is unimportant The data will still be subtracted properly for either type of curve units An example of this operation is shown in the graphs on the following page Subtract Curves Result A B Library Untitled db Library Curve Entry Operand 3 CurveN ame 3 Library Curve Entry Operand B 4 CurveName 4 Library Curve Entry Result 5 CurveName 5 r _ ot pcRTA User Manual 159 6 Processing Menu Original Curves A B pcRTA Impedance Z EXAMPLE3 Z File Edit Processing ies View Help Ohm 1000 Impedance Response 500
241. or the Control Panel settings used to make this measurement pcRTA User Manual 10 Cinema Applications Notes for A chain Alignment continued Here are the Control Panel Setup settings saved in the Control Panel Set file CINE AC2 CPS Amplitude Response Control Panel Noise Signal Generator Automatic On Off Pink Noise x Gen Output Level __ oc dBm Vims Input Source Multi Mic MultiMic Select Enable 1 Enable Mic2 Enable Mic3 Enable Mic4 Ave Multiplex Normalized Detector Peak Fast Slow Lea s 1 00 Full Band Flat ANSI Sum Bands Flat Type of Data dBm SPL Dynamic Range dBm Auto 120 to 20 Fixed 60 to 20 Fixed 80 to 0 Fixed 100 to 20 Fixed 120 to 40 Testing Mode Continuous Peak Hold Cycle Limit ANSI ANSI Filter 1 CurveName 1 Measurement Data Absolute Relative Control Panel Parameters Parameter Value Parameter Value Enable Mic3 Off Enable Mic4 Off Gen Auto On Off Off Gen Output Level N A Full Band Response N A RTA Bands Resp Flat N A dBm 1 00 Sec MultiMic Weighting Filter Type of Data Averaging Time Input Source Enable Mic1 On Enable Mic2 On pcRTA User Manual Average Off Multiplex On Normalized Off Dynamic Range Testing Mode Measurement Data Auto Continuous Absol
242. or the system to be able to construct the full image and enough disk space for the exported file 174 pcRTA User Manual Chapter 7 Utilities Menu Export Graphics File x File Name Directories bargrph ai bg ai y perta export tai 2 List Files of Type Drives At Adobe Illustrator v3 0 x c new c gt Exporting the File Once you have specified the options as desired press the Ok button and another dialog box will open to set the export file name and path The file name extension will be set based on your choice for the file format The default path is PCRTA EXPORT but you may change this as required Once you have entered the file name click the Ok button and the export process will begin One or more meter displays will be shown which indicate the progress of the graphics conversion You may abort the export operation by clicking the Abort button Conversion to Adobe Font Names 28 pcRTA User Manual 175 Chapter 7 Utilities Menu 176 Notes on Raster Formats Of the seven supported formats only the TIF and BMP will contain accurate DPI values in the files Many of the raster image formats do not allow for absolute size information If you need to maintain accurate absolute image size for importation into another application use the TIF or BMP formats Notes on Vector Formats If you are importing WMF files into Quark XPress or Page
243. oth Curve Copy Curve CurveName 3 CurveName 4 CurveName 5 CurveName 6 Oo Move Curve Delete Curve Delete All CurveName 7 CurveName 8 CurveName 9 CurveName10 CurveName11 Edit Data Show Info 20 Each curve entry can be given a name and additional library notes can also be added by the user to be displayed and printed on the graphs Processing Operations A menu of processing functions is also provided which allows mathematical operations to be performed on the curve entries within a library Curves can be inverted multiplied averaged summed etc pcRTA User Manual Chapter 2 General System Features 2 2 Measurement Modes The measurement mode refers to the type of data the analyzer software is currently configured to measure There are four basic types of measurement modes in the pcRTA Amplitude Impedance Reverberation and Noise Analysis The measurement mode is defined by the type of library which is currently in use Each type of measurement data is stored in specific libraries designed for the data to be stored Amplitude libraries are given the file extension DB Impedance libraries have an extension of Z Reverberation libraries have RT and Noise Analysis libraries are NA There are subdirectories which match each of these types of library files Depending on the measurement mode there will be different menus functio
244. p under normal use for a period of ninety 90 days from the date of purchase as evidenced by a copy of your receipt If failure of the product components has resulted from accident abuse or misapplication of the product then LinearX or third party licensors shall have no responsibility to replace he disk s or key s under this limited warranty This limited warranty and right of replacement is in lieu of and you hereby waive any and all other warranties both expressed and implied including but not imited to warranties of merchantability and fitness for a particular purpose The liability of LinearX or third party licensors pursuant to this limited warranty shall be limited to the replacement of the defective disk s or key s and in no event shall LinearX or third party licensors be liable for incidental indirect punitive or consequential damages including but not limited to loss of use loss of profits loss of data or data being rendered inaccurate or losses sustained by third parties even if LinearX or third party licensors have been advised of the possibility of such damages This warranty gives you specific legal rights which may vary from state to state Some states do not allow the limitation or exclusion of liability for consequential damages so the above limitation may not apply to you In addition to the foregoing you should recognize that all complex software systems and their documentation contain errors and omissions LinearX
245. panels to a file on disk and prompts you to enter select the file name for the file These files have an extension of CPS It is not necessary to add the extension yourself the pcRTA software will add the correct extension automati cally If you do type in an extension make sure it is the correct type so you will be able to recognize the file in the future as a Control Panel Set data file Control Panel Set files store all of the parameters for all types of control panels currently in use by the program This allows you to save your current measurement setups and later reload them to restore the previous settings all at one time This is much faster than editing all of the numerous analyzer parameters one at a time By default CPS files are located the main PCRTA subdirectory However you can save and load files from other paths if desired Save Control Panel Set File x Name cine ac2 cps cine ach cps cine bch cps cine nc cps cine rt cps dbdrag cps setupl cps spldrags cps List Files of Type Drives Control Panel Set Files cps c new c Cancel pcRTA User Manual 71 4 File Menu 4 8 Load Control Panel Set The Load Control Panel Set menu option loads a CPS file from disk which restores the control panel settings to the values in the CPS file These files have an extension of CPS After the Control Panel Set file is loaded all control pane
246. pecially when using sine waves at low frequencies Another factor that should be considered is whether the meter has auto ranging gain circuitry Itis common for SPL meters to have several gain ranges since the dynamic range of acoustic signals is so wide If the meter has an automatic circuit to change the gain this should be disabled High amplitude transients can be lost if the meter is trying to change gain ranges during measurement pcRTA User Manual 293 11 Car Audio Applications With all of these variables it is important to have the correct settings on your meter if you want accurate SPL readings Here are the settings most commonly used at competitions where pcRTA is the meter Noise Signal Generator Detector Type of Data Automatic On Off Peak dBm SPL Pink Noise M Fast Dynamic Range dB spl Slow Auto 33 to 173 Gen Output Level Legis o dBm Vims Full Band Fixed 93 to 173 Fixed 73 to 153 Fixed 53 to 133 Fixed 33 to 113 Testing Mode Continuous Peak Hold Cycle Limit 5 Input Source Flat Mic Input 1 ANSI MultiMic Select P Enable RTA Bands v Enable Mio Flat _ Enable Mioi ANSI _ Enable Mic hund Ave Multiplex ANSI Filter Measurement Data Absolute Relative 1 Pink Noise 0 1s E m Nonnabized N Cancel Control Panel Parameters Parameter Value Parameter V
247. play 3iband PORTA 1 00 EXAMPLE Aug 29 1994 Curve Legend Notes and Comments 4 250Hz square wave 1 sec pcRTA Amplitude dB EXAMPLE1 DB File Edit Processing Utilities View Help GenLevek 69 6 FullBand ANSFB RTABands AHSEFB itSrc Mic 2 AvrgTime 1 0 Sec Display 31band pcRTA User Manual 6 Processing Menu 6 3 Multiply Curves This operation will produce new curve by multiplying one curve by another curve Multiplying two curves is equivalent to adding their magnitudes in dB The curves may be either dB or linear units The software will automatically take care of the necessary conversions internally This can be a very useful operation for a variety of applications such as combining two response curves into one Also EQ or weighting functions can be multiplied into another curve The dialog box for this processing operation is shown below Three list boxes are shown for the selection of the two operand entries and the location of the result You can set the name for the result curve before or after this operation in the usual manner using the Curve Library edit dialog box To multiply curves select the operand A and B curve entries in the two top list boxes Next select the result curve entry and press OK If you wish to exit without performing the operation press CANCEL Whether or not the data is actually dB or linear units is un
248. play Set 70 4 7 Save Control Panel Set 71 4 8 Load Control Panel Set 72 4 9 PUMA ierit erii a Baci ent De ease unda 73 aMi eoe neo e taies S 76 pcRTA User Manual Table of Contents Chapter 5 Edit Menu 77 5 1 R N SIOP TeSt reion nie ea 79 5 2 Gen M 80 5 3 Curve oe a a dE EDAD dud 81 5 4 Control Panel Amplitude sisino 87 5 5 Control Panel Impedance sse 97 5 6 Control Panel Reverb Time 101 5 7 Control Panel Noise Analysis 105 5 8 Graph Setup Amplitude 111 5 9 Graph Setup Impedance 117 5 10 Graph Setup Reverb Time 119 5 11 Graph Setup Noise Analysis 123 5 12 Notes Comments enti ridi 129 5 13 Microphone Setup 131 5 14 MDF Convert dote EUER ee ede 137 5 15 Global Graph Design 139 5 16 SyStem OPIIONS iie rr E resi 145 Chapter 6 Processing Menu 147 6 1 Scale 149 6 2 Invert iaaa orte aa 151 6 3 Multiply Curves 153 6 4 Divide CUES es epo a 155 6 5 AU S 157 6 6 Subtract Curves i edt AE ct Pad eee 159 6 7 Curve Averaging 161 6 8 Curve SUmmallOni ss wichita ied aie Nadine
249. plications 10 4 A Chain Alignment The A chain is the source side of the system The audio signal that is recorded in the dubbing studio is first reproduced thru the A chain It may consist of an optical preamplifier using a soundtrack recorded on the film or it may be a magnetic preamplifier playing a tape that syncs to the film Alignment of the A chain normally involves the use of an oscilloscope and a real time analyzer This procedure shows the use of the pcRTA to measure the frequency response of the optical preamplifier during the adjustment process There is a description in the notes portion of this section of an alternative method for measuring azimuth adjustment that eliminates the need for an oscilloscope pcRTA User Manual 245 10 Cinema Applications STEP 1 Open new AMPLITUDE MODE curve library Go to the File menu and choose New then choose Amplitude The program creates a new amplitude library with the name Untitled db Edit Processing Utilities View Wind Amplitude New Open Impedance To give it a different name go to the File menu R Reverberation Save 75 Note AS and choose SaveAs SaveAs Save Graph Display Set Em Load Graph Display Set Save Control Panel Set Load Control Panel Set Print P Exit Q pcRTA Amplitud Edit Processing Utilities View Wind Save Graph Display Set Load Graph Display Set
250. plitude dB EXAMPLE1_DB Line Graph i File 19 Processing Utilities View Window Help Run Stop Test Del FullF Gen On Off Ins Curve Library F2 Control Panel Graph Setup F4 Notes Comments Microphone Setup System Options F10 Graph Design F9 Convert Installing the Files Chapter 10 Cinema Applications You may have already completed this procedure when installing the If so you can skip this step However before measuring you should verify that the MDF s for each input match the microphones connected to that input Failure to do so can result in significant errors in the measured data Mic Input 2 box Mic Input 3 Mic Input 4 Line Input The Load Mic Data dialog box will appear This dialog box allows you to browse for MDF files When you have selected a file click OK Load Mic Data File MDF x File Name Directories sn201181 mdf Aes sn201182 mdf 3 perta sn201183 mdf ea db 3201184 mdf a LL export na LJ rt List Files of Type Drives MicDataFiles mdf x c new c X pcRTA User Manual Microphone Input 1 5 Edit Clear j mind Seil dem Response Errors dB Full Hz 0 00 a Go to the Edit menu and choose Microphone Setup then choose Mic Input 1 The Microphone Setup dialog box opens which show
251. quencies pcRTA Amplitude dB NOISE DB Line Graph File Edit Processing Utilities View Window Help FullRng 108 248 qi pese Sound Pressure Level The time out determines how long the pcRTA will continue before it cuts off the measurement In the RT60 mode for example when the stimulus signal stops the pcRTA measures the decaying signal at each frequency until it drops by 60dB When the time out is reached the measurement stops Any bands which did not drop by 60dB will display the time out value on the RT graph If the stimulus signal was not 60dB above the noise floor at any given band that band will never fall below the RT limit and it will time out If you observe bands timing out even though the dynamic range is sufficient increase the time out value pcRTA User Manual Car Audio Applications Low Frequency Pressurization 15 15 12 9 9 6 6 3 3 o ok 100 200 500 1k 5k 10k En Sound Pressure Level IASCA Scoring Documentation Testing Controls v Print Each Graph Lib Name IASCA001 PSE Test Number LibCurve 1 L 2 Event Tite EET
252. r Other selection you may enter your own customer threshold and Q halving factor values The data generated in the last column ofthe chart will follow the criteria selected here Band Display Band Display v Ful v 630 Each of the 32 check boxes in the upper array of the group box enable or m disable the display of individual bands The two buttons All On and All Off 20 800 can be used to change all the bands status at one time The last check box 25 1000 allows the use of curve entry color coding off or rainbow color coding via 1250 on forthe bands When off the color used for all bands will be that of the 40 v 1600 assigned global curve entry color When on the band colors of any m displayed curve entries will all have the same rainbow color sweep v 50 v 2000 63 v 2500 v 80 3150 v 100 4000 1125 5000 v 160 6300 200 8000 250 v 10k 315 1205 v 400 16k yi 500 20k On All Off Rainbow Colors i 128 pcRTA User Manual 5 Edit Menu 5 12 Notes Comments The Notes and Comments menu option will open a dialog box which allows you to enter notes and comments to be included on the graphs There are eight comment lines provided which will appear on each graph The user can use these comment lines to include additional information about the measure ments or any other additional information desired The notes are saved in eac
253. r or at different positions in an environment When averaging the curves equal weighting is applied to each curve and a true RMS method is used The large list box shown below provides for multiple selection of curves in the library Click your mouse on a curve name to toggle its selection as a curve to be averaged The smaller list box is used to select the location for the result EE EE SES the same as one ofthe data Library Untitled db curves used to construct the average However the origi Select Curves to Average nal data will be overwritten 1 CurveN ame 1 when the operation is com 2 CurveName 2 pleted 3 CurveName 3 4 CurveName 4 amp lumvnName 5 An example of this opera CurveName tion is shown in the graphs 7 CurveName 7 on the following page Library Curve Entry for Result 20 CurveName20 pcRTA User Manual 161 6 Processing Menu Original Curves A B 162 Averaged Result pcRTA Amplitude dB TEST3 DB File Edit Processing Utilities View Help Curve Legend System Notes anc Comments 1 lam car number 1 DataType dBspl 2 This is another test GenNoise Pink GenLevek 395 FullBand Flat RTABands ANSKE InputSrc Lineln AyrgTime 1 0 Sec Display 31band TEST3 DB rg 90 1994 pcRTA Amplitude dB TEST3 DB File Edit Processing Utilities View Help Hr 9 100 5 Average of 18 2 KT
254. r 3 Tutorial 56 pcRTA User Manual Chapter 3 Tutorial 3 4 Example 3 Measuring Impedance This example will demonstrate how to use the pcRTA to measure impedance The pcRTA has a special mode for this and provides all of the necessary calculations internally to produce a final result curve in Ohms The generator output impedance is 500 Ohms Since the impedance range of devices such as loudspeakers is generally much lower a voltage divider is formed with the 500 ohm output impedance and the device The software measures the resulting voltage and solves the divider for the load impedance Since an RTA has only 31 bands the resolution of the impedance curve is limited to 31 points Moreover the test signal is noise averaged in 1 3 octave bands This is not enough resolution for producing speaker parameters which require extremely high detail and accuracy A swept sine wave analyzer such as LMS is ideal for this purpose However even the ability to measure rough impedance curves can be very useful if no other means is available This enables transducers or passive crossovers to be checked for shorts opens or other major defects very quickly These problems may show up under AC testing but may not be visible under DC testing with a simple DMM 2 Wire and 4 Wire Methods The basic idea of measuring impedance is to send the generator signal out to the device and measure the voltage at the device This can be done using a 2 wire m
255. r checked or unchecked as re Cr We of Car Auc Level Setting Test Event Tle re e 22028 quired before the scoring session be Contestant car number 1 RTA Response Test N Produce USAC Score Mic 2 3 Mic 4 Lingin Note that a special text box is pro Restart Sequence N vided below the contestant name field where instructions will appear Note If your printer driver has spooling enabled DO NOT start another test until the previous score has been completely printed The print spooler consumes much of the CPU time and this will cause errors in the time dependent testing algorithms Disabling print spooling is another means to eliminate this potential problem Parameters to Set before Testing Begins The microphone input source to be used during the testing is set in the control panel prior to the start of the scoring session Also the file for the microphone to be used must be already loaded into the system prior to testing to provide accurate SPL calibration During the testing you can select different input sources which allow for multiple testing stations to be utilized If you will be using the pcRTA internal Pink Noise Generator than you may also wish to set the generator level to an appropriate value However typical USAC testing generally uses a CD with Pink Noise as the source for the car stereo system Most of the other control panel parame
256. r j 2 2 NP Sa 5 55 Sie Curve Library E Scale 315 NE N S 28 za S 2 Auto Scale Button 250 General procedure for A chain Alignment The mechanical and optical checks of the A chain should be completed before this procedure is started Consult the manufacturer s documenta tion Load the pink noise film loop Connect the oscilloscope s X input to the left channel of the cinema processor and it s Y input to the right channel of the cinema processor Connect the Line In of the pcRTA to the left channel Press the Run Test button on the Tool Bar to view the signal on the pcRTA If you do not see the changing data you may need to press the Auto Scale button on the Tool Bar Adjust the azimuth of the projector optics for the narrowest diagonal trace on the oscilloscope Adjust the focus for the best high frequency response on the pcRTA The azimuth and focus adjustments are interdependent and you must alternate between these measurements until the best results are achieved When the azimuth and focus adjustments are complete adjust the high frequency slit loss equalizer for optimal flat response as viewed on the pcRTA Connect the pcRTA to the right channel and repeat the adjustments pcRTA User Manual Notes for A chain Alignment Here are the Control Panel settings saved in the Control Panel Set file CINE_ACH CPS A
257. r the next contestant enter in the new contestant name and repeat the process m pcRTA Amplitude dB 4 Text Chart File Edit Processing Utilities View Window Help dBsp FullHz 138 6 s 1 Max Volume 9 FE Ld Scale Auto P o a Down Zoom In Zoom Out VE Full GenLevel 0 0 GenNoise Pink FullBand Surn RTABands Flat Cursor 188 pcRTA User Manual Chapter 7 Utilities Menu 7 8 Drag Racing Scoring This utility provides a special routine for driving a dual column tree light display This routine assumes that there is an additional interface card installed in the same computer which contains an array of register latches located at two different I O port base addresses The user can enter the location of the two base address locations in the dialog box The routine is capable of handling any number of light segments from 8 to 128 Each bit represents one light the LSB corresponds to the lowest light and the MSB the top light The number of consecutive I O ports present at each base address is the number of bits divided by 8 The interface card outputs can then be used to control a bank of solid state relays or similar devices which are used to drive the tree lights This routine uses two mic channels 1 amp 2 each representing one contestant The run time of the contest can be specified for a
258. ral System Features Curve Library EXAMPLE1 DB Library Name 28 The group box displays the current name of the library being edited This is the current library in memory Pink Noise 10 sec ave White Noise 10 sec ave 250Hz square wave 1 sec 1 amp 3 Multiplied 1 amp 3 Divided Graphing Status This box will display the word Graph if the currently selected highlighted curve entry is selected for graph display This status box reflects the setting of the square markers Data Curve Status This box will display the word Data if the currently selected highlighted curve entry is selected as the data curve entry This status box reflects the setting of the circle markers There can only be one entry selected as the data curve This is where the data from the next measurement will be placed Name Editing Box This box is used to edit enter the name for a curve entry Whenever a curve entry in the list box is highlighted focused the name is automatically copied to the name editing box If you wish to edit the name simply click your mouse in this box and begin editing To save your changes simply click the mouse back into the main list box and the text from the editing box will be copied to the list box This function can also be initiated by pressing the N key while a curve entry name is highlighted focused Curve List Box The large list box displays the curve entry names within the library All library
259. rameters of the control panel Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Click OK to close the dialog box Print P Exit Q Load Control Panel Set File ETF Directories EE c perta cine ach cps mikel cps setupl cps List Files of Type Control Panel Set Files cps 248 pcRTA User Manual 10 Cinema Applications The Line Graph should look like the one shown here There is a data curve on this graph showing the ideal response of the optical preamp before adding the slit loss high frequency EQ pcRTA Amplitude dB CINE ACH DB Line Graph File Edit Processing Utilities View Window Help FullAng 6008 49 082 Sound Pressure Level 16 Optical Preamp Ideal Responde Input Linein Range Auto DataType SPL Abs AveTime 1 0 Sec GenLevel 0 0 GenNoise Pink FullBand ANSI C ATABands Flat pcRTA 1 95 CINE ACH DB il May 30 1906 Thr 3 52 pm Cursor You are now ready to start measuring the frequency response of the optical and or magnetic preamplifier s pcRTA User Manual 249 10 Cinema Applications Run Test Button lee
260. raster images you must choose a DPI dots per inch value which will determine the resolution With raster images it is very easy to produce extremely large files Be careful to note the Image Size parameter value given on the last line of the group box list If you attempt to construct an image size that is larger than your available resources permit you will receive an error message or your system may lock up Vector Images Vector images are mathematic formula representations of the artwork They contain coordinates and special commands unique to each format They can be both color or black amp white The resolution of the image is virtually infinite and will print with the full resolution of the final printing device While vector images are probably a less portable form of graphic representation they are extremely efficient and provide the highest quality resolution The following industry standard vector formats are supported WMF Windows Metafile Standard WMF Windows Metafile Placeable AI Adobe Illustrator v3 0 EPS EncapPostScript B amp W amp TIF EPS EncapPostScript CMYK amp TIF pcRTA User Manual 173 Chapter 7 Utilities Menu PRE x When Raster Image is selected the reso lution color and compression dialog Raster Image Graph to Export controls will be active When Vector Vector mage Amplitude dB Graph Image is selected the only active con trol will be the Graphics File Format list Graphics File Form
261. re that must be taken into account when setting up for measurements This has led to the development of what we call settings files These are files that remember the control panel settings and the graph display settings that were in use for a particular test Several of these files are provided with the software as templates to allow for quick setups when taking measurements This chapter will make extensive use of these settings files After the files have been loaded you can make changes to the control panel and graph display parameters and then simply save new files so that you can always recall the exact settings used for any given test Itis recommended that you keep copies of the default files pcRTA User Manual 233 10 Cinema Applications 234 pcRTA User Manual 10 Cinema Applications 10 2 General Setup The figure below is the opening screen of the pcRTA This is what you will see when you first open the program There are some things you can do now to clarify the information shown on the screen T pcRTA Amplitude dB EXAMPLE1 DB etx File Edit Processing Utilities View Window Help 71 Text Chart 15 2 Line Graph ol M Bar Graph Sound Pressure Level CT Curve Box LIN B E B l E n E EXAMPLE1 DB 5 Graph 250Hz square wave 1 sec 1 D Pink Noise D sec ave 2 Pink Noise 10 sec ave
262. ries gt Go to the Edit menu and choose Curve Library Library Untitled db Graph Data CurveName 1 Copy Curve cms cuve CurveName 2 Move Curve CurveName 3 CurveName 4 Delete Curve CurveName 5 CurveName amp Delete All CurveName 7 CurveName 8 Edit Data CurveName 3 CurveName10 Show Info CurveName11 A dialog box as shown here will be displayed which lists the names of the curve entries in the library When you select File New the library is initialized with simple names such as CurveName 1 etc These are really only temporary names until you set your own names for the curves At the left of each entry name is a square and a circle marker Note that only the first entry has these markers filled in The square marker indicates whether or not the curve entry is selected for display on the graph Any number of curves can be selected for graph display at the same time so more than one square may be marked The circle indicates which one of the twenty entries is marked to receive the next measurement data There can only be one data curve marked If another circle is marked the first one will be automatically turned off In this case entry number 1 is the data curve The next measurement will place data into curve number 1 This entry is also marked for display on the graph as well The list can be scrolled up and down using the scroll bar on the right To change th
263. ring Testing Controls Documentation Punt Each Graph Lib Name DUTLAWOT Test Number Lib Curve mw Event Title western Bass Olympics SPI Max Test Contestant Volume s f Produce SPL Score 2 3 Mic 4 imetin Restart Sequence Stop Testing Exit Help pcRTA User Manual Chapter 7 Utilities Menu Starting a Session To begin a scoring session press the Start Testing button and then enter the event name The first step in each of the scoring cycles is to enter the contestant name The Test ing Controls group box provides 2 buttons for conducting various tests involved with the scoring cycle Each can be operated individually or repeated as necessary They are generally executed in order from top to bottom for each contestant There is also an edit box which allows you to enter the test time in seconds The first test is for maximum SPL Press the SPL Max Test button and the analyzer will measure the maximum SPL over the time period with peak hold When using an M51 mic the maximum SPL level which can be measured is 150dB and when using the M52 mic the maximum SPL is 170dB After the test is finished you can repeat it if you need to 187 Chapter 7 Utilities Menu When completed press the Produce SPL Score button and the data will be written to the note fields in the screen and printed if you have selected that option as well Fo
264. rint this configuration will be used To change the configuration use the Setup button at the bottom of the dialog box Print Selection x Printing Options Printer Configuration Align in center of page Printer Name Canon BJC 4000 New Align at corner of page Printer Port LPT1 Scale factor 100 00 Orientation Portrait Bar Width Factor 0 900 Paper Size Letter 8 5 x 11 In __ Print Colors as Black White Device Drv CBJ95 pcRTA User Manual 73 4 File Menu Print Selection Ea Printing Options Align in center of page Printer Name Canon BJC 4000 New Align at corner of page Printer Port LPT1 Scale factor 2 100 00 rientation Portrait Bar Width Factor 0 900 Paper Size Letter 8 5 x 11 In Print Colors as Black White Device Drv CBJ95 Printer Configuration 74 Printing Options This group box provides several options which control how the graphics are printed on the page They are largely self explanatory Align in Center of Page This positions the artwork in the center of the available printing area The printing area is dependent on the page size selected for the printer Align at Corner of Page This positions the artwork at a corner of the available printing area The printing area is dependent on the page size selected for the printer and the specific corner will vary depending on whether landscape or portrait orientation is in
265. roduce Score Mic 2 Mic 3 Mic 4 Linein Restart Sequence Le Help Note that a special text box is provided below the contestant name field where instructions will appear Start Testing Note If your printer driver has spooling enabled DO NOT start another test until the previous score has been completely printed The print spooler consumes much of the CPU time and this will cause errors in the time dependent testing algorithms Disabling print spooling is another means to eliminate this potential problem Parameters to Set before Testing Begins The microphone input source to be used during the testing is set in the control panel prior to the start of the scoring session Also the MDF file for the microphone to be used must be already loaded into the system prior to testing to provide accurate SPL calibration During the testing you can select different input sources which allow for multiple testing stations to be utilized If you will be using the pcRTA internal Pink Noise Generator than you may also wish to set the generator level to an appropriate value However typical testing generally uses a CD with Pink Noise as the source for the car stereo system Most of the other control panel parameters will be automatically set by the scoring utility The scoring system uses the Bar Graph display mode You do have the option to select the dB value per division and the number of major and m
266. rogram Several examples are provided each selected to illustrate a different type of measurement These examples should provide a basic operational understanding of how to use the program to take basic measurements Note Some of the examples will require other external equipment and or environments that you may or may not have at your disposal If you do not have the necessary facilities for a specific example please skip the example There are many other additional features in the program that cannot be covered here in detail However the descriptions of these features are covered under their own specific chapters The various examples will take you through the essential features and explain the overall structure of the program Please take the time to work through at least the first example These actually require very little time and will answer many of your questions The following examples are provided E Example 1 Measuring the Generator Response M Example 2 Measuring SPL Response Bl Example 3 Measuring Impedance Read Chapter 1 If you have not already read chapter 1 and fully installed the system you must complete this first before starting the tutorial You will need to have the system calibrated and the MDF files setup for your microphone Read Chapter 2 If you have not already read chapter 2 it is recommended that you first go through that chapter before starting the tutorial Many of the key aspects of the overall
267. rt and stop If the Tool Boxis displayed the Run Test button will change to Stop Test after it has been pressed This button functions as a push on push off and toggles between these two states When it is pushed in the analyzer is conducting a measurement and placing the data into the currently selected curve entry marked for data When the button is out the measurement has stopped There are also two other means provided to activate this button 1 the DELETE key on the keyboard and 2 the RightMouse button Fither of these controls can be used to toggle the state of the Run Stop Test button Using the RightMouse button is very convenient for remote control purposes pcRTA User Manual 79 5 Edit Menu 5 2 Gen On Off 80 Choosing this menu option will turn on the generator output This menu selection toggles the generator output On and Off If the Tool Box is displayed the Gen On button will change to Gen Off after it has been pressed This button functions as a push on push off and toggles between these two states Whenitis pushedin the generatoris producing an output signal at the Line Output When the button is out the generator output is turned off The INSERT key on the keyboard can also be used to control this button pcRTA User Manual Data Curve Indicators Chapter 5 Edit Menu 5 3 Curve Library The Curve Library menu option will open a dialog box which controls the selection of curves for di
268. run occurs With the older 16450 UART the CPU must keep up with the serial port data speed or an overrun error will occur almost immedi ately Whether or not an overrun error occurs depends on a lot of different factors One of the primary factors is your computer s CPU speed A computer with a 386 CPU will overrun much easier than a 486 or a Pentium Also the speed of other elements in your system such as the video card can also play a major roll in how much time your N A CPU must spend on other duties Be aware of these factors and if you wish to check which kind of UART is installed in your serial port the PAC interface dialog will display them when you first open it pcRTA User Manual 209 Chapter 7 Utilities Menu Display Properties Window s Multi Tasking and Screen Saver Issues There are many tasks which the Windows system is expected to carry out in a more or less simultaneous fashion As well there can be multiple applications open at one time in the system All of these factors affect the amount oftime Windows can spend servicing any 215 application If you are running a measure Background Screen Saver Appearance McAfee ScreenScan Settings mentin the pcRTA minimize it and open another application the CPU may not be able to handle all of the tasks fast enough and an overrun will occur Another consideration is screen savers If you are running a long term or continuous measurement suc
269. rve to hold the imported data is selected in the list box File Data Frequency Range The frequency range and number of data points is controlled by the program and not by the file data itself The import system has extensive frequency interpolation and extrapolation processing and will translate the data file frequency points into the frequency data points required by the pcRTA system The system only retains 31 data points between 20Hz and 20kHz ASCII Data Import When you have made your choice for the curve entry to hold the data press Ok Another dialog box will open for choosing the data file to be B imported The default path is PCRTA EXPORT but you may choose another as needed Library Curve Entry to place Imported Data Select Library Entry 5 1 amp 3 Multiplied Reverberation Data Noise Analysis Data intervale Revesh Time Amplitude vs Time Time Import Data File x File Name Directories amptime dat class dat t class2 dat a m db dat export na 1 na 2 dat na 3 dat na 4 dat List Files of Type Drives Import Files dat x c new c pcRTA User Manual 169 Chapter 7 Utilities Menu Importing Data File Name DB DAT Line Number 30 ASCII Line Data Importing the File When the import process begins a dialog box as shown here will appear This dialog box displays
270. ry in the list box has a small square shown at the beginning of the line This square indicates whether or not the curve is selected for display on the graph Curve Library Editing x Library Untitled db CurveName 1 Copy Curve CurveName 2 CurveName 3 CurveName 4 CurveName 5 CurveName 6 CurveName 7 CurveName 8 CurveName 9 CurveName10 CurveNamel1 Move Curve When the curve is selected for display the square will be filled in with the assigned color for the curve The curve line color is set in the Graph Display dialog box Delete All Edit Data Show Info The square markers also function as selec tion buttons When the mouse is moved over a square and clicked the indicator will change state The square graphing indicators can also be controlled by using the G key on the keyboard Pressing the G key will change the state of the graph indicator on the currently selected entry Data Curve Indicators Circle Markers Each curve entry in the list box has a small circle shown at the beginning of the line This circle indicates whether or not the curve is currently selected as the data curve Only one curve can be the data curve When one circle is clicked ON the previous circle will be turned OFF When the curve is selected for data the circle will be filled in with the assigned color for the curve The curve line color is set in
271. s Print Each Graph Lib Name 1 5 001 z Level Setting Test Test Number 1 Lib Curve 1 PL Max Test button Contestant SPL Max Test RTA Score 37 1 Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln i Restart Sequence Stop Testing 328 pcRTA User Manual 11 Car Audio Applications The competitor now has 10 seconds to achieve the highest reading that they can The pcRTA will capture the loudest signal and continue to hold that level until a louder level is measured or 10 seconds elapses The SPL score appears in the text box below the Contestant field If desired the test can be run again by pressing the SPL Max Test button again After the 10 second SPL Max test press the button labeled Produce IASCA Score IASCA Scoring Documentation Testing Controls v Print Each Graph Lib Name 1 eene Test Number Lib Curve Event Tile button Contestant SPL Test SPL Score 0 f z Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln Restart Sequence Stop Testing This button will cause the pcRTA to score the RTA curve SQ value and place the score in memory This is the last step in the procedure To score the next competitor follow the procedure again starting from page 38 If you need to print someone s score after the car has left the lane follow the procedure on the next page
272. s the current parameters assigned to mic input 1 The parameters at this time will be blank or zero Press the Load MDF File button in the Microphone Setup dialog Microphone Setup x NOTE If you do not see any files with the MDF extension in the pcrta directory you should copy them from the 3 5 floppy disks provided with the mics into the pcrta directory on the hard drive using Windows File Manager or an equivalent program before proceeding 243 10 Cinema Applications The system will then read the file and derive the necessary parameters When completed the setup parameter fields will be filled in as shown in the dialog box below Microphone Setup x Microphone Input 1 Edit Clear Response Errors dB Author Date Model M53 dBspl Serial dBm Close the Microphone Setup dialog box by pressing OK If you use Cancel to close this box the MDF information will be discarded and you will have to load it again Repeat the above process for the other inputs Since each input is configured for a specific mic you will need to keep track of which mics have been setup for which inputs If you ever forget which mics are setup for which inputs just check the Microphone Setup dialog box for each input The parameter fields include a serial number that shows what MDF file was loaded for that input 244 pcRTA User Manual 10 Cinema Ap
273. s the level of the fundamental 250Hz pure frequency component The higher bands show the levels of the various harmonics of the square wave Square waves have odd harmonics so the largest harmonic amplitude occurs at 750Hz as indicated by the level of the 800Hz band The square wave oscillator is mainly used by the analyzer for self calibration But it is also very useful output when a nonrandom signal is desired Many applications require a test tone for level alignment or setup M pcRTA Amplitude dB EXAMPLE2 DB Bar Graph BEE fii File Edit Processing Utilities View Window Help lal Amplitude Response 0 Curve Library 4 Conn LI EB e o aio Zoom Full Rdrw SEO Sem vi Cursor ols pcRTA User Manual 49 Chapter 3 Tutorial For the last part of this example we will now save the library This can be done using the menu File SaveAs or by using the accelerator key CTRL S S Select File from the menu and then SaveAs A dialog box will appear to set the name For this example library enter the name EXAMPLE1 DB If you do not add the extension the program will automatically append the extension of DB Anytime you wish to save your changes in a library to disk it is very quick to use the S accelerator key It is always a good idea to periodically save any new changes to a library on a regular basis in case your s
274. sing the Line Input of the pcRTA to perform A chain measurements You may also need the Line Output to inject pink noise into the processor for B chain measurements These are unbalanced connections and shielded cable must be used to connect to them The pcRTA 100 ft snake was developed specifically for cinema installers It provides a means to bring the signals of four discrete microphones from the floor of the house up to the projection booth through a single cable If you have the pcRTA Snake as shown in the figure below you will use the black RCA plug to connect to the Line Input of the pcRTA and the red RCA plug to connect to the Line Output of the pcRTA Red RCA Plug LINE OUT DB15F To pcRTA Black RCA Plug LINE IN Mic Inputs 1 4 pcRTA 100ft Snake pcRTA User Manual 237 10 Cinema Applications If you do not have the pcRTA 100ft Snake you will use the pcRTA connector box as shown in the figure below To connect to the Line Input and Line Output on this box you will need 1 4 inch Phone plugs Line In connector pcRTA Connector Box MICROPHONE INPUTS DB15F DB15M To pcRTA Line Out connector Center Conductor 1 4 INCH PLUG N 0 o lt I Shield 238 pcRTA User Manual 10 Cinema Applications 10 3 Microphones The microphones that are designed to function with pcRTA are all calibrated to
275. splay on the graphs as well as the data entry selection and editing of curve entry names Additional commands are also provided for moving copying and deleting entries within the current library This menu option can also be activated from the tool bar and the DoubleClick zone in the graph area under Curve Legend The example below shows the various elements of the Curve Library dialog box Each of the key features are detailed Library Name Graphing Status Data Curve Status Name Editing Box Lx Curve Library Editing Library Untitled db Curve 1 Aer NAN RUN RUNE 2 CurveName 2 Move Curve 0 CurveName 3 4 O CurveName 4 Delete Curve 5 Q CurveName 5 amp Q CurveName 6 Delete All 7 CurveName 7 CurveName 8 Edit Data 9 CurveName 9 10 0 CurveName10 Show Info x Namel1 Function Buttons LT LR ER Ok Help Curve List Box pcRTA User Manual 81 5 Edit Menu Library Name Library Untitled db The group box displays the current name of the library being edited This is the RER i current library in memory CurveName 2 RS PP Graphing Status Delete Curve EU enemy This box will display the word Graph if the CurveName 6 Delete All CurveName 7 currently selected highlighted curve en CurveName 8 H Edit Data a try is selected for graph display This
276. st Limit RT20 This group box handles the reverb time limits The first three radio buttons provide selection for either RT20 40 or RT60 These reflect the decay RT40 threshold drop in dB In some instances background noise levels in a room may RT60 be too high to permit RT60 measurements TimeOut For example assume that the background noise level in a room is 70dBspl In order to take an RT60 measurement the stimulus test level would need to be at least 60 dB higher or 130dBspl This is a very high SPL level which may be beyond the power capability of the audio speaker system to produce In these cases using a lower threshold such as RT40 or RT20 may be much more practical These would require a lower stimulus level and the results can be scaled accordingly to produce an estimate of the true RT60 value The Time Out parameter controls how long the system will wait for the measurement level to decay to the RT threshold If the SPL level never reaches the RT limit after this amount of time the measurement is concluded and the resulting RT will be this timeout value Testing Mode Testing Mode re There are two basic types of testing modes which can be selected when taking measurements Continuous and Cycle Limit The edit box below is used to Bem 3 enter the number of measurement cycles to execute when the Cycle Limit mode is chosen Continuous means that the measurements will continue as long as the Run Test button in the To
277. st levels ever experienced SPL This section provides details to help the SPL competitor get the most accurate readings possible All sound level meters have the same goal but get there in different ways There are many variables involved in SPL measurements that can cause various meters to read differently Here we will discuss the most important variables and show how to setup the pcRTA for these measurements Microphones The measurement microphone is argueably the most important variable in the measurement chain The mic translates the acoustic level in the vehicle into an electrical voltage that the meter can read If the mic cannot provide a linear change in voltage as the SPL increases the meter will display a level that is not accurate There are two properties that the mic must have to produce the correct output voltage for a given SPL The firstis the excursion capability of the diaphragm The diaphragm is a stretched material that vibrates with the acoustic pressure in the environment Excursion is the movement of the diaphragm If the acoustic pressure causes the diaphragm to move far enough it can bottom out where further movement is not possible with increased SPL The second property is the maximum voltage swing of the mic preamp As the voltage from the capsule increases the preamp can become overloaded and start clipping or flattening the top and bottom of the waveform resulting in non linear increases of the preamp s outp
278. stimulus time an RT test limit and a time out measurement cutoff time The stimulus time should be long enough to fully excite the reverberant modes of the room 5 seconds is a good starting point for this parameter The RT test limit should be set according to the dynamic range available This can be thought of as the signal to noise ratio of the room The maximum output of the system divided by the noise floor will give the maximum RT limit that can be measured pcRTA Amplitude dB Line Graph File Edit Processing Utilities View Window Help CBS ES TER e E E en en ia ER NAM Sound Pressure Level dBspl dBspl io E The graph above shows a noise floor curve that was scaled up by 20dB 40dB and 60dB This gives a graphic indication of the required output level from the system to perform RT testing to each of the limits RT60 0 RT20 pcRTA User Manual 283 10 Cinema Applications 284 Maximum System Output Signal to Noise Ratio Noise Floor Notes for Reverb Time Measurement continued The next graph shows a system s maximum output the noise floor and the ratio of the two From this you can directly read the maxmium RT limit as being RT40 since the signal to noise curve is above 40dB at all fre
279. t channels Itis best to keep the bands of the equalizer as close to OdB as possible and not to have any drastic changes between one band and the next If your system requires drastic equalization chances are that something in the system needs to be reworked Check for major problems in the installation The one exception to this is in the frequencies from 50Hz to 200Hz Because of standing waves you may see dramatic peaks and or dips in the response at these frequencies For the most accuracy possible you should use spatial averaging to tune the system The next section discusses this technique pcRTA User Manual 307 11 Car Audio Applications 11 8 Spatial Averaging What is Spatial Averaging When measuring acoustic environments a single microphone will read the sound pressure at only one tiny point in space Errors in measurement occur because of standing waves and combing which create peaks and dips in the response curve that vary with different mic positions Spatial Averaging is a method of reducing the error due to this effect This technique is quite simple Take measurements at several points in space with the same stimulus and average the measurements The pcRTA has the built in capability to do spatial averaging in real time You must have at least two microphones to take advantage of this feature however If you have only one microphone you can manually perform spatial averaging but it is more time
280. t no damage comes to your analyzer is to observe a couple of precautions First handle the card by the edges avoiding contact with the gold finger tab area Secondly make sure to ground yourselfto discharge any static voltage retained in your body This can be done by touching any large metal surface such as the chassis of your computer just prior to removing the card from the anti static bag Selecting the 1 0 Port Address The pcRTA has two jumpers located above the tab area near the bottom of the PC board These jumpers control the selection of the port address used by the analyzer software There are four possible address selections 21E 25E 31E and 35E Note The analyzer does not use any interrupts or channels Typically you can use the default selection of 21E without difficulty and no changes are necessary to the jumpers However if you have a conflict with another card in your system at this address the jumpers can be changed as needed A port map is shown on the following page for the PC I O architecture
281. tch the type of library data required The Open option has four sub menus for the library type Amplitude Impedance ReverbTime and Noise Analysis The type of data to be measured is solely defined by the type of library being opened Library files by default are located in one of the four data subdirectories DB Z RT or NA depending on the library type However you can save and load files from other paths if desired Im pcRTA Amplitude dB Bar Gra Edit Processing Utilities View Window Help New gt 4 Save 75 Impedance Reverberation Saveds Noise Analysis Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Print P Exit Q 10 66 Open Amplitude dB File Ea File Name Directories examplel db ic perta db examplel db P Cy c example2 db iascaD01 db irs iasca002 db perryad db scoring db skyskan db test1 db E List Files of Type Drives Amplitude Files db c new c pcRTA User Manual Chapter 4 File Menu 4 3 Save File The Save File menu option saves the current library data in memory to the file name and path currently assigned If the current name is Untitled then you will be prompted to enter a real file name for the design pcRTA library files have the extension DB Z RT or NA to indicate the type of data library
282. te can be set to several different speeds Right Mouse Button Analyzer Control When this box is checked the right mouse button can be used to toggle the Run Test function On Off If the box is unchecked then the right mouse button is not used by the program This permits use by other Windows system functions pcRTA User Manual 145 5 Edit Menu 146 pcRTA User Manual Pees Sine Menu Chapter Scale Invert Multiply Divide Addition Subtract Averaging Summation pcRTA User Manual 6 Processing Menu 148 pcRTA User Manual 6 Processing Menu 6 1 Scale Curve It is very common to run into situations where scaling a curve up or down in magnitude is necessary This can be useful for correcting curves from other imported data or conversion shifts between different measurements The dialog box for this processing operation is shown below Two selections are provided for the scaling factor dB ratio or linear ratio Fither of these two scaling factors can be used regardless of the type of curve data The curve entry to be scaled is selected in the list box To scale a curve select the curve to be scaled in the list box Next check the type of scaling factor you wish to use Last enter the appropriate scaling value and then press OK If you wish to exit without scaling press CANCEL If your units are dB a positive value like 20dB will move the curve up while
283. tents menu option will open the pcRTA Help system and display a large window with the table of contents for the help file The underlined list of topics can be jumped to directly simply by clicking on the desired item The other Windows help system general commands can also be used to aid you in your use of help including Search Back and History pcRTA Help IDE File Edi Bookmark Options Help covert Seach 7 Pin 1111 PCRTA Table of Contents The following is a list of topic categories which provide additional sub menus to select the particular topic you wish to obtain help on Topic Categories Installation General Program Features Tutorial File Menu Edit Menu Processing Menu Utilities Menu View Menu Help Menu Appendix pcRTA User Manual 227 9 228 9 2 Search The Search menu option will open the pcRTA Help system and display a large window with an edit box for a topic search You have the choice of using the list box to scroll through the list to find a topic or by typing in a topic name and allowing the system to search for a matching name To jump to the selected topic press the GoTo button The other Window s help system general commands can also be used to aid you in your use of help including Contents Back and History Help Topics Help HE Index Find 1 Type the first few letters of the word you re
284. ters will be automatically set by the scoring utility The scoring system uses the Bar Graph display mode You do have the option to select the dB value per division and the number of major and minor divisions to be shown on the graph The scoring routine will use these values and will only adjust the top SPL value of the scale as needed pcRTA User Manual USAC Scoring Documentation Print Each Graph Lib Name USACOO01 Test Number 1 LibCuve 1 Testing Controls Event Title The World of Car Audio praec Mic 1 Mic 2 Mic 3 Mic 4 Lineln SPL Max Test Level Setting Test Contestant RTA Response Test Produce USAC Score Chapter 7 Utilities Menu Starting a Session To begin a scoring session press the Start Testing button and then enter the event name The first step in each of the scoring cycles is to enter the contestant name The Testing Controls group box provides 4 buttons for conducting various tests involved with the scoring cycle Each can be operated indi vidually or repeated as necessary They are generally executed in order from top to bottom for each contestant The first test is for maximum SPL Press the SPL Max Test button and the analyzer will measure the maximum SPL over a 45 second period with peak hold The standard USAC test uses a compact disk with predetermined program material FlashDance USAC Scoring Documentation
285. testant field pnt Title Contostant e eee Mic 1 Mic 2 Mic 3 Mic 4 Lineln Testing Controls pon d Press the Level Setting Test button IASCA Scoring Documentation Testing Controls vi Print Each Graph a 5 001 Level Setting Test Test Number 1 Lib Curve 1 Ferre Contestant SPL Mar Test E Produce IASCA Score Mic 1 Mic 2 Mic 3 Mic 4 Lineln 326 Level Setting Test button pcRTA User Manual 11 Car Audio Applications The text inside the button changes to Push When Done IASCA Scoring Documentation Testing Controls y Print Each Graph Lib Name 1 5 001 Test Number 1 LibCurve 1 Push when done Adjust your system for 90dB in Full Band Mic l Mic 2 3 Mic A Linen Restart Sequence Stop Testing Help Produce IASCA Score At this point the pcRTA is measuring the pink noise in the car Have the competitor set their system for a 90dB or 1dB indication on the Text Chart in the upper left corner of the screen and then press Push When Done Text Chart Set for 90dB plitude dB SCORING DB i it Pi ew Window Help Bar Graph furs 89 548 Sound Pressure Level g5 Push When Done button IASCA Scoring Documentation 1 Print Each Graph Lib Name IASCA001 Testing Controls Test Number 1 LibCuve 1
286. the Graph Display dialog box The circle markers also function as selection buttons When the mouse is moved over a circle and clicked the indicator will change state The circle data curve indicators can also be controlled by using the D key on the keyboard Pressing the D key will change the state of the data curve indicator on the currently selected entry Selecting a curve as the data entry will also automatically turn on the graphing indicator since this is typically needed as well pcRTA User Manual 83 5 Edit Menu Library Untitled db CurveName 1 CurveName 1 CurveName 2 CurveName 3 CurveName 4 CurveName 5 CurveName 6 CurveName 7 CurveName 8 CurveName 9 CurveName10 CurveNamel1 Copy Curve Move Curve Delete Curve Delete All Edit Data Show Info Move Curve This function button is used to move a curve from one entry position to another Both the data and the curve name will be copied The original curve entry is cleared Copy Curve This function button is used to copy a curve from one entry position to another Both the data and the curve name will be copied The original is not affected To use this function first highlight select the entry to be copied before pressing the button Then press the Copy Curve but ton Next highlight select the entry posi tion to place the copy If you wish to abort the command simply press the butto
287. the M52 mic the maximum SPL is 170dB After the test is finished you can repeat any of the above tests again if necessary When completed press the Produce IASCA Score button and the data will be written to the note fields in the screen and printed if you have selected that option as well For the next contestant enter in the new contestant name and repeat the process M pcRTA Amplitude dB IASCA002 DB Bar Graph BEES ii Fie Edit Processing Utilities View Window Help Sound Pressure Level TEETETE TETE LE CELL 250 200 s 63 80 Curve Legend Notes and Comments TASCA Scoring Utility Event The Big Sound Off _ 1 FullBand Sum N RTABands Fiat Total SPL amp RTA Results Score 147 1 Points _ js Mon 5 12 pm m of v Cursor Bar Graph Curve 1 Band 20k Data 75 8 dB 180 pcRTA User Manual Chapter 7 Utilities Menu 7 6 USAC Scoring This utility provides a special automated algorithm for producing comparison score according to the United States AutoSound Competition USAC Further information about the judging and test setups can be obtained directly from USAC There are two tests defined which constitute the objective portion of the sound quality judging SPL and RTA The maximum number of points for the SPL portion is actually unlimited but the RTA portion maximum is
288. the calibration routine press the Run Calibration button The entire calibration algorithm will take approximately 4 minutes to complete If all tests pass the new data will be automatically written to the Analyzer Calibration x Analyzer EPROM Data Port Hex Bus Clock MHz 8 3435 Pink Noise dBm Computer Calculation Speed Index White Noise dim Serial Number 153435 Revision AutoRange Gain 1 dB 19 38 Calibration Date Jan 21 1999 Thr 5 17 pm ences Cllr Production Date Sep 6 1996 Fri 1 55 pm AutoR ange Gain 3 dB RMS Scale Factor RMS Scale Offset dB GIE FullHz 1 478 FullHz 19 5 A Fil ullHz 1 ullHz 19 ANSI A Filter Gain dB 20Hz 1 474 20Hz 251 ANSI B Filter Gain dB 25Hz 1 475 25Hz 25 2 ANSI C Filter Gain dB 31 5Hz 1 470 31 5Hz 24 4 ANSI D Filter Gain dB 7 83 ANSI E Filter Gain dB 05 Sqw dBm Max 40Hz 1 472 40Hz 25 1 50Hz 1 469 50Hz 25 3 53Hz 1 470 63Hz 25 1 RMS Rates dB 5 Pink Noise Flatness dB 0 00 DAC Atten White Noise Flatness dB 0 00 Line Output ANSI A Curve Level dB 0 00 0 00 Line Input ANSI B Curve Level dB s 0 00 0 00 Mic 1 Input ANSI C Curve Level dB 0 00 0 00 Mic 2 Input ANSI D Curve Level dB 0 00 0 00 Mic 3 Input ANSI E Curve Level dB 0 00 0 00 Mic 4 Input pcRTA User Manual 215 Chapter 7
289. the decoding process on a line by line basis As each line in the file is read and decoded you will be able Reading Decoding Data Please Wait 170 to see how the programis interpreting the text data If you have a problem this display can be very helpful in diagnosing the problem The format of an example DAT file is shown below If the phase column is not present zero values will be used in place Frequency Hz Magnitude dB Phase Deg 2 0000000E 001 55 760 0 000 2 5178508E 001 64 894 0 000 3 1697864E 001 72 137 0 000 3 9905246E 001 78 470 0 000 5 0237729E 001 78 816 0 000 6 3245553E 001 79 534 0 000 7 9621434E 001 77 765 0 000 1 0023745 002 76 494 0 000 1 2619147 002 78 693 0 000 1 5886565 002 78 837 0 000 2 0000000 002 79 936 0 000 2 5178508E 002 82 776 0 000 3 1697864E 002 83 080 0 000 3 9905246E 002 82 715 0 000 5 0237729E 002 84 383 0 000 6 3245553E 002 85 288 0 000 7 9621434E 002 84 931 0 000 1 0023745E 003 85 141 0 000 1 2619147E 003 84 647 0 000 1 5886565E 003 85 698 0 000 2 0000000E 003 85 628 0 000 2 5178508E 003 85 391 0 000 3 1697864E 003 85 907 0 000 3 9905246E 003 87 179 0 000 5 0237729E 003 87 318 0 000 6 3245553E 003 86 566 0 000 7 9621434E 003 84 742 0 000 1 0023745E 004 82 024 0 000 1 2619147E 004 78 988 0 000 1 5886565E 004 76 372 0 000 2 0000000E 004 72 323 0 000 pcRTA User M
290. the system you can save the curve for future reference or to provide the customer with hard copy of the final response curves Simply click the Stop Test button when a channel is complete then go to the Curve Library and designate a new entry to receive the data Save the library when finished and you will have a record on the hard disk of the installation This information can be very valuable when returning to the theater for realignment of the system pcRTA User Manual 261 10 Cinema Applications Notes for B chain Alignment Here are the Control Panel settings saved in the Control Panel Set file CINE BCH CPS Amplitude Response Control Panel FE Noise Signal Generator Detector Type of Data Automatic On Off Peak dBm SPL Pink Noise Fast Dynamic Range dB spl Slow Gen Output Level Legis Auto 120 to 20 2 Fixed 60 to 20 eor Fixed 80to 0 dBm Vrms nn Fixed 100 to 20 Full Band Fixed 120 to 40 Input Source Flat Multi Mic ANSI Testing Mode MultiMic Select Continuous E Peak Hold v Enable 1 RTA Bands Enable 2 Flat 1 Enable Mic3 ANSI Measurement Data PLEASE E Absolute Relative ve Multiplex ANSI Filter y Normalized ANSI C x 1 CurveName 1 Control Panel Parameters Parameter Value Parameter Value Gen Auto On Off Input So
291. the values must be greater than zero Pressing Ok will keep your changes while pressing Cancel will abort any data changes Curve Data Edit x Library EXAMPLE1 DB Curve Number 1 Curve Name Pink Noise 0 1sec ave Full 100Hz 17 03 630Hz 16 81 4kHz 17 53 20Hz 125Hz 17 29 800Hz 17 68 SkHz 17 53 25Hz 15 76 160Hz 17 44 1kHz 17 35 Gk3Hz 17 57 31 5Hz 14 78 200Hz 1k25Hz 17 84 8kHz 17 52 40Hz 250Hz 1k6Hz 17 87 10kHz 17 59 7 59 50Hz 315Hz 17 14 2kH2 17 67 12k5Hz 17 66 63Hz 400Hz 17 35 2k5Hz 17 51 16kHz 17 62 80Hz 18 17 500Hz 17 26 3k15Hz 17 56 20kHz 17 65 pcRTA User Manual 85 5 Edit Menu Library Untitled db CurveName 1 CurveName 1 CurveName 2 CurveName 3 CurveName 4 CurveName 5 CurveName 6 CurveName 7 CurveName 8 CurveName 9 CurveName10 CurveNamel1 Copy Curve Move Curve Delete Curve Delete All Edit Data Show Info Curve Information x Library EXAMPLE1 DB Curve Number 1 Curve Name Pink Noise 0 1sec ave Measurement taken Mar 4 1999 Thr 2 48pm Generator ON PinkNoise GenLevel 0 00dBm DataType SPL_ RangeControl Auto ANSI Filter Flat FullBand Flat RTABands Flat Detector Leq 0 10 Sec Input Generator Transfer to Notes Mic 1 201181 Mic 2 Mic 3 Mic
292. tilities Menu General Operating Instructions and Setup The first step is to mount the pcRTA analyzer card into the PAC unit With the PAC power OFF remove the screws on the cover of the unit and remove the cover Mount the pcRTA analyzer card into one of the slots Replace the PAC cover and then fasten again with the screws Note Verify that the Voltage Selector switch is in the correct position for your local power 110VAC or 220VAC before connecting the AC power cord The next step is to connect the serial port cable to your computer You will need a free serial port Your mouse may be already using a port such as COMI so you will need to use one of the other three serial COM ports 2 3 or 4 Depending on whether your computer s connector is a DB25 pin male or a DB9 pin male you may or may not need to use an adapter on the line Turn on the power to the PAC unit either battery or external and after a few seconds the unit will beep to let you know it is ready for operation Start the pcRTA software and then go to the Utilities Menu and select the PAC Interface item The following paragraphs describe the operation and features contained in the interface dialog box Note After you have setup and activated the link for the first time you MUST run the Calibration routine to establish the correct operating parameters for the pcRTA even if you have previously done this already when the analyzer was mounted in your computer Moving t
293. tion will follow the programmed output level but is always ON regardless of the Gen On button The multimic mode is not possible in the NA mode due to timing requirements Detector This group box provides four selections for the time weighting or averaging of the measured data The detector values follow the requirements of ANSI S1 4 1983 etc The Peak selection provides the fastest measured response and provides nominally 20 updates per second The Fast selection is an exponential time average of 125mS and also provides 20 updates per second The Slow selection is an exponential time average of 1000mS and provides 1 update per second The Leq selection provides linear RMS time averaging with a period of 1 second and updates of 1 second Dynamic Range Control Dynamic Range dBm This group box allows you to select the dynamic range of the Fixed 60 to 20 Fixed 80 to 0 Fixed 100 to 20 Fixed 120 to 40 pcRTA User Manual analyzer inputs In the NA mode no autoranging is possible due to timing requirements Each range provides 80dB of measure ment capability If an overrange condition occurs during the NA run the run will be aborted and an error meassge will appear The run will need to be restarted using a higher range In order to determine the best range some initial measurements should be taken prior to starting the run 109 5 Edit Menu Offset Adjustments Start 6 000 Stop 8 000
294. tions to minimize the influence of any particular room mode The minimum spacing of the micro phones in an average shall be 1 0 m 3 3 ft Microphone Placement For RT60 NC and B Chain Alignment pcRTA User Manual 241 10 Cinema Applications On Axis vs Random Pressure Field Calibration and Conversion By default all MDF files produced by LinearX are calibrated for on axis free field response This type of calibration is utilized when the mic is directly on axis with the sound source However for reverberant fields such as large cinemas where the sound source is not localized a random pressure field measurement is typically performed In this case the mic is generally pointed upwards and the calibration data is referenced to a 90 degree off axis measurement The MDF Convert option provides the means to convert the default on axis MDF microphone response files into their equivalent random pressure field response files m pcRTA Amplitude dB EXAMPLE1 DB Line Graph File Processing Utilities View Window FullF Run Stop Test Del Gen On Off Ins Curve Library F2 Control Panel Graph Setup F4 Notes Comments Microphone Setup Graph Design F9 System Options F10 Mic Input 1 Mic Input 2 Mic Input 3 Mic Input 4 Line Input Select OnAxis file to convert to Random file x File Directories m
295. to match those settings To read the current settings of the EQ unit and recall the settings of a particular memory location or channel first select the desired memory and channel and click the Recall button The operating parameters of the EQ will cause the dialog box controls to match those values For more information on the EQ parameters and their meaning or operation please consult the EQ manufacturer s documentation 200 pcRTA User Manual Chapter 7 Utilities Menu Automatic Optimization of Response The pcRTA can be used to automatically adjust the EQ band levels to match the response measurement to a previously defined target curve entry In order to perform this function you must have previously setup an appropriate target curve in one of the library entries The curve entry to be used as the target is selected in the Library Curve Entry for Target list box This could be a flat line or any other shape desired Note The data curve entry must NOT be the same as the target curve or new measurement data will overwrite your target response It is also important to understand that the absolute target level must be in the same range as the expected measured RTA data For example if the measured SPL response is in the 90dB range a target that is a flat line at OdB would be impossible The optimizer would attempt to reduce the band levels by 90dB clearly out of the adjustment range of 12dB bands The correct target would
296. ts can be configured for an individual MDF file Since every microphone has unique characteristics which differ from others the mic which is setup for a specific input should always be used with that particular input Microphone Setup EX Microphone Input 1 Edit Clear Response Errors dB Author LinearX Systems Inc Date Dec 11 1997 Thr 4 53PM Model 53 dBspi 34 00 0 00 Serial 201181 dBme 35 51 027 pcRTA User Manual 131 5 Edit Menu Microphone Setup x Microphone Input 1 Edit Clear Response Errors dB Full Hz 0 40 Author LinearX Systems Inc 20Hz 1 06 25Hz 0 60 Date 11 1997 Thr 4 53PM 31 5 Hz 0 23 Model M53 aBspI S 00 40 Hz 0 00 Serial 01181 dem 15 51 63 027 Load Data File MDF x File Name Directories 22000000 ma sn201181 mdf sn201182 mdf sn201183 mdf sn201184 mdf ec E perta C3 db C3 export C3 na 2 List Files of Type MicDataFiles mdf bd 132 Load Mic Data File This button starts the process of loading an MDF file After this button is pressed another dialog box will be presented for selecting the MDF file After the MDF file is selected the data will be scanned and converted into the necessary calibration information required by the pcRTA pcRTA User Manual Microphone Setup x Microphone I
297. tus at one time The last check box allows the use of curve entry color coding off or rainbow color coding on for the bands When off the color used for all bands will be that of the assigned global curve entry color When on the band colors of any displayed curve entries will all have the same rainbow color sweep pcRTA User Manual 121 5 Edit Menu Reverb Reference Curve _ Theater Room Vol 1000 00 Reference Curve This group box contains selections for the standard theater RT reference curve The room volume can be entered in either cubic feet or cubic meters using the appropriate radio buttons The reference curves will appear on the Reverb Time Graph 122 pcRTA User Manual 5 Edit Menu 5 11 Graph Setup Noise Analysis This dialog box provides control over the appearace of the graphs used in the Noise Analysis mode There are five line graphs and one text chart in the NA mode Amplitude Time Probability Distribution Cumulative Distribution 3D Frequency Perspective 3D Time Perspective and the Statistical Analysis Chart Noise Analysis Graph Setup x Amplitude Time Graph Probability Distribution Graph Band Display dB Scale Time Scale dB Scale Percent Scale v Ful wv 630 Value at 5 M H Value at Top dB Interval 20 800 1 00 Lo f anm s 5 0 15 2
298. types have 20 curve entries Each entry in the list can be highlighted focused by using the mouse and scroll bar or by using the cursor keys on the keyboard Each entry also has a square and circle marker which is used to select and indicate the curve s status for graphing and data selection pcRTA User Manual Chapter 2 General System Features Curve Library EXAMPLE1 DB Graphing Indicators Square Markers Each curve entry in the list box has a small square shown at the beginning of the line This square indicates whether or not the curve is selected for display on the graph Pink Noise 10 sec ave White Noise 10 sec ave 250Hz square wave 1 sec 1 3 Multiplied When the curve is selected for display the 1 amp 3 Divided square will be filled in with the assigned color forthe curve The curve line coloris setin the Graph Display dialog box The square markers also function as selection buttons When the mouse is moved over a square and clicked the indicator will change state The square graphing indicators can also be controlled by using the G key on the keyboard Pressing the G key will change the state of the graph indicator on the currently selected entry Data Curve Indicators Circle Markers Each curve entry in the list box has a small circle shown at the beginning of the line This circle indicates whether or not the curve is currently selected as the data curve Only one curve can be the data cur
299. ub menus for the library type Amplitude Impedance ReverbTime and Noise Analysis The type of data to be measured is solely defined by the type of library being created If you attempt to exit the program with a library name Untitled you will be prompted to save the file first before exiting You have the option of exiting the program without saving the file explicitly or assigning a file name and saving the library under this new name The pcRTA software always initializes the last configuration from the PCRTA INI file and loads the last used library if possible each time the program is started m pcRTA EXAMPLE1 DB Bar Gra 0 Edit Processing Utilities View Window Help Amplitude Impedance E Reverberation Tr Moise Analysis Saveds Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Print 0 Exit pcRTA User Manual 65 4 File Menu 4 2 Open File The Open File menu option loads a library file from disk into memory and configures the program for a specific type of measurement When the library has been loaded the file name will appear in the top of the title bar along with the measurement mode Depending on the type of library pcRTA files have the extension DB Z RT or NA to indicate the type of library and data contained The measurement mode of the program will be updated to ma
300. uded in the measured Full Band level When set to ANSI the Full Band will measure a weighted response as specified by the weighting filter selected below This selection includes frequency content below 20Hz and above 20kHz as allowed by the selected ANSI filter In this mode the correction curve provided by any MDF file which has been loaded will not be included in the measured Full Band level When set to SUM the Full Band will measure the total RMS sum of all the 1 3 octave bands This selection only includes frequency content between 20Hz 20kHz and will follow the filtering selected for the RTA bands and not the Full Band In this mode the correction curve provided by any MDF file which has been loaded will be included in the measured Full Band level pcRTA User Manual 107 5 Edit Menu ANSI Weighting Filter ANSI A filter M Full Band RTA Bands Flat Flat ANSI ANSI Sum Type of Data dBm SPL Run Time Seconds Minutes Hours 24 000 108 RTA Bands Response This group box provides two selections Flatand ANSI The RTA bands refer to the 31 1 3 octave bands displayed across the graphs These bands can be controlled as a group separately from the full range band When set to FLAT the RTA bands will measure an unweighted response and ignores the setting of the weighting filter shown above When set to ANSI the RTA bands will measure a weighted response as specified by the we
301. uency pressurization 296 M 50 series mic 14 131 341 Magnification factor 26 219 Main screen 19 pcRTA User Manual Index Maximize 19 Maximum zoom level 219 MDF convert 137 242 file structure 136 installing 243 microphone setup 14 131 Measurement data 94 Measurement microphone 291 Measurement mode amplitude 87 description 21 impedance 97 new file 65 noise analysis 105 open file 66 reverb time 101 Measurements 37 Measuring impedance 57 313 reverberation 101 SPL 51 291 system response 287 transfer function 298 Menu bar 19 Mic data files 14 239 Mic inputs 131 Microphone correction 239 mounting 240 placement 241 290 power supply 254 setup 14 131 244 Minimize 19 Minimum output 88 Minimum zoom level 219 Move curve 84 Multi mode 265 319 Multi curve display 20 VII Index Multi way 163 MultiMic 254 Multiple measurements 163 Multiple microphones 16 135 Multiplex 254 Multiply curves 153 N New file 65 New library 65 Noise analysis control panel 105 graph setup 123 measurement mode 21 Noise criteria 266 Noise floor 266 274 Noise generator 98 Non correlated 163 Notes and comments 45 129 Offaxis 55 On axis 55 240 242 On line help 38 Open circuit 59 Open file 66 Optical preamp 249 Optimization 201 205 Oscillator 22 Output impedance 57 Output level 88 P PAC interface 207 211 PageMaker 176 Palette color 141 144 Passive crossover 298 302 315 Vill Past
302. urce MultiMic Gen Output Type A Noise Enable Mic 1 4 On Gen Ouput Level 0 00 dBm Average On Full Band Response ANSI Multiplex Off RTA Bands Resp Flat Normalized On Weighting Filter ANSI C Filter Dynamic Range Auto Type of Data SPL Testing Mode Continuous Averaging Time 10 00 Sec Measurement Data Absolute 262 pcRTA User Manual Notes for B chain Alignment continued Here are the Graph Setup settings saved in the Graph Display Set file CINE BCH GDS Chapter 10 Cinema Applications Amplitude Graph Setup x Bar Graph Display Line Graph Display Scale Top Value dB Div Full Range Scale Top Value dB Div Full Range EI 80 0 82 50 Display 4 800 50 Band Display Type Absolute Relative 1 3 Octave Type Absolute Relative 1 3 Octave 1 Octave z 1 Octave Major Minor Div 8 5 Single Band Div 8 5 Single Band Graph Wl Dot Rainbow gt Fu 2 _ 7 Length of Hash 30 19 gt Amplitude Reference Curves Bar Line Graphs Noise Contours SMPTE N Curve SMPTE X Curves Surround Curve Level 48 70 0 Text Chart Display Font Selections _TypeFace Style Size Color Box Background Single
303. ured levels in all bands over a specific run oftime The time can range from only a few seconds to many hours Unlike the other measurement modes where the analyzer is started and stopped randomly by the user the NA mode has a specific run length where the analyzer is started and stopped automatically However the measurement process can be paused and resumed during the run by the user The run may also be aborted This menu option can also be activated from the tool bar and the DoubleClick zone in the graph area under System The example below shows the various elements of the Control Panel dialog box The dialog box is separated into several different regions Each region controls similar associated parameters Noise Analysis Control Panel x Noise Signal Generator Type of Data Input Source ffset Adjustments Automatic On Off dBm SPL dB 1 Pink Noise Run Time Detector Start Output Level Seconds Peak Stop B mes dBm Vrms Hours Slow _ dB 2 ANSI Weighting Filter 15 Start ANSI A filter Dynamic Range dBm Stop Fixed 50 to 20 Full Band RTA Bands 3 Flat Flat Fixed 80 to 0 ANSI ANSI Fixed 100 to 20 Stat Sum Fixed 120 to 40 Stop pcRTA User Manual 105 5 Edit Menu Automatic On Off Pink Noise Output Level NE gt dBm Vims 106 Automatic On Off
304. ursor LineGraph Curve 1 Band 160 Data 78 0 dB pcRTA User Manual 33 2 General System Features 34 pcRTA User Manual Tutorial pcRTA Amplitude dB TEST le Edit Processing Uti ew Help Sound Pressure Level Curve Legend System Notes and Comments peRTA Impedance Z TEST Z Processing Utilities View Help Impedance Response Notes and Comments Curve Legend System Spee Fret Tanto us Gentoo Phe Gener 26 RTABonde Fit Korn anse Reverberation Time ply Sian ReverbTime RT TEST1 AT Edit Processing Uti jenen i jen s Bt Curve Legend System Notes and Comments 1 at dBm Data ype Sec 2 RT60 at t0dBm Genlioise Pink GenLevel 20 0 InputSre LineOut Stimuhis 1 Sec TimeOut 2 See RT lm it RT60 TestMode Contin DoRTA 1 00 TESTLRT MERE 7 30 am pcRTA User Manual Chapter 3 Tutorial 36 pcRTA User Manual Chapter 3 Tutorial 3 1 Introduction This is a brief instructional tutorial for the p
305. urve will be different Measuring impedance with the is very quick and easy Although the accuracy and resolution is very limited due to the 31 points and noise averaging it can provide important information for users without additional mea surement equipment mpedance Response 3 Speaker Tests Method 4 Wire DataType Ohms TestMode Cont GenLevel 2 5 GenNoise Pink AveTime 5 0 Sec wed 1 28 pm z 1 Cursor Impedance Graph Curve 3 Band 250 Data 22 6 Ohms A Start pcR TA Impedancetz 1 28PM pcRTA User Manual 61 Chapter 3 Tutorial 62 pcRTA User Manual File Menu New Open t Save S Saveds Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Print P Ext 70 pcRTA User Manual 4 File Menu 64 pcRTA User Manual Chapter 4 File Menu 4 1 New File The New File menu option initializes a new library and sets the measurement mode for the analyzer This option clears all data and sets default names for the curve entries The library is given the name Untitled You will be required to set a real name before the program will allow you to save the library file The New option has four s
306. us Clock Port 231E Calibration Date Feb 23 1999 Tue 12 09 pm Serial No 0 Rev Production Date Sep 6 1996 Fri 1 55 pm pcRTA User Manual 229 9 230 pcRTA User Manual Cinema Applications Chapter Reverberation Time 1 009 0 750 sa RT mar 0 250 RT typ pe IRT min 20 Hz 50 100 200 500 ik 2k 5k 10k 20k Sound Pressure Level dBspl dEspl pl 20 Hz 50 100 200 500 dk 2k 5k 10k 20k pcRTA Amplitude dB EXAMPLE1 DB E File Edit Processing Utilities View Window Help Run Gen Gras Curve IS cale Scale IS cale Ze Ze ire icy Ese Es Se E rs E85 7 Se Line Graph Text Chart EB Pressure Level 85 0 Cursor E B B B pcRTA User Manual 10 Cinema Applications 232 pcRTA User Manual 10 Cinema Applications 10 1 Introduction This chapter covers the measurement and adjustment of commercial cinem
307. use Scale Factor This editing field allows you to specify the amount of enlargement or reduction in the magnification of the printed image The value is entered in percent A full size 10096 plot represents an artwork width of 10 inches and a height of 8 inches Bar Width Factor This editing field allows you to control the amount of gap between the bars when printing bar graphs The value can range from 1 0 down to 0 5 The typical value is 0 9 pcRTA User Manual Chapter 4 File Menu Print colors as Black White When this box is checked all colors in the artwork graphics will be printed as black or white If this box is not checked and you are printing to a black amp white device the colors in the artwork will be dithered to produce gray levels This is a very useful feature when printing to a dot matrix device Gray halftones of low resolution on small lines or fonts may often result in unreadable graphics Printing all colors as black white will eliminate this problem and produce better looking plots on low resolution devices For printing on laser printers where higher resolution is available it may be a matter of choice as to the representation of color Gray lines of varying density may help to produce more identity between multiple lines on the graphs Setup Button Use this button when you wish to change the selected printer and or configuration When this button is pressed another dialog box will open Canon B
308. ut voltage See the figure below Normal Linear Sine Wave Clipped Non Linear Sine Wave pcRTA User Manual 291 11 Car Audio Applications 292 Meters Every SPL meter has different electrical characteristics and possible con figurations The main points of interest are the type of response that the detector uses the reponse time of the detector and the bandwidth of the signal reaching the detector The detector is the circuit that converts the electrical voltage from the mic into a numerical or graphical readout of the actual level There are three types of detection True RMS Average and Peak RMS detectors are the only type that gives a true indication of the power of the signal no matter what the waveform sine wave square wave noise or music The pcRTA uses true RMS detectors Average detectors are less expensive and use a simple rectifier circuit With sine waves an average detector will produce the same results as an RMS detector When measuring complex signals distorted sine waves noise etc averaging detectors will usually read 1 or 2 dB lower than RMS types Peak detectors have a very fast time constant and will indicate the peak voltage of a waveform When measuring noise or music a peak detector will read high compared with RMS These types are useful for measuring headroom or the ability of a system to reproduce high amplitude transients of short duration For measuring the amount of power a s
309. ute 255 10 Cinema Applications 10 5 B Chain Alignment 256 Alignment of the B chain can be done entirely with the pcRTA and your ears The process involves measuring full band C weighted SPL to set the outputs of the individual channels to the same level and then equalizing each channel while viewing the frequency response The Normalized option will be turned on in the Control Panel for these measurements This feature normalizes the sensitivity of all the mics at 1kHz so that they will each have equal weighting in the 4 mic average This is essential for proper adjustment of the equalizer There are many display options for viewing the full band SPL You can switch between a text display of the full band SPL and a graph of frequency response using the Window menu The Bar Graph and Line Graph each have the option of showing the full band SPL as a part of the curve or as a small text display in the upper left corner Using the multiple windows you can display the full band SPL with ANSI C weighting while simulta neously displaying the 1 3 octave bands unweighted as bars or a line This text will show two specific methods of viewing the full band SPL Both methods will use the multiple windowing capability The first involves maximizing the graphs then switching between a line graph and a full band SPL text chart This method is recommended for displays with a resolution of 640x480 VGA or 800x600 SVGA The second m
310. ve When one circle is clicked ON the previous circle will be turned OFF When the curve is selected for data the circle will be filled in with the assigned color for the curve The curve line color is set in the Graph Display dialog box The circle markers also function as selection buttons When the mouse is moved over a circle and clicked the indicator will change state The circle data curve indicators can also be controlled by using the D key on the keyboard Pressing the D key will change the state of the data curve indicator on the currently selected entry Selecting a curve as the data entry will also automatically turn on the graphing indicator since this is typically needed as well pcRTA User Manual 29 2 General System Features 30 pcRTA User Manual 2 General System Features 2 6 Data Cursor The Data Cursor provides a digital readout of the data at any point on the curve This feature is very useful especially in the Noise Analysis mode when evaluating the 3D plots since it is very difficult to see exactly where the data lies on all three axes The figure below details the fields in the cursor status bar There is a checkbox at the far left that shows hides the cursor The other fields will display relevant data to the type of graph you are viewing The Statistical Analysis Noise Analysis Mode and Text Chart Amplitude Mode graphs do not display a cursor because they ar
311. veAs SaveAs Save Graph Display Set Load Graph Display Set Save Control Panel Set Load Control Panel Set Print P A dialog box opens with the title Save ReverbTime RT File Type in the name you want for the file and click OK Save ReverbTime RT File File Name Directories i chris rt rt test rt ricinem rt ricinem3 rt ricinem4 rt rtcinemb rt rtcinema rt testl rt List Files of Type Drives ReverbTime RT Files pcRTA User Manual ap C Read Only You now have anew reverb time curve library with 20 blank entries ready to re ceive data 275 10 Curve Library Button 276 plications STEP 2 HE AE Control Bl Panel EE 2 a gt Setup Curve Library Scale Up Scale Ez d Auto ES Scale t 3 26 ut v ze 3 ull Sem x 27 ral Select and name a curve to receive the measured RT data Click on the Curve Library button on the Tool Bar The Curve Library dialog box opens In the figure below curve 1 is currently selected for saving the data and displaying it Before each measurement another curve must be selected in the Curve Library as the data curve or the previous test will be overwritten To select an Curve Name Edit Box Curve Library Editing Library Unt
312. vel reaches the maximum or minimum capable values the level will not change These buttons are type a matic and can be held down to continuously step the value pcRTA User Manual 5 Edit Menu ANSI Weighting Filter ANSI Weighting Filter E This list box provides six selections Flat ANSI A ANSI B ANSI C ANSI D ill and ANSI E The Flat selection provides the ability to use the extra gain FullBand RTA Bands plock for measuring extremely low signal levels Flat Flat ANSI ANSI The response of the ANSI weighting filters is shown on the following Sum page Filters A B and C were originally developed to simulate human hearing at various SPL levels ranging from low A to high C The D and E filters were developed for special acoustic testing relating to aircraft noise All filters are designed for a gain equal to OdB at 1kHz Full Band Response This group box provides three selections Flat ANSI and Sum The full band is the band displayed at the left of the graph and represents a full range frequency response rather than a 1 3 octave RTA band response This band can be controlled separately from the 1 3 octave bands When set to FLAT the Full Band will measure an unweighted response and ignores the setting of the weighting filter shown above This selection includes frequency content below 20Hz and above 20kHz In this mode the correction curve provided by any MDF file which has been loaded will not be incl
313. ver time periods from 0 05 to 50 seconds For typical mea surements an averaging time of 10 seconds produces excel lent results for Pink Noise This second measurement is now held in curve entry num ber 2 The last exercise for this example will be to display the 4 previous measurement along vi Cursor Bar Graph 44 2 Band 630 Data 16 8 dB 9 with this new data pcRTA User Manual Chapter 3 Tutorial This time we will bring up the Curve Library dialog box Library UNTITLED DB with yet another new method The graph artwork board has three areas near the bottom of the graph Pink T0 sec ave These areas are double click zones Pressing the left CurveNane 4 mouse button twice quickly over either of these three CurveName 6 areas will activate either the Curve Library Control Panel or Notes and Comments editor This is another CurveName 9 CurveName10 way to access these very common functions CurveName11 gt DoubleClick mouse over Curve Legend area gt Click the square marker in entry number 1 gt Press the OK button to exit and keep your changes Now we have added entry number 1 for display also As the graph below shows there are now two sets of bars displayed on the graph The width of the bars has been divided in half Also the Curve Legend area displays the curve names and color ass
314. ving The lower frequency bars will be constantly moving This is because the averaging time is a very short 0 1 sec Try stopping the run and then restarting it Use the RightMouse button gt Press the RightMouse button a few times to Start and Stop Your display should look something like the one shown on the following page It will not look exactly the same since your system and setup are different pcRTA User Manual 53 Chapter 3 Tutorial 54 M pcRTA Amplitude dB EXAMPLE2 DB _ ea x File Edit Processing Utilities View Window Help if Bar Graph EISE EINE 5 Amplitude dB de le 1 1 21PM As you have probably noticed each time you stop the measurement the reading is different This is because the averaging time is too short for measuring pink noise which randomly varies over time For accurate measurements a 10 second averaging time would be more practical For an accurate measurement we will change the averaging time to 10 seconds and save this new curve in entry number 6 gt Press the Curve Library button in the Tool Bar gt Click the circle data marker on in entry number 6 gt Click the square graph marker off in entry number 5 gt Edit the name of entry 6 to SPL Test 10 sec ave gt Press the OK button to exit and keep your changes gt Press the Control Panel button in the Tool Bar gt Set the
315. x The Floating selection provides a tool Floating Full Graph box that can be dragged anywhere on the screen and floats on Fixed Left Data Area top of the other graph windows The Fixed selections lock the Fixed Right RIRE Tool Box along one of the four edges of the frame window dem S Single Mode Depending on the resolution of your display it is possible that lt MultiMode all of the buttons may not be able to fit across the screen for Cursor Control some of the selections Choose an appropriate selection for Bitmap Selection Blink Rate your purposes and screen resolution Artwork View The artwork board in each graph can be sized differently using one of the two selections in this group box The Full Graph selection makes all of the artwork features visible including the lower regions of the graphs containing the Curve Legend System and Note Comment areas The Data Area selection adjusts the graph size to show the graph grid area only in the window view This mode is helpful if your display resolution is limited Window Update This group box controls the redraw behavior of the graph windows In the Single Mode only the window which has the current focus will be updated or redrawn In the Multi Mode all of the currently visible windows will be redrawn or updated Cursor Control This group box controls the appearance of the data cursor Several different bitmap selections are provided and the blink ra
316. xt lines following with the actual data Each line is a different frequency point A comma is placed between each line parameter Floating point notation will be used for the frequency values consisting of an E followed by the exponent power of ten Frequency Hz Magnitude dB Phase Deg 2 0000000E 001 55 760 0 000 2 5178508E 001 64 894 0 000 3 1697864E 001 72 137 0 000 3 9905246 001 78 470 0 000 5 0237729 001 78 816 0 000 6 3245553E 001 79 534 0 000 7 9621434E 001 77 765 0 000 1 0023745 002 76 494 0 000 1 2619147 002 78 693 0 000 1 5886565E 002 78 837 0 000 2 0000000E 002 79 936 0 000 2 5178508E 002 82 776 0 000 3 1697864E 002 83 080 0 000 3 9905246E 002 82 715 0 000 5 0237729E 002 84 383 0 000 6 3245553E 002 85 288 0 000 7 9621434E 002 84 931 0 000 1 0023745E 003 85 141 0 000 1 2619147E 003 84 647 0 000 1 5886565E 003 85 698 0 000 2 0000000E 003 85 628 0 000 2 5178508E 003 85 391 0 000 3 1697864E 003 85 907 0 000 3 9905246E 003 87 179 0 000 5 0237729E 003 87 318 0 000 6 3245553E 003 86 566 0 000 7 9621434E 003 84 742 0 000 1 0023745E 004 82 024 0 000 1 2619147E 004 78 988 0 000 1 5886565E 004 76 372 0 000 2 0000000E 004 72 323 0 000 pcRTA User Manual Chapter 7 Utilities Menu 7 2 Import ASCII Data The Import ASCII Data menu option will open a dialog box for importing an ASCII text data file curve The library cu
317. y Maximum charging current is about 1 25 amps To fully recharge a heavily drained battery will typically take about 5 hours When the battery is in discharge this field will display 0 0 amps Note Never leave the battery in a heavily discharged condition for long periods of time as this will greatly reduce battery life The battery should be recharged as soon as possible to at least a resonable level pcRTA User Manual 213 Chapter 7 Utilities Menu System Status Link Status Baud Rate 57 600 CPURev pcRTA Port 12 Voltage 12V Bus Voltage 5V Bus Voltage 5V Voltage Battery Voltage External Voltage Power Source Battery External System Status This group box contains a number of readouts which display the current system status within the PAC unit This data is updated each time the link is activated or when the dialog box is re displayed Link Status displays verification of whether or not the PAC link is active Baud displays verification of the baud rate detected in the PAC unit Rev displays the revision code of the PAC internal computer pcRTA Port displays the port address of the pcRTA card installed in the PAC unit if one is found This field will show 0 if no pcRTA card is installed in the PAC unit 12V Bus Voltage 12V Bus Voltage 5V Bus Voltage 5V Bus Voltage displays the actual measured supply voltages inside
318. ystem should crash or your computer power is lost File Name Directories EXAMPLE db ic perta db scoring db skyskan db test1 db test2 db test3 db test4 db tsq00001 db untitled db List Files of Type Drives Amplitude dB Files db c new c gt 50 pcRTA User Manual Chapter 3 Tutorial 3 3 Example 2 Measuring SPL Response Curve Library Editing x Copy Curve Move Curve Delete Curve Delete All Edit Data Show Info In this example we will now make use of a microphone for measuring sound pressure level SPL If you have not already setup your mic input s with the proper MDF files you should do so first before working this example Also you will need to have an audio system to test At a minimum this would consist of a power amplifier and loudspeaker You will need to connect the analyzer Line Output to the input of the amplifier Depending on the type of connector input for your amplifier wiring connectors or adapters may be required from the 1 4 jack of the connector box to the input of your power amplifier This should be done first before starting the example The microphone will need to be positioned by some manner in front of the loudspeaker to be measured Since this is only an example to demonstrate the process a perfect measurement is not necessary The microphone can be laid on the floor in front of the speaker or held in a mic stand if one
319. ystem will produce the RMS detector is the best The response time of the detector should correspond to the frequency being measured When measuring low frequencies the detector circuit must have a longer reponse time in order to accurately read the level of the signal In the case of a full range SPL meter the response time must be long enough to read the lowest frequency that the meter can measure In the case of a 1 3 octave real time analyzer a faster response time can be used if the lower frequencies are not of concern Some meters can be switched between Fast and Slow response times pcRTA can measure in Peak ultra fast response Fast Slow and Leq linear averaging over time The Leq type allows selection of the averaging time and should always be used unless you are trying to emulate another meter To accurately read signals down to 10Hz an averaging time of atleast 0 2 secondiis required the time it takes for two cycles to pass through the detector pcRTA User Manual 11 Car Audio Applications Bandwidth is the frequency range being measured The desired bandwidth encompasses at least the audible spectrum 20Hz to 20kHz and does nothave any weighting applied Weighting filters are included in most SPL meters They will add rolloffs to the high and low extremes of the frequency range to simulate the sensitivity of the human ear to different loudness levels These filters will reduce the SPL readings es

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