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Manual - Delta Ohm S.r.l.

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1. ccccscccsscccssccssccesccescccesceusccecceusseusceeeceseseesceesseeuesens 149 A3 MEASUREMENT OF THE SPECTRUM OF THE SOUND SIGNAL USING THE FAST FOURIER TRANSFORM FFT 151 A4 MEASUREMENTS IN PRESENCE OF NOISE WITH IMPULSE TONE AND LOW FREQUENCY COMPONENTS 156 ea EE E O EART A A ELT AI ione 158 AO SOUND ICE VE AVE TER eil iii clelia 160 FREQUENCY WEIGHTING airera ee a eS 160 SPECTRAL ANAL Sd iaia 160 TIME CONSTANTS AND EXPONENTIAL WEIGHTING lt 5 E ideali 161 IMPUE SEE INORG E Relitto pine ili const hae io Sardine oN ack ett ee 161 POUNSIENDEE A A n O el E ila 162 SIE SN iii si IN i n 163 A O a a a a e e E 165 IES e AAA iii a ie 165 ENVIRONMENTALINFEUENC E silla 166 PRECAUTIONS AND GENERAL HINTSOF USE i ll lla a 166 CLASSIFICATIONOFACOUSTIGSIGNALS i ulcera 168 AV ARCHITECTURAL AC US O lulu lalla 170 A7 1 MEASUREMENT OF SOUND ABSORPTION cccccsscccssccsscccscccsscessccesccesccesscesceesscessseesseesccessceusseesccuscesssenscss 173 Instrumentation and measurement CONCITIONS 0 cee eee cei iero eee ice eee eee eee eee eee iene 173 SO Ae Se eee ala oi ii i 173 SO OS oa Sid i a as cs arena elisir 173 A7 2 MEASUREMENT OF THE AIRBORNE SOUND INSULATION cccccseccsscccscccsccsccesccessceesccusccessceesceusccescceuscenscss 174 Instrumentation and measurement COnditions eeeecceeccceeccceccccscccuscccuscccscccuscccascceeseccuseccusceeusccuseceasceceeceaeceuseeeuceess 174 I
2. MODEM or RS232 the following signals are connected to the 8 pin male connector type M12 available on the instrument Pin _ Direction Signal Description 6 Output RTS Requesttosend 7 Output TD_ Transmitting data channel _ dk GND Reference ground E 90 The following signals are connected to the 9 pin sub D male connector of the HD2110RS cable Pin Direction Signal Description Sj GND _ Reference ground 8 DCE gt gt HD2II0L___ CIS Cleartosend 9 HD2110L gt gt DCE When the item MENU gt gt Instrument gt gt Input Output gt gt Serial Device is set on USB the fol lowing signals are connected to the 8 pin male M12 connector type available on the instrument Pin Direction Signal Description 2 VO DP Data 4 MO DM Data COS 6 Input __ VBUS Power supply 5V 8 H GND Reference ground While the sound level meter is connected to an active terminal DCE active via the RS232 interface the auto power off is disabled and the instrument cannot be switched off If the instrument 1s off the connection to an active terminal DCE active will turn 1t on Standard parameters of the instrument serial transmission are e Baud rate 38400 baud e Parity None e N bit 8 e Stop bit l e Protocol Hardware Data transmission speed can be changed through the Baud rate parameter inside the menu MENU gt gt Instrument gt gt Input Output g
3. JS s Sound source interruption If you use the continuous sound source interruption press the central NOISE key REVERBERATION TIME Batt L00 Mem 452 Step DS Turn on the source Activate the sound source and press the NEXT key REVERBERATION TIME Batt 100 Mem 957 Step Ob Confirm level stabilization Wait until according to the environment dimensions the sound of the source stabilizes Usually 4 5 seconds are enough even for wider environments then proceed pressing the NEXT key REVERBERATION TIME Batt 100 Mem 957 Step 08 Turn off the source within 5 seconds D O O Now turn the sound source off within 5 seconds the sound level meter will automatically measure the environment noise decay and will perform the calculations For the entire duration of the meas 79 urement 6 seconds from the source being turned off avoid undesired noises that could affect the measurement The following page will appear at the end REVERBERATION TIME Batt 100 Mem 452 Step 20 Reverberation Time calculated VIEW Euros CC Press VIEW to display the results of the measurement Pp REV PARAMETERS E CU RESI 130 LOmax 105 cedBleS 50 5dBle5 _ S 0 91s 0 95s 0 54s Using the sound source interruption method the EDT value is not calculated in the measurement of the reverberation time The sound level meter gives a complete description of the measurement both in the form
4. 5 asc ALeq LI I asc Confirm calibration AT Waiting for electric calibration 6 At the end if the values of the electrical calibration are acceptable press YES to confirm the new calibration LEFT arrow of the keypad press NO if you want to cancel the whole cali bration RIGHT arrow of the keypad 7 Finally the microphone polarization check is carried out Wait until Take out the calibra tor appears take out the preamplifier from the calibrator ACOUSTIC CALIBRATION ACOUSTIC CALIBRATION Last 2003 01 01 10 00 Last 2003 01 01 10 00 Calibr level 94 0dB Calibr level 94 0dB ALeq LU lama Leq 5 1 ac Take off the Checking microphone calibrator polarization 8 Extract the preamplifier from the calibrator and press EXIT 9 The procedure is over If calibration constants were incompatible with a correct working of the instrument calibration would fail and the message Calibration failed Consult the manual would appear In this case re fer to Troubleshooting page 133 and if necessary contact our service department MICROPHONE REPLACEMENT The HD2110L sound level meter is calibrated in the factory in conjunction with the micro phone If the microphone capsule sensitivity deviates too much from factory calibration the sound level meter blocks acoustic calibrations and reports the microphone as damaged The acoustic calibration can therefore fail even if the capsule 1s replaced or repaired or i
5. ISO 354 Standard The ISO 354 Standard Acoustics Measurement of sound absorption in a reverberation room was updated in 2003 The method consists of measuring the variation of the reverberation time associated with the intro duction of a sample of the sound absorbing material into the test chamber This procedure requires a test room with precise dimensions and acoustic absorption charac teristics The sound source used for the measurements must be as omnidirectional as possible like that described in the ISO 3382 The measuring equipment consists of one or more microphones with optimized response for diffused field The microphone used to take the measurements must be at least 1 m from the sample and the reflecting walls of the room and at least 2 m from the source The provisions on the characteristics of the recording equipment are the same as for ISO 3382 According to the formula of Sabine in the case of flat sound absorbing samples the acoustic absorp tion coefficient is defined by the expression DIS A a Sl A where c is the sound speed m s equal to 331 6 0 6 T C 344 m s at normal temperatures a is the absorption coefficient of the sample with an area S m V is the volume of the room m T is the reverberation time with the material placed in the room and T is the reverberation time without the material The measurements must be taken for octave bands from 125 Hz to 4 kHz or third oc
6. 4 Unscrew the stem B and disconnect the cable connected to the preamplifier 5 Unscrew the lock nut of the preamplifier C using if necessary a 14mm wrench Be careful not to twist the preamplifier cable 179 6 Remove the preamplifier D by pulling slowly down At this point the microphone is accessible and you can proceed with calibration SA For details on calibration see page 66 7 For assembly of the protection proceed as specified in the following paragraph A8 2 Assembly To assemble the unit a 1 5mm male hex key and a 14mm wrench are needed To assemble the protection completely start from Step 1 If you need only to assemble the preamplifier with the microphone after calibration from Step 4 1 Fit the rain shield HDWME2 on the metal grid support HDWME2 180 2 Insert the wind screen HDSAV3 HDSAV3 3 Apply the bird spikes and secure it using the three hex head screws located on the support at the base of the windscreen 181 4 Insert the preamplifier A into the support pushing slowly upward until its limit position 5 Screw the gland B using if necessary a 14mm wrench Be careful not to twist the preamplifier cable 182 6 Insert the cable connected to the preamplifier through the stem C and screw the stem to the support a 7 Screw the terminal placed at the lower end of the stem D releasing the cable laterally a 183
7. Remove one of the batteries and wait at least 5 minutes before reinserting it The instrument should turn on automatically when the battery is inserted 2 The detected sound levels seem incorrect Ensure that no condensation is present on the capsule or preamplifier Avoid turning the instru ment in conditions of possible condensation growth Use the outdoor microphone unit HD WME to perform measurements in conditions of high humidity or when it is raining Check that the warm up time indicated by a blinking letter W over the upper left status indi cator has elapsed Check measurement accuracy using the acoustic calibrator Load factory calibration Check that the microphone protection grid is screwed down on the capsule securely 3 Upon turning the sound level meter on it turns off automatically right after the introduction screen The batteries are flat 4 The sound level meter does not communicate with the PC Check that the sound level meter and PC communication speed is the same MENU gt gt Instru ment gt gt Input Output gt gt Baud Rate Check that the connection cable is plugged correctly in the sound level meter and is connected to a PC serial RS232 or USB port with the item MENU gt gt Instrument gt gt Input Output gt gt Se rial device set to RS232 or USB respectively If you use a USB interface check that the driver is correctly installed If you use Noise Studio program
8. dB so TO 60 50 1043475 1043555 10440535 10444115 10444195 1044275 10445355 1044435 Fig 29 SINGLE INTEGRATION When the integration mode is single the sound level meter resets the integrated parameters i e Leg starts measuring the instant sound levels 1 e SPL and calculates the integrated levels regularly until acquisition stops This mode provides at the end of the measurement session the integrated levels over the whole acquisition period The parameter MENU gt gt Instrument gt gt Measurement gt gt Integration Interval allows to suspend the display update when set time is over Now to store displayed data press REC and hold 1t down for at least 2 seconds then select the manual storage option Press PRINT if you want to send displayed data to the serial output While display update is paused HOLD mode the sound level meter continues measuring and calculating the sound levels press HOLD to let display update start again If you do not wish to continue beyond the set integration time press STOP in order to finish the acquisition When the integrating mode is SINGLE and the sound level continuous recording is active the ac quisition is automatically stopped once the set integration time has been reached The PAUSE CONTINUE key can be used to suspend the calculation of integrated levels tem porarily while instant levels are still being measured During a pause and as far as the integrated levels displayed on th
9. files If in addition to measurements reports and or events were also recorded an intermediate page is displayed allowing the display of meas Ss ures reports or events to be chosen see CONTINUOUS RECORDING OF REPORT AND EVENT GROUPS on page 45 When you replay the reports or events in SLM view the report and event parameters are re spectively displayed When you display the events they are displayed individually with a pause be tween one and the next During the pause START allows the next event to be reloaded and PAUSE to restart the replay The replay of measurements associated with event recording automatically enables the pauses at the beginning and end of each event trigger These pauses correspond to the time markers recorded when the trigger spots the event and at the end when saving the relevant data If the recording contains measurements reports and events the measurements are not registered continuously but only in coincidence of the sound events detected see EVENT TRIGGER FUNC TION on page 37 Disabling of measurements outside the events in combination with event and report re cording allows two different recording speeds to be maintained slow and fast associated with re ports and measurements respectively The maximum recording resolution is used only during events by enabling the Measurement group parameters recording see CONTINUOUS RECORDING OF REPORT AND EVENT GROUPS on page 45 while for the othe
10. page 43 Each display mode can be enabled by setting the associated item to ON Only the enabled ones will be recorded independently of the active screen when the continuous recording 1s started In order to avoid occupying memory space uselessly we recommend that only the needed items are enabled and set the others to OFF Auto Store activates the auto recording mode of SLM OCTAVE and THIRD OCTAVE option HD2110 01 screens as described in THE RECORD FUNCTION on page 43 By enabling this feature report time and event trigger are disabled Leq Short activates the continuous recording of equivalent levels integrated over 1 32 sec ond intervals This parameter needs the HD2110 06 FFT option SLM Parameters activates the continuous recording of parameters of the SLM screen Profile Param activates the continuous recording of parameters of the Profile screen Oct Spectrum activates the continuous recording of octave spectrum T Oct Spectrum activates the continuous recording of the third octave spectrum Third Octave option required e FFT Spectrum activates the continuous recording of narrow band spectra as limited by the band selected in the Parameter FFT band of the Spectrum Analyzer menu This parameter re quires the FFT option Activating Auto Store function SLM OCTAVE and T OCTAVE screens will be automati cally stored when the integration time is elapsed When this function is activated with the multi
11. the sound spectrum has been divided The division of the spectrum into bands and the specifications of the processing unit that calculates the spectrograms have been defined by IEC 61260 international standard 160 Time constants and exponential weighting Further processing of the microphone signal are needed when fluctuating sound levels have to be measured To evaluate a sound level varying with time two type of instantaneous responses have been defined by international standards IEC 60651 IEC 61672 One named FAST simulates the ear response the other one named SLOW provides a sound level quite stable even in case of fluctuating noises The choice of the type of response of the level meter combines with the selection of fre quency weighting to provide a wide spectrum of possible measuring parameters for example the A weighted sound level will be measured with a FAST time constant Lrap to simulate the auditory sensation The FAST time constant is equal to 0 125s while the SLOW constant equals 1s When measurements with a FAST time constant are carried out the instantaneous sound level will be strongly affected by the pressure trend in the last octave of second while it will not be affected by what happened more than one second before The sound level with a SLOW time constant will strongly depend instead on the trend of pressure in the last second while it will not be affected by sound events occurred more than 10 se
12. 0 3 dB 0 1 dB over the range 65 108kPa ELECTRICAL CHARACTERISTICS Pre heating time Lower than 1 minute It is displayed with letter W flashing and overlapping the symbol of measurement status Power Supply Internal batteries 4 alkaline or rechargeable AA 1 5V batteries The sound level meter does not have a battery charger Measurement duration gt 10 hours with alkaline good quality batteries reducing to 8 hours when using the outdoor microphone unit HD WME fitted with heated preamplifier External batteries It is possible to connect external batteries to the sound level meter through the male connector for external power supply 5 5mm socket The positive pole power supply must be connected to the central pin The battery should supply 9 12V at about 200mA h The maximum external voltage is 15V Mains mains adapter with 9 12Vdc 300mA continuous voltage Switch off selectable auto power off When the power supply voltage goes below 3 8V the sound level meter stops performing measurements It is still possible to access stored data in the internal memory and to download them to PC using the serial interface Below 3 5V the sound level meter turns automatically off Stored measurements and configuration parameters are safely stored even without power supply Maximum input levels The maximum tolerable sound level equals 146 dB The level of the electrical signal applicable to the microphone input whe
13. 4 If you press Yes the instrument continues measuring the frequency response starting from 32Hz if you press NO the procedure will be finished No calibration parameter of the in strument is altered during this procedure which has just a diagnostic purpose 5 The response by octave steps is measured up to 16kHz 6 A message will advise the user if the instrument is not capable to complete this operation FREQUENCY RESPONSE 0 5dB Diff dB 0 5dB 100 10k Hz Consult the manual EXIT At the end of the procedure the instrument shows the difference of the frequency response of the microphone preamplifier instrument chain with respect to the previously stored one If the response shows remarkable deviations from flatness leading to a procedure failure refer to Troubleshoot ing 133 and if necessary contact our service department DIAGNOSTIC CHECK The diagnostic test is a program that verifies a series of electrical critical parameters The following are checked supply voltages microphone polarization and sensitivity the type of pream plifier and the temperature At the end of the procedure should it fail a table will be shown with the results of the inspection If necessary refer to Troubleshooting page 133 and if necessary con tact our service department REVERBERATION TIME MEASUREMENT The Reverberation Time program is available as an option on HD2110L sound level me ter The measurem
14. It reduces ZOOM the vertical scale of the time profile and of the frequency spectra ENTER key The ENTER key confirms the selected parameter When setting parameters from the menu to quit setting without saving a parameter just press any key except SELECT ENTER and the four arrows or press MENU Upon turning on press and hold down the ENTER key to load the factory setup RIGHT key The RIGHT key selects the next character in the active line of the menu It jumps to the next pa rameter during the selection of a measuring variable that needs the definition of more than a pa rameter see SELECT It expands ZOOM Y the vertical scale of the time profile and of the frequency spectra 141 DOWN key The DOWN key selects the following line in the menus or decreases the selected parameter Increases the vertical scale limits of the time profile and of the frequency spectra moving the graph downwards CURSOR Keypad wa It activates the cursors in a graph Press it repeatedly to activate in sequence the first cursor L1 the second one L2 or both of them in tracking AL To disable the cursors press the key again Use the LEFT and RIGHT key of the keypad to move the flashing selected cursor over the graph Relevant values are shown at the top of the display The time profile contains time and level or time distance and level difference between the two cur sors When the instrument works as spectrum analyze
15. Thus the amplitude of each of the sine and cosine components forming the audio signal is calculated using the Fast Fourier Transform FFT algorithm Finally the spectrum of amplitudes according to frequencies 1 e the spectrogram is finally displayed graphically 63 125 250 500 1000 4000 2000 8000 ft Hz The spectrum analysis added to wideband sound level measurement for example A weighted provides information on possible noise concentration on some frequencies tone com ponents or allows the distortion level to be defined Sound level meters usually perform spectrum analysis using narrow octave or third octave bands by inserting filters analogue or digital in order to measure only the components of a narrow fre quency range Using a set of filters covering the entire audio field the spectrum of constant per centage bandwidth bands can be obtained By applying this technique to modern digital sound level meter analyzers there is a limit on the number of different filters that can be implemented when performing a spectrum analysis in real time that is when the sound level is captured continuously When you want to increase the band number in which to subdivide the entire spectrum that is increasing frequency resolution the FFT technique must be used With this technique a segment of the sound trace sampled at high frequency is trans formed into a spectrum through the FFT algorithm Nyquist Theor
16. lt value gt CRLF A4 SET TIME lt hh gt lt mm gt CRLF AS SET DATE lt aaaa gt lt mm gt lt gg gt CRLF A6 SET x SLM PARAMETER lt Parameter abbreviation gt lt parameter attribute gt CRLF A7 SET PROFILE PARAMETER lt Parameter abbreviation gt lt parameter attribute gt CRLF A8 SET lt COMMAND gt lt value gt CRLF A10 SET lt COMMAND gt CRLF C1 KEY lt COMMAND gt CRLF C2 KEY lt COMMAND gt lt value gt CRLF DI STT lt COMMAND gt lt OPTION gt CRLF El DMP lt COMMAND gt CRLF If you enter properly in the string you can get either a help for the compilation of the desired command or the current status of the instrument configuration parameters Here are the formats of the commands that use the character 0 CRLF Provides the list of the groups of commands AY SET CRLF Provides the command list of the SET group A10 SET lt COMMAND gt CRLF Provides the current status of the specified command C3 KEY CRLF Provides the command list of the KEY group D2 STT CRLF Provides the command list of the STT group D3 STT lt COMMAND gt CRLF Provides the current status of the specified command E2 DMP CRLF Provides the command list of the DMP group 9 SET GROUP SETUP The following table shows the list of the commands of the SET group SETUP VERBOSE Acknowledge ON OFF default ON Always ON upon power on Percentile level 1 in 1 99 default 1 Percentile level 2 in 1 99
17. s RS232 port you have to use the dedicated serial null modem cable code HD2110RS fitted with a 9 pole female connector As alternative the sound level meter can be connected to a PC USB port by using the dedicated cable HD2110USB fitted with type A USB con nector n 16 Male connector for external power supply 5 5mm 2 1mm socket It requires a 9 12Vdc 300mA power supply The positive pole power supply must be connected to the central pin n 17 Jack type socket 2 5 mm for A weighted analog DC output and Fast time constant re freshed 8 times per second n 28 Jack 3 5 mm for the analogue input output LINE located on the right side of the coni cal part detail the jack can be enabled to work as instrument input through a menu specific item MENU gt gt Instrument gt gt Input Output gt gt Input otherwise it operates as an non weighted analogue output n 29 8 pole DIN connector for preamplifier or extension cable The connector located on the in strument front face has a positioning notch and a screw ring nut to ensure proper locking CERTIFICATO DI CONFORMITA DEL COSTRUTTORE MANUFACTURER S CERTIFICATE OF CONFORMITY rilasciato da issued by DELTA OHM SRL STRUMENTI DI MISURA DATA DATE 2012 06 13 Si certifica che gli strumenti sotto riportati hanno superato positivamente tutti i test di produzione e sono conformi alle specifiche valide alla data del test riportate nel la documentazi
18. 8 To secure protection for outdoor use you can use the threaded end D or you can apply the fit ting E on a tripod The terminal E has two threads and 1 4 x E o Ci Ci Cd F ha w 184 A9 DEFINITIONS Frequency is the number of oscillations per second expressed in Hertz Hz Wave Length is the distance between two adjacent maximum values of pressure expressed in me ters m Period is the interval of time necessary to make a complete oscillation expressed in seconds s Sound Propagation Speed is the distance covered by the sound wave front in the unit of time ex pressed in meters second m s The propagation speed depends on the medium and in the air at ambient temperature it equals to about 344 m s Decibel a decibel symbol dB is defined by X dB 20 108 0 x 0 where X 1s the measured quantity Xo 1s the reference value of the measurement itself to which correspond 0 dB Sound Pressure the sound pressure is the value of the change of atmospheric pressure caused by acoustic perturbations expressed in Pascal Reference Sound Pressure sound pressure taken as reference for the calculation of the pressure level it equals 20 10 Pascal and corresponds to the average human audibility threshold at a fre quency of 1 kHz Effective Value sound pressure effective value pms is the value of constant pressure that is ener getically equivalent to the instantan
19. CU MA 130 LOmax 105 2dB1ed5 L res 50 5dBlce5 REVERBERATION TIME Batt 100 Mem 15 Step 20 EDT 0 85s r1 00 T10 0 92s r1 00 Teo 0 96s r0 99 T30 0 95s r0 99 Reverberation Time calculated VIEW CURSOR From top to bottom are shown the maximum sound pressure level per octave band reached by the noise source LO max the background sound pressure level per octave band LO res the first decay time EDT and the three estimations of the reverberation time Tio T20 and T30 each with the correlation coefficient r The results of the measurement refer to the variable indicated in the first two lines of the table LOmax and LOres in the picture above To display another variable press the SELECT button the current variable starts blinking Using the arrows select the new variable from those available the sound pressure level per octave band from 125Hz to 8kHz LO the sound pressure level per third of an octave band from 100Hz to 10kHz LTO Pressing the right arrow selects the central frequency of the filter allowing to modify their value Pressing the left arrow returns to the selection of the parameter to be displayed Pp REV PARAMETERS DI REV PARAMETERS CL is CO REI 130 LOmax Lle 4dBL05 E 2LO0max Dl SdB 597 IdBles w L0res dBll5 EDT U bes rl 00 T10 0 79s rl 00 leu 0 84s T30 0 84s 0 b7s 0 79s 0 84s 0 84s Confirm the selection by pressing the ENTER key The sound level
20. Programmed acquisition event identification and synchronized audio recording Environmental noise module cod NS5 Analysis of acoustic pollution and environ mental noise sources Performs statistical analysis and spectral analyses automatically identi fies noisy events and noise sources with tonal and impulsive properties Analysis are made according to EU legislation regarding acoustic pollution For a detailed description of software features actually available please contact your authorized local distributor Firmware To be upgraded via the serial port with NoiseStudio software OTHER SPECIFICATIONS Printing E E Case E E E Time n Direct printing of logged parameters printing of a single event Continuous Printing Monitor Dimensions Length x Width x Height 445x100x50mm equipped with preamplifier Weight 740g batteries included Materials ABS rubber Date and time clock and date updated in real time Max deviation 1min month 122 REFERENCE STANDARDS IEC 60651 2001 Type 1 IEC 60804 2000 Type 1 IEC 61672 1 2002 Class 1 Group X IEC 61260 1995 by octave and one third octave bands Class 1 ANSI S1 4 1983 Type 1 ANSI S1 11 1986 by octave and one third octave bands Order 3 Type 1 D Wide Range EMC STANDARD REGULATIONS e Protection degree P64 e Safety EN61010 1 e Electromagnetic compatibility Immunity general standard EN61000 6 2 2005 Industrial environment e F
21. Stop bits 1 Flow control Hardware Cable length max 15m 118 Microphone connecting cable The preamplifier can be connected to the sound level meter body through a connecting cable up to 100m long CPA HD2110L specifications are not significantly affected by the con necting cable STATISTICAL ANALYSIS Sampling 1 8 s Classes from 0 5 dB Measurement range 21dB 140dB 4 percentile levels programmable between L to Loo Statistical graphs calculation and display Graph of the level distribution of probabilities Graph of the percentile levels from L to Loo SPECTRAL ANALYSIS Sampling 48 kHz Reference Attenuation 0dB Range of reference 20dB 130dB Reference Level 94dB Octave bands from 16Hz to 16KHz Third octave bands from 16Hz to 20KHz or from 14Hz to 18KHz with Third Octave option Frequency weighting only display linear Z C or A Temporal weighting only multi spectral analysis linear Leq or exponential Fast or Slow Central frequencies ratio base 2 Weighted average spectra multi spectrum even MAX or MIN with sampling time from 0 5s to 1 hour Narrow band spectrum FFT FFT option HD2110 06 Window Blackman Harris Overlap 66 LF Band from 7 Hz to 311 Hz resolution 1 5 Hz Uncertainty lt 0 7dB from 13 Hz to 290 Hz MF Band from 176 Hz to 2484 Hz resolution 11 72 Hz Uncertainty lt 0 7dB from 234 Hz to 2332 Hz HF Band from 1406 Hz to 21938 Hz
22. and simulates the perception of low sound levels When on the contrary the sound level is corrected by C weighting it 1s referred to as Lcp and simulates the perception of high sound levels When there is no interest in sound perception measurements are carried out using Z weighting LIN for IEC 60651 that represents a constant response to all frequencies in the sound field Spectral Analysis The spectral analysis by bands is used to analyze in detail the features of a complex sound For this analysis the range of audio frequencies between 20 Hz and 20 kHz is divided into bands typically with a constant percentage bandwidth corresponding to an octave or to a third octave The sound level is calculated for each band considering only the noise components with frequencies included within the band limits for octave bands the upper limit always equal the double of the lower limit while for the third octave bands the upper limit equals 1 26 times the lower limit so that an octave band is divided into three third octave bands For example the band centered at 1kHz will consider the sounds DE n between 707Hz and 1414Hz for octave and between 891Hz and 1122Hz for third octave bands 20 dB The analysis result is usually shown in a graph called spec trogram where the sound levels ou LA 4 are represented in graphic format 100 160 250 400 630 16k 25k 4k 6 3k 10k 16k i 4 for each of the bands in which 90 dB 60 dB a
23. default 10 Percentile level 3 in 1 99 default 50 Percentile level 4 in 1 99 default 90 OF x STAT PARAMETER Parameter for statistical analysis EVN ON TIME Trigger activation delay in seconds from 0 to 10 C EVN OFF TIME As Tagger deactivation delay in seconds from Oo 35 EVN PRINT _ A8 Fnablingeventtriggerprinting ON OFF default OFF Continuous recording of Profile parameter ON OFF de fault OFF Continuous recording of SLM parameters ON OFF de fault OFF Continuous recording of Octave spectrum ON OFF de fault OFF Continuous recording of Third Octave spectrum ON OFF default OFF Continuous recording of FFT spectrum ON OFF default OFF REP PARAMETERS Recording of REPORT parameters 1 5 ON OFF default OFF REP OCTAVE Recording of Octave spectrum ON OFF default OFF REP TOCTAVE Recording of Third Octave spectrum ON OFF default OFF EVN PARAMETERS Recording of EVENT parameters 1 5 ON OFF default OFF EVN OCTAVE Recording of Octave spectrum ON OFF default OFF EVN_TOCTAVE Recording of Third Octave spectrum ON OFF default OFF EVN STATISTICS NC Statistical recording ON OFF default OFF CAL LEVEL Acoustic calibrator level in dB 90 0 130 0 default 94 0 default 94 0 MIC_CORR WND SHL CORR Wind shield correction OFF SAV WME default OFF 94 AMB MIC CORR Microphone drift corrections ON OFF default ON MIC CT Thermal dri
24. disable the AutoDetect function Menu Option gt gt Port Set tings and set the connection directly to the COM port to which the instrument 1s connected with the same baud rate of the sound level meter Menu gt gt Instrument gt gt Input Output gt gt Baud Rate 134 5 It is not possible to activate continuous recording By pressing REC and RUN the instrument starts measurements without recording The instrument does not have available memory for additional data Download the data and or erase the memory 135 KEYBOARD DESCRIPTION ALPHA key This key allows to enter alphanumeric characters in the recording title in case of single re cordings the header of the recording file is shown when the REC key 1s hold down for at least 2 seconds the progressive number and the date are entered by the instrument and cannot be modi fied Some alphanumeric characters can be entered in this string initially empty The request for entering a header also appears after a multiple logging session took place see also the description of the REC key below Press ALPHA The cursor will change its form from a full rectangle to a line indicating that you are in character entry mode Press the desired alphanumeric keys and press ENTER to con firm each character If the letter entered is different from the last one you don t need to press EN TER to confirm and the string will automatically move forward Use the DOWN key to delete
25. resolution 93 75 Hz Uncertainty lt 0 7dB from 1875 Hz to 21938 Hz Isophone curves calculation and display with Third Octave option According to ISO 226 2003 only unweighted spectra 119 REVERBERATION TIME MEASUREMENT OPTIONAL Reverberation time calculation by sound source interruption with wizard Reverberation time calculation with impulse response integration technique Schroeder s back integration and background noise correction algorithm Frequency Range octave from 125 Hz to 8 kHz and third of octave from 100 Hz to 10 kHz Third Octave option Spectrum sampling 32 spectra per second Measurement range 110 dB Optimized interpolation of the decay profile with correlation coefficient calculation Ordinary Least Squares method Simultaneous calculation of EDT T 10 T 20 T 30 estimations of the reverberation time T6o according to ISO 3382 standard Possibility to calculate directly the Teo on the decay sound profile by positioning of cursors over an interval selected by the user VISUALIZATION Graphic display Backlit 128x64 pixels on a 56x38mm surface Display modes SLM sound level meter screen with 5 selectable parameters Time profile of a selectable parameter with sampling time from 1 8s to an hour Octave band spectra between 16 Hz and 16 kHz and third octave optional spectra between 16 Hz and 20 kHz or from 14Hz to 18KHz Narrow band spectrum FFT from 7Hz
26. 4kHz with 1ms total duration s OF Leq Short Profile 80 70 level dB 60 50 40 34 35 36 37 38 39 40 time s Fig 18 Leq Short Profile The FAST level profile was been inserted hatched for comparison From the Leq profile with sufficient time resolution you can rebuild the FAST SLOW and IM PULSE levels with this formula LA At LAeg M LA 10 log 1 0 ee 7 10 ee 7 where LA is the 1 th exponential level with t time constant calculated from the profile of the Leq Short LAeq integrated at At intervals For example the FAST level is calculated with the formula LAF _1 At LAeq 1 At LAF los log 10 10 ep 0 10 ee 0 125 The calculation of the pressure level with IMPULSE time constant is more complex as time con stants are different for increasing and decreasing levels respectively equal to 35ms and 1500ms After calculation of the profile with time constant equal to 35ms using the previous formula the IMPULSE level can be calculated with the formula i a LAI 10 ogg MAX 0 ee i Where the logarithm argument is the maximum value between the previous level exponen tially weighted with time constant equal to 1500ms and the exponential level with time constant equal to 35ms LAI j In the following figure the FAST SLOW and IMPULSE levels are recalculated from the Leq Short profile at 1 32s with the previous formulas FAST SLOW IMPULS
27. 60942 standard acoustic calibrators are used For this purpose can be used the HD2020 and the HD9101 type 1 acoustic calibrators The check that the reference sound level provided by the acoustic calibrator is correctly measured by the sound level meter it 1s normally acceptable that the difference between the sound level measured by the sound level meter and the nominal level of the calibrator be lower than 0 5dB has to be carried out before and after a series of measurements to ensure that measured val ues are correct When the difference between calibrator reference level and measured level is greater than 0 5dB it s necessary to execute a new calibration Warning to prevent damaging the sound level meter it is important during the calibration procedure to follow carefully the on screen instructions and the indications provided by this manual Operating Procedure Switch on the sound level meter if necessary press STOP to finish the measurement on progress and perform the following procedure The program will automatically control that the warm up time indicated by a flashing W is over 1 Press PROG and with the help of the DOWN arrow select Acoustic calibration Press SELECT to start calibration 2003 01 0L 10 00 00 ACOUSTIC CALIBRATION Last 2003 01 01 10 00 Calibr level 94 0dB Batt 15 Mem Ad 54 SELECT PROGRAM _ Electric Calibration Acoustic Calibration Frequency Response DI Y IL Leg
28. Acoustics Measurement of sound insulation in buildings and of building elements Part 7 Laboratory measurements of impact sound insulation of floors was issued in 1998 The on site measurements are carried out on completed buildings and concern the entire ceiling The measurement procedure is similar to that used in the laboratory and gives the value of the stan dardized treading noise level Ln with lateral transmission and the standardized treading level Lnr The normalized impact noise level L is calculated by using the same methods described for the laboratory The standardized impact level Lar is calculated as follows T LE 10log 7 0 where T3 is the reverberation time of the receiving environment and To is the reference reverbera tion time equal to 0 5 s 177 A8 OUTDOOR UNIT HDWME ASSEMBLY DISASSEMBLY AND MAINTENANCE Below are the operational guidelines for disassembly assembly and maintenance of the outdoor unit HDWME A8 1 Disassembly To completely disassemble the unit a 1 5mm male hex key and a 14mm wrench are needed To separate all components of the unit proceed as follows to extract the group preamplifier microphone capsule to calibrate start from step 3 1 Remove the bird spike by loosening the three hex head screws at the base of the windscreen 2 Pull up the windscreen HDSAV3 and rain protection HDWME2 178 3 Unscrew the terminal placed at the lower end of the stem A
29. Autofeed Enabled Connect the sound level meter to the printer by means of the special HD2110RS cable Follow the instructions in the documentation supplied with the printer 105 CONNECTION TO A PC WITH USB INTERFACE The HD2110L sound level meter fitted with USB interface can be connected to a PC s USB port by using the HD2110USB cable The USB port connection requires the previous installation of a driver contained in the Noise Studio software Before connecting the USB cable to the PC install the Noise Studio software With Windows 7 operating systems it s necessary to boot the PC disabling the request for driver signature as explained in the USB driver s installation guide included in the Noise Studio CDRom Proceed as follows l 10 Set the instrument menu item MENU gt gt Instrument gt gt Input Output gt gt Serial De vice to USB Confirm and exit from the menu Do not connect the instrument to USB port until requested from the wizard Insert Noise Studio installation CDRom and wait for AutoPlay window to appear In Win dows Vista and Windows 7 operating systems it s shown the window below select auto run exe execution see note 1 in the next paragraph gt AutoPlay Lu 4 Unit DVD RW E CDRoot a Esegui sempre questa operazione per software e giochi Opzioni generali Apri cartella per visualizzare i file The starting screen of N
30. Fig 55 The cumulative probability will be null for levels higher than the maximum measured level The percentile levels are calculated interpolating the cumulative distribution For example if from the analysis of the noise of a traffic road you detect that the sound level usu ally A weighted examining the auditory impact remains higher than 74dB half the time the per centile level Lso is 74dB The integrating sound level meters directly supply the time integrated parameters such as equivalent level and sound exposure level in addition to maximum and minimum On the other hand the statistical analysis is a prerogative of statistical analyzers 164 Noise Dose The measurement of the Dose of noise is used in the field of noise monitoring in a work ing environment meant as a percentage fraction of a maximum daily exposure to noise The organizations taking care of safety in working environments have defined some stan dards for the measurement of the noise dose considering the energy content of sound pressure and comparing it with a maximum daily equivalent level over an 8 hour time interval that 1s in Italy equal to 85 dBA A weighted equivalent level when no hearing protection is available ISO 1999 standard considering only sound energy sets out that an increase of 3 dB in the sound level halves the exposure time to keep the dose equal Italy applies ISO 1999 definition Health corporations in other countries hav
31. THE RECORD FUNCTION on page 43 The REC key combined with START STOP RESET also activates the data logging 139 Starting from the STOP condition if you press REC and hold it down and then press START STOP RESET the data logging of measured values is started stored views are those se lected from MENU gt gt DataLogger one or more of the available views can be enabled To stop logging press START STOP RESET you will be requested to enter the heading The in strument adds to the heading a progressive identification number that cannot be modified as well as the current date Press ENTER to confirm or ALPHA to enter or edit the title GPQR amp RUN STOP RESET key n a If you press RUN while in stop all the initial values of the integrated measurements like Leq SEL MAX MIN levels will be first cleared RESET and then measurement starts Pressing the key again STOP the measurements will be stopped If pressed while in pause all integrated parameters will be cleared During the replay of stored data if you press this key while in pause the next data will be displayed if you press it and hold it down the replay will be executed in fast forward mode 7TUV S SELECT key This key activates the adjustment mode of displayed parameters by selecting them in se quence For example the following parameters can be selected and adjusted in the time profile dis play sampling interval and displayed parameter Use t
32. UP and DOWN keys to modify the selected parameter Press ENTER to confirm a change or press MENU to cancel it Press MENU to exit the menu or the submenu Some of the parameters available via menu can also be set directly during the measurement phase like for example integration interval measuring range etc by use of the SELECT UP DOWN LEFT RIGHT and ENTER keys When you access the menus the available memory will be displayed as well as battery level date and time See a detailed description of the menu items on page 49 and following pages ae Q PRINT key Press PRINT to send the screen page to the RS232 serial interface in a printable format Data can be downloaded to a PC or sent to a serial printer like for example the HD40 1 see page 105 directly connected to the sound level meter In this last case set the parameter MENU gt gt In strument gt gt Input Output gt gt Serial Device to PRINTER to get a printing format compatible with a portable 24 column printer If the key is pressed and soon released the single screen page is sent to the serial line the let ter P will be displayed If the key is hold down the continuous printing Monitor will be started and the letter M will be displayed to stop it press PRINT again or press START STOP RESET to stop logging 3GHI PROG key The PROG key is used to access the menu of the instrument programs Use the UP and DOWN arrows to select t
33. Us 01 00 05 2003 01 01 10 00 00 Batt 15 Mem Ad 54 SELECT PROGRAM re O A dBA Memory Navigator Electric Calibration Acoustic Calibration Frequency Response DLD aac 793 ABC Diagnostic Check Fig 37 Use the UP and DOWN arrows to select the calibration to be carried out O WXYZ 2003 01 01 10 00 00 Batt 354 Mem 3d 54 SELECT PROGRAM Electric Calibration gt TUV Acoustic Calibration Frequency Response Diagnostic Check 60 when you press SELECT the calibration display will appear ELECTRIC CALIBRATION Last 2005 01 01 10 00 Calibr level 4 0dB Leq O Uasc Run calibration YES NO CURSOR a al ee The screen shows date and time of the last calibration and the calibrator sound level accord ing to the configuration of the respective parameter MENU gt gt Calibration gt gt Calibr Level An swering positively to the request to continue the selected calibration program will start Calibration procedures are carried out in automatic mode and the operator is guided by the on screen instructions The calibration result is displayed when the procedure is over and you can choose whether to con firm it or not If confirmed the new calibration will be stored In order to grant the highest measuring accuracy when the wind shield mounted select Wind Shield Correction from the CALIBRATION menu to apply a correction to the sound level met
34. and the ground The Delta Ohm sound level meters per form spectral corrections to the measures to ensure tolerances in accordance with the IEC61672 class 1 in every situation The easiness of disassembly and reassembly of the unit allows to perform periodic testing of the elec tro acoustic characteristics the same way as a stan dard measurement microphone using a standard calibrator for 2 microphone The unit consists of a central body and the follow ing parts HD SAVS3 windscreen 3 HD WMEl anti bird spike 4 HD WME2 rain shield 2 HD WMES stainless steel holder 1 Microphone capsule with optimized frequency response for free field Microphone preamplifier HD 2110PW or HD2110PEW heated preamplifier for 200V polarized or electret microphones with CTC calibrator and differential driver HD 2110PEW heated preamplifier for prepolarized microphones with CTC calibra tor and differential driver Connection cable 5m other lengths up to 100m available on request For more details on the outdoor unit HDWME refer to the chapters dedicated to calibration on page 62 and its assembly and disassembly in appendix on page 178 The Preamplifier The preamplifier amplifies the weak signal provided by the microphone The preamplifier has a gain selectable between 0 and 10 dB and is supplied with a charge partition calibration device which allows to measure the frequency response of the whole ampl
35. are both active The parameter level being lower than the minimum measurable level is indicated by a series of dashes Press CURSOR again to disable the cursors The instrument full scale is determined by the selection of the input gain by choosing from the menu MENU gt gt In strument gt gt Measurements gt gt Input gain Dl E SPECTRUM MODE BY OCTAVE AND THIRD OCTAVE BANDS The spectrum analyzer operation mode allows the visualization of frequency spectrum by octave bands from 16Hz up to 16kHz and by third octave bands from 16Hz to 20kHz Third Oc tave option The spectral analysis is carried out and possibly stored on unweighted samples Z while the display can also be A or C weighted for a fast evaluation of audibility of different spec tral components The spectrum by octave bands or by third octave bands is combined for possible compari sons with a wideband level that can be set as A C or Z weighted The selected wideband weighting is called auxiliary weighting and plays an active role in the maximum or minimum multi spectrum analysis The spectrum recording mode can be chosen between e Linear averaging AVR with integration times from Is up to 99 hours e Multi spectrum MLT even maximum MAX or minimum MIN with programmable par tial integration interval from 0 5s to 1h either linearly LIN or exponentially EXP averaged with FAST 0 125 s or SLOW weights 1 s The average
36. by measuring partial Leg If you need to get the total Leq after measuring partial Leg you can use the formula y L T oe Lo 10 108 p 10 1 186 where T vi Example Let s suppose we measured Leg 80dB over 1 h Leq 2 90dB over 2 h Leg3 50dB over 5 h L eq l L Las T 10 7 10 7 10 I 1 1 Lar 10 log Leg 1 Leg 2 Leq 3 partial equivalent levels T T2 T3 integration times of partial equivalent levels Leg t total equivalent level In the example T 1h 2h 5h 8h The result 1s 1 10 2 10 5 10 84 2dB 8 LT 10 Joeu Continuous Equivalent Sound Pressure Level Impulse weighted referred to as Lareg it is de fined over a T time interval as Lipu E hieg T 10 10 4S d t T 0 where T is the time interval under examination fictitious variable for the integration over elapsed time up to t measurement instant par the instantaneous squared pressure with A frequency weighting and Impulse time constant p o the square of reference pressure 187 Sound Exposure Level represented by the Lg symbol or SEL it is defined over a given tl t2 time interval like jz De 0 where T to t is the time interval under examination p t the square of instantaneous pressure po the square of reference pressure Leg t continuous equivalent sound pressure level over T interval To l1s The lev
37. ccccscccccccccccccccccccccccccccccccccccccccccccccccccccccccoccees 88 INSTRUMENT STORAGE iii Ss 89 SERPALZINTERFACE cabala aaa 90 COMMUNICATION PROTOCOL a al 92 AS unable ees 93 KEPGROUP tl dt 99 STEGROBP STATU SA OS 100 DMP GROUP DUMP Jianne aca 102 CONNECTIONTO ANO a Laion ri alia 103 CONNECTION TOA PRINTER iii 105 CONNECTION TO A PC WITH USB INTERFACE ccccscosceccecceccscecceccecescescescescscescscesescescescessecescescescscessesceseecescascesceses 106 INSTAECATION NOTE anale 107 VERIFICATION OF PROPER DRIVER INSTALLATION ccccecescecscecscecccecccecesescecesceceececeecsceececesescsesctsescesescucesceseees 107 HD2010MC MEMORY CARD READER 2 cccccccccccccccccccccccccccccccccccccccccccccceccccccccccccccccccccccccecceccscccccccoccees 109 DESCRIPTION OF THE INTERFACE FOR MEMORY CARD HD2010MC ccc ccceccsccccccecceccecesceccescecescesceseecescesceseeses 109 PREPARATION OFA NEW MEMORY CARD clelia ble 109 CONNECTION OF HD2010MC TO THE SOUND LEVEL METER AND USE OF THE MEMORY CARD cceccececcececcececeececeecs 110 POR USING DATA DIRECTLY PROM MPC e iO ila le 111 DATA TRANSFER FROM SOUND LEVEL METER TO MEMORY CARD cccececesceccecececcecescscccscucescucescecescecescscscscesescusesces 111 TECHNIGAT SPEGIFNCATIONS olii a tsa a dN lie i ll ilo 111 TECHNICALSPECIRICATIONS Reload lil iaia 112 NEEFROLOGICALGHARACTERISTICS silla riali ade 112 ECECPRICALGHARACTERISTICS rodi ee E II OLI 117 STATI
38. collisions or vibrations to the receiving environment via the solid structure of the building Together with the measurement of the insulation from airborne noise it permits classification of the buildings acoustic insulation properties The reference standards are ISO 140 6 and ISO 140 7 Instrumentation and measurement conditions The measurement of the impact noise insulation is the sum of lab measurements and on site measurements The specific properties of the construction materials used are measured in the labo ratory while the installation techniques and performances of the materials used in the construction are checked on site The necessary instrumentation to perform the measurements is composed of a standard impact sound source measurement microphones of at least class 1 according to IEC 651 and IEC 804 The measurement equipment must be calibrated conforming to the IEC 942 standard The frequency must be analyzed using 1 3 octave band filters according to IEC 1260 The fre quency range must go from at least 100Hz to 5000Hz The standard sound source is described in Appendix A of ISO 140 6 and consists of a series of 5 hammers of 0 5 kg each falling from a height of 4 cm in a sequence of 10 impacts per second Even though the effect on the floor and the sound level perceived in the lower floor are much higher than those usually associated with human steps such levels are necessary to ensure that the sig nal noise ratio is good
39. e Recording of the reports every 10 min Menu gt gt Instrument gt gt Measurements gt gt Report gt gt Int 10 min containing the 5 PARAMETERS Menu gt gt Recording gt gt Report gt gt Pa rameters gt gt ON the SPECTRUM FOR THIRD OCTAVE Menu gt gt Recording gt gt Report gt gt Spectrum T Ott gt gt ON and the STATISTICAL ANALYSIS Menu gt gt Recording gt gt Report gt gt Statistics gt gt ON 6 7 10 66 481 3384 bytes hour gt maximum duration 8MB 3384 24 103 days The table below gives the sound level meter storage capacity in Auto Store mode recording auto matically at the end of each period equal to the set integration time the SLM screen parameters with average spectra AVR by octave and by third octave bands The storage capacity 1s expressed as the time necessary to get the memory full Integration Interval Capacity Ss gt 45days 150 A3 MEASUREMENT OF THE SPECTRUM OF THE SOUND SIGNAL USING THE FAST FOURIER TRANS FORM FFT The Fourier theorem shows that any wave form in the time domain can be represented by the sum properly weighted of a series of sine and cosine functions The spectrum analysis through FFT consists of calculating the widths that is the weights of the sine and cosine components forming the sound signal The sound level is sampled at high fre quency and then compared to the concerned audio band for example 48kHz
40. gt Overload Level you can program the maximum measurable limit at lower levels see page 112 An empty arrow indicates that the limit has been exceeded while a full arrow indicates that the overload is in progress No sub range indication is needed because the minimum measurable level is limited only by the electrical noise as shown in the technical specifications The integration time Tint programmable between 1s and 99h is displayed to the right of the overload indicator When the integration mode is set on MULT the Tint symbol on the SLM will flash see the DESCRIPTION OF THE DIFFERENT INTEGRATION MODES chapter on page 39 15 In the right corner at the top there 1s the battery symbol The more the symbol 1s empty the more the battery has run down When the instrument autonomy reaches 10 corresponding to about 30 minutes the battery symbol will start flashing A protection device prevents the instrument from making measurements with insufficient battery levels and automatically switches off the 1n strument when the battery level is at the minimum The battery level expressed in percentage 1s visible in the menu main screen page and in the program page press MENU and PROG to access them To jump back to the measurement screen press MENU and PROG again Pressing SELECT you will select in sequence the parameters relevant to the displayed page While the selected parameter flashes you can change it with the UP a
41. gt Serial Device eee The instrument automatically gets into the modem configuration mode The successful con figuration will be confirmed by the message Modem Configured Should the configuration fail the sound level meter will automatically switch to PC mode and the message Configuration failed will be displayed When the modem is configured it is possible to make the remote connection running NoiseStudio Monitor program Possible under voltages on the modem do not create problems as the configura tion is recorded and automatically loaded on turning it on The table shows the HD2110CSM cable connections M12 connector i 8 pole DB25 serial connector o 103 Connectors front external view Fig 39 HD2110CSM cable connector pin numbers 104 CONNECTION TO A PRINTER The HD2110L sound level meter can print the levels displayed in a format compatible with a portable 24 column printer such as the HD40 1 Printer and sound level meter must be configured properly Sound level meter configuration 1 Set the parameter MENU gt gt Instrument gt gt In put Output gt gt RS232 Baud Rate to 38 4k 2 Set the parameter MENU gt gt Instrument gt gt In put Output gt gt Serial Device to PRINTER Printer configuration 1 The printer Baud Rate must be the same of the sound level meter 38400 baud 2 Data bits 8 3 Parity None 4 Stopbit 1 5 Handshaking Xon Xoff 6
42. impulse response moving backward from the end of the decay up to the instant when the impulse was received Particular attention must be given to the choice of the start time for the integration Indeed by choosing too long a time that is to say longer than the decay interval of the sound level an inte grated decay curve will be obtained that will show an imaginary double gradient caused by the inte gration of the background noise In contrast by choosing a time too close to the beginning that is to say near to the instant when the impulse was received the measurement dynamic will be reduced which is useless The ideal choice is the right compromise between maximizing the decay length and minimizing the effect of the background noise Consequently the measurement of the background noise is extremely important when using the impulsive source technique and must be measured with the maximum care in order to avoid completely distorting the measurement of the reverberation time Delta Ohm s sound level meter HD2110L can automatically perform the backward integra tion of Schroeder by applying advanced numeric techniques to remove the undesirable effects of the background noise In the case where two different gradients of the integrated decay curve can be identified the two relevant estimated reverberation times can be reported from the slope of the respective decay seg ments which must be at least 10 dB each Early Decay Time EDT In a
43. instrument To ensure that measurements performed by the sound level meter are made in conditions of stability the letter W will flash over the indicator of the instrument status throughout the whole period needed to stabilize the microphone polarization signalling the warm up period necessary every time the instrument 1s switched on The HD2110L sound level meter stores all calibration typical parameters with respective date and time in a reserved area Calibration types can be Acoustic calibration by means of a 1kHz sound level generator like HD2020 Electric calibration Capacitive Transducer Calibration with the possibility to measure the frequency response of the whole measurement chain microphone included Calibration is necessary every time that the calibrator level measured by the sound level meter deviates from the nominal value for more than 0 5dB The acoustic calibration includes the capacitive transducer one and before carrying it out it is suggested to ensure that the environment where you are operating is suitable no sudden sounds no vibrations on the surface where the instrument is placed instrument thermal stability The electric calibration allows a quick inspection of the electric parameters of microphone and instru ment The calibration procedure includes the inspection of the microphone polarization Calibration programs are in the PROGRAMS menu accessible through the PROG key PO I
44. level display The figure shows the percentile levels graph corresponding to the distribution of probabilities shown in the above paragraph From the sound level distribution of probabilities you can calculate the cumulative distribu tion of probabilities on the same classes The cumulative distribution is equal to 100 for the classes with levels under the measured minimum and 0 for the classes with levels over the meas ured maximum From the minimum measured level class the cumulative distribution decreases for the relevant probability of each class until the class corresponding to the maximum measured level where it becomes zero The L Loy percentile levels are calculated interpolating the cumulative distribution of probabilities The vertical axis shows the sound levels in decibels and the percentile index is on the horizon tal axis The display shows the sampling interval in the left lower corner and the chosen measure ment parameter for the statistical analysis in the first line left of the status indicator and the possible overload indicator The amplitude of the vertical scale corresponds to 5 divisions The amplitude of each division is called scale factor of the graph and appears in the middle of the vertical axis This parameter is selectable in real time among 20dB 10dB or 5dB by division The scale factor can be set using the RIGHT zoom and LEFT zoom keys Use the UP and DOWN arrows to set the graph full scale
45. must be lower than T 12 There are no advantages in reduc ing the linear integration time below this value The HD2110L executes a linear integration of the sound level in 1 32s intervals it s therefore able to calculate the reverberation time according to ISO 3382 starting from reverberation times equal to 0 375s The measurement device estimates the reverberation time by measuring the gradient of the decay curve over a decay of at least 20 dB and then estimating the necessary time for a decay equal to 60 dB according to the definition of reverberation time Of course with this type of device the recording and the measurement need to be repeated for all the positions of the source and the mi crophone and for all the octave and third octave frequency bands too Using a modern analyser like the HD2110L the analysis can be performed in parallel for all the bands this is known as multi spectrum analysis as a spectral analysis is carried out at regular time intervals Estimations of the reverberation time T 19 T29 e T30 The reverberation time measurement taken by analyzing a reverberation sample equal to 60 dB is usually not feasible due to the insufficient signal noise ratio of the source The reverberation time is usually estimated starting from the measurement of the decay time over a limited stretch equal to 20 dB or 30 dB starting from 5 dB under the stationary level These reverberation time es timations are indicated as T6o 20 or T29
46. of a table and graphically See the paragraph describing the results Reverberation Time Analysis of the Re sults SO Integrated impulse response If you use an impulse as the sound source for the measurement at step 04 select the item ZM PULSE REVERBERATION TIME REVERBERATION TIME Batt 100 Mem 957 Batt 100 Mem 957 Step DU Step DU Select sound source EXIT NOISE IMPULSE Esos Cd DOr E CO and as indicated in the next page activate the source of the impulsive noise gun shot balloon explosion within 5 seconds from pressing the button The sound level meter will automatically measure the environment noise decay and will perform the calculations For the entire duration of the measurement 6 seconds from the source being turned off avoid undesired noises that could affect the measurement The following page will appear at the end Activate the source Within 5 seconds REVERBERATION TIME Di REV PARAMETERS Batt 100 Mem 15 CL RM 130 LOmax 105 2dB1e25 Step c0 50 5dB125 0 85s Reverberation Time 0 9258 calculated 0 96s VIEW 0 95s CURSOR The sound level meter gives a complete description of the measurement both in the form of a table and graphically See the paragraph describing the results Reverberation Time Analysis of the Re sults The next step is accessed by pressing PROG where you can save SAVE key review the values again VIEW key or close the curren
47. once the Tint time is over the inte grated levels will be set to zero and a new cycle of measurements starts Recording in Auto Store mode allows to store on memory octave and third octave spectra in AVR mode together with the parameters displayed on the SLM screen at a frequency equal to the Tint time To activate a cursor at any moment press CURSOR If you press it again a second cursor will be activated if pressed for the third time both cursors will be activated in tracking Use the LEFT and RIGHT arrows on the keypad to shift the selected cursors to the desired position to detect the measured level and the nominal frequency of the selected band Press CURSOR again to disable cursors When the cursors are visible press and hold CURSOR down for more than 2 seconds to ac tivate the calculation of the isophone curves as described in the paragraph Spectrum mode by octave and third octave bands and Using cursors and isophone curves on page 24 129 STORAGE OF MEASUREMENTS The HD2110L offers three different storage modes Third Octave and FFT spectra are available as options I The Continuous Recording is activated pressing simultaneously REC and START keys and implies the storage of one or more screen pages SLM PROFILE OCTAVE THIRD OC TAVE FFT and Leq Short profile The screen pages to be stored can be selected one by one in the Recording menu The SLM screen when enabled 1s recorded every 0 5
48. operator during measurement alters the sound field thus keep the instrument as far as you can from your body For a better accuracy position the sound level meter on the tripod above all for spectral analysis Best results are got if only the preamplifier is mounted on the tripod and the extension cable is used to connect it to the instrument 167 CLASSIFICATION OF ACOUSTIC SIGNALS Acoustic signals can be classified according to the possible analysis techniques First of all we can divide the acoustic signals into two classes stationary and non stationary signals Stationary Signals these are the signals which average values mean value equivalent value etc do not depend on time Among the stationary signals there are the deterministic and the random signals Deterministic Stationary Signals these are the stationary acoustic signals that can be described with a function of time that is as a sum of sinusoidal signals These signals are periodical if the si nusoidal components are all multiples of a main frequency They are also called quasi periodical Random Stationary Signals these are the signals that can be described only in statistical terms Among the non stationary signals can be identified continuous and transitory signals Continuous Non stationary Signals these are the signals that never have a null value Transitory Non stationary Signals these are the signals that have a non null value only in deter mined
49. second are displayed as maximum band levels linearly integrated every 1 32s The page of the six numeric parameters is not active un til the reverberation time has been measured When the source level has been verified and the signal noise ratio is sufficient the rever beration time measurement can be started The sound level meter guides the user through the whole measurement procedure by means of messages on the display The sound level meter and the noise source must be set up impulsive or continuous according to the type of measurement selected and when ready continue by pressing the PROG key Measurement of the background noise The first step involves the measurement of the background noise without any other noise sources when ready press the GO key REV PARAMETERS REVERBERATION TIME Batt 100 Mem 45 Step Dl Background noise measurement GO The current noise level is recorded and integrated for two seconds and then saved in the sound level meter internal memory In the next step 04 the type of noise source that will be used for the measurement is chosen con tinuous noise source NOISE or impulsive source IMPULSE According to your choice the measurement session will proceed in two different ways first the sound source interruption tech nique will be illustrated and then the integrated impulse response REVERBERATION TIME Batt 100 Mem 957 Step DU Select sound source EXIT NOISE IMPULSE
50. so as to issue energy only in the band concerned with a perceptible improvement of the signal noise ratio In the case of the parallel analysis by therefore simultaneously acquiring the decay of all measurement bands the source will usually be a pink noise source that can overcome by at least 30 dB the background noise for all the concerned bands at least from 100 Hz to 5 kHz To perform the measurement firstly a stationary regular sound needs to be generated by maintaining the source on at a constant volume for a time of at least one fifth of the reverberation time In addition to the sampling of the constant level reached in the environment and of a decay of at least 20dB the background noise needs to be sampled in order to assess the measurement condi tions Because of the random nature of the excitation signal the measurement technique with the sound source interruption presents a remarkable variability in the measurement especially at low frequen cies and therefore requires the calculation of averages in order to reduce the irregularities of the de cay curve and to improve the accuracy of the slope measurement The minimum number of meas urements according to the standard is equal to 3 According to ISO 5725 the repeatability of the reverberation time measurement according to the number of averages calculated is equal to 200 370 gt Fay BNT BNT ta respectively for T39 and T29 where r is expressed as a percentage a
51. spectrum AVR is linearly integrated band by band throughout the integration time shared with the SLM mode from 1s to 99h If integration is performed in single mode MENU gt gt Instrument gt gt Measurement gt gt Inte gration Mode SINGLE the instrument will automatically switch into the HOLD mode when reaching the set integration time allowing to check the result and eventually print or store it Press HOLD to continue with the display update If the continuous recording is activated by pressing simultaneously REC and START keys the integration time will act like a timer stopping automatically the measurement when the time Tint is elapsed If the acquisition mode is AVR and the integration is in multiple mode MENU gt gt Instrument gt gt Measurement gt gt Integration Mode MULT the instrument will automatically reset the levels at the end of the programmed integration time starting a new integration cycle see the DESCRIPTION OF THE DIFFERENT INTEGRATION MODES on page 39 When Auto Store function is active see THE RECORD FUNCTION on page 43 spectra acquisition 1s automatically set to linear averaging AVR The multi spectrum analysis MLT allows to measure a continuous sequence of spectra linearly or exponentially averaged over the programmed profile time from 0 5s to 1h While line arly averaged spectra provide the equivalent levels for each band on the profile time the exponen tially averaged
52. tave from 100 Hz to 5 kHz ISO 10534 1 Standard The ISO 10534 Standard Acoustics Determination of sound absorption coefficient and impedance in impedance tubes Part 1 Method using standard wave ratio was issued in 1997 According to this standard a noise is generated inside a tube by placing a speaker at one end and a sample of the material to be analyzed at the other end The acoustic absorption coefficient can be calculated from the ratio between the maximum and the minimum sound pressure inside the tube moving a microphone along the longitudinal axis This method has the advantage of being able to perform the measurement on small samples of material and takes advantage of not needing a test room The repeatability of the measurement is optimum but gives in this case a measurement of the absorption coefficient only with a normal angle of incidence 173 A7 2 MEASUREMENT OF THE AIRBORNE SOUND INSULATION Airborne propagation is the propagation of sound energy from the emission environment to the receiving one both directly or through dividing walls Together with the measurement of the in sulation from impact noises it permits the classification of the acoustic insulation properties for the buildings The reference standards are ISO 140 3 and ISO 140 4 Instrumentation and measurement conditions The measurement of the airborne insulation consists either of lab measurements or on site measurements In the laboratory t
53. the instrument has reached thermal equilibrium that there is no condensation on metal walls and that tempera ture relative humidity and pressure are within the limits specified by the manufacturer The use 166 of the sound level meter in conditions of high humidity with consequent condensation can cause damages Check the battery level of both sound level meter and calibrator Check that the sound level meter is calibrated by measuring the calibrator reference sound level This inspection has to be repeated at the end of measurements to assure the sound level meter stability Use the windshield when necessary The shield grants a good protection against shocks Its use is suggested also indoor above all in presence of machines with mechanical parts in movement When available activate the proper adjustment on the sound level meter to compensate the shield effect on the microphone frequency response Determine the type of acoustic field where you have to operate and eventually apply the correc tions that the sound level meter provides Consider the measuring environment the kind of sound source and the position in which measurements are carried out Position the microphone according to the type of acoustic field considering also the correction made by the sound level meter if any The choice of frequency weighting and of time constant usually depends on the standard used to carry out measurements Consider that the presence of an
54. the pro file view sound level LEV it can be programmed with 1dB steps Trigger Polarity it 1s possible to choose increasing POS or decreasing NEG levels for the trigger on the profile view sound level LEV For the increasing levels trigger the Trigger Threshold will be higher than the Bottom Threshold for the decreasing levels trigger the Trigger Threshold will be lower than the Bottom Threshold Minimum Duration a duration filter is available to eliminate false triggers It is activated upon detection of the event only if the trigger condition persists for a number of seconds at least equal to this parameter It is used only if the Source parameter is set to LEV Stop Delay when the trigger conditions are not present anymore the event ends after a num ber of second equal to this parameter has elapsed Printing printing of a warning string TAG can be enabled through the serial interface for each event DATA LOGGER In the Data Logger menu the parameters relating to the logging of the measured data can be found It collects the settings concerning the recording of the sound levels measured in each screen the re port and event parameters If no parameter is enabled for recording all OFF the instrument warns of the impossibility to record The recording parameters are divided in three sub menus Measurement Report and Event Measurements In this menu continuous recording is defined as described in THE RECORD FUNCTION
55. the same noise phenom ena In the left one with normal central frequencies the tone component is not highlighted while clearly visible in the right picture with shifted frequencies However the tone components check 1s not yet complete Indeed in order to apply the penalty provided the detected tone component must touch an isophone line according to ISO226 2003 equal to or higher than the highest reached by other spectrum components HD2110L can trace the isophone curves in real time as required by the norm using a function associated to the cursors as described on page 24 The following figure illustrates this check for the right spectrum in previous figures from which the tone component located above about 80Hz is not penalized as the associated isophone is not the highest reached by the spectrum the isophone is lower than the spectrum in other parts and so is certainly less audible in other portions gt MIN 30s Ll 6dB IU HEZA Fig 50 3 Verify the low frequency component If the frequency analysis performed with the modes described in the previous point shows the presence of such tone components allowing application of the KT corrective factor in the 20Hz 200Hz frequency range the correction is also used for the low frequency component for the night reference time exclusively 157 A5 THE SOUND The sound is a variation of pressure audible by the human ear Its propagation starting from the s
56. the serial interface The transferred data are those of the active display mode at the time PRINT was pressed Data are continuously transferred until PRINT is pressed again or until the acquisition is stopped The Monitor function can be activated even in the STOP acquisition mode it will start as soon as the instrument turns into RUN mode The Monitor works independently from any recording of data on memory Using the Monitor function it is possible with the help of a PC to make measurements limited only by the PC storage capacity 132 TROUBLESHOOTING The HD2110L sound level meter is provided with a diagnostic program DIAGNOSTIC CHECK that automatically checks the instrument main parameters This program can be run at any time to check the instrument operating conditions See a detailed description on page 71 One of the parameters being analyzed is the sensitivity of the amplification channel that in cludes through a charge partition circuit CTC the microphone capacity Measurement is made at IkHz The program FREQUENCY RESPONSE is available to analyze the performance of the whole amplification chain at different frequencies It carries out the measurement of the frequency response of the hole chain by means of the CTC technique see page 64 Running these two programs regularly allows to keep under control the status of the instrument mi crophone included and allows a prompt identification of potential problems DIAGNOS
57. to 22 kHz FFT option needed Level distribution of probabilities in 0 5dB 1dB or 2dB classes Graph of the percentile levels from L to Loo Display mode for the reverberation time measurement Numeric screen providing the following parameters for the chosen band source maximum level background noise level EDT and three Teo estimation T 10 T 20 T 30 Correlation coefficients of the Tso estimations Sound level decay profile for the selected band Graph of reverberation times for all octave bands from 125 Hz to 8 kHz for the selected es timation among EDT T 10 T 20 or T 30 Graph of reverberation times for all third octave bands from 100 Hz to 10 kHz for the se lected estimation among EDT T 10 T 20 or T 30 Third Octave option needed MEASUREMENT STORAGE 8MB non volatile memory allowing approx 77 hours of continuous recording of a parameter 8 times a second or automatic recording Auto Store every 5 seconds for more than 96 hours of 5 parameters octave and third octave bands spectra 120 Security of stored data Independent of battery charge PROGRAMS Calibration and diagnostics programs Acoustic calibration at 1 kHz with sound level calibrator in the range 94 dB 124 dB Electrical calibration with built in generator Diagnostic check program Frequency response with built in generator Reverberation time measurement program This program allows rever
58. use any High humidity storage Direct sun irradiation over the instrument High temperature source near the instrument Presence of strong vibrations Steam salt and or corrosive environments solvent for cleaning SERIAL INTERFACE The instrument is provided with a versatile serial interface with double protocol RS232C and USB The interface settings depend on the item MENU gt gt Instrument gt gt Input Output gt gt Se rial Device e PRINTER connection with RS232 interface of the portable serial printer MODEM connection with RS232 interface to a modem RS232 connection with RS232 interface to a PC equipped with COM type physical port USB connection with USB interface to a PC where the VCOM driver is installed MC connection to the optional module HD2010MC for data recording on memory card see page 109 The RS232 setting allows to connect the sound level meter to a COM type physical port of a PC This connection does not need any particular program to work as it is allowed by the common ar chitecture of PC equipped with RS232 COM port The maximum speed of data transfer 1s up to 115200 baud In the last few years in order to meet the needs of the new audio and video peripherals the USB standard has been used for information serial transfer Recently many PC manufacturers do not offer the COM type ports any longer which are usually replaced by the USB type ports There is a 4 wire connection two wires for
59. with steps equal to the selected scale fac tor In this way the graph can be shifted UP or DOWN according to the pressed key An analogue bar indicator on the display right side provides the non weighted instantaneous level of the input sound pressure level as for the SLM mode bar The parameter chosen for statistical analysis can be changed without accessing the menus but sim ply using the SELECT keys the four arrows UP DOWN LEFT and RIGHT and ENTER for more details see Selecting parameters on page 18 Using the Cursors The CURSOR LEFT and RIGHT keys on the keypad enable and move the cursor The second line at the top of the display shows the percentile level indicated by the cursor Press CURSOR again to disable the cursor 2 36 x EVENT TRIGGER FUNCTION The Event trigger function can be enabled only with the single integration mode During measurement this function can be used to isolate a sound event identifiable by sound level variation or by synchronization to an external signal or manually by pressing a key The noise descriptor used by the trigger function is selected in the PROFILE view Menu gt gt Trigger gt gt Source LEV The level variation that triggers the event can be positive or negative Menu gt gt Trigger gt gt Trigger Polarity and the trigger threshold Menu gt gt Trigger gt gt Trigger Threshold and Menu gt gt Trigger gt gt Bottom Threshold can be different from the deactiva
60. with the frequency the reverberation time also depends on frequency and is generally higher at low frequencies which are usually more difficult to absorb compared to high frequencies The reverberation time is one of the parameters used in the acoustic characterization of different environments such as class rooms gyms and sports stadiums congress and conference halls theatres and rooms for shows etc The reverberation time is also used to measure other acoustic parameters of building materials such as the sound absorption the airborne sound transmission the impact sound insulation etc The standard that defines the measurement of the reverberation time is ISO 3382 Measurement of the reverberation time of rooms with reference to other acoustical parameters describing the possibility of performing the reverberation time measurement with two methods the sound source interruption technique meaning a stationary noise can be used and the integrated impulse response technique which therefore implies an impulsive source can be used The sound level meter HD2110L with the option for the reverberation time measure ment can measure the reverberation time using both the sound source interruption technique and the impulse source technique The measurement is carried out in parallel for both wide band channels A C and Z and for octave bands from 125 Hz to 8 kHz and third of an octave from 100 Hz to 10 kHz with Third Octave option The soun
61. 1 32s with A C or Z weighting can be used for a de tailed examination of the time profile of sound pulses This acoustic descriptor called Leq Short is calculated by square integration of the sound pressure every 1 32s The Leg Short at 1 32s cannot be displayed by the instrument and is only available for re cording The word Leq Short short equivalent level indicates that the level is integrated on a se quence of short intervals not the whole measurement time From the Leq Short profile you can cal culate the equivalent level on the total and on parts of the measurement time A Leg Short parameter can also be selected in the SLM screen However the latter is calcu lated twice per second and therefore corresponds to the square sum of 16 Leq Short values on 1 32s From the stored Leq Short profile calculated 32 times per second it is also possible to ap proximate the FAST SLOW and IMPULSE levels well To calculate the sound pressure level with exponential time constant you need a time profile with a time resolution at least equal to the time constant For example to calculate FAST levels profiles from the Leq Short you need at least a 1 8 per second time resolution as the FAST time constant To calculate the IMPULSE profile you need a Leq Short on lower intervals of 35ms In the following figure as an example a Leq Short profile is shown integrated at 1 32s 31 25ms intervals matching a sound pulse composed of 4 sinusoidal cycles at
62. 2 cursor or both cursors in tracking will be activated in succession the selected cursor will flash Use the LEFT and RIGHT arrows on the keypad to move the selected cursor on the graph The second line of the display shows level and frequency of the band indicated by the active cursor or the Li L level and frequency difference between the two cursors when they are both ac tive At the extreme limits of the three bands in which the audio spectrum is subdivided the in strument error may exceed the accuracy limits set by the sound level meter class In this case the spectrum is shown as a single line not an area see paragraph TECHNICAL SPECIFICATIONS on page 112 The instrument full scale is determined by the selection of the input gain by choosing MENU gt gt Instrument gt gt Input gain 3 x STATISTICAL GRAPHS The statistical analyzer mode allows analyses on the sound pressure level with FAST time constant sampled 8 times per second or short equivalent level integrated every 0 125s or peak level calculated twice per second with any frequency weighting only C or Z for peak level The statistical analysis is done with 0 5dB classes for sound levels from 21dB to 140dB and provides graphic display of the sound level distribution of probabilities and percentile levels The graphs can be enabled in Menu gt gt Statistical Analyzer gt gt Display Statistics Disabling the displays does not influence the programm
63. 20 Press MODE to select the PROFILE screen in which the time profile of a parameter is shown graphically Press SELECT to set the sampling time and choose the parameter to be dis played as described in the paragraph Time Profile Mode on page 20 As alternative you can set measuring parameters from menu as described in the chapter DESCRIPTION OF THE MENU FUNCTIONS on page 49 Once parameters have been set with the START STOP RESET key the execution 1s started If the sound level meter is set to the single integration mode MENU gt gt Instrument gt gt Measure ment gt gt Integration Mode SING once the Tint time defined in the SLM page 1s over HOLD will be displayed display update will stop Meanwhile the instrument goes on measuring to con tinue display updating just press the HOLD key When the continuous recording is activated and the Tint time goes over the acquisition 1s stopped automatically If you press HOLD during the measuring phase the display update will be temporarily inter rupted When HOLD 1s pressed again the updating will continue Even if the display 1s not updated the instrument will go on measuring If you press PAUSE the acquisition will be temporarily suspended While in pause press START STOP RESET to clear the graph Press PAUSE once more to start measuring again If you press CURSOR at any moment a cursor will be activated If you press CURSOR once more a second cursor will activate
64. 20dB minimum to 200dB maximum with 1dB steps The shown level defines the overload threshold when the input gain corresponds to 0dB Input Gain The overload threshold automatically scales with the input gain Lev 1 2 3 and 4 Percentile in the statistical analysis of sound events Ly percentile levels are defined as the levels of noise exceeded for N time percentage throughout the whole meas urement interval For example L represents the sound level exceeded by 1 of the meas urement time These items define 4 percentile levels selectable between 1 and 99 with 1 steps The corresponding variables are shown in the SLM view as L1 L2 L3 and L4 com bined with the respective percentage SOUND LEVEL METER The Sound Level Meter menu features all parameters relevant to SLM and Time Profile display modes These items can be changed directly from the respective displays as described in Selecting parameters on page 18 The first five items of the menu from Par 1 to Par 5 define the five measuring parameters and the respective frequency weightings relative to the SLM display mode The item Prof defines the measuring parameter with the respective frequency weighting relevant to Time Profile display mode Press RIGHT to change the time weighting of measuring parameters when selected When the time weighting flashes use the UP and DOWN arrows to change it The list of adjustable parameters 1s shown in Appendix Al on page 144 SPE
65. ABC Insert and turn on the calibrator NEXT EXIT DO 2 The first screen shows the date of the last calibration Date and in the line below the calibrator sound level to be used in the calibration in progress this value can be modified before starting the calibration program by selecting Calibration Level from the MENU see page 55 Insert the microphone in the calibrator hole and switch it on 3 Select the sound level indicated on the sound level meter display 94dB is the reference value then press NEXT to continue 4 Now the instrument measures the sound level applied and waits for it to become steady the measured level will be displayed The indication Waiting for level stabilization will be viewed When the sound level has stabilized the measured value is compared to the reference one and if the difference is acceptable it is logged In this case the message Turn off the Calibrator will appear Press NEXT to continue ACOUSTIC CALIBRATION Last 2003 01 01 10 00 Calibr level 94 DdB Oo n Leq 1 0 dBc Turn off the calibra tor Gem CD NEXT 5 After the acoustic calibration the electric calibration will be automatically started This stage of the procedure generates the reference data for the following electrical calibrations ACOUSTIC CALIBRATION Last 2003 01 01 10 00 ACOUSTIC CALIBRATION Last 2003 01 01 10 00 Calibr level 94 0dB Calibr level 94 0dB 13 E ni ALeq Ic
66. AMS The item PROGRAMS PROG key includes the following functions display of the stored data NAVIGATOR electric and acoustic calibration ELECTRIC CALIBRATION and ACOUSTIC CALIBRATION diagnostic test of instrument FREQUENCY RESPONSE and DIAGNOSTIC CHECK reverberation time measurement REVERBERATION TIME optional program download data on MC this program allows to copy the measures saved in the sound level meter in the external memory card see the chapter Description of the interface for memory card HD2010MC on page 109 Each program is here below described in details MEMORY NAVIGATOR It allows to access data stored on the instrument internal memory display and print them with no need to download them to a PC It works both with single session data and with multiple ones Press PROG gt gt Navigator gt gt SELECT to access it The following screen will appear 2003 01 01L 10 00 00 Batt 15 Mem 4e 52 Push CLEAR to erase memory SELECT to access data EXIT CLEAR SELECT Euros CC Fig 36 Navigator menu If you press CLEAR the content of the instrument memory will be cleared The user will be asked a confirmation before clearing Press SEARCH to access the first session of stored data data on memory De 2003 01 01L 10 00 00 Batt 15 Mem Ad 54 Type N Date Mult 00001 2003 01 01 ABC EXIT LOAD NEXT Besides the file name given by the user ABC in the example above for each file
67. CTRUM ANALYZER Spectrum Analyzer menu includes the specific parameters relative to the display modes of spectra either Octaves third Octaves and FFT These items can be changed directly in their displays ex cept for the 1 2 Band Shift parameter e Aux Pond the frequency weighting of the wideband channel combined with the spectrum and displayed with a vertical bar on the right of the spectrum A C and Z weightings are available e Mode the spectrum update mode by small octave or third octave bands either Multi spectrum MLT Maximum MAX Minimum MIN or Average AVR Mean the type of average of the spectrum linear LIN or exponential EXP Mean Weight the weight of the exponential averaging FAST or SLOW Spectrum weighting spectrum can be unweighted Z or C or A weighted 1 2 Band Shift activates the shift of band in the third octave analysis see the paragraph on page 25 Changing this parameter implies to switch off the instrument The setting will be ef fective upon the next power on This parameter will be automatically set to OFF upon the next instrument power on e FFT Band sets the portion of the audio spectrum for the narrow band analysis Possible choices are high frequencies HF from 2 kHz to 22 kHz mean frequencies MF from 250 Hz to 2 5 kHz and low frequencies LF from 10 Hz to 300 Hz This parameter needs the FFT option e Octave Display enables ON or disables OFF displaying of oc
68. E Profiles LAI LAS LAF level dB time s Fig 19 The maximum level determination uncertainty at the sound pulses for FAST SLOW and IM PULSE recalculated from a profile at 1 32s is less than 1dB NARROW BAND SPECTRUM FF T OPTION The narrow band spectrum analyzer mode provides the display of the frequency spectrum calculated by Fast Fourier Transform FFT on the 12 5Hz 22000Hz audio field divided in three bands information on FFT calculation on page 151 of the appendix At high frequencies HF band the spectrum is calculated by applying the FFT on intervals of 512 samples at 48kHz The HF band spectrum considering the application of anti aliasing filters and spectrum resolution goes from 1850Hz to 22000Hz for a total of 215 bands spaced about 94Hz apart The calculation is performed by overlapping the samples between subsequent FFTs by about 65 At medium and low frequencies MF and LF bands the spectrum obtained through subse quent decimations ranges from 234Hz to 2300Hz and 13Hz to 292Hz for a total of 180 and 191 bands spaced 12Hz and 1 5Hz apart respectively The sound level meter calculates the narrow band spectrum from 13Hz to 22000Hz integrating the instantaneous spectra linearly In the following figure the one third octave band can be compared with narrow band FFT spectra related to a complex signal composed of the overlapping of two close frequency pure tones Thi
69. EQ bi Leq Y Lxeg JBX Equivalent continuous level X Z C A pies Sound pressure maximum level SPL pax X Z C A Y F S I 2 Sound pressure minimum level SPL pin X Z C A Y F S I nn percentile with nn 1 99 LAI LegI Equivalent continuous level with Impulse Sa dBA frequency weighting Average spectrum AVR by octave and one third octave bands Statistical analysis on a selected parameter PARAMETER ABBREV DEFINITION WEIGH FREQ e Leq i l a Lxeg dBX Equivalent continuous level X Z C A LFp Sound pressure level with FAST time con ERC dBX stant SPLrasr Event group acoustic parameters 5 selected parameters PARAMETER ABBREV DEFINITION WEIGH FREQ NIETO Leq i 7 Lxeg ABX Equivalent continuous level X Z C A pices Sound pressure maximum level SPL max X Z C A Y F S I yee Sound pressure minimum level SPL min X Z C A Y F S I 14 Tt is possible to program up to 4 different percentile levels 147 PARAMETER ABBREV DEFINITION WEIGH FREQ LeqI Equivalent continuous level with Impulse LAleq frequency weighting Average spectrum AVR by octave and one third octave bands Statistical analysis on a selected parameter PARAMETER ABBREV DEFINITION WEIGH FREQ E L eae Equivalent continuous level X Z C A ae dBX LFp Sound pressure level with FAST time con X Z C A dBX stant SPLf AST 148 A2 MEMORY CAPACITY DURING THE LOGGING FUNCTION The table below gi
70. ETER AND USE OF THE MEMORY CARD Connection of the HD2010MC 1 Switch off the sound level meter 2 Connect HD2010MC to the M12 connector of the sound level meter ensuring the correct fas tening of the connector s ring nut While inserting please make sure that the arrow printed on the reader is turned upwards The reader has to be connected to the sound level meter in vertical position 3 Insert the memory card in the slot of HD2010MC interface 4 Switch on the sound level meter and set the menu item MENU gt gt Instrument gt gt Input Output gt gt Serial device on MC 5 The sound level meter identifies the device The display of the sound level meter shows MC connected and the remaining dimension of memory The LED on the card reader signalizes the connection 6 If the display visualizes Connection failed check carefully if the memory card has been in troduced correctly into the slot and if the connector is plugged in properly When HD2010MC interface is connected to the sound level meter any recording is automati cally sent to the memory card rather than to the internal memory of the sound level meter During recording the LED on the reader flashes upon receipt of every data package When memory is used up entirely the recording will be interrupted To disconnect HD2010MC interface from the sound level meter 1 Switch off the sound level meter 2 Disconnect HD2010MC interface NOTE S
71. IGHT key moves rightwards the cursor or the two active cursors flashing It is used in the FFT screen to move the frequency axis upward when the cursors are not active It is used in the decay profile screen reverberation time measurement it is used to move the fre quency axis upward when the cursors are not active 143 ANNEX Al HD2110L MEASURING PARAMETERS The following paragraphs give the acoustic descriptors that can be displayed in numeric or graphic formats and stored with the respective abbreviations used to identify them ACOUSTIC DESCRIPTORS NUMERIC DISPLAY Instantaneous levels refreshed every 0 5s Wideband PARAMETER ABBREV DEFINITION WEIGH FREQ ee Legs i Lxeg Short dBX Short equivalent level 0 5s X Z C A o Sound pressure level SPL X Z C A Y F I Integrated Acoustic Levels Wideband PARAMETER ABBREV DEFINITION WEIGH FREO O Leq 7 Lxeg ABX Equivalent continuous level X Z C A a Sound pressure maximum level SPL max X Z C A Y F S I Sound pressure minimum level SPL min X Z C A Y F S I 0 A welghting CO ESO rra a CO ES di dBA rate Lpop fos le nl rr ae dBA rate Losna eee CN ment time SEL Dose ial Dose percentage with programmable ex eee con change rate threshold level and criteria Dose e Daily estimated dose with programmable ned exchange rate threshold level and criteria Leg Equivalent continuous level with Impulse LAleq frequency weightin
72. IS lla 51 DYE A SIR ME N Ir oliena 51 BOUND LEVEL METE R Sp lla 53 SPEC TRUN IA A A O O A A 53 STAT TICALA A A TT 53 IRIGGER elia 54 DE AE AAA E E E E S 54 MEASURE MEN T lea 54 REPORT ante 55 EVEN I asili A leale lalla loan 55 ATRIO lola 55 SFOGFREER io lella 56 PROGRAMS vada 57 MEMORS NAVIGATOR s csc e do e de att ea 57 CALIBRATION a de i 60 PERTODICCATIBRA TON o o o le e o Oe 62 Maintenance OF microphone CU de o 63 ELECTRICA TIBRATION sl et ltd i la a eee 64 ACOLUS HE CACIBRATION tercero del aa late e to ll dia e ei 66 MICROPHONE RE PR AG Bein tea e e e dae e e sata 68 DEGNO Ee EEE E A AN A MO etme TEN Se aE dt ee AE AEE e ey eee Eee ee ane 69 ERPOUENCISRESPONSE i ioni re LADIES E dol ld ole ido edo iii 69 DIACGNOS CAE Ra o Li il e 71 REVERBERATION TIME MEA SUREMENT ss T2 INSTRUMENTATION AND MEASUREMENT CONDITIONS evi eece rie ricci rie rie riore sce rie riore eci sce rie nie cizcenie T2 MEASUREMENT USING A STATIONARY NOISE ccccccosceccecceccccescecceccecescescscesceecescectscescescestsseecesceseesessascescesessascesceses 73 MEASUREMENT USING AN IMPULSIVE NOISE ccccscoscecceccececcesceccsccecescescecesceecesceccecescscestesescescescesessescescesescascesceses 75 OPERATING PROCEDURE FOR REVERBERATION TIME MEASUREMENT csccscoccecceccececcesceccecescescescscesceccescesescasceseess 76 FIRMWARE UPGRADE 00d de 87 OPTIONS UPGRADE GB an 87 BATTERY SYMBOL AND BATTERY REPLACEMENT 1
73. LLPP PLL LK LEP PM PP FP PEF PMP SOT fe o gt N IP Y Freq Hz Fig 22 In this case the pair of tones is clearly visible The desired frequency resolution is about 1 When recording of the single narrow band spectrum is activated the whole spectrum composed of the three HF MF and LF bands is logged while during continuous recording only the band selected in Menu gt gt Spectrum Analyzer gt gt FFT Band is logged When the continuous recording is activated with the single integration mode the integration time acts like a timer for data acquisition stopping automatically the measurement when the time is elapsed This display mode does not have a specific Monitor function The narrow band spectrum of the currently displayed band is sent to the serial interface together with other measurements when the monitor function is enable in MEASUREMENT mode see paragraph PRINT AND MONI TOR FUNCTIONS on page 42 The integration mode the Auto Store function and the HOLD key influence this display mode Display Description The graph gives the narrow band spectral analysis it is divided in various screens that can be browsed sequentially using the two arrows Left lt and Right gt Displayed Band LF MF HF Acquisition Time Narrow Band Spectrum Maximum Level Scale Factor Wideband Leve Minimum Level ih 1250 15h Fig 23 Description of the FFT mode The overload indicator and FFT indicating the narrow b
74. Level symbols SEL or Lg IEC 60804 IEC 61672 The sound exposure level is defined as the constant sound level for 1 second that contains the same energy of the event being examined By standardizing the SEL value 1 second it is pos sible to compare sound events with different durations Statistical Analysis If you need to examine from a statistical viewpoint the distribution in time of the sound pressure level you have to use the percentile levels A percentile level symbolized as Lx is defined as the sound level being exceeded by the X percentage during the total time To calculate the percentile levels you first need to classify the sampled sound level according to regular intervals usually 1 8s in width classes usually between 0 1dB and 2dB 163 At the end of the acquisition the probability for each class is calculated by dividing the sam pling frequency by the total number of samples The result is the sound level distribution of prob abilities shown below OC N UO A A Q0 N O B dB on on ho m a bo cn ho o a ho Fig 54 After this the cumulative distribution is calculated This is based on the sound level distri bution of probabilities beginning with a 100 probability for all lower classes with a value lower than the minimum measured level and for each class progressively subtracting the corresponding distribution probability of the level probabilities 100 55 60 65 70 75 80 85 90 dB
75. Ou 5 o _O N N 9 O lt O WO TR N DO FT O LL DOAN N 9 DO r_r N NM O O O O N N ODD TOO Q0 rr rl MDM YF vu O OO N QD Do AO a o 9 vr cr r r rererere re rererere rererere nr A N AN Freq Hz ig 4 Fig 40 The peak is visible in the spectrum but the frequency resolution does not allow the analyzed tone frequency to be determined with sufficient accuracy For real time digital sound level meter analyzers which must provide the sound signal spectrum continuously the FFT processing time is often binding and limits the spectrum resolution The techniques used to overcome this problem are basically two sampling frequency control and audio signal frequency shift By halving the sampling frequency with the same audio segment samples the resolution 1s doubled Alternatively it is possible to apply a decimator filter that is a filter extracting a level for each n samples in the series For example applying a decimator filter with a 10 factor to the series in our example segments composed of 480 samples decimated each 100ms can be obtained Apply ing the FFT to these segments you get each 100ms a frequency spectrum from 0 to 2 4kHz with a 10Hz resolution The decimation process can be extended until reaching the required resolution to the detriment of the spectrum extension which is reduced proportionally to the resolution increase The other technique used to increase the resolution 1s the shifting of all frequencies forming t
76. R WARNING Stop measurement to continue YES NO DEDO Press YES and then ON OFF to switch off the instrument Auto Power Off Function The instrument has an AutoPowerOff function that automatically turns the instrument off af ter about 5 minutes if no key is pressed during the intervening time Before switching off the in strument will make a series of beep in this phase you can press a key to prevent the instrument from switching off The function can be disabled from the MENU via the Auto Power Off item MENU gt gt Instrument gt gt System gt gt Auto Power Off OFF In this case the battery symbol flashes to re mind the user that the instrument will not switch off automatically but only if the lt ON OFF gt key is pressed The Auto Power Off function 1s temporarily disabled when an external power supply 1s used or when the instrument is recording or running a program TABC Q MENU key The HD2110L sound level meter requires according to its use many parameters to be set If you press MENU you can access all instrument parameters for the following functions Instrument 137 Sound Level Meter SLM Spectrum Analyzer Statistic Analyzer Trigger Recording Calibration Sequencer Inside the menus you can Move from one item to the other within the same menu by means of the UP and DOWN ar rows Press SELECT to choose an item to be modified Use the
77. Rev 4 0 June 13 2012 HD2110L Spectrum Analyzer Integrating Sound Level Meter ENGLISH Our instruments quality level is the results of the product continuous development This can bring about differences between the information written in this manual and the instru ment that you have purchased We cannot entirely exclude errors in the manual for which we apologize The data figures and descriptions contained in this manual cannot be le gally asserted We reserve the right to make changes and corrections without prior notice amp S O 00 E AUR 10s 00 01 08 8 01010 0 00 OO OES FE DER E ina IT 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 2T 28 29 Microphone Preamplifier Input Output TRIGGER connector Jack stereo 3 5mm Symbol showing measurement status RUN STOP PAUSE RECORDING or HOLD Keypad LEFT key in graphic mode it moves the selected cursor towards lower values Keypad CURSOR key in graphic mode it allows to select one or both of the two cursors HOLD key it temporarily stops display updating ALPHA key combined with other keys it allows to enter alphanumeric strings MENU key it activates the different configuration menus of the instrument REC key recording combined with START STOP RESET it activates the continuous data recording on memory data logging When pressed for at least 2 seconds the displa
78. SO 140 Part3 Labimeasuremenis ici lille liana 174 ISO 40 Part Oti siemeasufeimenis sila ina A RA I A A ear 175 A7 3 IMPACT SOUND INSULATION MEASUREMENTS sscccseccsssccsccescccscccsccesccesccesccesccesseesscessseusseesscesscesssenscss 176 Instrumentatton and measurement conditiofiS vicario ilaria 176 150 140 Parco Lab measurement i sa 176 FSO 140 Bare 7 On Site measure MES sra id Pel ese da dd dt AAA tddi 177 AS OUTDOOR UNIT HDWME ASSEMBLY DISASSEMBLY AND MAINTENANCE cirie 178 AS Le DIS ess 178 IS O lele AN 180 AZ DENNTION tt ooo ico eds 185 191 Bello GUARANTEE E TERMS OF GUARANTEE All DELTA OHM instruments are subject to accurate testing and are guaranteed for 24 months from the date of purchase DELTA OHM will repair or replace free of charge the parts that within the warranty pe riod shall be deemed non efficient according to its own judgement Complete replacement is excluded and no damage claims are accepted The DELTA OHM guarantee only covers instrument repair The guaran tee is void in case of incidental breakage during transport negligence misuse connection to a different voltage than that required for the appliance by the operator Finally a product repaired or tampered by un authorized third parties is excluded from the guarantee The instrument shall be returned FREE OF SHIP MENT CHARGES to your dealer The jurisdiction of Padua applies in any dispute The electr
79. STICAL ANA SS riali atei ri 119 SPECTRALAN AS a E O lia 119 REVERBERATION TIME MEASUREMENT OPTIONAL i 120 Aa EPA TON nee A E a A oe ee ae ee Ritira 120 MEASURE MENTS TO RAGE eee ane e A e RN RE Ate Pe aS ONE 120 PRO A A ne es ek A ER A es a A Oe EN ea ON CEM Rn PO 121 OTHERSPECRCAFTON nestle re dai auth abate Na enn etti 122 REFERENCE STANDARDS osna EE latenti 123 EMEG STANDARDREGULATMONS 5 sab cosa 123 E ERG aL Liliana 123 ORDERINGCODES GB RL AL 124 WHATSHAELTDOTME lt a onesto el di 127 NEASUREMENTFPROCEDORE lui lle 127 STORAGE OF MEASUREMENT S lilla 130 MEASUREMENT OF NOISE DOSE asi A rana re aa 131 SERIE cca 132 BLU NINE RA IR ROIO OTO ee ee 132 TROUBLESHOOTING srren AR A A ENEA 133 RES FOR INGE ACTOR V5 O de a Sedo 134 RESTORING FACTORY CALIBRATION pillola 134 IISCEEREANEOUSPRORP EMS sleale 134 KEYBOARD DESCRIPTION aeeai AE rn enni 136 ANNEX oan O T ta dis 144 Al HD21 10L MEASURING PARAMETERS ci csccssesccosssvceccsscsseccescstesevcesbeacbicedovetovespecsstedeoedebaseecbacsversesecoecboecdecsteosess 144 ACOUSTIC DESCRIPTORS NUMERIC DISPLAY iii 144 ACOUSTIC DESCRIPTORS GRAPHIC DISPLAY scsssssssssesssessseseseseseseseseseseeeseeessecseeesseeseseseeesseeseeesesessecsecessesseneess 146 ACOUSTIC DESCRIPTORS THAT CAN BE STORED ccccssccscccsccscccscceusscesccescceusseusccesccescseesceesccessseesseesccuseceusseuscss 147 A2 MEMORY CAPACITY DURING THE LOGGING FUNCTION
80. Some parameters can be modified without accessing the menus but simply using the SE LECT key the four arrows UP DOWN LEFT and RIGHT and ENTER key They are the dis played parameter its frequency weighting and the profile time for more details see the paragraph Selecting parameters on page 18 In this display mode Recording and Monitor functions work as in the SLM mode the only difference is that the time interval with which data are recorded or sent to the serial interface is pro grammable and corresponds to the sampling interval except for 1 8s and 1 4s sampling times where 4 values and 2 values every 0 5s are respectively recorded or sent to the interface The integration mode and the Auto Store function do not influence this screen recording func tioning The sound level displayed on this screen can be used as source for the event trigger see para graph EVENT TRIGGER FUNCTION on page 38 Using the Cursors To activate cursors on the graph press CURSOR on the keypad If you press CURSOR re peatedly either L1 or L2 cursor or both AL cursors in tracking will be activated in succession the selected cursor will flash Use the LEFT and RIGHT arrows on the keypad to move the selected cursor on the graph The second line at the top of the display shows the level of the measuring parameter and the time indicated by the active cursor or the time interval and the L L2 level difference between the two cursors when they
81. TIC CHECK 1 The DIAGNOSTIC CHECK program fails Replace batteries and try again after waiting for the end of the stabilization time and 1f the problem remains contact service CALIBRATION 1 The ELECTRIC CALIBRATION program fails Ensure that the instrument is not subject to high noise and or vibrations Try again after having waited for the end of the stabilization time and if the problem re mains run the ACOUSTIC CALIBRATION program 2 The ACOUSTIC CALIBRATION program fails Ensure that the instrument is not subject to high noise and or vibrations and that acoustic calibrator and sound level meter are steadily aligned and that the microphone is properly plugged in the calibrator cavity Check that the seal rubber ring is present and undamaged Try again after having waited for the end of the stabilization time and if the problem re mains load the factory calibration following these steps e Ensure that acquisition is on STOP e Remove one of the batteries while the instrument is switched on this operation ensures that all the instrument internal circuits are discharged e Wait few minutes then press and hold ENTER down and insert the battery you had re moved The instrument will switch on and will display a warning relevant to the load of factory calibration Release ENTER and press the key on the right near the CONTINUE key e After having waited for the stabilization time run the program ACOUSTIC CALIBRA TION Should t
82. The selected program is performed upon pressing the SELECT key some programs can be aborted at any time by pressing RIGHT on the keypad When you access the programs the available mem ory will be displayed as well as battery level date and time 4 JKL CO PAUSE CONTINUE key The PAUSE key interrupts the calculation of integrated measurements Leq SEL maximum or minimum levels spectra etc as well as recording The instantaneous levels are still measured and displayed in the SLM screen Press PAUSE CONTINUE to start measuring again The integrated parameters are cleared if you press RUN STOP RESET while in PAUSE during a measurement session The last seconds of integration can be excluded from the calculation of inte grated parameters shown on the SLM screen for example to eliminate the effect of an undesired noise using the LEFT and RIGHT keys while in PAUSE The maximum erasing interval is pro grammable from 5 seconds to 60 seconds via MENU gt gt Instrument gt gt Measurement If you press the RUN STOP RESET key while in pause during the replay of a recording the next stored data will be displayed If you press it and hold it down the replay will be performed in fast forward mode REC key If REC is pressed and hold down for at least 2 seconds the displayed data are stored as a single report You can also activate the automatic recording of the parameters displayed on SLM OCTAVE and T OCTAVE pages see
83. VERBERATION TIME after power on program YES CONTINUE The sound level meter will automatically turn off Turn 1t back on with the ON OFF key a written confirmation of the activation of the reverberation time measurement program will appear 8 If the option to measure the reverberation time is not present a warning message will appear Program not enabled Please contact the manufacturer In this case you need to contact your vendor to purchase this feature 76 WARNING REVERBERATION TIME program activated CONTINUE The page that now appears is the basic page Maximum level Background noise level Early decay time Estimations of reverberation time Correlation coefficients _ From top to bottom there are the maximum level per octave band reached by the noise source LO max the background noise level per octave band LO res the Early Decay Time EDT and the three estimations of the reverberation time Tio T20 and T39 each with the correlation coefficient r Before starting the reverberation time measurement it is convenient to verify the source sound level and perform any preliminary investigation in order to set the noise generator to measure the reverberation time The Profile view shows 8 times per second the maximum equivalent level integrated every 1 32s The parameter can be selected either for octave or third of octave bands In the views concerning the frequency spectrum two spectra per
84. WARNING When you use the serial interface the communication between instrument and computer or printer with serial input works only if the instrument and PC or de vice baud rates are the same Take care of this note when using data transfer programs requiring a manual configuration of the serial port parameters such as i e Hyper Terminal The NoiseStudio program combined with the HD2110L automatically sets the serial port so that no action by the operator is required RS232 Bits non modifiable parameter number of bits of which transferred data are made up the value is 8 RS232 Stop Bits non modifiable parameter stop bit the value 1s 1 RS232 Parity non modifiable parameter parity bit the value is none OFF Serial Device identifies the device connected to the serial port The connection possibilities are PRINTER connection to a printer with RS232 input RS232 connection to a PC equipped with RS232 port physical port MODEM connection to a modem with RS232 input see Connection to a modem on page 103 USB connection to a PC by USB port see Connection to a PC with USB interface on page 106 MC connection to the memory card reader HD2010MC available on request see Description of the interface for memory card HD2010MC on page 109 Measurement The Measurement item includes the acquisition general parameters Input Gain With Input Gain 0 the measuring range upper li
85. a frequency response optimized for the diffused field the standard setting will be RI Random Incidence Set the parameter on FF to activate the cor rection and make measurements in free field This setting 1s necessary to carry out measure ments according to IEC standards When using the outdoor unit HDWME the setting for the measurement of noise from air traf fic is FF while the setting for the measurement of noise coming from the ground 1s RI e Wind Shield Correction Allows to correct the frequency response of the sound level meter when the HD SAV windshield provided with the sound level meter or the HD WME outdoor shield is used When this parameter is set to SAV or WME the sound level meter frequency response is corrected for the windshield or the outdoor shield presence respectively For de tails on the correction to apply see the section on page 62 e Microphone Environmental Correction activates the correction for the microphone sensi tivity drift with ambient temperature When this parameter is active ON the thermal drift of the sensitivity of both instrument and microphone is adjusted by a factor equal to the Mic C parameter e Microphone C microphone thermal drift This parameter is factory set and cannot be modi fied by the user SEQUENCER e Timer programmable acquisition delay in seconds minutes or hours up to a maximum of 99 hours see paragraph Delayed acquisition timer on page 48 PROGR
86. able L1 L4 percentile level calculation The following figure shows the level distribution of probabilities on the 6 minute measure ment of the noise issued by a climatic room During measurement an acoustic calibrator was switched on for about 2 minutes near the microphone The distribution of probabilities shows the different population of the examined noise clearly From lower levels the first peak about 63dBA reflects the room background noise caused by the ventilation system The second peak about 65dB concerns the cooling compressor activa tion The third peak about 69dB is the tone issued by the calibrator O N A ND N O 00 55 2 65 2 75 2 85 2 dB a n ho In the following figure the cumulative distribution for the same sample above can be seen The cumulative distribution is built from the 100 of the levels under the measured minimum and subtracting the probability of each you get 0 for the levels over the measured maximum 100 The percentile levels are calculated interpolating the cumulative distribution The statistical analyzer resets the classes at the beginning of measurement and it will continue ac cumulating the statistics until the end of the measurement When the continuous recording is activated with the single integration mode the integration time acts like a timer for data acquisition stopping automatically the measurement when the time is elapsed When the level integration is performed in
87. age of the check After this first step the whole scan ning is started over the whole spectrum In case an acoustic response incompatible with the instrument correct working were de tected the test would fail and the message Calibration failed Consult the manual would appear In this case refer to Troubleshooting page 133 and if necessary contact our service department Operating Procedure To access the program Frequency response switch on the sound level meter If necessary press STOP to finish the measurement on progress and follow the next procedure 1 Press PROG and use the UP and DOWN arrows to select Frequency response MN Tint 0s 07 08 25 B 2003 01 01 10 00 00 20 MI 50 Batt 35 Mem 52 5 58 9 asc SELECT PROGRAM 52 5 dBA Wo Memory Navigator 838 dBA Electric Calibration 50 3 dBA Acoustic Calibration 7185 dBc Frequency Response Diagnostic Check 69 2 Press SELECT to choose the program and then YES to confirm FREQUENCY RESPONSE 2003 01 01 10 00 00 Batt 15 4 Mem tce 524 SELECT PROGRAM Electric Calibration Acoustic Calibratio af 100 ik 10k Hz any an Freq Response check Frequency Response e NO 3 The instrument measures the level difference at 1kHz with respect to the value stored in the last check and then requires to confirm the new calibration FREQUENCY RESPONSE 0 5dB Diff dB 0 5dB 1k 10k Hz Confirm ref level YES NO
88. al cor rection is set on RI a frequency correction is applied so as to get a flat frequency response in diffused field With this setting the sound level meter HD2110L is in accordance with the ANSI standards and by mounting the outdoor protection HD WME in a vertical position it is suitable to detect environmental noise coming from the ground For additional details on spectral correction applied to HD2110L sound level meter when used with HD WME please refer to specific microphone manual Self generated noise The intrinsic noise measured replacing microphone with capacitive adapter for the different frequency weightings both for rms levels and for peak levels is shown in the table below Intrinsic Noise e e 2 26 32 39 4 10 is 21 25 34 40 The intrinsic noise shown in the table below is for the constant percentage bandwidth either oc tave or third octave Input Gain Intrinsic Bands dB 2 0 16 14 13 13 13 13 14 15 18 21 24 MO 17 14 10 9 8 8_ 8_ 109 115 Input Gain ad 31 5 Input Gain Linearity range The linearity range is almost independent of frequency in the 31 5 Hz 12 5 kHz interval and it is shown in the following table according to the input gain Input Gain dB wate ia n LpkZ The lower limit of the linearity range by constant percentage bandwidth can be taken by the in trinsic noise table and adding 7 dB T
89. alicell ela 21 SPECTRUM MODE BY OCTAVE AND THIRD OCTAVE BANDS s00 s0ssssenssessnssssensnnnsssnsnnnessnssnnssensnnsnssnsnnnnssnssnacensees 22 DISPEAY DESCRIPTION ns 23 USINGCURSORS AND ISOPHONE CURVES Suda a rali a A sata 24 THIRD OCTAVE FILTERS SHIFTED BY HALF BAND THIRD OCTAVE OPTION iii 25 MEASUREMENTS WITH THE FET OPTION 4d 21 LEQ SHORT Amt 375 TET OPTION lella 27 NARROW BAND SPECTRUM FET OPTION ioni olato atea rated 30 DISPLAY DESCRIP TON a a a AEA 32 USING THE CURSOS tna RL Ri 32 SPATISTICAEGRARHS eil 33 LEVEL DISTRIBUTION OF PROBABILTTES li iaia 35 Usmo TG CMS ORS a alito 29 PERCENTIEELEVELSGRAPH science 36 Uso ASC een 36 EVENT TRGGEREUNCIION e iii dii i i iii 37 DESCRIPTION OF THE DIFFERENT INTEGRATION MODES 22 cccsccsssccsccccccccccccscccscccssccsscccscsccssceeese 39 SINGEEINTEGRATION bibi biliari eredi 40 MUETPER INTEGRATION bll ana 41 PRINT AND MONITOR FUNCTION Sou ias 42 BINARY FORMAT MONITOR alla licia ba 42 THE RECORD EUNGEHON astal elle int alal 43 MANUAL AND AUTOMATIC SINGLE RECORDING o ooooccnccnnnconnccnnoconiconnncnnoconoronncconoconorcnnoconoronarcnnoconronarcnnocnnos 43 CONTINUOUS RECORDING eee dl to todita 44 CONTINUOUS RECORDING OF REPORT AND EVENT GROUPS c oocccoccnnncnnnconnccnnnconononnncnnoconanonnncnnnccnaronuncnunicns 45 DA lia 48 DESCRIPTION OF THE MENU FUNCTIONS ili 49 ISLA A A A A AAN 50 EVN TRIE NG A TON rei Reit 50 A eeotnanies 50 A
90. analysis of sound events When measuring traf fic noise near airports railways and roads the sound level meter can be used as a multi parameter sound recorder combining spectrum and statistical analyser features Remote electrical calibrations and diagnostic tests can be executed using its remote control functions The HD2110L sound level is able to perform all measurements prescribed by the regulations concerning the evaluation of environmental noise The impulsive events identification 1s easy thanks to the ability to analyze noise profile with parallel FAST SLOW and IMPULSE time con stants All measurement parameters can be stored for a later analysis With third octave option it s easy to identify tonal components spectrum of minimum level evaluated with a wideband frequency weighting Z C or A 1s displayed and stored the fre quency spectrum 1s calculated both for standard center frequencies from 16Hz to 20KHz and for non standard shifted one sixth octave central frequencies from 14Hz to 18KHz Audibility of to nal components can be evaluated in post processing using the Noise Studio PC software or directly on site thanks to real time function of isophone curves plot implemented in the sound level meter The HD2110L sound level meter with the Reverberation Time options can perform all measurements prescribed by the regulations on building acoustics evaluation ISO 140 The sound level meter powerful DSP calculates 32
91. and Teo 30 or T30 In practice a linear interpolation 1s carried out using the least squares method on the decay starting from the point 5 dB lower than the stationary level and stopping for example 35 dB below this level The gradient of the line gives the decay rate in dB s from which the reverberation time can be extrapolated MEASUREMENT USING A STATIONARY NOISE To perform the reverberation time measurement with the sound source interruption tech nique an omnidirectional usually a dodecahedral loudspeaker source should be used powered by a wide band signal that covers the acoustic spectrum required for the measurement The wide band signal issued by the source 1s usually of two types white or pink The issued noise 1s defined as white when the spectrum density is constant all over the audio frequency range It 1s defined as pink when the spectrum density is inversely proportional to the frequency Analyzing the spectrum of a white noise source by bands with a constant percentage width as oc tave or third of octave bands the sound level increases with frequency by 3dB per octave Instead J3 ig in the case of the pink noise source the sound level spectrum analyzed by constant percentage bands remains constant over the whole frequency range The analysis can be done sequentially for each band or in parallel for all the bands For the sequential analysis it is possible to use a source which has already been filtered
92. and display update will stop Now you can print or store the values Meanwhile the instru ment goes on measuring to continue display updating just press the HOLD key When the con tinuous recording is activated and the Tint time goes over the acquisition is stopped automatically If you press HOLD during the measuring phase the display update will be temporarily inter rupted When HOLD is pressed again the updating will continue Even if the display is not updated the instrument will go on measuring Pressing PAUSE acquisition and calculation of the integrated parameters will be temporar ily interrupted When in PAUSE the calculation of integrated parameters such as for example Leq and the maximum levels is suspended in this phase the contribution of the last seconds of acquisi tion can be deleted using the Back Erase function and the LEFT and RIGHT keys as described in the paragraph Back Erase Function on page 19 While in PAUSE all integrated parameters can be cleared pressing START STOP RESET Press PAUSE once more to start measuring again Press PRINT at any time to print the on screen data To activate the continuous printing Monitor press and hold down PRINT for at least 2 seconds A flashing M overlapping the status indicator shows that the Monitor function 1s active The Monitor function remains active even jumping to other measuring views and can be disabled pressing PRINT again or START STOP RESET to stop measuremen
93. and spectrum display mode the dis played band HF MF or LF and the acquisition time are shown in the first line of the display after the acquisition status symbol The narrow band spectrum is displayed in decibels on a logarithmic scale with linear frequency axis The values on the left side of the graph are the full scale the scale factor and the scale begin ning The amplitude of the vertical scale of the displayed graph corresponds to 5 divisions The am plitude of each division is called scale factor of the graph and appears in the middle of the vertical axis Using the RIGHT zoom and LEFT zoom keys this parameter is selectable in real time among 20dB 10dB or 5dB by division Use the UP and DOWN arrows to set the graph full scale with steps equal to the selected scale factor starting from the instrument full scale In this way the graph can be shifted UP or DOWN depending on the key you have pressed An analogue bar indicator on the display right side provides the non weighted instantaneous level of the input sound pressure level as for the SLM mode bar Using the Cursors The linear frequency axis prevents display of the entire narrow band spectrum on a single screen the LEFT and RIGHT arrows on the keypad can be used to move the frequency axis in the desired area when the cursors are not active To activate cursors on the graph press CURSOR on the keypad If you press CURSOR re peatedly either L1 or L
94. and therefore to ensure that the results are reproducible ISO 140 Part 6 Lab measurements ISO 140 Part 6 Acoustics Measurement of sound insulation in buildings and of building elements Part 6 Laboratory measurements of impact sound insulation of floors was issued in 1998 The purpose of this standard is to determine a laboratory measurement method for the transmission of the impact noise through the ceilings by using a standardized impact generator The results ob tained can be used to compare the insulating properties of the ceilings and to classify them accord ingly Two types of test are prescribed one for the complete ceiling and one for the floor to be installed on the standard ceiling In the first case the value of the standardized impact noise level Ln is calculated as defined by the expression A L 10log 0 where Lz is the average sound pressure level measured in the receiving environment when the gen erator is functioning on the floor Az is the equivalent absorption area of the same environment and Ao is the reference equivalent absorption area equal to 10 m For the floors the measurement that describes their acoustic behaviour is the attenuation of the im pact noise defined by the expression DL L L where Ln 1s the standardized treading noise level measured when the generator is functioning on the standardized ceiling 176 ISO 140 Part 7 On site measurements ISO 140 Part 7
95. are indi cated the type single multiple automatic or reverberation the progressive number given by the instrument upon logging and the date Press NEXT to jump to the next file press LOAD to upload the current file If you press LOAD the instrument goes back to standard display and the STOP and battery sym bols alternate with the R Replay and P Program letters respectively The types of files recorded are four Sing Single screen in manual recording Auto SLM OCTAVE and THIRD OCTAVE option screens in automatic recording Mult Multiple screens in continuous recording RT Reverberation measurements with the option Reverberation Time File type Auto Press START to see the data session the screens of the measurement session will be displayed as per the acquisition order During the replay the display mode can be changed jumping from a screen page to another press PAUSE CONTINUE to interrupt and re start the on screen reproduc tion or press STOP to finish it At the end the instrument will position on STOP A single screen page can be sent at any moment to the serial interface While the replay is in pause press START if you want to display the next data If while in pause the START key is hold down the replay will be forwarded fast File type Mult Press START to see the data session if no reports and or events were recorded the measurement session screens will be displayed as for the Auto
96. as a reference for the calibrations made by the user Every time a periodic calibration of the sound level meter is carried out at the factory cali bration constants are stored as a reference for following comparisons The factory calibration can be loaded onto the instrument to make a comparison or to correct a wrong calibration This procedure will also load the instrument default parameters so that is there are any data stored on memory these will be deleted Follow this procedure to proceed with this operation Download any data stored on memory Ensure that logging is on STOP mode Remove the external power supply 1f connected Remove one of the batteries the instrument will obviously switch off Wait some minutes this operation assures that all the sound level meter internal circuits are discharged Press and hold down the ENTER key while inserting the missing battery The instrument will automatically turn on and will show a warning message indicating that fac tory parameters have been loaded Press CONTINUE to confirm and make an acoustic calibration to store calibration constants If this operation 1s not carried out or in case the acoustic calibration should give a negative result upon the next power on factory calibration data will be replaced by those stored in the last suc cessful calibration Electrical signals inserted by a generator connected to the HD2110L preamplifier via a ca pacitive adapter re
97. asurement to continue Fig 34 Press YES and you will be allowed to change the selected parameter Some of the parameters listed in the menu can be modified also directly from the measurement dis plays see the chapter concerning the different display modes from page 14 onwards The menu is nest structured that is it is organized in menus and submenus To select a menu item use the UP and DOWN arrows until the selected item flashes When the parameter next to a menu item does not flash it means that the item cannot be changed lt This parameter can be changed lt This parameter CANNOT be changed Press SELECT to access the selected submenu or to modify the selected parameter Use the UP and DOWN arrows to edit the flashing selected parameter press ENTER to confirm the new value press MENU to cancel the entered changes Press MENU to exit a menu and return to the upper level until you get the measurement display again 49 DI Tint Ws 01 08 25 amp 2005 01 01 10 00 00 20 MA 1130 Batt 95 Mem 92 5 56 9 asc SELECT MENU 525 dBA Instrument 838 dBA JA Sound Level Meter 50 3 dBA Spectrum Analyzer 18 5 dBc ose Fig 35 When you access the menus current date and time are displayed as well as the battery charge level and the available memory If you are in a submenu the SELECT MENU item becomes SELECT SUB MENU The dots at the end of a list mean that there are other items following the vi
98. asurement status of the sound level meter H HOLD RUN the instrument is measuring W WarmUp PAUSE the calculation of integrated measurements P Print and the recording of measurement have been sus M Monitor pended Instantaneous parameters are still being R Replay measured and displayed REC the instrument is measuring and recording Fig 10 STOP the instrument is not making any measure ment HOLD the calculation of integrated measurements has come to the end of set integration interval or HOLD was pressed W Warm Up signal that appears upon the instrument power on and that disappears after ap proximately 1 minute It warns the user to wait the time necessary to the instrument to reach steady conditions in order to ensure best performances P Print indicates that printing is in progress M Monitor indicates flashing that continuous data printing has been started R Replay appears flashing when the Memory Navigator program is in use to view a file saved in the instrument memory see page 57 Just on the right of the symbol indicating the logging mode there is the symbol showing a possible overload An arrow directed upwards indicates that the input level has exceeded the maximum measurable level The maximum measurable level corresponding to the selected measurement range is given in the technical specifications see page 112 Using an appropriate parameter MENU gt gt Instrument gt gt Measurement gt
99. at throughout the whole audio range The MC21 microphone meets the requirements of IEC 61094 4 international standard for WS2F type Optionally it s possible to install other types of microphones having the same electro mechanical specifications than MC21 and complying with the IEC 61094 4 standard like for example the MC22 microphone with optimized diffuse field frequency response For more details and specifications on microphones available for HD2110L sound level meter please refer to the specific manuals The Outdoor Microphone Unit HD WME The HD WME microphone unit is suitable for long lasting outdoor monitoring even in a fixed unattended location The unit is adequately protected from rain and wind and the heated pream plifier together with the protective membrane coating of the microphone capsule provide stabil ity of acoustic parameters over time and allow you to make measurements over a wide range of environmental conditions The Delta Ohm sound level meter preamplifier matched with the outdoor microphone unit 1s equipped with a circuit for electrical calibration of the preamplifier microphone chain a tech nique that uses a charge distribution The frequency response of the unit in free field meets the specifications of class 1 according to IEC 61672 and IEC60651 The microphone unit HD WME must always be positioned vertically to allow the anti rain to perform its function and can be used both to detect the noise from the air
100. ation time decay curves Calculation of sound insulation indexes according to ISO 717 1 1996 and ISO 717 2 1996 This program requires the reverberation time option installed in the sound level me ter NS4 Monitor module for the acoustic monitoring and remote control via PC or via modem Pro grammed acquisition event identification and synchronized audio recording NS5 Environmental noise module for analysis of acoustic pollution and environmental noise sources Performs statistical analysis and spectral analyses automatically identifies noisy events and noise sources with tonal and impulsive properties Analysis are made according to EU and Ital ian legislation regarding acoustic pollution Spare parts and accessories HD WME microphone outdoor shield Includes HD WMES3 stainless steel mechanical support wind shield HD SAV3 rain shield HD WME2 anti bird spikes HD WMEI HD WMEI anti bird spikes for outdoor shield HD WME HD WME 2 rain shield for HD WME outdoor protection HD SAV3 wind shield for HD WME outdoor protection HD SAV Windscreen for 4 microphone BAT 40 spare battery pack for HD40 1 printer with in built temperature sensor RCT the kit includes 4 thermal paper rolls 57mm wide and 32mm in diameter 126 WHAT SHALL IDO IF This chapter deals with the step by step description on how to carry out the most recurrent measurements in the acoustic field with the HD2110L sound level meter I
101. ation of program completion time are displayed on the screen The data transfer from the sound level meter to the memory card doesn t delete the internal mem ory of the sound level meter I order to cancel the content of the internal data memory of the sound level meter it 1s necessary to use the Navigator program To cancel the data of the card use only the formatting function of Noise Studio the erasure of single files contained in the memory card is not foreseen The Navigator program is not able to manage registrations which have been effected with external devices as interface for HD2010MC memory card TECHNICAL SPECIFICATIONS Type of card MMC and SD Maximum capacity 2GB Power supply provided by sound level meter Function indicator LED on the reader Connector 8 pole female M12 111 TECHNICAL SPECIFICATIONS The HD2110L sound level meter is a type 1 integrating sound level meter with frequency analysis by octave and third octave bands with Third Octave option as well as with statistical analysis HD2110L complies with the following standards EC 61672 2002 5 Class 1 Group X EC 60651 2001 10 Class 1 TEC 60804 2000 10 Class 1 TEC 61260 1995 8 Class 1 Amendment 1 2001 09 ANSI S1 4 1983 Type I ANSI S1 11 1986 Order 3 Type 1 D Optional Range Microphone models Type 1 2 inch with 50 mV Pa sensitivity polarized at 200V or pre polarized electret For de tailed information please consult the micr
102. ave and third octave band are recorded over the same interval MEASUREMENT OF NOISE DOSE The Dose represents the percentage of a maximum value of noise exposure throughout a day L L Lo SE Do 10 1 dt T 0 C where D Q exposure percentage for an Exchange Rate equal to Q Te daily exposure time usually 8 hours T measurement time L sound pressure level when it is higher than the Threshold Level and otherwise Li Criterion Level for a daily exposure corresponding to 100 of the dose Q Exchange Rate q parameter independent of the exchange rate and equal to e 10 for Q 3 dB e 5 log2 forQ 5 dB e 4 log2 forQ 4dB The sound level meter calculates the following parameters DOSE A the percentage of the daily effective dose and DOSE d A the estimated daily DOSE according to the programmed parame ters The DOSE calculation is characterized by three parameters 1 DOSE Criterion is the SPL constant value which continuous exposure for 8 hours determines a 100 DOSE 2 DOSE Threshold that represents the SPL level under which the DOSE is not increased 3 Exchange rate is the variation of the SPL value that determines a double or half duration of ex posure with the same DOSE Criterion Provided values are 3 4 or 5dB The three configuration parameters are contained in the submenu Measurement MENU gt gt Instrument gt gt Measurement once they have been set select the submenu Sound Level M
103. aves reflected by walls are dominant and therefore where the sound level is determined by sound pressure waves coming from all direc tions is called diffuse field While measurements in indoor environments are usually treated as diffuse field measurements those outdoor are generally treated as free field measurements Since the microphone has dimensions comparable to the highest frequencies of the sound spectrum it is designed to get an optimized response for a given acoustic field There are three types of microphone for free field diffused field and pressure The microphone for free field is designed to have a constant sensitivity at any sound field frequency for sound signals coming from the front side making automatic adjustments to high frequencies to compensate the increase in pressure at the membrane level due to its presence The microphone for diffuse field is instead designed to have a constant sensitivity at all fre quencies for sound signals coming from all directions The microphone for pressure measurements is used for laboratory measurements even though having a characteristic similar to that of a microphone for diffuse field might also be used in reverberant fields When a diffuse field microphone is used in free field it usually provides precise values when it is oriented at 70 80 as to the sound source If it 1s pointed to the source direction it pro vides too high values above all at high frequency Vice v
104. backwards To save the file name press ALPHA again to exit the character entry mode and then press ENTER to confirm the heading The ALPHA key also allows a marker during continuous recording to be entered in order to signal specific events To record a marker just press ALPHA and then a numeric key from 1 to 9 HOLD HOLD key The HOLD key can be used to temporarily suspend the display update while the instrument continues making the requested measurements A H in the left corner at the top shows that the display is in this phase Press the key again to go back to standard measurement While the instrument is in HOLD mode you can jump from a screen page to the other activate the cursors on the graphic pages print and store data Recording and the Monitor function are not affected by the HOLD status oO ON OFF key To switch on or off the instrument press the ON OFF key for at least one second Upon turning on the instrument shows for a few seconds the manufacturer s logo and the program ver sion firmware Then it switches to the SLM working mode Sound Level Meter and displays 5 instantaneous or integrated measurement parameters in numeric form 136 gt Tint Us dI 11 LI Before switching off the instrument press STOP to end the ongoing measurement If you do not do it a message will request you to stop the measurement in progress WARNING Stop the meas urement to continue SELECT PARAMETE
105. beration time measurement according to a wizard using both the sound source interruption technique and the integrated impulse response Wizard for the reverberation time calculation using the steady sound source interruption and the impulse response integration Schroeder s back integration methods and background noise cor rection algorithm Frequency range octave from 125Hz to 8KHz and optionally third octave from 100Hz to 10KHz Spectra sampling 32 spectra per second Dynamic range 110dB Optimized interpolation of the decay profile with correlation coefficient calculation Ordinary Least Squares method Simultaneous calculation of EDT T 10 T 20 T 30 estimations of the reverberation time Teo according to ISO 3382 standard Possibility to calculate directly the Teo on the decay sound profile by positioning of cursors over an interval selected by the user Interface and processing PC programs NoiseStudio base module for downloading and graphical display of data stored and the set ting of the instrument Noise Studio includes several additional modules for the analysis and post processing of sound pressure level data acquired with Delta Ohm sound level meters The functions of these modules are specifically studied for determined applications such as the analysis of noise in the workplace or the analysis of environmental noise from traffic and are enabled with license dongle CH20 and can be activated with hardware ke
106. bove the limit fre quency the decay will be linear and therefore it will be much easier to measure its gradient and therefore obtaining the reverberation time According to ISO 3382 when a correlation coefficient below 0 95 1s obtained calculating the linear regression on the sound level decay it is not possible to define the reverberation time unambiguously For large dimension spaces whose limits are defined by Schroeder s frequency the high modal density makes the sound field approximating a plane wave propagating with equal probabil ity in all directions defined as diffuse field 171 In practice this approximation is valid above Schroeder s frequency in environments that are not excessively absorbing and at a sufficient distance from the sound source and the walls With this approximation it is possible to calculate the reverberation time T starting from the geometrical char acteristics of the room using the formula of Sabine T 0 161 A where T is the reverberation time in seconds V the volume in cubic meters and A the equivalent ab sorption area of the room in square meters A 0 5 where the absorption of the room s walls and the possible objects in it are summed as indicated by S being the 1 th surface with absorption coefficient a The absorption coefficient is characteristic of the material and depends on the frequency and the sound incidence angle Since the equivalent ab sorption area varies
107. but also via the telephone line by means of two modems While the modem that connects the PC to the telephone line must not meet any particular requirement but being Hayes compatible the modem connected to the HD2110L sound level me ter has to be configurable by the sound level meter itself and shall not interfere with improper mes sages during the delicate data transmission phase from the sound level meter to the PC Delta Ohm s r l suggests three types of modems to be used Multitech MT2834ZDX Digicom SNM49 Digicom Botticelli The connection with these modems has been tested Other modems might be used but due to the great variety available on the market we cannot provide service for the connection to mo dems other than those listed here The modem connected to the HD2110L sound level meter must be configured before being used for data transmission The configuration is carried out automatically by the sound level meter itself according to the following steps 1 Connect the modem to the HD2110L by means of the HD2110CSM proper cable with M12 connector Connect the modem to the telephone line and the power supply Switch on the modem Switch on the HD2110L sound level meter Set the baud rate at 38400 baud at least via the parameter MENU gt gt Instrument gt gt In put Output gt gt RS232 Baud Rate 6 Select MODEM as serial connection through the parameter MENU gt gt Instrument gt gt In put Output gt
108. c onds before We can say that the sound level with a SLOW constant is approximately an average of the instantaneous levels of the last second Impulsive Noises If the sound has a short duration it is called impulsive 1 e writing with a typing machine the noise caused by a hammer or by a gun are classified as impulsive sounds To assess their impact on the auditory apparatus consider that the more the sound is short the less the ear can hear it For this reason a time constant has been defined in the international standards IEC 60651 IEC 61672 called IMPULSE very fast 35 ms for increasing sound pressure levels and very slow 1 5s for decreasing levels LAlmax ce LAFmax LASmax dB 80 19 10 65 14 31 236 125 14 51 45 625 14 31 55 125 14 32 04 625 14 532 14 125 145223625 143235125 145242625 143252125 Fig 51 In case a sound source emits noises with a strong impulsive component the level measured with the IMPULSE constant will be much higher than the SLOW level Fig 51 shows the sound level profile measured simultaneously using the FAST SLOW and IM PULSE time constant by a surface mount machine The displayed levels are the maximum levels calculated on intervals equal to 1 8s 161 The most variable profile is the FAST profile 8dB while the less variable is the SLOW one 3dB The IMPULSE profile is systematically higher than FAST and SLOW as it reflects the impulsive nature of the noise iss
109. cipale USE eS Hub principale USE Hub principale USE e Periberica dbarchiviazione di massa USE LL DYDICO Rordrives Ba Human Interface Device HID Le Modem S Mouse e altre periferiche di puntamento 8 Periferiche di imaging 4 Periferiche di sistema Porte COM e LPT Porta di comunicazione COMI Y Porta di comunicazione COMZ F R RR R R 23 Schede di rete Schede video 8 Schermi gt Tastiere A A When USB cable is unplugged the above items will disappear and they will appear again as soon as the instrument is plugged to USB port In the documentation supplied with the Noise Studio CDRom it s available a detailed version in cluding images of the USB driver management guide 108 HD2010MC MEMORY CARD READER The reader HD2010MC can be used on the sound level meters provided with M12 serial connec tion If they aren t provided with M12 input they can be modified in order to be able to use the memory card reader HD2010MC DESCRIPTION OF THE INTERFACE FOR MEMORY CARD HD2010MC The reader HD2010MC allows to expand the storage capacity of the sound level meter By employ ing SD type or MMC card type it is possible to record for example a sound level profile continu ously for several months In addition it 1s possible to download data from the internal memory of the sound level meter to the card This function can turn very useful when the effected measure ments need to be downloaded
110. ctral analysis both in octave and in third octave bands option Third Octave The noise frequency spectrum is calculated 2 times per second and linearly integrated for up to 99 hours Alternatively it s possible to perform multi spectral analysis both max and min weighted both exponentially and linearly Spectra or multispectral profile starting from 1 second are displayed in parallel with a wide band A C or Z weighted level allowing a fast comparison between spectrum and wide band level Moreover frequency spectrum can be displayed both as un weighted spectrum and as A or C weighted for a fast evaluation of different spectral components audibility In addition to standardized bands from 16 Hz to 20 kHz spectral analysis in third octave bands option Third Octave can be performed with shifted bands these filters have center fre quencies moved downward by one sixth octave in a range from 14 Hz to 18 kHz While viewing the spectrum in third octave bands it s possible to activate the function to plot on the display the 1so phone contours for a fast analysis of spectral components audibility As a Statistical analyser the HD2110L samples the sound signal 8 times per second with A frequency weighting and FAST time constant and analyses it statistically according to 0 5 dB classes Statistical analysis is shown in a graphic form as probability distribution and cumulative distribution with percentile levels from L to Loo It s
111. d Octave requires the filter s Calibration and can normally be installed only at Delta Ohm IST Aes BATTERY SYMBOL AND BATTERY REPLACEMENT The battery symbol H in the upper right corner of the display constantly provides the charge status of the instrument batteries The more the batteries discharge the more the symbol gets empty Ball When the battery voltage reaches the minimum value for a correct operation the symbol flashes At this point only 5 minutes of autonomy are left and batteries should be replaced as soon as possi ble If the instrument is still used the battery voltage will decrease still further and the in strument cannot ensure anymore a correct measurement data recording is automatically in terrupted as well as data logging and the instrument goes into STOP mode Under a given level the instrument will automatically shut off Data stored on memory will remain The in strument cannot be switched on again until the battery level remains low The battery charge level is available on the menu main screen and on the program screen expressed as a percentage value Press MENU or PROG to view it When the level is indicated by 0 5 minutes of autonomy are left The battery symbol changes into a plug when the instrument is connected to an external power sup ply Note the battery symbol also flashes when the auto power off is disabled AutoPowerOFF OFF To replace the battery switch the instrume
112. d level is linearly integrated 32 times per second without interruptions and simultaneously on all measurement bands allowing reverberation time measurements down to 0 37s As the sound decay is measured for at least 5 seconds the maximum reverberation time that can be measured according to ISO 3382 is equal to 12s corresponding to the minimum decay allowed equal to 25dB 172 AT 1 MEASUREMENT OF SOUND ABSORPTION The absorbing materials and elements are largely used in the acoustic modelling of building elements above all the ceiling every time the reverberated sound energy has to be reduced Their use limits the reverberation time and when placed at given distance from the sound source they help to diminish the total sound pressure level in the environment The absorption of the sound en ergy issued is one of the methods used to reduce the noise level when the propagation of the sound occurs inside enclosed spaces such as ducts or when you need a soundproof booth The absorbent materials can also be used to reduce the sound reflection on acoustic barriers The reference stan dard is ISO 354 Instrumentation and measurement conditions The acoustic insulation coefficient can be measured using different methods each requiring different instrumentation The ISO 354 standard of 2003 describes a method based on reverberation time measurement while the ISO 10534 standard describes a method based on simple measure ments of the sound level
113. ddition to the traditional reverberation time starting from the integrated impulse re sponse the Early Decay Time EDT can be obtained from the first 10dB of the decay itself Com pared to the traditional reverberation time T correlated to the physical properties of the measured environment the EDT is correlated with the subjective perception of the reverberation and is there fore useful to evaluate the dependence of the EDT T ratio on frequency in the different points of the environment OPERATING PROCEDURE FOR REVERBERATION TIME MEASUREMENT In this chapter we will describe the steps needed to measure the reverberation time Turn on the sound level meter and enter the program selection mode by pressing PROG bi Tint 0s 01 06 25 A 2004 01 01 10 00 00 O 0390 Batt 15 Mem 42 5 SELECT PROGRAM WS Memory Navigator Pop EA Electric Calibration 50 3 dBA Acoustic Calibration 185 dBc Frequency Response Reverberation Time By using the arrows select the program Reverberation Time and confirm with SELECT 2004 01 01 10 00 00 Batt 15 Mem Ad 5 SELECT PROGRAM Memory Navigator Electric Calibration Acoustic Calibration Reverberation Time The program must be loaded into the memory to continue press the left arrow of the display key board YES and on the next page press the right arrow corresponding to CONTINUE WARNING WARNING Please confirm Automatic power off loading of Change effective RE
114. duction of the sound wave at each interaction with the wall materials Consequently when the sound source is interrupted after some time sound is no longer perceptible The sound level will be maintained infi nitely after the interruption of the sound source in an hypothetical room having walls with no ab sorption or transmission Modal Theory By analyzing the sound level distribution in a room in which a sound source 1s operating it can be seen that the sound level has highs and lows that depend on the position and dimensions of the room This effect is explained by the Modal Theory This theory explains how the direct wave of the sound source combines with the waves re flected by the walls forming a series of maximum and minimum sound level spots Therefore any enclosed space can be thought of as a multi resonant system and so a certain number of resonance frequencies or characteristic modes of the room can be examined These modes are distributed in the spectrum with a density proportional to the square of the frequency This implies that the sound level widely fluctuates from point to point in an environment where low frequency sounds having a stationary speed are issued These fluctuations will decrease when the frequency of the sound issued by the source increases Schroeder 1996 defined a characteristic frequency called Schroeder frequency above which it is possible to ignore the modal theory and therefore consider the sound fi
115. e see chapter DESCRIP TION OF THE DIFFERENT INTEGRATION MODES on page 39 Integration Auto Store OFF Auto Store ON Recording twice per second enabled Automatic recording of SLM page to by Recording menu Automatic Stop gether with OCTAVE and optional at the end of the set integration inter THIRD OCTAVE spectra in AVR mode val at the end of the set integration interval SINGLE Automatic recording of SLM page to Recording twice per second enabled gether with OCTAVE and optional by Recording menu Automatic reset THIRD OCTAVE spectra in AVR mode of integrated levels at every integra at intervals equal to the set integration tion interval time At the beginning of each period in tegrated levels and spectra are set to zero MULTIPLE Display Description Left at the top of the display there are the recording status symbol and the overload indicator described at the beginning of this chapter In the midst there is the integration interval and on the right the acquisition time hours minutes seconds When the integration mode is set on MULT MENU gt gt Instrument gt gt Measurements gt gt Integr Mode MULT the Tint symbol flashes The battery symbol is in the right corner indicating battery level Integration interval Acquisition time Minimum level Maximum level Bar showing istantaneous level Displayed parameters Fig 11 Description of the display in SLM mode The analogue ba
116. e SLM page are concerned you can delete the last integration seconds through the Back Erase Function data exclusion described on page 19 The sound level meter has a further timer for interval acquisition MENU gt gt Instrument gt gt Measurement gt gt Report Time This parameter can be used to break up the measurement time into programmable duration intervals from 1 second to one hour and calculate a set of 5 selected inte grated levels for each interval namely Leq maximum and minimum levels SEL and statistical levels The average spectrum AVR for each interval can also be calculated by both octave band or third octave band and using statistical analysis MENU gt gt Recording gt gt Report These data can not be displayed directly but can be recorded by enabling continuous recording The report levels can be displayed by loading the recording from the sound level meter memory using the Navigator and selecting the Report mode for the replay The interval acquisition can be enabled only in single integration mode 40 MULTIPLE INTEGRATION When the integration mode is multiple the sound level meter automatically makes a continu ous sequence of acquisition intervals having a duration equal to the integration time set through the parameter MENU gt gt Instrument gt gt Measurement gt gt Integration interval Each acquisition interval is preceded by the reset of integrated levels and the Tint symbo
117. e adopted a different principle that takes into ac count the ear recovery times during pauses and allow to increase the level by 4 dB DOD or 5 dB OSHA before halving the exposure time Acoustic Field Sensors and transducers in general are designed not to disturb the physical quantity to be measured Exactly as a thermistor would limit to the minimum the temperature disturbance caused by its presence also the microphone is designed not to alter heavily the acoustic field where it works The alteration of acoustic field becomes important at frequencies corresponding to sound pressure wavelengths comparable to the microphone dimensions diffraction phenomenon For ex ample with 10 kHz sound pressure wavelength equals about 3 4 cm comparable with the dimen sions of a typical microphone Essentially there are two types of acoustic fields the free field and the diffuse field The field is defined free when the sound level decreases by 6 dB doubling the distance from the source This condition is usually met with a good approximation at a distance from the source higher than its bigger dimension and in any case higher than the bigger wavelength of the gener ated noise The free field is significantly disturbed by the closeness of rigid walls capable of reflect ing sound levels comparable with those due to the acoustic pressure waves coming directly from the source The acoustic field in an environment where sound w
118. e and are represented with the symbol L where x is the percentage value for example Lio gives the sound level exceeded in the 10 of the measuring time For the calculation of the percen tile levels the analyzer makes a sampling of the Lp sound level with FAST time constant and A frequency weighting at a frequency usually equal to 10 Hz Sound levels measured in this way are classified over the whole measurement range according to given amplitude intervals usually a frac tion of decibel called classes When starting the measurement all classes will have a null number of samples while at the end of measurements the classes will contain a number of samples depending on the rate with which a sound level has been measured inside the respective interval At the end of the measurement time the distribution of probabilities will be first calculated dividing the content of any class by the total number of samples and multiplying the result by 100 then the cumulative distribution of probabilities will be calculated having a value of 100 for lev els lower than the first class containing at least a sample and taking lower values down to zero for levels higher than the last class containing samples From the definition of the statistical levels it is evident that L will be very near to the maximum measured level while Loo will be very near to the minimum measured level Therefore while levels Li Ls and Lo are representative of the peaks of the acoust
119. e enclosed environment being tested Any solid body hit by a sound wave acts on the wave through reflection absorption and transmission Part of the sound wave is reflected part is absorbed by the material the solid body is made of a fraction of the wave goes through the entire solid body and is thus transmitted by it Thinking about an enclosed space in which there is a sound source the effect of the walls will be to reflect the incident sound that bouncing from wall to wall will propagate in all directions The walls e will also transmit part of the sound so that even in the rooms close to the one being examined it will be possible to perceive the sound is sued by the source Finally part of the sound energy will be absorbed by the walls themselves and dissipated as heat From the listener s viewpoint the sound will be perceived first of all as coming directly from the source but right after with only a small delay as coming from all the other directions The perception N delay between the direct sound wave and the reflected waves depends on the path travelled by the sound wave propagating at a speed equal to 343 m s at normal temperatures The well known effect of the echo is associated to the delay time between the direct wave and the re flected wave equal at least to one twentieth of a second with travel differences of at least 20 m 170 The absorption and the acoustic transmission 1s responsible for the progressive re
120. e entire measurement The multiple integration mode serves this purpose The multiple integration divides the measurement in equal intervals according to the set in tegration time Tint Each single interval begins by resetting the levels and ends when the set inte gration time is elapsed the integration levels sequence ends when manually interrupted by the RUN STOP key The following figure shows the Leq Short profile calculated twice per second and the integrated Leq over intervals of 20s during a measurement time of 1 minute in multiple mode The Leq Short profile is similar to that of the previous figure The Leq Short profile shows the mul tiple integration mode divided the measurement time three intervals of 20 seconds each isolating the three noise phases Some markers point out the beginning of each interval when the Leq was reset Three equivalent levels at about 75dB are obtained corresponding to each interval To select the integration mode select the proper parameter MENU gt gt Instrument gt gt Meas urement gt gt Integration Mode as SING for single integration or MULT for multiple integration To perform the setting directly from the keyboard press SELECT to choose the integration interval When the integration interval numeric value flashes press RIGHT to set the multiple inte 39 gration mode or LEFT to set the single integration mode When the integration mode is set on MULT the Tint symbol flashes
121. e level of which exceeds the two adjacent bands by at least 5dB The spectrum for tone components research must be the minimum levels with FAST time constant and the tone components must be stationary in time and frequency The sound level meter 1s set up from the menu as described below 1 MENU gt gt Spectrum Analyzer e Auxiliary weighting A e Mode MINIMUM e Mean EXP e Mean Weight FAST e 1 2 Shift Band OFF 2 MENU gt gt Calibration e Mic Response FF or RI e Wind Shield Correction ON or OFF 3 MENU gt gt Instrument gt gt Measurement e Spectrum Step enter a higher integration time than the duration of a possible fluctuating sound source or occasional noises to eliminate them from spectrum calculation e Integration interval enter a higher integration time than the total analysis time 156 There is also the possibility that the pure tone falls into the cross zone between two adja cent 1 3 octave filters and produces an increase in both without either of them exceeding the adja cent bands by at least 5dB In order to analyze this possibility use the 1 2 Shift Band function which can be enabled from the menu MENU gt gt Spectrum Analyzer gt gt 1 2 Shift Band which shifts the central frequen cies filters half band downward and matches the new central frequencies with the crossing frequen cies of standard filters see page 25 In the following figures are shown two 1 3 octave band spectra of
122. e selected as usual by SELECT and the arrows upon con firmation by pressing ENTER the page 1s refreshed to show the new results The CURSOR button activates the cursors the following data are reported when the component is selected on the graph by the blinking cursor RT 100 Hz in the following example the reverbera tion time estimation and the respective correlation coefficient Display and printing of the results The set of results obtained with the analysis of the reverberation time can be sent to a PC connected via the special serial cable supplied with the device The HyperTerminal program sup plied with versions of Windows up to XP or an equivalent program can be used to receive the data In addition to the values acquired as a table all the main characteristics of the sound level meter and measurement conditions are supplied An in depth analysis of the results can be performed by using the NoiseStudio program supplied with the sound level meter This software displays processes prints and exports the data stored in the sound level meter using the SAVE command PROG gt gt SAVE both as tables and as 2D and 3D graphs Please see program s Help menu for the details Important with the saving operation SAVE key the current measurement session is closed and the sound level meter is set up for a possible new session By using the Navigator feature PROG gt gt Navigator it is possible to review the measurement ses
123. ecays obtained using the stationary noise technique as demonstrated by Schroeder and as recognized by ISO 3382 that considers the repeatability of a sin gle measurement with the impulse response technique equal to the repeatability associated to the average of 10 measurements carried out using the stationary noise technique The impulse response can be obtained by using different methods and not necessarily using a sound source of an impulsive nature Let us only consider the example of the impulsive source generated by a gunshot or the explosion of a balloon as they are the most frequently used even though they are not always usable or advantageous From the idea that the impulsive source produces an ideal impulse the signal detected will be the direct response to the impulse of the environment This approach is radically different to that of the stationary noise source as no stationary conditions are reached and therefore the answer is strongly dependent both on the position of the source and of the microphone The reverberation times measured directly from the decay of the impulse response are slightly lower than those pro duced by the decay of a stationary noise and do not coincide with the Sabine s definition Schroeder s Integral Schroeder 1965 demonstrated that the decay defined by Sabine can be obtained from the impulse response calculating the integral of the response itself Such an integral must be calculated on the square of the
124. ecorded noise levels The USB interface high transfer speed combined with RS232 flexibility allow fast data transfer from sound level meter internal memory to PC memory but also to control a modem or a printer For ex ample in case the internal memory is not sufficient that s the case of long term monitoring it s possible to activate the Monitor function Such function allows to transmit displayed data through the serial interface recording them directly on PC memory The HD2110L can be fully controlled via a PC using the multi standard serial interface RS232 and USB using a dedicated communication protocol Through RS232 serial interface it s possible to connect the HD2110L to a PC also by means of a modem Together with the logging of the overall noise level profiles the spectral analysis 1s carried out in real time for octave bands and for third octave bands as an option The sound level meter calcu lates the spectrum of the sound signal twice a second and integrates it linearly for up to 99 hours The average spectrum or the multi spectrum profile starting from 1s are displayed together with an A C or Z wideband overall level this allows a fast comparison between spectrum and overall level Moreover the spectrum can be shown both as linear and as A or C frequency weighted for a fast evaluation of the different spectral components audibility In parallel with overall noise profiles acquisition 1s performed the real time spe
125. ected among the following Parameter Attribute Description Lpk Z or C Instantaneous peak level Z or C weighted Leq Z CorA Equivalent level LFmx Z CorA FAST maximum sound pressure level LSmx Z CorA SLOW maximum sound pressure level LImx Z CorA IMPULSE maximum sound pressure level LFmn Z CorA FAST minimum sound pressure level LSmn Z CorA SLOW minimum sound pressure level LImn Z CorA IMPULSE minimum sound pressure level LE A A weighted exposure level SEL KEY GROUP The following table shows the command list of the KEY group 99 STT GROUP STATUS The following table shows the command list of the STT group STATUS HOLD Interrupts display update Restarts measuring Starts recording The STT ACQUISITION command provides information on the acquisition status as shown in the following example STT ACQ STT ACQUISITION STOP BATTERY 32 MEMORY 95 4 DUMP TIME 00 00 01 TEMP CORR 0 01dB LAST CALIBRATION 2003 07 31 08 37 The STT DISPLAY commands are listed in the table below D1 D1 PROB DISTR DI __ Displays the level distribution of probabilities CUMUL DISTR D1 Displaysthe percentile levels graph Display the spectrum by one third octave bands The STT DISPLAY command provides information relevant to the sound level meter actual dis play as shown in this example STT DIS STT DISPLA Y Mode PROFILE The following table lists the STT MONITOR commands 100 Starts the Moni
126. el of Lg sound exposure is expressed in decibel and can be frequency weighted For exam ple Lag will indicate the level of frequency weighted sound exposure with A filter Dose In the field of environmental noise monitoring preventing auditory injuries the measurement of the noise Dose is used It is meant as a percentage fraction of a daily maximum exposure to noise 100 7 DOJE fio dt C exposure percentage for an Exchange Rate equal to Q daily exposure time usually 8 hours measurement time sound pressure level when it is higher than the Threshold Level and otherwise Criterion Level for a daily exposure corresponding to 100 of the dose Exchange Rate parameter independent of the exchange rate and equal to e 10 for Q 3dB e S log2 for Q SdB e 4 log2 forQ 4dB O O COTE Roig 188 TABLE OF CONTENTS CONNECTOR FUNCTION lla 4 INTRODUGTION elba ini 6 BLOCK DIAGRAMS DO Er aerea 10 HIE VIG ROP ONE oriol 11 THE OUTDOOR MICROPHONE UNIT HD WME uuu cece cece secccscccssccssccescccsscessceusccesccesceesseesccescseusseesccuscceussenscss 11 ABRE AMP orcas 12 ERNIA AA 6 RR RR A ITEM OOO 13 DESCRIPTION OF DISPLAY MODES 00000 aan 14 SENFSOUNBLEVEEMETER MODE lla 17 DESPA Y DESCRIPTION aaa aT o A AE EUR 18 SELECTING PARAMETERS A ta NT 18 BACK gt ERASE FUNCTION DATA EXCLUSI N ura ias 19 TIME PROFILE MODE olearia 20 DISPLAY DESCRIPLION clienti 20 USING THES CURSOR S
127. eld from a static point of view This frequency is equal to 1 2 T fim E 2000 Z T estimated reverberation time V volume in m This limit frequency divides the environments in two types those of large dimensions where consideration of modes has no significance and small ones where the low frequencies field is important While in the case of large dimension environments the acoustic field can be analyzed from a Statistical point of view in the case of small dimensions it 1s almost impossible to make any quantitative prediction about acoustic behaviour Definition of Reverberation Time In technical acoustics measuring the speed with which after the source has been turned off the sound ceases in the environment is of primary importance This measurement is performed cal culating the time required for the sound level in an observation point to decay by 60dB starting from the moment the source was turned off Such a time interval is called Reverberation Time The reverberation time is usually measured by exciting up to permanent stationary conditions the space examined using a wideband source so as to excite the most of resonance modes The source 1s then abruptly interrupted and the sound pressure level decay 1s recorded filtered by octave or third octave bands Analyzing the decay curve for central frequencies lower than the Schroeder frequency non linear behaviours with double gradients can be seen while for frequencies a
128. em shows that to obtain a spec trum extending until a frequency f the audio signal must be sampled at double frequency that is at 151 least over 2f Basically to get a spectrum extending until 20kHz the microphone signal must be sampled at a frequency of at least 44 kHz There is a correspondence between the sound level sampling frequency the number of sam ples used for FFT calculation and its spectrum resolution For example if the sampling is per formed at 48kHz and the FFT is calculated on 480 samples audio trace of 10ms the resolution 1s 48000 480 100Hz In other word every 10ms a spectrum will be composed of 480 2 240 ampli tude values corresponding to the frequencies included in the 100Hz 24kHz interval with 100Hz in crements By increasing the audio segment length the spectrum resolution increases to the detri ment of processing time that grows almost geometrically The minimum frequency according to which the audio segment amplitude is given then corresponds to the frequency period equal to the segment length In the following figure a sinusoidal signal with 224Hz frequency is analyzed by FFT on 512 samples at 48kHz The spectrum resolution is just under100Hz 120 co 60 Ln 40 20 0 Y OO rr FTF OO _ TO O rr Y O O Y 0 O r Y O O rr Y O O r Y O O r Y O HD r Y O 0 O Or OT O O 0 OQ O rr 0 O O 0 QDD oOo 0 O O 0 a oO r A O Om AD LD rr o SO O O N N NO Y SO WO r r N N DO
129. en when we are blindfolded Soundproofing and sound insulation in enclosed spaces is being studied to reduce the in terference between adjacent rooms or from external sources The guiding principle is known as passive defence It is assumed that possible intervention on noise sources like vehicle traffic noise or noise emanating from industrial and commercial activities are generally difficult or com plex and therefore you have to intervene on the building to protect the people working and living there from the undesired noises either external or from other parts of the building itself Therefore studies have been carried out on both the acoustic insulation through the measurement of the sound insulating power of the materials that form the dividing walls and secondly on their sound absorp tion through the measurement of the sound absorption coefficient Absorbing elements reduce the reverberation time and also generally reduce the sound pressure level in a closed environment They are also used to insulate a noise source with respect to the surrounding space thus reducing the noise reflected by the acoustic barriers Even though it is impossible to analytically describe the acoustic behaviour of an actual en closed space there are simplified models for the quantitative predictions in applied acoustics Qualitatively the most important factors in the description of acoustic behaviour are reflection and absorption and the modes of th
130. ent of reverberation time requires the use of a sound source an omnidirec tional microphone and a measuring device that can measure the sound decay in the environ ment being tested The reference standards for reverberation time measurements are UNI EN ISO 3382 2008 and ISO 354 1985 The typical application of reverberation time measurements are characterization of rooms for music reproduction theatres auditoria or sound insulation measurements in residential buildings or schools INSTRUMENTATION AND MEASUREMENT CONDITIONS The EN ISO 3382 2 Standard Acoustics Measurement of room acoustic parameters Part 2 Reverberation time in ordinary rooms was published in 2008 This standard sets the criteria and imposes the choices on which instrumentation to use and on measurement conditions in order to make the results as repeatable and comparable as possible Concerning the sound source it has to meet the strict requirements for omnidirectionality of emission and signal noise ratio in all concerned acoustic bands typically in the octaves from 125Hz to 4kHz The omnidirectionality must be accurately verified the maximum acceptable deviations as an aver age for each 30 around the source are the following Max Departure dB In order to evaluate the minimum acoustic level of the source for each octave band so as to measure the reverberation time analysis of a decay equal to at least 20 dB starting from 5 dB under the stationa
131. eous value p in a given time interval T where T tp t is the considered time interval p t is the sound pressure squared at time t in t tz interval rms means ROOT MEAN SQUARE that is square root of the average of squared values Sound pressure effective value is expressed in Pa and takes importance in sound measurement since the value is directly connected to the quantity of energy contained in the sound signal Crest Factor is the ratio between the maximum and the effective value of a quantity measured in a given time interval with reference to the arithmetic average value Sound Pressure Level is defined by the expression Prns L 20 log Po where Prms pressure effective value Po reference sound pressure 185 L sound pressure level also referred to as SPL is expressed in dB Sound Pressure Level with Frequency Weighting The sound pressure level can be weighted in frequency applying a filter that changes in a predetermined way the signal spectral structure Acous tic standard filters are referred to as A and C Sound Pressure Level with Time Weighting The sound pressure level can be exponentially weighted over the time with a given time constant It 1s defined by the expression t Lp p e 7 e 10 08 LO y Lr Po where T time constant expressed in seconds Y symbol associated to the applied time constant fictitious variable for the integration over elapsed t
132. er MENU gt gt In strument gt gt Measurement gt gt Report Time from a minimum of 1s to a maximum of hour The 5 integrated parameters the spectra and the statistics are automatically cleared at the beginning of every report time The 5 reported parameters can include FAST SLOW and IMPULSE weighted maximum and minimum levels Peak level Equivalent level sound pressure level SEL Preset percentile levels L1 L2 L3 and L4 Activation of the report time is an alternative to the multiple integration mode The report time can be set only in single integration mode The Event group is recorded per each detected event see paragraph EVENT TRIGGER FUNCTION on page 37 at the end of the event itself The 5 integrated parameters the spectra and the statistics are automatically cleared at the beginning and are integrated for the entire dura tion of the event The 5 event parameters can include FAST SLOW and IMPULSE weighted maximum and minimum levels Peak level Equivalent sound pressure level SEL The event trigger feature can be activated only in single integration mode Therefore it is not possible to enable event recording while multiple integration mode 1s selected When the Measurement group recording is activated together with the Report and Event groups recording the Measurement group continuous recording is enabled only with the events sensed by the event trigger This allows a lot of memory to be saved minimizin
133. er frequency response and compensate the effects of the HD SAV shield provided with the in strument All measurement parameters with wideband frequency weightings and with constant per centage bandwidths either octave or third octave are automatically adjusted Besides the windshield correction the adjustment for the acoustic field can be activated too With the standard microphone which has a frequency response optimized for the Free Field no correction is applied when the correction is set on Free Field When you set the correction on Random Incidence RI the correction for random incidence sound will be activated This setting is necessary to perform measurements according to ANSI standards see the parameter of the menu CALIBRATION gt gt Microphone Response For example if you choose the MC22 microphone which has a frequency response optimized for the diffused field the standard setting will be Random Incidence RI Set the parameter on Free Field FF to activate the correction and make measurements in free field This setting is necessary to carry out measurements according to IEC standards The HD2110L sound level meter is suitable for measurements on site in a temperature range be tween 10 C to 50 C in a static pressure range between 65 kPa and 108 kPa and in a relative hu midity range between 25 and 90 The microphone itself has defined drift coefficients of acous tic sensitivity w
134. eriod level oscillations are consid ered negligible To get stable and repeatable levels the integration time can be adjusted In this case con sider that the uncertainty in determining sound levels will depend not only on the integration time but also by the bandwidth of the filter being examined In the case of the white noise the following formula provides the uncertainty due to the statistical error 4 34 i V B Tint The following table as an example gives such uncertainty for some filters with constant percent age bandwidth of third octave for some integration times 168 Central Frequency Hz T ER AT ER En AT ANA 4 1 1 0 8 0 6 0 4 0 3 0 2 30 058 1 0 0 1 02 e 1 4000 00 0 e Je e il e da Lei Some acoustic signals can be analyzed in statistical terms The statistical analysis provides information complementary to that provided by the calculation of the equivalent level for signals strongly time dependent Actually signals with completely different time evolutions and conse quently with an impact completely different on the auditory apparatus can have the same equiva lent level For example in the analysis of the noise made by car traffic it is convenient to measure the so called statistical levels or percentile levels providing a description of noises fluctuating in time The statistical levels provide the sound level exceeded by a certain percentage of the meas uring tim
135. ersa a microphone optimized for the free field will provide too low values when measuring in reverberant fields and in all cases in which it will not be oriented towards the sound source 165 Modern sound level meters like HD2110L apply corrections that can modify microphone responses according to the acoustic field in which they are used In this way you can for example make measurements in indoor environments in presence of multiple sound sources and anyway in a reverberant field with a microphone optimized for free field by activating the correction specific for random incidence Applying this adjustment the free field microphone will give a response similar to that of a diffuse field microphone ENVIRONMENTAL INFLUENCE Temperature Sound level meters are designed to work at temperatures included in the range 10 C 50 C Most accurate sound level meters like HD2110L can have adjustment circuits for thermal drifts aiming to reduce at minimum the measuring error over the whole temperature range It is sug gested however to avoid sudden variations that might cause condensation Furthermore be sure that the instrument is in thermal equilibrium before carrying out a measurement or a calibration just wait an hour after temperature has changed Humidity The HD2110L sound level meter and the microphone are not affected by relative humidity up to 90 However protect the microphone from rain and snow and keep it clean In ca
136. ession the selected cursor will flash Use the LEFT and RIGHT arrows on the keypad to move the selected cursor on the graph The display second line shows level and central frequency of the filter indicated by the active cursor or the level difference between the two cursors when they are both active The instrument full scale is determined by the selection of the input gain by choosing from the menu MENU gt gt In strument gt gt Measurements gt gt Input gain 24 The level is shown in dB for unweighted Z spectra while it s in dBA or dBC for A and C weighted spectra respectively In the octave and third octave spectrum mode cursors can be also positioned on the bar repre senting the wideband channel In the AVR and MLT modes with linear average filters having a level lower than the mini mum measurable are indicated by the cursor with a series of dashes If you press and hold down the CURSOR key for at least 2 seconds while the unweighted Z spectrum by third octave is displayed the real time tracing of isophone curves according to ISO226 2003 will be activated Fig 14 Isophone curves Press CURSOR again and hold it down for at least 2 seconds to disable the isophone tracing When the isophone curve 1s active the cursors perform different functions with respect to the standard display described above The L cursor is combined with the isophone tracing Lz holds standard functions AL presents t
137. eter MENU gt gt Sound Level Meter and choose according to the type of measurements to be made be tween the parameters DOSE A or DOSE d A 131 The integration time can be entered directly in the SLM measuring window Now the in strument is ready to carry out the measurement press START After Tint time has elapsed the in strument turns into the HOLD status and displays the DOSE calculated over the set time STATISTICAL ANALYSIS Up to 4 percentile levels are selectable in the SLM display mode MENU gt gt Instrument gt gt Measurement gt gt Percentile Lev 1 4 programmable between L and Loo The statistical analyzer samples the sound pressure A weighted level with FAST time constant 8 times per second The levels are accumulated in 0 5dB classes The percentile levels are calculated interpolating the cumu lative distribution It is possible to choose which parameter the statistical analysis 1s performed on equivalent level sound pressure level with FAST time constant and peak level The complete statistical analy sis is available with the distribution of probabilities graph and the L to Log percentile level graph DATA PRINTING The displayed values can be printed at any time in all display and acquisition modes Besides the Monitor function can be activated via the serial line when you press PRINT and hold it down for at least 2 seconds This function allows to continuously send displayed data in real time to
138. evel LSmn Z CorA SLOW minimum sound pressure level LImn Z CorA IMPULSE minimum sound pressure level Leql A Equivalent sound pressure level with Impulse time constant Lav4 A Average level with 4 dB exchange rate Lpop A weighted Lav5 A Average level with 5 dB exchange rate Losna A weighted LE A A weighted exposure level SEL EA A A weighted sound exposure in Pa h Dose A A weighted dose Dose d A A weighted daily dose LI A Percentile level calculated on A weighted FAST pressure level 2 A Percentile level L3 A Percentile level L4 A Percentile level OL Time percentage in which an overload has occurred PROFILE Mode Parameter Attribute Description Lpkmx ZAC Z or C weighted maximum peak level Leq Z CoA Z Cor A weighted equivalent level LFmx Z CoA FAST maximum sound pressure level LSmx Z CoA SLOW maximum sound pressure level LImx Z CoA IMPULSE maximum sound pressure level LFmn Z CoA FAST minimum sound pressure level LSmn Z CoA SLOW minimum sound pressure level LImn Z CoA IMPULSE minimum sound pressure level LOeq 16Hz 16kHz Equivalent level with octave bandwidth 16Hz 16kHz LOFmx 16Hz 16kHz FAST maximum sound pressure level with octave bandwidth 07 2 LOSmx 16Hz 16kHz LOFmn 16Hz 16kHz LOSmn 16Hz 16kHz LTOeq 16Hz 20kHz LTOFmx 16Hz 20kHz LTOSmx 16Hz 20kHz LTOFmn 16Hz 20kHz LTOSmn 16Hz 20kHz SLOW maximum sound pressure level with octave bandwidth FAST minimum sound pressure level w
139. f necessary see the description of the key functions from page 136 and the different display modes from page 14 onwards MEASUREMENT PROCEDURE The HD2110L sound level meter can simultaneously acquire 5 parameters twice a second the time profile of a parameter with sampling interval programmable from 1 8 second to one hour and the spectra both by octave and optional third octave bandwidth with sampling time program mable from 0 5 seconds to one hour The available parameters are those listed in the tables of ap pendix Al on page 144 Measured parameters are displayed on different displays selectable by means of the MODE key Sound Level Meter SLM See also the description on page 17 Use the MODE key to select the SLM display where 5 measuring parameters are shown in numeric format Press SELECT repeatedly to set the integration time Tint the measuring range and the parameters to be displayed as described in the paragraph Selecting Parameters of chapter SLM sound level meter Mode on page 17 As alternative you can set measuring parameters from menu as described in the chapter DESCRIPTION OF THE MENU FUNCTIONS on page 49 Once parameters have been set start the measurements by pressing the START STOP RESET key When the sound level meter is set in single integration mode MENU gt gt Instrument gt gt Measurement gt gt Integration Mode SING when the Tint time is over the HOLD indication will appear
140. f the sound level meter is set to the single in tegration mode MENU gt gt Instrument gt gt Measurement gt gt Integration Mode SING once the Tint time in common with the SLM screen is over HOLD will appear and the spectrum updating will 128 be temporarily suspended Meanwhile the instrument goes on measuring to continue display up dating just press the HOLD key When the continuous recording is activated and the Tint time goes over the acquisition is stopped automatically If you press HOLD during the measuring phase the display update will be temporarily inter rupted When HOLD is pressed again the updating will continue Even if the display is not updated the instrument will go on measuring Also data acquisition can be temporarily suspended with the key PAUSE To clear the graph when in pause press START STOP RESET Press PAUSE once more to start measuring again Press PRINT at any time to print the on screen data To activate the continuous printing Monitor press and hold down PRINT for at least 2 seconds A flashing M over the status indica tor shows that the Monitor function is active The Monitor function remains active even when jumping to other measuring views and can be disabled pressing PRINT again or START STOP RESET to stop measurement If on the contrary the sound level meter is set with the multiple integration mode MENU gt gt Instrument gt gt Measurement gt gt Integration Mode MULT
141. f using a capsule with different characteristics from the one supplied If you wish to change the microphone capsule you must use the relevant wizard in Nois eStudio software under Instrument management gt gt microphone substitution program The proce dure is described in detail in NoiseStudio s online Help DIAGNOSTICS The HD2110L sound level meter is provided with a testing program of the main electrical parameters that can also examine the frequency response of the measuring and amplification chain FREQUENCY RESPONSE The Frequency Response program provides the instrument frequency response micro phone included over the whole audio range comparing it to the data relative to the last periodic calibration available or the factory calibration if the instrument is new The use of this program al lows to check the frequency response of the chain made up by microphone preamplifier and sound level meter Most of the problems connected to a microphone preamplifier malfunction can be iden tified using this program The check is executed at octave frequencies from 31 5Hz to 16kHz Before beginning the scanning the response at 1kHz is taken as a reference confirm the new data to continue Note the confirmation of the value at 1kHz does not involve any change of the instrument calibration but it is only useful to give the user the chance to cancel the operation in progress in case there is any malfunctioning in the first st
142. ft of mic sensitivity UNMODIFIABLE SEQ TIMER SAS Acquisition delay in s m 1 59 or h 1 99 The value that some parameters can take is listed in the following table The default value is in bold format IN CHANNEL LINE 300 A PAT 304K 0 OAK ee OT DEVICE ae PR PR ee ERASE TIME Ss n A SING INT MODE MULT SPECT_POND SPECT AUX POND TRG OUTPUT RUN a FFT BAND a Morse a SPECT TYPE M MINIMUM 0 125s 95 Parameter 2s 10s PROFILE TIME 208 30s N 10m 30m 0 5s 10s SPECTRUM TIME 30s N 10m 20m 30m 10s REPORT TIME 10m 20m 30m lh LIN A OFF EVN TRIGGER EXT MAN SPECT MEAN WEIGHT FAST 96 UNIR an ma MIN S LIS lanle Seleb Nn e rr i SLOW e WND SHL CORR EVN PRINT The parameters that can be displayed in SLM and PROFILE modes are selectable among those of the respective lists SLM Modes Parameter Attribute Description Lpk ZorC Instantaneous peak level Z or C weighted Lpkmx ZorC Peak maximum level LegS Z CorA Short equivalent level Z C or A weighted Leq Z CorA Equivalent level LFp Z CorA FAST sound pressure level LSp Z CorA SLOW sound pressure level LIp Z CorA IMPULSE sound pressure level LFmx Z CorA FAST maximum sound pressure level LSmx Z CorA SLOW maximum sound pressure level LImx Z CorA IMPULSE maximum sound pressure level LFmn Z CorA FAST minimum sound pressure l
143. g A 144 Other PARAMETER ABBREV DEFINITION WEIGH FREQ Hipa 6 OL Percentage of the measurement time in Overload i o which an overload occurs 145 ACOUSTIC DESCRIPTORS GRAPHIC DISPLAY Time Profile HISTORY Wideband Levels PARAMETER ABBREV DEFINITION WEIGH FREQ e Equivalent level Sound pressure maximum level SPL max X Z C A Y F S I LY Sound pressure minimum level SPL min X Z C A Constant percentage bandwidth levels O EE igiene 7 O OCTY max dB FC bands SPLinax FC 16Hz 16kHz Sound pressure minimum value by octave OA dB FC bands SPL prin FC 16Hz 16kHz i Loca AE octave bands esiguo aote TOCTYmax dB FC third octave bands SPLmax FC 16Hz 20kHz i TOCTY min dB FC third octave bands SPLmin FC 16Hz 20kHz Statistical Analysis PARAMETER ABBREV DEFINITION WEIGH FREQ emi LXpk Peak level Equivalent level XL GA LXFp Sound pressure level with FAST time con Lam dex Sag LOA 146 ACOUSTIC DESCRIPTORS THAT CAN BE STORED Measurement group acoustic Levels All the levels that can be displayed above related to the SLM PROFILE OCTAVE and T OCTAVE option HD2110 01 screens With FFT option active the LAeq integrated profile at 1 32s and the narrow band FFT spectral analysis calculated each 0 5s can also be recorded Report group acoustic levels 5 selected parameters PARAMETER ABBREV DEFINITION WEIGH FR
144. g information losses during the events the maximum quantity of logged information occurs while with outside sound events the recording of the level 1s also carried out according to a reduced time resolution as defined in MENU gt gt Instrument gt gt Measurement gt gt Report time La Fig 30 shows the recording flow for the Report and Event groups 45 The Measurement group recording period depends on the item in the Menu gt gt Recording gt gt Measurement with the maximum time resolution The maximum recording frequency of the Meas urement group is equal to 2 records per second for items with shorter time resolution such as a Profile with profile time shorter than 0 5s and Leq Short at 1 32s a larger amount of values is re corded When the Leq Short recording is enabled at 1 32s 16 levels are stored twice per second In the following example also the Report group items are memorized with a Report time amounting to 10s 4 Fig 30 A 0 5s 10s When the trigger function detects an event identified by the overcoming of the trigger thresh old or by the external TRGIN signal or when ENTER is pressed a time marker is recorded Similarly when the end of event conditions are sensed as identified by the deactivation threshold being reached or by the external TRGIN signal or when ENTER is pressed and after the set stop delay has elapsed another time marker is recorded After the time marker when the eve
145. g of the event reports is defined as described in the paragraph CONTINUOUS RECORDING OF REPORT AND EVENT GROUPS Each item can be enabled separately as with the measurement recording In order to avoid occu pying memory space uselessly we recommend to enable only the needed items and set the others to OFF e Par 1 Par 5 define five integrated event parameters with relevant frequency weightings e Parameters enables recording of the 5 parameters Par 1 Par 5 defined previously e Oct Spectrum activates the recording of average spectrum A VR by octave band e T Oct Spectrum activates the recording of average spectrum AVR by third octave band Third Octave option required e Statistics activates the recording of the event statistics CALIBRATION e Calibration Level Sound level of the reference sound source used for the sound level meter calibration Allowed values vary from 90 0dB to 130 0dB with a 0 1dB resolution e Microphone Response allows to select the type of frequency response of the microphone according to the sound field The standard setting for the standard microphone is Free Field FF since it has a frequency response optimized for free field Set the parameter to Ran dom Incidence RI to activate the correction for sound random incidence This setting is 55 necessary to carry out measurements according to ANSI standards Likewise if you choose the MC22 microphone which has
146. gress ELECTRIC CALIBRATION Last 2003 01 01 10 00 Calibr level 44 0dB Leg SI Faec Run calibration CURSOR du ur a E 4 Press YES to continue and NO to quit If you press YES the calibration is run wait till the procedure will be over 6 At the end the calibration result will be shown and you will be asked to confirm a new cali bration GN ELECTRIC CALIBRATION Last 2003 01 01 10 00 Calibr level 34 0dB 7 7 ALeq Hid dBC Confirm calibration YES NO A 7 Press YES keypad LEFT key to confirm or NO keypad RIGHT key to refuse the calibra tion just finished At the end the instrument will switch to the SLM display in STOP mode The stabilization on a value far from the reference one indicated by a ALeq higher than some tenths means that one of the components of the microphone preamplifier instrument chain was af fected by a considerable drift and if this difference exceeds the maximum limit admissible by the instrument calibration will fail In this case refer to Troubleshooting page 133 and if necessary contact our service department ACOUSTIC CALIBRATION In order to keep the acoustic sensitivity of the microphone sound level meter chain steady over time and in the different usage conditions a reference sound source is used which generates a pure tone at a reference frequency with a given pressure level stable over time For this function type according to IEC
147. h the possibility to filter false events by requiring that the variation of the sound level has a spe cific duration For each event it s possible to store 5 integrated parameters the average spectra in octave or third octave option Third Octave bands and the noise levels probability distribution during the event The storage of event s parameters does not exclude normal and interval re cording The function of event triggering can be activated also manually using a key or via a hard ware external signal sent to the TRGIN input The sound level meter can activate an external device using the TRGOUT output in parallel with data acquisition or the occurrence of sound events The advanced features of the analyzer allow the acquisition of multi descriptors noise profiles in parallel with report sequences with dedicated parameters average spectra and full statistical analysis Moreover during recording the trigger function is able to identify sound events and re cord their analysis with 5 chosen parameters average spectrum and statistics integrated for the event s duration During data logging are available up to 9 different markers to record specific events and con sider them in the profiles post processing phase A timer allows to schedule a delayed acquisition start Different recordings can be later recalled from internal memory and displayed on the graphi cal screen using the Replay function that shows the time history of r
148. he audio signal applying a complex multiplication to all audio samples heterodyne The results are audio segments detected at the original frequency but with shifted frequency spectrum contents If we apply a shift equal to 12 kHz to the original samples we get a spectrum every 10ms composed 152 of 240 amplitude values corresponding to the frequencies included in the 12Hz 24kHz interval with 50Hz increments In the following figures the same signal is analyzed by FFT on 512 samples at 6 kHz FFT MF and at 750 Hz FFT LF respectively obtained through decimation of the original samples at 48 kHz FFT MF FFT LF dB dB 40 20 0 0 Vo YO 6D SD od x D O ok A 1 9 oO SA io NAPPO PP Ip SIRO LES PS Lat VPM SPE BLM MPL MG OPP NT Freq Hz Freq Hz Fig 41 Fig 42 The decibel level scale does not allow the frequency resolution of the FFT spectrum to be fully ap preciated The following figures show the FFT spectrum of a square wave signal with both vertical scale in decibels and linear scale in Pascal FFT FFT 120 12 Pa EV MN WA ny Ml i i 4 0 SAN S N SID DID POS O AV 98 APD Oy x PWG MHS SASSI V Q oY 9 6 DO ad dh AK 9 1 4 oO 0 0 A VMN 1H 19 gd 4 BD DA _ 9 8 DA PDP Pe Wrage LA SN ANA SSS OID PP PF GSP PE DO Gh ov SY N DT CNR NP Freq Hz Freq Hz Fig 43 Fig 44 The linear scale spectrum shows the reno
149. he four arrows to change the values with the UP and DOWN arrows you can modify the parameter while with the LEFT and RIGHT arrows you can jump from selecting the measure ment parameter to selecting the respective frequency weighting When you have finished with the adjustments wait a few seconds or press ENTER to confirm and quit the selection mode SWXYZ UP key The UP key selects a previous line in the menus or increases the selected parameter De creases the scale limits of the time profile and of the frequency spectra moving the graph upwards 140 quis MODE key The MODE key selects the different display modes of the instrument from SLM to Time Profile Octave Third Octave spectra option HD2110 01 Sound level distribution of probabili ties and cumulative distribution with percentile levels With FFT option also the FFT screen is included in the sequence It is possible to disable the display of the screen related to the spectrum analyzer and the statistical analyzer using the appropriate parameters in the relevant menus All operating modes are active at the same time even though not displayed using the MODE key you can select the display mode without affecting measurement LEFT key The LEFT key selects the previous character in the active line of the menu It jumps to a previous parameter during the selection of a measurement variable that needs the definition of more than a parameter see SELECT
150. he program press SELECT to activate the selected program These are the available programs Memory Navigator Views data stored on memory allows to access stored data and view them on the instrument display It works both with single session data and with multiple ones See details on page 57 138 Electric Calibration single frequency 1kHz with electrical signal coming from the built in sinusoidal reference generator See details on page 64 Acoustic Calibration is used for the sound level meter tuning at 1kHz with an acoustic cali brator See details on page 66 Frequency Response shows in graphic format the difference of the frequency response of the microphone preamplifier instrument chain with respect to the one stored in the last pe riodic calibration or with respect to the factory calibration See details on page 69 Diagnostic Check this program checks several instrument parameters supply voltages mi crophone polarization and sensitivity the type of preamplifier and the environmental pa rameters see details on page 71 Reverberation this is a reverberation time calculation program optional that can calculate reverberation times using both the sound source interruption technique and the impulse source technique See details on page 72 Download data on MC this program allows you to copy the sound level meter measure ments in the external memory card see details on page 109
151. he program fail contact the service department FREQUENCY RESPONSE I The FREQUENCY RESPONSE program fails Ensure that the instrument is not subject to high noise and or vibrations Repeat after having waited for the stabilization time If the problem remains run the pro gram ACOUSTIC CALIBRATION and try again if successful 133 RESTORING FACTORY SETUP The default configuration of the instrument parameters factory setup can be recalled at any time by means of a combination of keys This operation does not clear the content of data mem ory While the instrument is off press and hold down ENTER and power on the sound level meter All the menu items are simultaneously brought back to the default value RESTORING FACTORY CALIBRATION The Factory Calibration can be recalled at any time by means of a combination of keys This operation does not clear the content of data memory While the instrument is off remove one of the batteries and wait at least 5 minutes for the sound level meter internal circuits to discharge Press and hold down the ENTER key while reinserting the battery the sound level meter will automatically turn on Confirm the load of factory calibration The sound level meter calibration parameters are restored to the last factory calibration all menu items are simultaneously brought back to the factory parameters default MISCELLANEOUS PROBLEMS 1 The instrument does not turn on after battery replacement
152. he specific properties of the building materials are measured while on site the installation techniques and performances of the materials used in the construc tion are checked The necessary instrumentation to perform the measurements consists of a stable sound source with a white noise spectrum and measurement microphones conforming at least to class 1 specifications according to the IEC 651 and IEC 804 standards The measurement equip ment must be calibrated conforming to the IEC 942 standard The analysis of the frequency is done with 1 3 octave band filters satisfying the specifications of the IEC 1260 standard The frequency range starts from at least 100 Hz and goes up to 5000 Hz ISO 140 Part 3 Lab measurements ISO 140 Part 3 Acoustics Measurement of sound insulation in buildings and of building elements Part 3 Laboratory measurements of airborne sound insulation of building elements was issued in 1995 The standard defines a laboratory method to measure the airborne sound insulation of the building elements such as walls floors windows and doors fa ades except for the elements classifiable as having small dimensions for which a special method is prescribed in ISO 140 10 The results ob tained can be used to design and or to classify such elements The sound reduction index R of the wall not only depends on the geometric and physical proper ties of the wall itself but varies with the frequency and original direc
153. he upper limits correspond to 141 dB and 131 dB respec tively for input gain equal to 0 dB and 10 dB The starting point for the linearity range measurement corresponds to the reference level 94 dB at kHz The starting point at different frequencies takes into account the attenuation of the fre quency weighting Integration time Integration time can be set up from Is up to 99 hours Measurement Dynamics with Electromagnetic Fields Minimum measurable level equal to 60dBA with carrier from 26 MHz to 1 GHz and amplitude equal to 10V m modulated 80 at 1 kHz 116 Reference Conditions The measuring range is that with input gain equal to 10 dB The level corresponds to 94 dB The acoustic calibration can be performed at a sound level included in the range 94dB 124dB The reference direction of the acoustic signal is the preamplifier longitudinal axis The reference acoustic field is the free field with the supplied standard microphone Operating conditions Storage temperature 25 70 C Operating temperature 10 50 C Working relative humidity 25 90 RH not condensing Static pressure 65 108kPa Protection degree IP64 In case of condensation the sound level meter should not be operated Drifts Temperature 0 3 dB over the range 10 50 C with microphone drift correction activated Relative humidity 0 3 dB over the range 25 90 RH not condensing Static pressure
154. hen the Auto Store function is activated the spectrum analysis is automatically set to AVR mode The integration time corresponding to the storage interval is programmable from the SLM screen or from menu MENU gt gt Instrument gt gt Measurement gt gt Integration Interval CONTINUOUS RECORDING Pressing at the same time REC and START STOP RESET keys activate the continuous data recording on memory Before starting the continuous recording select the data to be logged via the RECORDING menu item see details on page 54 Press PAUSE to stop recording temporarily press CONTINUE to restart it As soon as you go back to the RUN status a special record is stored containing indications about the possible erase see the Back Erase Function data exclusion in SLM mode on page 19 besides date and time The HOLD key does not affect data recording Logging interval in continuous recording mode changes according to type of data In SLM a series of values are recorded every 0 5s In History Profile the interval is programmable and it corresponds to the sampling inter val except for 1 8s and 1 4s sampling times where 4 and 2 values are respectively re corded every 0 5s e In the spectral analysis the time interval equals the set profile time in case of multi spectrum analysis MLT MAX and MIN and it 1s fixed at 0 5s in AVR mode When the continuous recording is active if the integration mode 1s set to single the integrat
155. ic signal Loo Los and Log are representative of the background noise Other parameters characterizing the sound level have been derived from the statistical levels For example in the measurement of vehicle traffic noise the Traffic Noise Index has been de fined as TNI 4 Lio Loo Leg That provides higher values in the case of a sound level strongly fluctuating and thus characterized by a bigger difference between Lio and Loo 169 A7 ARCHITECTURAL ACOUSTIC Introduction The aim of studying acoustics in buildings is to improve living conditions Architectural Acoustics studies both the diffusion of sound in enclosed spaces in order to improve the sound quality of music and the spoken words and to soundproof sound sources and insulation against un desired noises The purpose of studying sound diffusion in enclosed environments is to improve sound dis tribution and the quality of auditory perception intelligibility of words and the control of echo etc The main parameter that describes an enclosed space from an acoustic viewpoint 1s reverberation time The difference between the perception of hands clapping in a common living room and a large hall for example in a sports hall forms part of the experiences we all feel The phenomenon needs to be interpreted by thinking of the sound wave propagation interacting with the walls and gives sound that colour which allows us to evaluate the dimensions of the space ev
156. ical and electronic equipment marked with this symbol cannot be disposed of in public landfills According to the UE Directive 2002 96 EC the European users of electrical and elec tronic equipment can return it to the dealer or manufacturer upon purchase of a new one The illegal disposal of electrical and electronic equipment is punished with an administrative fine This guarantee must be sent together with the instrument to our service centre IMPORTANT Guarantee is valid only if coupon has been correctly filled in all details Instrument Code O HD2110L Serial number RENEWALS Date Date Inspector Inspector Date Date Inspector Inspector Date Date Inspector Inspector CE CONFORMITY C Safety requirements for electrical equipment EN61010 1 EMC Generic standards Immunity for industrial environments EN61000 6 2 2005 NY EMC Generic standards Emission standards EN61000 6 3 2007 db Electrostatic discharge immunity test EN61000 4 2 level 3 Radiated radio frequency electromagnetic field immunity test EN61000 4 3 level 3 RoH Electrical fast transient burst immunity test EN61000 4 4 level 3 x 2002 951567 Immunity to conducted disturbances induced by RF fields EN61000 4 6 Electromagnetic Interference Line conducted disturbances EN55022 2007 class B Electromagnetic Interference Radiated emissions IEC CISPR 22 class B 192
157. ide at the extremities do not significantly contribute to the spectrum analysis The following figure highlights the problem showing the continuous sequence of two segments on which the Cosine Bell was applied 1 5 I ill lt i l 0 0 005 0 01 0 015 0 02 154 In other words the spectrum analysis obtained from an audio trace by dividing it in adjacent segments cannot be considered in real time as it does not use all the samples simultaneously but only the central ones To avoid this they must be partially overlapped so that the ignored samples at the ends are consid ered in the next segment This process is called overlapping of segments Overlapping 0 5 pit wiit 0 w2 t wit plt wlt 0 5 0 0 005 0 01 0 015 0 02 t s Fig 47 The figure shows that the insertion of a 50 overlapped segment allows complete recovery of the trace areas attenuated by the window The sum of the three segments gives a real time an swer Of course the overlapping increases processing time by 50 155 A4 MEASUREMENTS IN PRESENCE OF NOISE WITH IMPULSE TONE AND LOW FREQUENCY COMPONENTS According to Decree of 16 March 1998 the environmental noise and residual noise meas urement must be corrected for the possible presence of noise with impulsive tone and low fre quency components This appendix illustrates
158. ification but also on the microphone capacity Many of the micro Neu ebrion phone malfunctions reflect in a capacity drift LL Signal source identifiable by means of this calibration tech 01899 amplfer nique Transducer The electric calibration uses as a ref CONCA CIO erence the result of the last acoustic calibra Fig 38 tion and according to it corrects any possible drift of the instrument The electric calibration adjusts the acoustic response of the microphone sound level meter chain both for wideband channels and for those with a constant percentage bandwidth In case of high instrument drift with respect to the previous calibration it is suggested to carry out an acoustic calibration and to check the instrument frequency response to verify that there are no other problems in the measuring chain Operating Procedure Switch on the sound level meter if it is the case press STOP to finish the measurement in progress and make the following procedure 1 Press PROG and use the DOWN arrow to select Electric Calibration 2 Press SELECT to start the function 3 The inner signal generator will be turned on and the measured output signal will be com pared with the one detected in the last acoustic calibration The value that appears on the display 51 3dBC in the example below before starting cali bration is the valued measured by the microphone upon pressure of the PROG key and is not relate to the calibration in pro
159. ification chain microphone included diagram described on page 64 A special output driver allows to transmit the microphone signal via a cable up to a 100 m dis tance The preamplifier of HD2110L can measure noises up to 140dB with a flat frequency re sponse up to 40 kHz The following preamplifiers are available HD2110P preamplifier with standard Y connector for 200V polarized microphones This preamplifier equipped with CTC calibration device for electric calibration can be directly connected to HD2110L sound level meter or connected using the extension cable up to 100m length HD2110PE preamplifier similar to HD2110P but suited for pre polarized Electret micro phones HD2110PW heated preamplifier with standard Y connector for 200V polarized microphones and cable driver This preamplifier equipped with CTC calibration device for electric calibra tion can be directly connected to HD2110L sound level meter or connected using the Smt extension cable other lengths on request HD2110PEW preamplifier similar to HD2110PW but suited for pre polarized Electret mi crophones The Instrument The signal of the preamplifier comes to the instrument receiver and its output is sent to the LINE connector and to the A D converter input The instrument can be set to use the LINE channel in place of the signal coming from the preamplifier The analogue signal is converted into numeric format at 25 bit from the A D The excepti
160. ility of the spectral components by real time comparison with the isophonic curves ISO 226 2003 Calibration certification according to IEC61260 included HD2110 04 Reverberation Time option Reverberation time measurement by source interrup tion and the impulse response method HD2110 06 FFT option FFT spectral analysis over the entire audio range with variable resolu tion from 1 5 Hz to 100 Hz and 1 32s Short Leq profile calculation HD2020 class 1 calibrator according to IEC60942 2003 with LCD display Emission level 94 114dB IKHz It includes ISO9001 calibration report HD91010 class 1 acoustic calibrator according to IEC60942 1988 Emission level 94 114dB 1KHz It includes ISO9001 calibration report MC22 4 type 1 diffuse field microphone type WS2D according to IEC 61094 4 MC23 2 type 1 free field microphone type WS2F according to IEC 61094 4 Suitable for out door measurements CPA 10 10m extension cable for HD2110P preamplifier CPA 20 20m extension cable for HD2110P preamplifier CPA 50 50m extension cable for HD2110P preamplifier VTRAP Tripod max height 1550 mm VTRAP H4 Tripod max height 4m HD2110 SA Support for fixing the preamplifier to the tripod HD2110RS RS232 null modem serial cable with DB9 connector HD2110USB USB cable with A type connector SWD10 Stabilized mains power supply Vin 100 240Vac Vout 12Vdc 1A HD2110MC interface module for datalogging and download i
161. ime up to t measurement instant p the instantaneous squared pressure p o the square of reference pressure The sound pressure level can be weighted over the time with two standard time constants FAST F and SLOW S corresponding to 0 125 s and 1 s respectively A third time weighting called IM PULSE I has been defined for the identification of impulsive components presenting a time con stant for increasing levels equal to 35 ms while for decreasing levels it equals 1 5 s The sound pressure level can be weighted both in frequency and in time For example Larp will in dicate a frequency weighted level with A filter and with FAST time constant Sound Pressure Peak Level referred to as Lpx it equals the absolute value of the maximum sound pk 1t eq pressure in a given time interval expressed in decibel Sound pressure peak level can be frequency weighted Continuous Equivalent Sound Pressure Level referred to as Leq 1t is defined over a T time inter val as Ir ps Lar 10 oez Od where T to t is the time interval under examination fictitious variable for the integration over elapsed time up to t measurement instant p the instantaneous squared pressure p o the square of reference pressure The equivalent sound pressure level can be frequency weighted For example Laeqr will give the equivalent sound pressure level over T interval frequency weighted with A filter Total Leg calculated
162. information transfer other two wires for the power supply As far as the data transfer is concerned the main differences with respect to the RS232 interface RS232 are e The transfer occurs in simplex mode 1 e it s impossible to carry out simultaneously a transfer in both the directions e The data are transferred as package size e The transfer time is defined by only one of the two units the master e The transfer speed is fix at 1 5Mbit s 12Mbit s or 480Mbit s according to the USB stan dard and the kind of connected device The two devices connected through the USB interface are identified as master and slave The master supplies power to the slave and decide the sense and the transfer time scheduling The USB interface of sound level meter 1s a sort of slave and then it has to be connected to a USB master able to supply with the necessary power and to manage the communication The sound level meter HD2110L is equipped with a serial connecting cable for PC with COM type ports code HD2110RS or USB code HD2110USB The HD2110RS cable is a null modem cable with 9 way sub D female connector The HD2110USB cable is fitted with an USB connector type A On request the connection cable for modem or printer DCE with a 25 way sub D male connector code HD2110CSM or with a 9 way sub D male connector code HD2110 CSP can be supplied When the item MENU gt gt Instrument gt gt Input Output gt gt Serial Device 1s set on PRINTER
163. ion whether or not to transfer the Measurements Report or Event measure ments needs to be selected The data is transferred in binary packets to limit the band required for the transfer which are those enabled in Menu gt gt Recording gt gt Measurement Report and Event Consult the user s manual of NoiseStudio Monitor NS4 module that can make full use of this function for details on the binary format acquisition possibilities 42 THE RECORD FUNCTION 9 MNG The REC key supervises the function of recording data on the instrument memory Two recording modes are available single manual or automatic and continuous re cording MANUAL AND AUTOMATIC SINGEE RECORDING When only the REC key is pressed for at least 2 seconds the displayed screen will be re corded as a single record When you press REC and before the instrument stores the active screen you will be asked to confirm the recording title Press ALPHA to edit the title see KEYBOARD DESCRIPTION on page 136 This operation can be performed in RUN HOLD PAUSE and STOP modes When the single recording is activated while the instrument is in STOP mode you will be first required to choose between automatic and manual storage Record data AUTO MAN CURSOR lt If the manual recording has been selected il will happened what above described single record If on the contrary the automatic AUTO recording mode has been selected the so
164. ion time acts like a timer stopping automatically the acquisition as soon as the set time 1s elapsed Integration time is programmable from the SLM display or using the relative menu item Menu gt gt Instrument gt gt Measurement gt gt Integration interval When the integration mode is set to multiple a special marker Last 1s stored together with the last data just before the integrated levels clearing at the beginning of each integration period see DESCRIPTION OF THE DIFFERENT INTEGRATION MODES on page 39 When spectrum analysis is set to AVR mode the spectra are cleared in addition to the statistical levels and the inte grated parameters displayed on the SLM screen 44 CONTINUOUS RECORDING OF REPORT AND EVENT GROUPS When performing the measurements in single integration mode you can also record reports and events The data associated to sound level direct measurement as o SLM screen parameters PROFILE screen parameter Octave and third octave band spectra Leq Short at 1 32s FFT option Narrow band spectrum FFT option are included in the Measurement group Together with the Measurement group recording you can also enable the Report and Event groups recording The Report and Event groups are composed of the following storable parameters 5 integrated parameters Average spectra in octave and third octave bands Statistics The Report group is recorded at programmable intervals using the paramet
165. ith octave bandwidth SLOW minimum sound pressure level with octave bandwidth Equivalent level with third octave bandwidth 16Hz 20kHz FAST maximum sound pressure level with third octave bandwidth SLOW maximum sound pressure level with third octave bandwidth FAST minimum sound pressure level with third octave bandwidth SLOW minimum sound pressure level with third octave bandwidth The parameter for statistical analysis can be selected among the following Parameter Attribute Description Lpk AC Z or C weighted peak level Leq Z CorA Z Cor A weighted equivalent level LFP Z CorA FAST sound pressure level The attribute of the parameter that can be displayed in SLM and PROFILE modes indicates the re spective frequency weighting The integrated parameters for report measurements can be selected among the following Parameter Attribute Description Lpk Z or C Instantaneous peak level Z or C weighted Leq Z CorA Equivalent level LFmx Z CorA FAST maximum sound pressure level LSmx Z CorA SLOW maximum sound pressure level LImx Z CorA IMPULSE maximum sound pressure level LFmn Z CorA FAST minimum sound pressure level LSmn Z CorA SLOW minimum sound pressure level LImn Z CorA IMPULSE minimum sound pressure level LE A A weighted exposure level SEL LI A Percentile level calculated on A weighted FAST pressure level L2 A Percentile level L3 A Percentile level L4 A Percentile level The integrated parameters for event measurements can be sel
166. ith temperature and static pressure that imply a measurable drift of the Microphone preamplifier instrument chain even though within the limits specified for class 1 according to IEC 61672 2002 new standard The microphone supplied with the HD2110L has the following maxi mum drift coefficients of the acoustic sensitivity in the above mentioned operating range For additional details on the drift coefficients please refer to the specific microphone man ual Also the sound calibrator used for checking the sound level meter has sound pressure level drift coefficients to be taken into account 61 PERIODIC CALIBRATION The periodic calibration of the HD2110L sound level meter is needed to ensure the trace ability to the laboratory standards and 1s carried out in accredited laboratories The HD2110L sound level meter is calibrated at Delta Ohm Acoustic Laboratory before being sup plied to the user Factory calibration which is always made on new instruments and at every periodic cali bration every 2 years at least includes the measurements of the acoustic response in pressure of the microphone preamplifier instrument chain stored on the sound level meter non volatile mem ory together with the microphone acoustic sensitivity Right after the measurement of the acoustic response in pressure also the Capacity Transducer Calibration sound level meter electrical calibra tion including the microphone is carried out to be used
167. ivating the Monitor function even 1f you press the MODE key the type of screen sent to the serial interface will not change The PRINT function can also be selected starting from the STOP status In this case the function will automatically activate as soon as the instrument switches into the RUN mode If the instrument gets into the PAUSE mode the function will remain active but sent data will be combined with the P symbol indicating the suspension status of the integrated parameter calculation The Monitor function does not interfere with data recording on memory and can be activated simul taneously The screen pages on which it can be activated are SLM PROFILE OCTAVE and T OCTAVE 2 DEF The print interval varies according to type of data e In SLM a series of values is sent every 0 5s e In PROFILE the interval is programmable and corresponds to the sampling interval except for 1 8s and 1 4s sampling times where 4 and 2 values respectively are sent every 0 5s e In the OCTAVES and T OCTAVES spectral analysis the time interval equals the pro grammed profile time in case of multi spectrum analysis MLT MAX and MIN and is fixed at 0 5s in the AVR mode BINARY FORMAT MONITOR The MEASUREMENT mode of the Monitor function enables the transfer of all measure ments performed by the sound level meter to a recording system linked to the serial interface with out limiting those currently displayed Before starting acquisit
168. ively TIME PROFILE MODE This display mode presents the time profile of a selectable parameter You can display a pa rameter out of the integrated one like Lomax Lpmin Leg and Lpkmax either with wideband frequency weightings or with octave or third octave bands option Third Octave Integration and sampling time is programmable between 1 8s and 1h from 1 2s to 1h for the levels with constant percentage bandwidth filters the last 100 measured samples are displayed The HD2110L sound level meter calculates the sound level weighted A C or Z 128 times per second The Profile screen gives the best time resolution by providing up to 8 values per second exponentially 1 e LFmx and linearly i e Leq weighted For example when you choose to dis play a profile of the maximum FAST pressure level LFmx a flow of 128 samples per second of the FAST pressure level is examined and the maximum level is displayed at regular intervals ac cording to the set profile time Pressing HOLD the display update will be stopped however the instrument continues meas uring and pressing HOLD again will restart display updating The HOLD status does not affect neither Monitor continuous printing nor recording opera tions When the continuous recording is activated with the single integration mode the integration time acts like a timer for data acquisition stopping automatically the measurement when the time is elapsed This screen page is n
169. l on the SLM will flash When spectrum analysis is set to AVR mode the spectra by octave and third octave bands and the statistical levels are cleared in addition to the parameters displayed on the SLM screen When the continuous recording is activated with the multiple integration mode the last recorded data before each reset is marked by a special label Last in order to rapidly find the calculated integrated levels on each acquisition interval This integration mode together with the Auto Store function MENU gt gt Recording gt gt Measurements gt gt Auto Store allows to record the SLM parameters together with the octave and third octave band spectra at a given frequency see THE RECORD FUNCTION on page 43 Automatic recording occurs at the end of each integration interval When the Auto Store function is activated the REC symbol blinks alternating with the sound level meter acquisition status indicator in the left upper corner The multiple integration excludes the possibility of using the Report Time parameter to record using intervals and the event trigger The statistical analysis and the other integrated levels are cleared at the beginning of every integration period The following table gives the different measurement and storage modes of the HD2110L Integration Auto Store Continuous Recording Single Recording Press Ca to start The integration ends when t T Int Enter in HOLD mode It is possib
170. l giving the same audibility loudness at different frequencies The dotted curve named MAF Minimum Audible Field indi cates the minimum audible threshold Music voice and noises in general are usually distributed throughout a wide interval of fre quencies Borderline cases are the pure tone a sound made up by a variation of pressure at a given frequency and the white noise a sound uniformly distributed throughout all frequencies it sounds like the TV audio rustling when it is not tuned in any station 158 120 0 110 0 100 0 ps Y ti Y F y Ye 5 20001 i K SS Le o w o k DE ci mas ho QD o e o o HEL ue o o o 1000 Freq Hz o o o o 100000 Noises characterized by the presence of a pure tone are more bothering at the same level with respect to noises distributed over a wide interval of frequencies The reason is to be found in the sound energy concentration in the ear mechanics Usually the sound level is not static but it changes with time If the variation is very rapid the ear cannot feel the real intensity In case of sound pulses we know that the ear has a reduced perception already for durations lower than 70 ms For this reason noises with an impulsive feature are u
171. lassified when the tone is located far from crossing frequencies be tween adjacent third octave bands in this case the band of the spectrum containing the frequency of the pure tone can be easily identified since it is higher than the adjacent average and provides the sound level of the tone If on the contrary the frequency of the tone emitted by the source is located exactly at the crossing of the two adjacent bands the two bands will show levels higher than the surrounding av erage value each of them with a level 3 dB lower than the true level of the tone The HD2110L sound level meter can be programmed to calculate the third octave band spec trum with central frequencies shifted by half band 1 6 octave with respect to standard values in such a way that shifted bands are exactly in the middle of crossing frequencies of standard bands From the comparison between standard and shifted spectra you can determine the presence of a pure tone with any characteristic frequency and measure its level wc ERE LID iii D Fig 15 Fig 16 In Fig 15 a pure tone at about 70Hz frequency is within the crossing between standard bands with central frequencies of 63Hz and 80Hz The spectrum of Fig 16 shows the pure tone using 1 6 octave shifted bands from 14 Hz to 18 kHz Follow this instructions to activate the shifted spectrum from the menu select Spectrum analyzer MENU gt gt Spectrum analyzer g
172. le to continue by pressing HOLD or to Automatic stop when t T Int the displayed data Press Ce Cn to start Press Ce to record SINGLE stop using Press Ca to start Automatic stop when t T Int with recording of the SLM OCTAVE and T OCTAVE screens Press Ca to start Press Co Ca to start The integration of the sound levels Continuous recording with LAST occurs according to intervals equal marker at the end of each integra to T Int The integrated levels are tion period Stop by pressing the displayed data cleared at the beginning of every interval Press Co to record MULTIPLE Press Ca to start The integration of the sound levels occurs according to intervals equal to T Int The integrated levels are cleared at the beginning of every interval and recorded at the end PRINT AND MONITOR FUNCTIONS If you press and soon release the PRINT key you can send to a PC or to a printer via the RS232 serial interface the screen page in ASCII format displayed when pressing the key The serial printer con be the HD40 1 please see on page 105 On the instru ment display a letter P replacing the status indicator highlights data transfer gt If the PRINT key is hold down until the letter M Monitor function and the recording status indicator flash alternatively the displayed screen will be continuously sent to the serial inter face press PRINT again or STOP to end the operation After act
173. le time and THIRD OCTAVE spectra to or to 0 5s in AVR mode Automatic Stop at the gether with SLM at the end of the end of the set integration interval set integration interval SINGLE Only AVR mode Recording of OCTAVE and T OCTAVE spec Automatic recording of OCTAVE tra enabled by Recording menu The recording and THIRD OCTAVE spectra to interval is equal to the set spectrum profile time gether with SLM at intervals or to 0 5s in AVR mode When set in AVR equals to the set integration time mode spectra are cleared at the beginning of Integrated levels are cleared at the every integration period beginning of each integration pe riod Integration MULTIPLE Display Description The display upper line changes according to the selected update mode whether multi spectrum MLT MIN or MAX or average weighted AVR In the first case after the recording status symbol and the overload indicator the display shows the graph updating mode MLT MAX or MIN the partial integration time the number of spectra already displayed and the partial integration time of the current spectrum If the update mode 1s the average weighted one AVR the display will show the integration interval parameter shared with the SLM display mode and on the right the current recording time The values on the left side of the graph are the full scale the scale factor and the scale begin ning The amplitude of the vertical scale of
174. lectromagnetic compatibility Immunity general standard EN61000 6 3 2007 Residential environment commercial and light industry e Electrostatic discharges EN61000 4 2 level 3 e Susceptibility to EMI EN61000 4 3 level 3 e Fast electric transients EN61000 4 4 level 3 e Immunity to conduced disturbances EN61000 4 6 e Electromagnetic interference Conduced emissions EN55022 2007 class B e Electromagnetic interference Radiated emissions IEC CISPR 22 class B NATIONAL LAWS Workplace noise D Lgs 81 2008 European Directive 2008 46 CE and UNI 9432 2008 norm Noise pollution Law 447 of 26 10 95 D L 194 of 19 08 2005 and European Directive 2002 49 CE D P C M of 01 03 91 D M of 16 03 98 Entertainment noise D P C M 215 of 16 04 99 Noise emission from machines D Lgs 262 of 4 9 2002 and European Directive 2005 88 CE Room and building acoustics evaluation option Reverberation Time UNI 11367 2010 UNI EN ISO 3382 123 ORDERING CODES HD2110L kit 1 Class 1 integrating sound level meter and spectral analyzer kit with advanced data logging function and 8 MB memory Real time spectral analysis class 1 according to IEC61260 1997 in octave bands from 16 Hz to 16 kHz Full statistical analysis with calcula tion of percentile levels from L1 to L99 Capture and analysis of sound events with trigger function Combined data logging profiles reports and events The Kit includes HD2110L sound level meter MC21 micropho
175. lipping off the memory card while the sound level meter is running and interface is connected causes the loss of all data In order to replace the memory card switch off the sound level meter 110 To disable HD2010MC temporarily Set the menu item MENU gt gt Instrument gt gt Input Output gt gt Serial device on a different device than MC In order to re enable the reader set the menu item on MC FOR USING DATA DIRECTLY FROM PC In order to read and copy files from the memory card to the PC use a memory card reader for PC the card will be recognized as external peripheral mass storage device Do not write cancel or modify the files through the PC In order to cancel the memory card use the formatting function see chapter Preparation of a new memory card DATA TRANSFER FROM SOUND LEVEL METER TO MEMORY CARD Data can be transferred from the internal memory of the sound level meter to the external memory by executing the sound level meter program PROG key gt gt Data download to MC This program allows copying of the measurements recorded in the sound level meter into the exter nal memory card The program can be activated only after having connected the memory card interface HD2010MC as described in the chapter Connection of HD2010MC to the sound level meter and use of the memory card During data download which occurs automatically the remaining memory space of the card and the estim
176. lly performed during the periodic calibration and can be performed at Delta Ohm or at an accredited laboratory for calibration of measurement microphones It is recommended to calibrate the unit annually Avoid using the unit in the presence of vapours containing oils conductive or corrosive sub stances Condensation on the membrane should be avoided because it significantly modifies the acoustic response causes corrosion and contributes substantially to the accumulation of residues that hardly can be removed When the outdoor unit HD WME is applied to the sound level meter and it s switched on the preamplifier heating prevents condensation on the membrane When the sound level meter is switched off the preamplifier heating 1s disabled and condensation on the microphone may occur For this reason when the HD WME unit 1s not used it should be stored in a dry place ELECTRIC CALIBRATION The electric calibration using the partition of charge injected into the microphone preampli fier in charge amplifier configuration Capacitive Transducer Calibration even if it cannot completely replace the acoustic calibra tion provides however a useful means to keep under control the instrument drifts mi crophone included The figure on the right shows the diagram of the CTC technique consisting in sending an electrical signal to the preamplifier through a high stability ca pacitor so that the output signal does not de pend only on ampl
177. ment gt gt Measurement gt gt Integration Interval the measurement will be automatically interrupted immediately after recording Single screen storage is obtained by pressing REC for at least 2 seconds when the instrument is in RUN or STOP mode If the instrument is in STOP mode you will be prompted to choose be tween automatic and manual storage the current screen will be stored 1f choosing the latter 130 The Continuous Recording allows to record the time profile of instantaneous and integrated levels and at the same time to make a multi spectrum analysis even maximum or minimum This means that you can record for example the sound pressure level with FAST time constant 8 times per second and at the same time the sound pressure levels with SLOW and IMPULSE time con stant the peak level the Leq over 0 5s and the Los percentile level twice per second And at the same time you can record the spectrum of the minimum sound pressure level with FAST constant time The Auto Store recording mode combined with the multiple integration mode allows in stead to store sound levels and spectra at prefixed intervals resetting them automatically at the be ginning of each interval Thus you can record for example the Leq the SEL the maximum sound pressure level with SLOW time constant the peak maximum level and the Los percentile level at in tervals programmable between Is and 99 hours At the same time the average spectra for oct
178. ments required to evaluate workers noise exposure D L N 81 2008 UNI 9432 2011 and ISO 9612 2011 standards According to UNI EN 458 the personal protective equipment can be selected through octave band spectrum analysis OBM method and a comparison of the A and C weighted equivalent levels that can be measured simultaneously SNR method If an undesired sound event produces an over load indication or simply alters the result of an integration its contribution can be excluded using the versatile Back Erase function The impul sivity of a noise source is easily evaluated according to criteria defined in UNI 9432 standard measuring the A weighted equivalent sound pressure level with Impulse time constant LAeq l The cyclic fluctuating and impulsive noise sources identification is simple thanks to the powerful recording functions of HD2110L analyser which allows using a single measurement setup to solve the most of situations encountered in working environments The combination of powerful measurement and recording functions of HD2110L with the analysis functions of the post processing Noise Studio supplied with all sound level meters software module Worker s protec tion allows a fast and efficient management of noise measurements for health and safety evalua tions in workplaces The HD2110L sound level meter is suitable for sound level monitoring acoustic mapping and the assessment of the acoustic climate with capture and
179. meter will calculate the new values and update the page showing the results To move from the table of the results to the graphs profile octaves and thirds of octave repeatedly press the MODE button as indicated below by pressing this key the display will move to the time profile view to the octave spectrum to the third of octave one optional and then return to the re sults 8 amp 3 E Results gt Profile Octave Third octave Profile The Profile view shows the time trend of the acquired sound level If you used the impulsive source method the graph shows Schroeder s integral of the sound level acquired The following picture shows an example of a time profile obtained using the impulsive source method dBLesHz The upper number on the right 3 09 indicates the time in seconds in correspondence of the right border of the visible window of the graph When the cursors are not active you can move the graph horizontally on the time axis using the arrows This function helps examine the decay profile when the measurement is taken in wide spaces where the reverberation time is longer than three seconds The integration time fixed at 1 32s and the central frequency of the constant percentage bandwidth filter are shown below The parameter displayed LOeq at 125Hz in the example of the figure is the same parameter which the parameters view refers to Even here it 1s possible
180. mit corresponds to 140dB with Input Gain 10 the measuring range upper limit equals 130dB Select the proper gain accord ing to the level of sound to be measured Quick Sampling integration period used to measure reverberation time and Leq Short Profile Step integration interval in displaying the time profile It changes from a minimum of 1 8s to 1 hour max Spectrum Step integration interval of the single spectrum when the multi spectrum updating mode 1s selected MLT MAX or MIN It varies from a minimum of 1 2s to 1 hour max SI 2 Integration interval Once this time has been reached the instrument automatically switches to HOLD interrupting display update It can be set from a minimum of 1s to a maximum of 99 hours When continuous recording is activated the integration time acts like a timer for data acquisition stopping automatically the measurement when the time 1s elapsed If set to Os the timer is disabled and the integration becomes continuous Report Time report parameters are integrated over intervals corresponding to the set time At the beginning of every interval report parameters are automatically cleared Report time can be set to 1 2 5 10 20 and 30 seconds 1 2 5 10 20 30 minutes and 1 hour A report time can be set only for the single integration mode see parameter Integration mode Max Back Erase maximum erase interval of data recorded in SLM mode The available val ues are 5s 10s 30s and 60
181. multiple mode or the reports recording is acti vated the statistical graphs are cleared at the beginning of every interval Statistic analysis is presented in two graphical representations probability distribution and cumulative distribution LEVEL DISTRIBUTION OF PROBABILITIES Displayed Parameter Acquisition time gt LAeq 00 05 38 5 Maximum Level Scale Factor Wideband Level Minimum Level Sampling Interval Probability Fig 24 Description of the distribution of probabilities display The figure shows the distribution of probabilities of the A weighted equivalent level with a 0 125s sampling interval The vertical axis shows the sound levels in decibels and the probabilities are on the horizontal axis The display shows the sampling interval in the left lower corner and the chosen measurement parameter for the statistical analysis in the first line to the left of the status indicator and the possi ble overload indicator The amplitude of the vertical scale of the displayed graph corresponds to 5 divisions The am plitude of each division is called scale factor of the graph and appears in the middle of the vertical axis This parameter is selectable in real time among 20dB 10dB or 5dB by division These corre sponds to the 2dB 1dB or 0 5dB classes in the graph The scale factor can be set using the RIGHT zoom and LEFT zoom keys Use the UP and DOWN arrows to set the graph full scale with steps e
182. n MMC or SD memory card A 2GB SD memory card 1s included HD40 1 the kit includes 24 column portable thermal printer serial interface 57mm paper width 4 NiMH 1 2V rechargeable batteries SWD10 power supply instruction manual 5 thermal pa per rolls Post processing software modules CH20 dongle for PCs running Windows Inserted into a USB port enables the use of PC post processing software modules NS1 Workers Protection download and process of noise measurements in workplaces for health and safety applications Noise exposition analysis is made according to EN ISO 9612 2011 standard and UNI 9432 2011 Exposition levels are calculated taking into account uncertainties and PPE Personal Protective Equipment efficiency as well as impulsivity of noise sources NS2A Acoustic Pollution module for acoustic climate analysis on a daily weekly and annual basis including road railways and airport noise The software performs statistical and spectral analysis and automatically identifies noisy events The analyses are performed in compliance with the national and EU legislation on acoustic pollution and noise mapping NS3 Acoustic Insulation evaluation of airborne sound insulation according to national and inter national standards Calculation of reverberation time in rooms and calculation of partitions and fa 125 cades insulation and tapping noise according to ISO140 standards Post processing of reverber
183. n the microphone cap sule is replaced by the proper capacitive adapter must not exceed 20 Vrms The level of the electrical signal applicable to the LINE input must not exceed 7 Vrms 117 LINE Output 3 5mm mono jack Preamplifier output signal Non weighted output protected against short circuit Gain 7 mV Pa and 21 mV Pa respectively for an input gain equal to 0 dB and 10 dB not calibrated Linearity 110 dB with output maximum level equal to 1 5 Vrms Series impedance 1 kQ Typical Load 100 kQ LINE Input 3 5mm mono jack Gain 7 mV Pa and 21 mV Pa respectively for an input gain corresponding to 0 dB and 10 dB 7Vrms maximum level internally limited at 12 Vpp Input load gt 100 kQ Source typical impedance 50 Q TRGOUT output 3 5mm stereo jack Digital output 0 3 3V protected against short circuit Impedance pull up 1 KQ Impedance pull down 300 TRGIN input 3 5mm stereo jack Current input threshold 0 5mA max 20mA Voltage input threshold 2V max 10V Series impedance 470 Q DC output 2 5mm mono jack Short circuit protected output A weighted output with FAST constant time updated 8 times s Gain 10 mV dB Linearity 110dB Series impedance 1kQ Typical Load 100kQ Serial interface Socket 8 way M12 Type RS232C EIA TIA574 or USB 1 1 or 2 0 not insulated Baud rate between 300 and 230400 baud Data bits 8 Parity None
184. nd B is the bandwidth of the filter used respectively equal to 0 71f and 0 23f for filters with bandwidth equal to an octave or third of octave In addition to calculating the reverberation time T30 or T29 it is necessary to analyze the de cay curve visually to check the possible presence of anomalies in the decay and also for possible double gradients It must be remembered that if the linear correlation coefficient calculated with Ordinary Least Square method on the interpolated stretch 1s lower than 0 95 it is not possible ac cording to ISO 3382 to consider the measurement valid and therefore the reverberation time cannot be defined In some cases it is possible to measure two different slopes one for the initial stretch of the decay curve and one for the final stretch According to ISO 3382 the signal noise ratio must respectively be at least 45 dB and 35 dB for the T3 and Tx measurements MEASUREMENT USING AN IMPULSIVE NOISE ISO 3382 contemplates the possibility of performing the calculation of reverberation time from the response to the impulse of the environment being tested by using a numeric technique de veloped by Schroeder This technique allows starting from the measurement of the environment re sponse to the sound impulse to obtain the same decay curve that would have been measured by the stationary noise technique Indeed each decay curve obtained using this technique corresponds to the average of an infinite number of sound d
185. nd DOWN keys Press EN TER to quit the selection mode automatic exit after 10s In graphic display mode use the UP DOWN LEFT and RIGHT keys to change the vertical scale parameters The LEFT and RIGHT keys reduce and expand the vertical scale while the UP and DOWN keys decrease and increase the levels of the vertical scale the graph is so shifted up wards or downwards respectively SLM SOUND LEVEL METER MODE This is the display mode upon power on Five parameters selectable among the following ones can be displayed simultaneously e Instantaneous acoustic broadband levels such as Lp Leg Short and Lyx either with wideband frequency weightings or by octave or third octave bands The pressure levels displayed are the maximum levels reached every 0 5s e Integrated acoustic broadband levels such as Lomax Leg Lieq and Lpkmax either with wideband frequency weightings or with octave or third octave bands updated every 0 5s Up to 4 percentile levels selectable between L and Log Sound exposure level Average level with 4 dB exchange factor Average level with 5 dB exchange factor Daily personal exposure level Dose and daily Dose with programmable Exchange Rate Criterion and Threshold Levels Overload Time in The display is updated every 0 5 seconds Data recording varies depending on the selected integration mode single or multi and on the acti vation or not of Auto Store function as described in the following tabl
186. ne HD2110P preamplifier HD SAV windscreen CPA 5 5m extension cable HD2110RS RS232 or HD2110USB USB serial cable Noise Studio software Basic module and carrying case ACCREDIA calibration certificate according to IEC 60651 and IEC 60804 of the chain consisting of sound level meter preamplifier and microphone ACCREDIA calibration certificate ac cording to IEC 61260 of the octave filters bank HD2110L kit 1E Class 1 integrating sound level meter and spectral analyzer kit for outdoor measurements with advanced data logging function and 8 MB memory Real time class 1 spectral analysis according to IEC61260 1997 in octave bands from 16 Hz to 16 kHz Full statistical analysis with calculation of percentile levels from L1 to L99 Capture and analysis of sound events with trigger function Combined data logging profiles reports and events The Kit includes HD2110L sound level meter Microphone outdoor protection HD WME MC23 microphone with corrosion resistant membrane HD2110PW heated pream plifier with 5 m cable up to 50 m on request HD2110RS RS232 or HD2110USB USB serial cable Noise Studio software Basic module and carrying case ACCREDIA calibra tion certificate according to IEC 60651 and IEC 60804 of the chain consisting of sound level meter preamplifier and microphone ACCREDIA calibration certification according to IEC 61260 of the octave filters bank HD2110L kit 11E Class 1 integrating sound level meter and spec
187. ng its propagation transports energy it is impor tant to account for the duration of the sound event in order to interpret the energy content correctly This is particularly important in assessing the impact of the sound produced by machines or general pollution sources on the auditory apparatus It 1s obvious that a strong noise generates a growing damage proportional to exposure Evaluation of potentially harmful noise is therefore easy with constant level sounds 162 If the sound varies in time you have to use a measurement parameter defined in the interna tional standards IEC 60804 recently replaced by IEC 61672 called equivalent level symbol La The equivalent level is defined as the constant level having the same energy content of the fluctuating level in the period being examined The A weighted equivalent level Laeg will be used to measure the energy content and then the harmful potential of a fluctuating noise source during a given period A LIMANA in sl In the figure the equivalent level profile is highlighted It is stabilizing within few minutes to a level just above 71dBA Considering an intermittent source of noise for example a train passing by it is obvious that the equivalent level can give a measurement of the mean energy level after considering many passages If you wish to measure the energy content of a single passage you need to use a different measurement parameter the Sound Exposure
188. ng parameters need to be set first and then the delayed acquisition timer programmed in the parameter Menu gt gt Sequencer gt gt Timer After programming the sound level meter you only need to press the REC and RUN keys together as if starting a logged measurement confirm with the YES key The instrument switches into stand by and turns off see Fig 32 pA al ct WARNING Dr A 5MNO 6PQR 3 Automatic eq 1 dBC ralla ill li Bi EA lt e 3 acquisition 50 3 dBA by timer 18 5 dBc 3 YES NO Fig 32 Delayed acquisition timer warning screen The instrument will turn back about one minute before the set delay to allow execution of the warm up time before starting the automatic acquisition During this waiting minute the TIMER message blinks showing the automatic acquisition feature has been activated Fig 33 Waiting for the timer to start The acquisition will end when the set integration time Tint has elapsed and the instrument will automatically turn off after disabling the timer 48 DESCRIPTION OF THE MENU FUNCTIONS The menu collects all of the parameters through which the instrument functions are set The menu can be accessed even when the instrument is measuring but parameters can be modified only if the instrument is in STOP mode If this is not the case a message will invite you to stop the current measurement WARNING Stop measurement to continue WARNING Stop me
189. nsidered except for the case of a small conference room where it is possible to consider only the single typical position of the lecturer The height from the floor 1s usually equal to 1 5m For each position of the source different microphone positions need to be analyzed by con sidering the actual distribution of the listeners The distance of the measurement points should be at DI x least 2m and they must be at least 1m from walls or reflecting surfaces The average height from the floor considering that listeners are usually seated should be 1 2m The minimum distance from the source must be equal to d nin Si 2 cT where V is the volume of the environment in m e is the sound speed 343 m s at normal tempera ture and T is the estimated value for the reverberation time Usually the minimum distance is not less than 3 meters The analyzing device can be reduced to the minimum by using a simple recorder that can guarantee the minimum time resolution required to measure the decay ISO 3382 considers two possible types of measurement for the sound level to be registered the sampling of the acoustic level exponentially weighted and the recording of linearly integrated levels In case the acoustic level exponentially weighted 1s measured it 1s necessary for the exponential average time to be lower than and as close as possible to T 30 where T is the reverberation time For the linear integra tion sequence the time of each integral
190. nt is closed the record containing the Event group information is logged When the event trigger uses the Profile view sound level as source Menu gt gt Trigger gt gt Source LEV the event data are recorded only when the trigger threshold Menu gt gt Trigger gt gt Trigger Threshold exceeds the minimum duration time Menu gt gt Trigger gt gt Minimum Duration The following figure shows the recording flow for the Measurement Report and Event groups The Measurement group recording is enable only during the event outside the events only Reports are recorded In the following example a report is recorded every 10s 10s 0 5s 10s Fig 31 Recording flow for the Measurement Report and Event groups When the trigger threshold is exceeded for a shorter period than the minimum duration time the re cord containing the Event group information is not logged With the FFT option it is possible to record in addition to the above for continuous re cording see the previous paragraph also the Leq Short profile at 1 32s and the narrow band spec tral analysis FFT The recording interval varies depending on type of data e For the Leq Short is equal to 1 32s e For the narrow band FFT spectral analysis 1s equal to 0 5s T amp Delayed acquisition timer A timer is available to enable data acquisition according to a programmable delay of up to 99 hours To perform an acquisition with delayed start the recordi
191. nt 5 of previous paragraph Note 2 if the sound level meter has been connected to USB port before USB driver installation in Windows 2000 and XP operating systems it appears the window new hardware installation In Windows Vista and Windows 7 it appears an installation error under device manager in both cases cancel operation disconnect instrument and restart the complete procedure starting from the beginning of this guide Verification of proper driver installation To verify the proper installation procedure proceed as follows On Windows 2000 and XP operating systems Select START gt gt Settings gt gt Control Panel double click on SYSTEM icon Select Hardware gt gt Device Manager On Windows Vista and Windows 7 operating systems Select START gt gt Control panel then click on Device Manager icon Connect instrument to USB port The following items should appear e Port COM and LPT gt gt USB Serial Port COM The value is the number assigned to virtual serial port e Controller USB Universal serial bus gt gt USB serial converter 107 Controller IDE ATAJATAPI Controller SCSI e RAID 8 Controller USB Universal serial bus eS Controller host avanzato da PCI a USE Sis eS Controller open host SiS 7001 da PCI a USB Controller open host SiS 7001 da PCI a USB Controller open host SiS 7001 da PCI a USB Hub principale USE eS Hub prin
192. nt off then unscrew anticlockwise the two screws of the cover of the battery space After replacing batteries 4 1 5V alkaline batteries type AA close again the cover and fasten the two screws clockwise Check date and time If this operation takes less than two minutes no clock adjustment should be needed As an alternative to alkaline batteries you can use rechargeable batteries Batteries with lower capacity usually show greater impedance causing a worsening of the electrical noise gener ated by the sound level meter with repercussions on the measurement dynamic Therefore zinc carbon and rechargeable NiCd batteries are not recommended WARNING ABOUT THE USE OF BATTERIES Batteries should be removed when the instrument is not used for an extended time Flat batteries must be replaced immediately Avoid loss of liquid from batteries Use waterproof and good quality batteries if possible alkaline If the instrument does not turn on after battery replacement Remove one of the batteries Wait at least 5 minutes for the sound level meter internal circuits to discharge Put the new battery in If the batteries are charged the instrument should turn on automatically INSTRUMENT STORAGE Instrument storage conditions e Temperature 25 70 C e Humidity less than 90 R H no condensation e To be avoided I ae eal The instrument case is in ABS plastics material and the protection belt in rubber do not
193. o power off function that automati cally switches it off after 5 minutes the instrument is in STOP mode and no key has been pressed Before switching off the instrument will make a series of beep press any key to pre 50 vent the instrument shutting off The function is active 1f this menu item is ON If you set Auto Power Off OFF the instrument will not automatically shut off In this case the bat tery symbol will flash even if batteries are fully charged Input Output Submenu for the choice of parameters relevant to the instrument inputs and outputs Input the input source can be selected among microphone MIC or LINE connector TRGOUT Source TRGOUT output can be activated either during measurements RUN or when a sound event has been triggered EVN When this parameter is set to OFF the TRGOUT output is not active e TRGOUT Polarity TRGOUT output polarity can be positive POS or negative NEG e Baud Rate this parameter and the next ones define the properties of the serial connection Selectable baud rate values go from a minimum of 300 to a maximum of 230400 baud The higher 1s the value the faster is the connection therefore when possible it is suggested to se lect the highest available value to speed up data transfer as much as possible If the instrument is connected to a printer with RS232 serial input or with a serial parallel converter the value to be set is the one provided by the printer manufacturer
194. of devices like windshield HD SAV or all weather protection unit HD WME In order to make measurements with the maximum possible precision in different situations the HD2110L sound level meter can automatically apply 113 spectral corrections needed to measure in random field conditions or with the windshield or with the all weather outdoor protection Spectral correction for diffuse field measurement is enabled set ting parameter Menu gt gt Calibration gt gt Mic Resp Correction gt gt RI while correction for HD SAV installed is enabled setting parameter Menu gt gt Calibration gt gt Shield gt gt SAV For additional information on the values of corrections applied to the HD2110L sound level meter please refer to the manual of supplied microphone Corrections for the acoustic field The Free Field microphones have a frequency response that is optimized for the free field ie sound waves coming from the front with direction coincident to microphone s axis In order to obtain a flat frequency response in diffuse field 1 e sound waves from all directions set the cor rection for the acoustic field Menu gt gt Calibration gt gt Microphone Response Correction on RI With this setting the sound meter HD2110L with Free Field microphones meets the ANSI stan dards Delta Ohm can also supply microphones with frequency response optimized for Random Field In order to obtain a flat frequency response in a free field it s nece
195. of the sound pressure Similarly the increase of the level is equal to 6 dB for each doubling of the sound pressure The use of decibels to indicate the sound level has besides the evident advantage to reduce the measurement numeric range the advantage of providing a good approximation of the audible perception that follows the sound pressure on a logarithmic scale Not all pressure variations are audible When a pressure variation is due for example to climatic variations it changes too slowly to be heard but if it is fast like for example that pro duced by striking the drum or by bursting a balloon it can be heard by the human ear and is conse quently identified as a sound The number of pressure oscillations second is called sound frequency and is measured in cy cles per second or Hertz Hz The audible frequency range extends between approximately 20 Hz up to 20 kHz Under 20 Hz we enter the infrasound field while over 20 kHz we enter in that of ul trasounds Hearing sensitivity is not constant throughout the whole range of audio frequencies but it shows a consistent loss at very low or high frequencies Sensitivity is at its maximum in the range between 1 kHz and 5 KHz The variation of auditory sensitivity according to sound frequency also depends on the sound inten sity Isophone curves equal loudness level contours defined in ISO 226 2003 standard are shown in the following graph and provide the sound pressure leve
196. oise Studio will be opened if the operating system prevents software to start please see note 1 in the next paragraph From starting window of Noise Studio click on USB drive installation to start the driver in stallation procedure The program checks the Windows operating system version and copies related drivers in a temporary folder At the end a message appears asking to plug the sound level meter connection cable to PC USB port press OK and close Noise Studio software pressing EXIT key Connect the sound level meter to USB port and turn it ON when Windows recognise the instrument it appears a message a new device has been detected 99 Wait some seconds until the message new hardware is installed and ready to work appears Driver installation procedure is ended whenever the instrument will be connected it will be automatically recognized 106 Installation Notes Note 1 for Windows Vista and Windows 7 operating systems 1 For software installation 1s requested Administrator permission 2 If the operating system prevents the software to open boot the PC as administrator user insert installation CDRom and when the following window appears select open folder to view files General options il Open fi folder to view files a s Explorer 3 In the following screen click with right mouse key on file Autorun and select Execute as ad ministrator 4 Continue from poi
197. onal resolution of the converter which covers a 140 dB range allows to keep a high resolution over a measuring range of about 110 dB where the digitization error is negligible The levels either wideband A C and Z or with constant percentage bandwidth both octave and optionally third octave are calculated in parallel in the DSP Peak C and Z levels are also calculated The levels calculated by the DSP are transmitted to the microprocessor for further processing ready to be displayed stored and printed The microprocessor controls all the instrument processes management of the electrical calibra tor Flash memory display keyboard and multi standard serial interface RS232 and USB DESCRIPTION OF DISPLAY MODES I o J DO Li Co un NA NUO 7 om co Fig 5 Octaves gt FFT MF 00 05 38 8 60 10 20 Hz 150 IK 1250 15 Fig 7 FFT option gt LAeq 06 05 38 5 f 00 cu CU 1 85 10 90 Fig 8 Probability Distribution The HD2110L measures simultaneously 5 selectable parameters statistic ones too at a fixed frequency corresponding to 2 measurements s moreover it measures a selectable parameter at in tervals programmable between 1 8s and 1h at the same time it calculates the octave and third oc tave Third Octave option band spectra with a maximum frequency of 2 spectra s and with op tion narrow band FFT spectrum As statistical analyzer it calculates the p
198. one tecnica We certify that below mentioned instruments have been tested and passed all production tests confirming compliance with the manufacturer s published specification at the date of the test Le misure effettuate presso un Laboratorio di Taratura Accredia sono garantite da una catena di riferibilit ininterrotta che ha origine dalla taratura dei campioni di prima linea del Laboratorio presso l istituto metrologico nazionale Measurements performed in an Accredia Calibration Laboratory are guaranteed by a uninter rupted reference chain which source is the calibration of the Laboratory first line standards at the national metrological institute Tipo Prodotto Integrating Sound Level Meter Product Type Nome Prodotto HD2110L Product Name Responsabile Qualit x Head of Quality A DELTA OHM SRL 35030 Caselle di Selvazzano PD Italy Via Marconi 5 Tel 39 0498977150 r a Telefax 39 049635596 Cod Fisc P Iva 1T03363960281 N Mecc PD044279 R E A 306030 ISC Reg Soc 68037 1998 INTRODUCTION L HD2110L is an handheld integrating sound level meter performing either spectral or statis tical analysis The instrumentis designed to deliver maximum performance in the analy sis of acoustic phenomena with particular attention to regulations on environmental noise and build ing acoustics Attention has been paid to the possibility to adapt the instrument s functions to the legislation and to meet the needs of i
199. ophone s specific manual Microphone model can be changed using the program NoiseStudio provided with the sound level meter Preamplifier models Suitable for Y inch microphones with 50 mV Pa sensitivity HD2110P preamplifier for 200V polarized Y microphones and cable driver This preampli fier is equipped with CTC calibration device for electric calibration can be directly connected using a cable of up to 100m length HD2110PE similar to HD2110P model but suited for pre polarized electret microphones HD2110PW heated preamplifier for outdoor unit HD WME for 200V polarized Y micro phones and output driver for cable up to 100m length This preamplifier equipped with CTC calibration device for electric calibration can be connected to sound level meter with a sup plied 5m cable other length on request HD2110PEW similar to HD2110PW model but suited for pre polarized microphones elec tret Accessories The foreseen use of the following accessories does not alter the HD2110L sound level meter specifications Windshield HD SAV with spectral correction Menu gt gt Calibration gt gt Shield gt gt SAV Extension cable connecting the preamplifier to the sound level meter body up to 100m long Stabilized power supply SWD10 Portable thermal printer HD40 1 Tripod VTRAP with preamplifier holder HD 2110SA Outdoor protection unit HD WME with spectral correction Menu gt gt Calibra
200. ot recorded in the Auto Store mode Display Description Displayed parameters Acquisition time Maximum level Scale factor Analogic bar Minimum level Sampling interval Weighting Fig 12 Description of the Profile mode display For example Fig 12 shows the time profile of A weighted Leq with a 0 125s sampling in terval Selecting Lpmax as parameter and 1s as sampling time you can for example view the time profile of the FAST weighted maximum pressure level calculated every second The integration interval is shown in the left corner at the bottom of the display Always at the bot tom in the centre the display shows the measurement unit and the frequency weighting of the measuring parameter The amplitude of the vertical scale of the displayed graph corresponds to 5 divisions The amplitude of each division 1s called scale factor of the graph and appears in the middle of the vertical axis Using the RIGHT zoom and LEFT zoom keys this parameter is selectable in real time among 20dB 10dB or 5dB by division 2 DI x Use the UP and DOWN arrows to set the graph full scale with steps equal to the selected scale factor starting from the instrument full scale In this way the graph can be shifted UP or DOWN depending on the key you have pressed An analogue bar indicator on the display right side provides the non weighted instantaneous level of the input sound pressure level as for the SLM mode bar
201. ource occurs in the form of waves and is thus subject to all the phenomena typical of the waves such as refraction and diffraction The propagation speed depends on the medium and in the air at ambient temperature it equals about 344 m s The ear sensitivity is quite high and able to perceive pressure variations equal to about 20 uPa corresponding to 5 parts a milliard of the atmospheric pressure This incredible sensitivity 1s joint to the capacity to bear pressure variations more than one million times higher For conven lence it was decided to indicate the sound pressure level in decibel rather than pressure in Pascal in order to reduce the numeric extension The decibel dB symbol is defined by X dB 20 108 0 x 0 where X 1s the measured quantity Xo 1s the reference value of the measurement to which corresponds 0 dB In acoustics the pressure is the measured quantity and the reference value corresponds to 20 uPa the minimum audible pressure Therefore the sound level corresponding to a 20 uPa 0 00002 Pa pressure variation will be indicated as 0 dB The sound level corresponding to a 20 Pa sound variation will be indicated with 120dB a level at the limit of the pain threshold An increase by 10 times of the sound pressure corresponds to a level increase by 20 dB while an increase by 100 times of pressure corresponds to an increase in level by 40 dB the sound level increases by 20 dB against each increase of a factor 10
202. placing the microphone can be used for periodic tests The capacitive adapter specific for microphone model is an accessory that can be supplied by Delta Ohm S r l Other ca pacitive adapters can be used provided that the device equivalent capacity is included between 15 pF and 33 pF Before executing the electric or acoustic checks it s necessary to disable the spectral correc tions by setting the following parameters Menu gt gt Calibration gt gt Microphone Response Corr gt gt FF for sound level meters mounting Free Field microphones and Menu gt gt Calibration gt gt Microphone Response Corr gt gt RI for sound level meters mounting Random Incidence microphones Menu gt gt Calibration gt gt Shield Correction gt gt OFF To check the frequency response of the microphone sound level meter chain you can use either the electrostatic coupling technique or the multi frequency acoustic calibrator For more in formation on the suggested technique to be used for frequency response verification of microphone sound level meter chain please refer to microphone s user manual Maintenance of microphone capsules To avoid permanent alteration of the frequency response and consequently a degradation of specifics so as to exit the class tolerance limits is necessary to prevent accumulation of dust and dirt particles on the microphone membrane The microphone capsules must be periodically cleaned This operation is usua
203. ple integration mode recording 1s performed automatically according to the set integra tion time Integration time is programmable from SLM display or using the relative menu item Menu gt gt Instrument gt gt Measurement gt gt Integration interval The activation of the re cording mode is indicated by the REC symbol flashing over the status indicator Recording starts by pressing RUN key To disable the Auto Store function press the REC key briefly Report In this menu the recording of the reports is defined as described in the paragraph CON TINUOUS RECORDING OF REPORT AND EVENT GROUPS on page 45 Each item can be enabled separately as with the measurement recording In order to avoid occu pying memory space uselessly we recommend to enable only the needed items and set the others to OFF The integration interval recording time of the reports is programmable using the rela tive menu item Menu gt gt Instrument gt gt Measurement gt gt Report Time e Par l Par 5 define five integrated parameters with relevant frequency weightings e Parameters enables recording of the 5 parameters Par 1 Par 5 defined previously e Oct Spectrum activates the recording of average spectrum A VR by octave band e T Oct Spectrum activates the recording of average spectrum AVR by third octave band Third Octave option required e Statistics activates the recording of the statistics Event In this menu the recordin
204. possible to choose the descriptor to sample between Lrp Leg or Lpx with A C or Z fre quency weightings only C or Z for Lpx With the HD2110L sound level meter it s possible to analyse external audio signals using the LINE input For a later analysis unweighted LINE output allows to record the sound signal on a tape or directly on a PC with audio acquisition board The calibration can be made either using an acoustic calibrator type 1 according to IEC 60942 or the built in reference generator The electric calibration employs a special preamplifier and checks the sensitivity of the measuring channel microphone included A protected area in the non volatile memory reserved to factory calibration is used as a reference in the user s calibra tions allowing to keep instrument drifts under control and preventing the instrument from wrong calibrations The user can check on site the complete sound level meter s functionality thanks to a diagnostic program The most of instrument damages including those to the microphone can be identified thanks to a complete analysis program that includes a frequency response check of the complete meas urement chain composed by microphone preamplifier and sound level meter A periodic check us ing diagnostic programs allows to perform safely acoustic measurements removing the risk of hav ing to repeat them for a malfunction discovered too late The HD2110L sound level meter can perform the measure
205. pressing NO recording will continue without interruption The above settings can be made through the instrument configuration menus See a detailed description on page 49 Back Erase Function data exclusion To stop a measurement in progress when recording press the PAUSE CONTINUE key All data logged until the moment key was pressed are used for calculation of integrated parameters However there are some cases when it is useful to clear the measurements recorded just before pressing PAUSE for example because they were caused by unexpected events and not characteriz ing the sound being examined During measurement press PAUSE CONTINUE integrated measurements update will be in terrupted At this point press the LEFT arrow to delete the last recorded data The integration time value will be temporarily replaced by the word Clear followed by the time interval in seconds to be deleted Use the LEFT and RIGHT keys to increase or decrease the erase interval Displayed inte grated parameters change accordingly allowing to choose the erase time depending on the effective need When pressing PAUSE CONTINUE again measurement will start again and the integrated parameters will have been removed from the selected interval The erase maximum time divided into 5 steps is set from menu MENU gt gt Instrument gt gt Measurement gt gt Max Back Erase Settable values are 5 10 30 or 60 seconds with 1s 2s 6s or 12s steps respect
206. qual to the selected scale fac tor In this way the graph can be shifted UP or DOWN according to the pressed key An analogue bar indicator on the display right side provides the non weighted instantaneous level of the input sound pressure level as for the SLM mode bar The parameter chosen for statistical analysis can be changed without accessing the menus but simply using the SELECT keys the four arrows UP DOWN LEFT and RIGHT and ENTER for more details see Selecting parameters on page 18 Using the Cursors To activate cursors on the graph press CURSOR on the keypad If you press CURSOR re peatedly either L1 or L2 cursor or both AL cursors in tracking will be activated in succession the selected cursor will flash Use the LEFT and RIGHT arrows on the keypad to move the selected cursor on the graph The second line at the top of the display shows the level and central frequency of the class and the relevant probability indicated by the active cursor or the probability for the levels in the interval be tween the two cursors when they are both active Press CURSOR again to disable the cursors PERCENTILE LEVELS GRAPH The graphic display is available for the sound level distribution of probabilities and also for the percentile levels Displayed Parameter Acquisition time Maximum Level Scale Factor Wideband Level Minimum Level Sampling Interval Percentile Index Fig 25 Description of the percentile
207. r shows the sound pressure instantaneous level in a 110dB interval Big in the centre of the display is the main measurement parameter followed by four further pa rameters All displayed parameters can be freely selectable among the available ones There are no restrictions in the selection of frequency weightings Measuring parameters are displayed with a shortened label followed by the numerical value by the unit of measurement and when necessary by the frequency weighting The correspondence between the label and the effective parameter is to be found in appendix on page 144 Integrated parameters like Leq and Lmax or Lmin which imply the time increase of the sampled sound level are displayed with a series of dashes until the parameter remains lower than the minimum measurable level Before starting a new logging the sound level meter automatically resets all measurements If the multiple integration mode is enabled MENU gt gt Instrument gt gt Measurement gt gt Integration Mode MULT integrated levels will be automatically set to zero at regular intervals equal to the set integration time Tint Selecting parameters Some measuring parameters integration interval measuring range and the five parameters can be changed directly via the SLM screen Pressing SELECT you choose the different parameters in sequence While the selected parameter flashes you can change it with the UP and DOWN keys If a parameter wi
208. r the display shows starting from the left the se lected measuring parameter together with the sound level and the nominal frequency corresponding to the band selected by the cursor The cursor can also select the wide band level on the right side of the display Pressing and holding down CURSOR for at least 2 seconds when the third octave optional spectrum is displayed the tracing of the isophone curves will be activated according to ISO226 2003 This function is useful for example when evaluating the audibility of pure tones according to Decree of 16 March 1998 see a detailed description in the Appendix on page 156 Press CURSOR again and hold it down for at least 2 seconds to disable the isophone tracing When the isophone curve is active the cursors play some additional functions as to standard display described above the cursor L1 is combined with the isophone tracing L2 keeps standard functions AL shows two values the first one represents as in the standard case the L2 L difference the sec ond one provides the difference between Lo and the isophone LEFT Keypad The LEFT key moves leftwards the cursor or the two active cursors flashing It is used in the FFT screen to move the frequency axis downward when the cursors are not active It is used in the decay profile screen reverberation time measurement to move the frequency axis downward when the cursors are not active 142 gt l RIGHT Keypad The R
209. r acquisition elements only the Report group parameters are recorded using a lower time resolution When the simultaneous recording of measurements reports and events is enabled and the event trigger uses the Profile view sound level as source Menu gt gt Trigger gt gt Source LEV the measurement recording begins as soon as the sound level exceeds the trigger threshold Menu gt gt Trigger gt gt Trigger Threshold without waiting for the minimum duration time Menu gt gt Trigger gt gt Minimum Duration The measurement recording ends as soon as the stop delay has elapsed Menu gt gt Trigger gt gt Stop Delay after the level exceeded the deactivation threshold Menu gt gt Trigger gt gt Bottom Threshold File type Sing and RT The relevant data are loaded and displayed automatically RT files require a few seconds for the data processing required for display After having examined a file size press PROG to jump back to the Memory Navigator menu press LOAD to reload the current session NEXT to display the properties of the next session or EXIT to quit At the end of the list of stored files End of Dump will be displayed Press REWIND to go back to the first file of the list CALIBRATION Calibration is periodically carried out to ensure the validity of measurements performed by the sound level meter and to control possible long term drifts of the measuring chain microphone preamplifier
210. rd octave band spectrum level dB D S o wm o N Il n Ui A Sos NY gt SS SS LE K Central Freq Hz FFT level dB w 9 PO SF POS OSE amp O PO PA E DI ANS N PO E PSP ps DIS PP SE EEL EE PEE EEE EEE ECE CLL Gos Freq Hz Fig 20 The FFT spectrum in Fig 21 concerns the HF band and has 230 lines spaced about 94Hz apart To obtain equally spaced bands or lines the frequency axis is logarithmic for the constant percent age bandwidth bands and linear for constant bandwidth bands FFT It is obvious from comparing the two spectra that FFT resolution is definitely higher for high frequencies As the frequency resolution of one third octave bands is constant for all the spectrum and equal to 23 the HF band of the FFT spectrum has a better resolution from about 500Hz where it is less than 20 At the desired frequency for the signal shown in the figure FFT resolu tion is about 10 comparable to a one sixth octave band spectrum However the resolution is not sufficient as yet to identify the dual tone The FFT spectrum in the following figure concerns the MF band and has 210 lines spaced of about 12Hz FFT Spectrum 110 100 90 80 k i 40 level dB 30 20 10 VII o gt dd 0 0 6 GA AA O DO LA A PIO HOAX DA GM GY PE
211. rding e In addition to octave bands real time frequency analysis is performed also in narrow bands FFT on the whole audio range with a variable frequency resolution from 1 5Hz up to 100Hz Narrow band frequency analysis calculates 2 spectra per second without any penalty on the sound level meter dynamics and in parallel with octave and third octave spectra Reverberation Time option Through this option the HD2110L can carry out reverberation time measurements according to the techniques of the sound source interruption and of the impulse response according to EN ISO 3382 2 2008 requirements This measurement is made simultaneously for octave band from 125 Hz to 8 kHz and if option is installed for third octave band from 100 Hz to 10 kHz The sampling in terval equals 1 32s and the calculation of EDT T10 T20 and T30 reverberation times 1s made automatically for all bands Block Diagrams HD2110L MICROPHONE AMPLIFIER A GAIN O gt m m T o S E i a in O m A S PDIF DIGITAL DAIO AUDIO DIGITAL SIGNAL PROCESSOR Q RS232C USB KEYBOARD Fig 2 Instrument s Block Diagrams FLASH MEMORY f _ L PREAMPLIFIER INSTRUMENT The block diagram shows the main elements of the HD2110L sound level meter 10 The Microphone The provided microphone is the condenser type MC21 it is polarized at 200 V and has a Y standard diameter The frequency response in free field is fl
212. robability distribution and percentiles To be able to display all these data the HD2110L provides 7 different display modes as shown in the figures below O26 00 03 amp Fig 6 Third of octaves option Fig 9 Percentiles In order to jump from a screen page to the next one press MODE at any time The display will show in a sequence first the SLM screen with 5 measuring parameters in numeric format the Profile screen with the time trend of a parameter the screens of Octave and Third Octave op tion with the octave from 16Hz to 16 kHz and third octave spectra from 16 Hz to 20 kHz re spectively the FFT narrow band screen option the distribution of probability and percentiles screens Upon power on the sound level meter displays the SLM screen The display of the OCTAVE and THIRD OCTAVE screens can be disabled using the rele vant menu parameters Menu gt gt Spectrum Analyzer gt gt Display Also the PROBABILITIES and PERCENTILES screens can be disabled using the menu parameter Menu gt gt Statistical Analyzer gt gt Display Statistics see paragraph DESCRIPTION OF THE MENU FUNCTIONS on page 49 4 On progress overload indicator A memory Some indications are shown in all modes They are see the figure on the right Measurement status indicator gt RUN Overload indicator Il PAUSE Battery level indicator REC The first symbol in the left corner at the top shows di STOP the me
213. ry level is sufficient By estimating that the background noise of the environment in or der not to influence the measurements should be at least 10 dB under the minimum level consid ered for the decay the source emitted sound level should be at least 30 dB higher for each band compared to the background noise Normal loudspeakers are usually not suitable to be used as sources for reverberation time measurement because of high emission directionality Usually a series of twelve speakers 1s used with their faces arranged on the figure of a dodecahedron Concerning the microphone choice it is important to evaluate its directionality and its fre quency response characteristics In fact Y microphones with frequency response optimized for pressure field are the best choice It 1s also possible to use microphones optimized for random field or alternatively for free field applying the correction for random incidence Measurement position The measurement position is important because the measurement results depend on the posi tion both of the source and of the microphone It is therefore fundamental to consider a number of positions suitable to describe the environment being tested both for the source and for the micro phone The position of the source should consider the actual points where the sound source will be located according to the most usual occupancy of the environment Typically a minimum number of two or three source positions are co
214. s the erase interval is settable with 1s 2s 5s or 10s steps respec tively See description on page 19 Integration mode Two integration modes are available the former is single SING and the latter is multiple MULT Please see the paragraph DESCRIPTION OF THE DIFFERENT INTEGRATION MODES on page 39 The multiple integration mode requires an Integration interval different from zero be set and disables Report Time and Event Trigger Exchange Rate is used together with DOSE Threshold and DOSE Criterion in DOSE calculation It represents the variation of the sound pressure level corresponding to the double or the half of the exposure maximum time with the same Criterion Level indicated as DOSE Criterion Its value can be equal to 3dB 4dB or 5dB DOSE Threshold it is the noise level below which the DOSE 1s not increased The value can be set in the 0dB 140dB interval with 1dB steps DOSE Criterion it is the noise level providing a DOSE equal to 100 after an 8 hour expo sure The value can be set in the 60dB 140dB interval with 1dB steps Overload Level according to the selected input gain the instrument provides two measuring ranges the former with a 130dB upper limit the latter with a 140dB one If the sound level exceeds the 131dB and 141dB limits respectively the display will highlight the overload 1n dication A and A The indication can be activated also at lower input levels programming this parameter from
215. se of bad weather it is suggested to use a windshield and in case of use in very humid environments the proper microphone dehumidifier should be applied Pressure Microphone sensitivity depends on atmospheric pressure Sensitivity increases as pressure decreases and the change of sensitivity measured at 250 Hz is always lower than 0 03dB kPa in the range 85kPa 108kPa as required by IEC 61672 for class 1 sound level meters Sensitivity drift with ambient pressure is usually worse at high frequencies even if the sensitivity maximum differ ence in the range 85kPa 108kPa remains within 0 5dB over the whole sound spectrum Wind To reduce wind disturbance as much as possible it 1s suggested to use the proper wind shield consisting of a polyurethane porous globe to be placed on the microphone This useful accessory protects also from dust dirt rain and snow The presence of a windshield slightly alters the microphone frequency response and more accurate sound level meters are pro vided with a correction curve to compensate this effect Vibrations Even though microphone and sound level meter cannot be easily affected by vibrations it 18 better to isolate both instrument and microphone from strong vibrations Magnetic Fields The influence of electrostatic and magnetic fields on the sound level meter is negligible PRECAUTIONS AND GENERAL HINTS OF USE e Ensure that ambient conditions fit the use of a sound level meter Take care that
216. seconds The PROFILE screen is stored at intervals equal to the set profile time MENU gt gt Instrument gt gt Measurement gt gt Profile Time OCTAVE and T OCTAVE screens are stored twice per second if the spectral analysis is per formed in AVR mode otherwise for MLT MAX and MIN modes screens are stored at inter vals equal to the spectrum profile set time MENU gt gt Instrument gt gt Measurement gt gt Spec trum Profile Time When the Leq Short profile recording is enabled at 1 32s 16 levels are stored twice per second The selected band of the narrow band spectra FFT is stored twice per second It is also possi ble to record the Report and Event groups data each composed of 5 programmable levels av erage spectra for octave and third octave band and statistical analysis The Event group data are recorded at the end of each event and the Report group data are recorded at programmable intervals from 1s to 1 hour The REC symbol as status indicator shows when the sound level meter 1s recording If you press STOP recording will be stopped and you will be asked to enter the title While recording you can press PAUSE to suspend recording When integration mode 1s multiple MENU gt gt Instrument gt gt Measurement gt gt Integration Mode MULT the integrated levels are cleared just before the beginning of each measurement cycle A special marker Last identifies the last acquired data per each cycle The A
217. shifted upwards START STOP RESET key when pressed in STOP mode it starts the measurements RUN mode In RUN mode it stops the measurements When pressed in PAUSE mode it resets the integrated measurements such as Leq SEL MAX MIN levels etc PROG key activates the program selection mode PRINT key transfers the displayed data to the RS232 serial port When pressed for more than 3 seconds it enables the continuous printing Monitor Monitoring will be stopped by pressing the key once more ON OFF key turns the instrument on and off Keypad RIGHT key in graphic mode it moves the selected cursor towards higher values Battery symbol indicates the battery level The more the symbol is empty the more the battery has run down Un weighted LINE input or output connector 3 5mm jack Preamplifier or extension cable connector CONNECTOR FUNCTION The instrument is equipped with six connectors one in front two to the side and three at the bot tom The figure on page 2 shows n 3 Connector for input output digital TRIGGER jack stereo Y 3 5mm TRGOUT output can be enabled using menu function MENU gt gt Instrument gt gt Input Output gt gt TRGOUT Source Input TRGIN can be selected for event trigger using the parameter MENU gt gt Trig ger gt gt Source TRGOUT GND TRGIN Fig 1 TRIGGER stereo connector n 15 M12 connector for RS232C multi standard serial port and USB For the connection to a PC
218. sible ones press the DOWN arrow to display them INSTRUMENT The Instrument menu includes all data relevant to the instrument identification as well as some general parameters of the instrument itself input and output settings and measurement global pa rameters It consists of four submenus as described below Identification It includes the information that identify the instrument and the microphone These are all items that cannot be changed by the user Instrument instrument name Serial N instrument serial number Version current firmware version loaded Microphone microphone model Mic S N microphone serial number Mic Response type of microphone response FF stands for Free Field DF for Diffused Field Class IEC61672 Class of tolerance according to IEC61672 2002 Memory memory available on the instrument The standard capacity is 8Mbyte Options firmware options Ext range shows the activation of extended range measurement mode System It allows to configure some system parameters e Time current time e Date current date expressed as year month day e Display contrast allows to adjust the display contrast When the ambient temperature changes the display contrast slightly changes it can be adjusted entering a higher value to in crease the contrast or a lower one to decrease it The value can be set between 3 minimum and 9 maximum e Auto Power Off the instrument is provided with the aut
219. sions saved directly on the sound level meter display but with some limitations compared to the open session the parameter results and time profile views cannot be displayed To display the different estimations EDT Tio T20 and T30 of the reverberation time for the octave and third of octave bands just press the MODE key re peatedly Direct printing of results pressing the PRINT button is active for the saved sessions too FIRMWARE UPGRADE The firmware that is the program managing all of the instrument functions can be upgraded by transferring the file from a PC to the HD2110L through the RS232C serial port In this way all the instrument functions can be upgraded Up dating files are available at the authorized dealers To make the upgrade 1s used the firmware upgrade function of NoiseStudio program For details see NoiseStudio Handbook online help OPTIONS UPGRADE The sound level meter options HD2110 01 Third Octave and HD2110 04 reverberation time or HD2110 06 FFT may be purchased at a later time and activated by the user through the software Noise Studio Alternatively you can send the unit to Delta Ohm for the update Upon option s purchase we provide a serial code related to the sound level meter this code is needed to make the upgrade To proceed with the upgrade use the Upgrade options tool in Nois eStudio See the online manual NoiseStudio Handbook for details Note The HD2110 01 Thir
220. spectra are calculated starting from the maximum weighted FAST or SLOW spectra calculated every 0 5s Therefore while the linearly averaged multi spectrum MLT analysis con sists of a sequence of spectra giving the equivalent levels by band integrated on the programmed profile time the exponentially averaged multi spectrum MLT analysis instead consists of a se quence of instantaneous spectra displayed at intervals corresponding to the programmed profile time The maximum or minimum MAX or MIN multi spectrum analysis can be also carried out where the spectra of the maximum or minimum levels over the set profile time will be measured In this mode displayed spectra depends on the trend of the programmed wideband auxiliary level The instrument will display at intervals corresponding to the profile time the spectra corresponding to the maximum or minimum level measured in the programmed interval with a 0 5s resolution The MAX or MIN multi spectrum analysis linearly weighted consists of a continuous sequence of spectra composed of equivalent levels integrated on 0 5s for each band corresponding to the maximum or minimum equivalent level measured every 0 5s with the selected auxiliary weighting Da The MAX or MIN multi spectrum analysis exponentially weighted consists of a continu ous sequence of spectra corresponding to the maximum or minimum instantaneous level weighted FAST or SLOW measured every 0 5s with the selected au
221. spectra second and it can measure reverberation times both using the sound source interruption and the impulsive source integration technique according to UNI EN ISO 3382 The HD2110L sound level meter analyses the noise level decays with the Or dinary Least Squares method simultaneously both by octave from 125Hz to 4KHz and if option Third Octave is installed by third octave bands from 100Hz to 12 5KHz according to survey en gineering and precision methods defined in UNI EN ISO 3382 1 2009 and 3382 2008 The HD2110L can be configured in accordance with different customers needs the available options can be activated on the new instrument as well as later on when requested by the user The provided options are Third Octave option Option Third Octave adds a double bank of third octave filters from 16 Hz to 20 kHz and from 14 Hz to 18 KHz shifted downwards by one sixth octave in class 1 according to IEC 61260 The filter bank works in parallel to all other measurements The audibility of the different spectrum components can be evaluated applying A or C frequency weightings or thanks to the isophone equal loudness level curve calculation function supplied with the instrument and available directly on the sound level meter s display FFT option FFT option adds the following functions e The linearly integrated level on 1 32s Leg Short with frequency weightings A C or Z is available for reco
222. ssary to set correction for acoustic field on FF Menu gt gt Calibration gt gt Microphone Response Correction With this set ting the sound level meter HD2110L with diffuse field microphone meets the IEC standards For additional information on microphone FF RI corrections please refer to specific micro phone manual Outdoor microphone unit HD WME The windshield and rain protection units mounted on HD WME outdoor protection modify microphone frequency response in order to apply the correction to sound level meter overall re sponse it s necessary to set the specific parameter Menu gt gt Calibration gt gt Shield gt gt WME With this setting applied HD2110L sound level meter with HD WME protection fully complies to type specifications according to IEC 61672 standard in such configuration as HD WME must be used in vertical position the sound level meter is able to measure accurately environ mental noise from above 0 incidence like for example the noise generated by aircraft over flights 114 Axial frequency response of HD WME protection with MK223 microphone measured in an anechoic chamber Class 1 tolerances are shown Toll Class 1 dB Axial acoustic response 10 1000 10000 100000 Hz When the parameter Menu gt gt Calibration gt gt Correction screen is set on WME and the correction for the acoustic response of the microphone Menu gt gt Calibration gt gt microphone spectr
223. sually considered at the same level more dangerous 159 A6 SOUND LEVEL METER The sound level meter is the instrument that measures the sound level Usually it is made up by a microphone the sound sensitive element by an amplifier by a signal processing unit and by a reading and data display unit The microphone converts the sound signal into a corresponding electrical signal The sensi tivity of microphones for level measurements does not depend on the sound signal frequency The preference of the type of microphone usually goes to the condenser type that grants excellent fea tures like accuracy stability and reliability The amplifier is necessary to bring the electrical signal to a measurable amplitude and to strengthen the signal to allow cable transmission The processing unit takes care of calculating all measuring parameters necessary to characterize a sound event Frequency Weighting If you have to assess the auditory impact of a noise source you will have to make some cor rections to the acoustic signal provided by the microphone in order to simulate the sound percep tion this means that the microphone sensitivity will have to be adjusted to simulate the frequency response of the human ear Two correction curves named A weighting and C weighting have been defined as international standard IEC 60651 recently replaced by IEC 61672 When the sound level is corrected by A weighting it is referred to as Lap
224. t If the Auto Store function is activated MENU gt gt Instrument gt gt Recording gt gt Auto Store the spectrum analysis is automatically set to AVR mode In this setting at the end of the integration time the levels shown on the SLM screen and the spectra by octave and third octave bands will be recorded automatically Acquisition 1s the stopped If integration mode is multiple MENU gt gt Instrument gt gt Measurement gt gt Integration Mode MULT the integrated levels are cleared just before the beginning of each measurement cy cle and a new cycle of measurements starts In this setting also each spectrum is reset on every cy 127 cle if the spectral analysis 1s performed in AVR mode When the continuous recording is activated a special marker Last identifies the last acquired data before resetting of the integrated levels Recording in Auto Store mode allows to store on memory octave and third octave spectra in AVR mode together with the parameters displayed on the SLM screen at a frequency equal to the Tint time Press REC for 2 seconds at any time to store the displayed data As soon as data are saved on memory a screen will allow you to enter the recording title If you activate recording with the sound level meter in STOP mode a screen allowing to activate the Auto Store combined with the multiple integration mode will appear first History Mode Time Profile See also the description on page
225. t gt Baud Rate see page 51 Available baud rates are 230400 115200 57600 38400 19200 9600 4800 2400 1200 600 300 The other transmission parameters are fixed The HD2110L is provided with a complete set of commands to be sent via the serial port of a PC COMMUNICATION PROTOCOL The command consist of ASCII strings with a variable length ending in CR LF The instrument provides always a response after a command has been received if the command 1s not accepted the response string 1s always NAK CR LF It is possible to disable the response when it is not expressly requested by the command modifying the VERBOSE setup parameter see the SET paragraph Commands are divided into 5 groups as shown in the following table N of Commands SETUP parameter configuration KEY 2 KEY keyboard simulation _ STATUS instrument status DUMP memory dump Each group contains a given number of commands Each command is identified by a specific string The generic syntax of a command is the following lt group gt lt command gt lt value gt CR LF Ex SET INPUT_GAIN 10 r n sets the INPUT GAIN parameter to 10dB see SET paragraph Only capital characters are acknowledged Each token can be shortened at the minimum number of characters that univocally identify it The example can be shortened as follows SET INP 10 r n Here are the possible command formats A3 SET INTEGRATION TIME lt SS MM HH gt
226. t gt ENTER key Select 1 2 Band Shift and set it ON press ENTER to confirm and the following screen will appear WARNING Automatic Power Off Change effective after power on CONTINUE IDI Press CONTINUE and the instrument will switch off Upon the next power on a message will be displayed stating that third octave filters have temporarily been shifted by half a band downwards Press CONTINUE to confirm In this operation mode the time profile and octave spec trum screens have not been activated while all the other functions are operative Switch the instrument off and then on again to restore its standard working 2 DO MEASUREMENTS WITH THE FFT OPTION The FFT option provides an additional display mode shown in the following figure gt FFT MF 00 05 3684 60 il 20 iHz 150 IK 1250 15h Fig 17 FFT Press MODE at any time to jump from a screen page to the next one the SLM PROFILE OC TAVE THIRD OCTAVE Third Octave option FFT FFT option PROBABILITIES and PERCENTILES screens will be displayed in this sequence The display of FFT screen can be disabled using the relevant menu parameters Menu gt gt Spectrum Analyzer gt gt Display FFT The FFT option adds the narrow band spectral analysis FFT and the acquisition of the equivalent level profile integrated on intervals equal to 1 32s Leg Short LEQ SHORT AT 1 32s FFT OPTION The equivalent level integrated every
227. t measurement session to start a new one EXIT key REVERBERATION TIME Batt L00 Mem 452 Step 19 Reverberation Time calculated EXIT STORE VIEW To restore the normal functioning of the sound level meter and to exit the reverberation time measurement program turn off the instrument ON OFF button and then turn it back on Measured not correctly performed The measurement procedure is terminated if the maximum delay of 5 seconds is not satisfied for the generation of the impulsive noise or the continuous source turn off the following message appears REVERBERATION TIME Batt 100 Mem 515 Step 31 Reverberation Time not measured NEXT cursos 4 Cp The same message 1s displayed if the signal noise ratio between the generated signal and the back ground noise is not large enough Besides one or more results may be missing if the signal noise ratio between the generated signal and the background noise is not sufficient to perform the respective reverberation time estimations as shown in the following page DI REV PARAMETERS CL RARI il LOmax 40 5dBle5 L res 65 5dBle5 EDT 0 85s rl 00 T10 0 92s r0 I6 Reverberation time Analysis of the results At the end of the measurement as indicated above the results are supplied in a table or graphically Parameters Pressing the right arrow on the display keyboard corresponding to the VIEW key brings the table up onto the screen DI REV PARAMETERS
228. tave band spectra e T Octave Display enables ON or disables OFF displaying of third octave band spectra option HD2110 01 Third Octave required e FFT Display enables ON or disables OFF displaying of narrow band spectra option HD2110 06 FFT required STATISTICAL ANALYZER The Statistical Analyzer menu collects the specific parameters related to the statistical graphs display modes These items can be changed directly in their screens e Param the parameter used for selected statistical calculations Lrp Leq and Lp with A C and Z only C and Z for Lx weightings The sampling frequency is equal to 8 samples s only 2 samples s for Lpx e Class width statistical analysis is performed by 0 5dB classes e Display Stat enables ON or disables OFF displaying of the distribution of probabilities and percentile levels graph 538 TRIGGER The Trigger menu collects the specific parameters related to the event trigger Source the trigger source can be chosen among profile view sound level LEV pressing ENTER key MAN or external TRGIN signal EXT TRGIN Polarity the external signal TRGIN polarity can be chosen between positive POS or negative NEG Consult the paragraph TECHNICAL SPECIFICATIONS Trigger Threshold the trigger threshold on the profile view sound level LEV it can by programmed with 1dB steps Background Threshold the deactivation threshold different than the trigger one on
229. th attribute is selected like for example LFp FAST weighted pressure level in Fig 11 the relative frequency weighting will also flash A in the example In this case pressing UP and DOWN you can modify the selected parameter without changing the attribute for example if you press DOWN you can go from LFp A weighted to LSp A weighted Pressing RIGHT you ll jump to the attribute selection which will be the only one to flash Use then the UP and DOWN keys to change the attribute For example if you press UP you can go from A weighted LSp to Z weighted LSp Pressing LEFT while selecting the attribute you return to parameter selection Pressing SELECT let you choose the next parameter pressing ENTER or automatically after approximately 10s will let you exit the selection mode 18 Also the integration mode see page 39 can be set using the LEFT and RIGHT keys press SELECT to choose the integration interval When the integration interval numeric value flashes press RIGHT to set the multiple integration mode or LEFT to set the single integration mode When the integration mode is set on MULT the Tint symbol flashes Parameters can be modified only when the instrument is in STOP mode if you try to make changes to any of the parameters while the instrument is in a status other than STOP you will be asked to stop the measurement in progress pressing YES will stop recording and will allow you to go on modifying parameters
230. the displayed graph corresponds to 5 divisions The am plitude of each division is called scale factor of the graph and appears in the middle of the vertical DI da axis Using the RIGHT zoom and LEFT zoom keys this parameter is selectable in real time among 20dB 10dB or 5dB by division Use the UP and DOWN arrows to set the graph full scale with steps equal to the selected scale factor starting from the instrument full scale In this way the graph can be shifted UP or DOWN according to the pressed key A bar on the display right side shows the wideband level weighted Z C or A as selected The applied frequency weighting 1s shown under the bar In the display lower left part it s shown the spectrum frequency weighting A C or Z user selectable the time average mode linear Leq or exponential with FAST or SLOW time con stants Partial integration interval Number of partial intervals Analysis mode Partial acquisition time Maximum level Octave band spectrum Scale factor Wideband level Minimum level Frequency weighting Spectrum weighting Integration interval Acquisition time Analysis mode Third octave band spectrum Fig 13 Display Description in Octave and Third Octave mode Using cursors and isophone curves To activate cursors on the graph press CURSOR on the keypad If you press CURSOR re peatedly either L1 or L2 cursor or both L cursors in tracking will be activated in succ
231. the mechanism for the assignment of penalties for noise from these com ponents Any of such penalties equal to 3dB A and they are applicable both to residual noise and environmental noise 1 Verify the impulsive component Noise is considered as having impulsive components when the following are present the event is repetitive e the difference between LAImax and LASmax exceeds 6dB e the event duration at 10dB from LAFmax value is shorter than Is The impulsive sound event 1s considered repetitive when occurring at least 10 times over one hour period at day and at least 2 times over one hour period at night The repetitivity must be demonstrated through recording of the LAF level during the measurement time TM The HD2110L sound level meter when 1t works as a data logger can record the instantaneous sound level trend with FAST time constant 8 times per second and simultaneously also the levels with Slow and Impulse time constant twice per second By analyzing the trace with the supplied NoiseStudio basic version software you can identify the presence of the impulse The maximum level can be evaluated directly on the field by using SLOW and IMPULSE time constant corre sponding to an impulse detected analyzing the sound level profile and with FAST time constant by using the cursors 2 Verify the tone component The base for detection of tone components CT in the noise spectrum is the recognition of a single 1 3 octave band th
232. time intervals Stationary signals can be analyzed over different time intervals obtaining comparable and repeatable mean levels A frequency analysis can be made with a sequential spectrum analyzer measuring the sound level band by band until the interested spectrum 1s covered Spectra of periodical stationary signals will be striped which means that they will have non null levels only in the bands with characteristic nominal frequencies Random stationary signals will have instead a continuous spectrum An example of determi nistic stationary signals could be a note or a chord played by a musical instrument while for ran dom stationary signals the example might concern car traffic noise or air conditioning noises Non stationary signals have sound levels depending both on the period of measurement and on integration time The time taken for the analysis is critical for this type of acoustic signals and the frequency analysis has to measure all levels in every band of the spectrum at the same time The analyzer suitable to this kind of measurement is called to operate in real time Among the non stationary signals we can include talking or impulsive signals such as a balloon burst The calculation of integrated mean values over a given time interval might be used in spec tral analysis of deterministic stationary signals according to the signal main frequency If the aver age time is at least 3 times higher than the acoustic signal main p
233. tion gt gt Shield gt gt WME Memory card reader HD2110MC METROLOGICAL CHARACTERISTICS Frequency Weighting A C Z for RMS measurements 112 C Z for peak level measurements Filters with bandwidth corresponding to octave from 16 Hz to 16 kHz Filters with bandwidth equal to third octave from 16 Hz to 20 kHz option HD2110 01 Filters with bandwidth corresponding to third octave from 14 Hz to 18 kHz translated by 1 6 octave downwards with respect to standard central frequencies option HD2110 01 Z weighting is flat along the whole sound spectrum with the following features Attenuation Frequency Range dB Hz 63 20 k 25 22 5 k 12 5 23 5 k While the filters with bandwidth equal to an octave are all type 1 according to IEC 61260 the conformity class of the filters with bandwidth corresponding to a third octave is indicated in the following table Class Standard Filters Freq shifted Filters Hz Hz 16 20 14 18 22 25 20K 28 18K Frequency response The figure below gives the frequency response of the HD2110L sound level meter with MK221 mi crophone with and without the HDSAV windshield respectively dotted line and solid line In order to evaluate the sound level meter qualitative behaviour the limits set by IEC 61627 for class 1 have been reported in the figure 5 0 dB re 1 kHz The frequency response of the microphone depends on the presence
234. tion threshold Menu gt gt Trigger gt gt Trigger Threshold and Menu gt gt Trigger gt gt Bottom Threshold The following figure shows an example of a positive polarity sound event capture The sound level Lar exceeds the trigger threshold for time TO and later the bottom threshold for time T2 Time profile at 125 ms started 05 05 2005 14 22 21 LAF max Trigger Threshold Bottom Threshold 14241635 Pre trigger gg Minimum Duration Stop Delay A FI b ts A __ TO Tt T2 T3 Event parameters integration with pre trigger Time Marker recorded Time Marker recorded Event confirmed Event group data recorded Fig 26 Description of the event trigger parameters To prevent short duration pulses being detected as sound events a minimum trigger duration can be set up to a maximum of 10s Menu gt gt Trigger gt gt Minimum Duration If the threshold is exceeded for less than the set time the event is neglected Also a minimum deactivation duration can be set when the deactivation threshold 1s exceeded the event close 1s delayed for the set time up to a maximum of 255s Menu gt gt Trigger gt gt Stop Delay In the example since the trigger conditions exceed the minimum duration that 1s they persist at least for time T1 the event levels integration begins including the 2 seconds before the threshold 1s reached pre trigger This pre trigger time cannot be modified The event levels integra
235. tion ends at time T3 that 1s after the stop delay from the T2 time corre sponding to the bottom threshold being reached The event trigger feature can be activate also by an external electrical signal connected to the TRGIN input Menu gt gt Trigger gt gt Source EXT and by pressing the ENTER key Menu gt gt Trigger gt gt Source MAN In both cases the minimum duration parameter has no effect and the event begins as soon as the trigger 1s detected When the event trigger is assigned to the external trigger it 1s possible to choose the activa tion signal positive or negative polarity Menu gt gt Trigger gt gt TRGIN Polarity For each identified event HD2110L calculates the following e 5 programmable selectable parameters maximum and minimum levels peak level equiva lent sound pressure level and SEL e Average spectrum by octave and one third octave bands e Full statistical analysis These parameters are not displayed but can be stored completely or partially at the end of each level The menu Recording gt gt Event allows selection of the 5 parameters and storage The event parameters integration begins 2 seconds before triggering This pre trigger time cannot be modified A special printing function synchronized with the trigger is available for communication of the event itself via RS232 Menu gt gt Trigger gt gt Print If the trigger is enabled the sound level profile is displayed with black background
236. tion of the sound R is experimentally determined in diffused field acoustic conditions using a room divided by a wall consisting of the dividing element For each frequency band once the average sound pressure levels of the disturbing environment L and in the receiving environment Lz are known the sound reduc tion index R dB of the wall tested is obtained from the expression R L L 10log 2 where S is the surface of the dividing element and A is the equivalent area of acoustic absorption of the receiving environment m The equivalent area of acoustic absorption A can be calculated by measuring the reverberation time of the receiving room where Lz is measured and using the formula of Sabine Of course in the laboratory any energy propagation other than that which goes directly through the dividing wall was excluded The standard also defines the provisions for the background noise and for the correction of the measurements when the background is not lower than 15 dB compared to the levels measured in each frequency band The measurement method used in the lab should re spect the repeatability conditions in agreement with ISO 140 2 This process must be controlled and verified periodically ls ISO 140 Part 4 On site measurements The ISO 140 standard Part 4 Acoustics Measurement of sound insulation in buildings and of building elements Part 4 Laboratory measurements of airborne sound insulation between rooms
237. to select using the SELECT button and the arrows the parameter to be displayed Upon confirmation with ENTER the profile graph and the values displayed in the parameters view are updated The profile can be analyzed by using the cursors By repeatedly pressing the CURSOR but ton the cursors L1 and L2 are sequentially activated and finally the two cursors AL The cursor se lected blinks and the relevant data appear on the display in the second line from the top When they are active individually L1 or L2 the display shows the noise level and the corresponding time in seconds When they are both active in tracking the second line of the display shows in this order the difference AL L2 L1 of the noise levels the time interval between L1 and L2 and the rever beration time estimation calculated by interpolating the part of the decay between L1 and L2 AL _ 307 O44 no 20 30 1 3ds dBlesSHz Reverberation time by octave and third of octave Third Octave option By pressing the MODE key once the display shows the estimation of reverberation time by octaves soon after the profile view Pressing MODE again the estimation by third octave bands can be shown The spectrum by octave bands shows the reverberation times Tio T20 T30 and the early decay time EDT for each band from 125 Hz to 8 kHz and the spectrum by third of octaves from 100 Hz to 10 kHz The times are expressed in seconds The variable 7 0 720 T30 or EDT ar
238. tor function Terminates the Monitor function Monitor ci Te PROFILE Monitor by single parameter The following table lists the STT RECORDER commands Starts the Record function Terminates the Record function AUTO Enables the Auto Store function STT MONITOR and STT RECORDER commands provide information on the monitor and re cording status as shown in the following example STT REC STT RECORDER Measurement SLM PROFILE OCTAVE THIRD OCTAVE OFF 101 DMP GROUP DUMP The table below features the list of the DMP group commands DMP DUMP RECORD Requires the transmission of the current record CLEAR It starts the memory dump in binary mode Data download sequence 1s DMP ON r n The heading ending in the string MEMORY DUMP r n is printed if there are any data on memory DMP RECORD r n Prints the previous record in binary format DMP NEXT_RECORD rn Prints the current record in binary format If this is the last record it prints the string END OF DUMP r n DMP CLEAR r n optional Clears memory DMP OFF r n Ends data dump Data dump can be interrupted through the sequences DMP OFF r n Ends data dump 102 CONNECTION TO A MODEM HD2110L sound level meter can be remotely controlled using a modem connection Op tional Monitor module NS4 PC program part of NoiseStudio software package can fully man age the sound level meter not only via a simple RS232 serial connection or USB
239. tral analyzer kit for indoor and outdoor measurements with advanced data logging function and 8 MB memory Real time class 1 spectral analysis according to IEC61260 1997 in octave bands from 16 Hz to 16 kHz Full statistical analysis with calculation of percentile levels from L1 to L99 Capture and analysis of sound events with trigger function Combined data logging profiles reports and events The Kit includes HD2110L sound level meter Microphone outdoor protection HD WME MC23 microphone with corrosion resistant membrane HD2110PW heated pream plifier with 5 m cable up to 50 m on request HD2110RS RS232 or HD2110USB USB serial cable Noise Studio software Basic module and carrying case ACCREDIA calibra tion certificate according to IEC 60651 and IEC 60804 of the chain consisting of sound level meter preamplifier and microphone ACCREDIA calibration certification according to IEC 61260 of the octave filters bank With respect to the KitlE version it also includes o HD2110P preamplifier o HD SAV windscreen o CPA 5 5 m extension cable ACCREDIA calibration certification according to IEC 60651 and IEC 60804 of the chain consisting of sound level meter HD2110P preamplifier and microphone 124 Options accessories and software HD2110 01 Third Octave option spectral analysis with double bank of third octave filters from 16 Hz to 20 kHz and from 14 Hz to 18 kHz according to IEC61260 Evaluation of au dib
240. tral components audibility by comparing with the equal loud ness curves HD2110L sound level meter can capture the noise time profile with complete freedom on the choice of time constants or frequency weightings The sound level meter stores automatically the sound level multi descriptor analysis as atape recorder with a storage capacity of more than 46 hours at the maximum temporal resolution For long term monitoring of the noise level it s possible to store at intervals from 1 second to 1 hour 5 programmable parameters in parallel with full statistics and the average spectrum in oc tave and optionally third octave bands With its memory the HD2110L can store multi parametric analysis and statistics at 1 minute intervals for more than 46 days For long term monitoring it 1s possible to further increase the storage capacity of the analyzer using the optional HD2010MC memory card interface This device is equipped with a Secure Digi tal Memory Card of 2GB With HD2110L sound level meter it s possible to make measurements with a linearity range of more than 110dB limited in the lower part of the range only by the inherent noise For example setting the upper limit of the measuring range to 140dB it s possible to measure the noise levels typical of a quiet office with the ability at the same time to measure accurately peak levels up to 143dB The HD2110L is equipped with a versatile trigger function for the capture of sound events wit
241. ts users It s possible to integrate the sound level meter at any time with options to extend the applications the firmware can be updated directly by the user using the supplied NoiseStudio software HD2110L meets type 1 specifications according to IEC 61672 1 2002 and IEC 60651 IEC 60804 standards Compliance with IEC 61672 1 has been verified by INRIM primary metrological Insti tute ref certificate no 37035 01C The constant percentage bandwidth filters meet the specifications of IEC 61260 Class 0 and micro phone meets IEC 61094 4 HD2110L 1s an integrating sound level meter suitable for the following applications Environmental noise levels evaluation noise monitoring with noise events capture and analysis spectral analysis in octave bands from 16Hz to 16kHz complete statistical analysis with percentile levels calculation from L to Log measurement in working environments selection of Personal Protective Equipment methods SNR HML and OBM soundproofing and acoustic reclamation production quality control machine noise measurement building and architectural acoustics with Reverberation time option By activating the Third Octave option the sound level meter also performs the following func tions e third octave spectral analysis from 16Hz to 20kHz and from 14Hz to 18kHz center fre quency shifted bands e measurement of noise pollution with tonal components identification e real time evaluation of spec
242. ued by the machine Impulsive sounds independently on their spectrum are more dangerous for the human ear as the energy involved in the short time lapse in which they develop does not allow the ear to take any defence Therefore the equivalent level being equal a noise source containing impulsive com ponents is generally penalized Unfortunately while the ear sensitivity decreases according to the duration of noise the risk of an auditory injury does not decrease For this reason sound level meters usually have a built in circuit for the measurement of the acoustic signal peak value LAegs Fok LAlp dB 95 85 65 14 32 09 14 32 22 14 32 35 14 52 46 14 33 01 14 53 14 14 33 27 14 33 40 Fig 52 The non weighted peak level and the IMPULSE level relevant to the surface mount machine are illustrated in the figure As you can see the peak level is at least 10dB higher than the IMPULSE level The parameter PEAK referred to as Lpx has been defined in the international standards IEC 60651 IEC 61672 It provides the peak level reached by the sound pressure in a given time interval The response time of the peak level is very fast lt 100us and it is able to measure the sound level of very short sound events for example a gunshot with sufficient accuracy Equivalent Level The approximation obtained by considering the levels with FAST or SLOW time constant as short term averages is quite rough If the sound duri
243. und level meter is set in Auto Store recording mode The parameter MENU gt gt Recording gt gt Measurements gt gt Auto Store is activated and the REC symbol blinks over the status indicator To execute automatic recording it s enough to press the START key as soon as the measure ment time Tint is elapsed the parameters displayed in the SLM screen and the octave and third oc tave spectra if option is installed will be automatically stored If the integration mode is single acquisition will be blocked if the mode is multi a new inte gration and storage cycle will begin preceded by all parameters reset To disable the Auto Store mode it s enough to press shortly the REC key while the instrument is in STOP mode The automatic recording can be also activated from the corresponding menu item MENU gt gt Re cording gt gt Measurements gt gt Auto Store When the parameter MENU gt gt Instrument gt gt Measurement gt gt Integration Mode is set on MULT the acquisition is repeated at intervals equal to the set integration time the automatic reset of integrated levels 1s performed at the beginning of each interval see DESCRIPTION OF THE DIFFERENT INTEGRATION MODES on page 39 This integration mode combined with the 43 Auto Store function allows to record at a given frequency the parameters displayed on the SLM screen together with the spectra both by Octave and by Third Octave bands W
244. uto Store mode can be activated either through the parameter MENU gt gt Recording gt gt Auto Store or by pressing REC and holding it down for at least 2 seconds with the sound level meter in STOP mode Then select the AUTO option when you are requested to choose the re cording option Activating the Auto Store recording mode together with the multiple integration mode MENU gt gt Instrument gt gt Measurement gt gt Integration Mode MULT allows to record at intervals equal to the set integration time MENU gt gt Instrument gt gt Measurement gt gt Integration inter val the data displayed on SLM OCTAVE and T OCTAVE screens Set in this way and once the integration time has been reached the sound level meter will first record data then set all integrated levels to zero and finally start a new integration period On pressing START the instrument begins recording and the recording is completed by pressing STOP after which you will be prompted to enter its title A flashing REC over the RUN status indicator shows when the sound level meter is recording Press REC with the instrument in STOP to disable the Auto Store mode The Auto Store recording mode combined with the single integration mode MENU gt gt In strument gt gt Measurement gt gt Integration Mode SING allows to record automatically the data displayed on the SLM OCTAVE and T OCTAVE screens at the end of the set integration in terval MENU gt gt Instru
245. ves the sound level meter storage capacity when it works as a data logger continuous recording expressed as time necessary to fill memory The e symbols indicates the active functions Time Profile Third Octave Time in hrs In order to estimate the memory capacity it 1s necessary to consider the data recording frequency and the size of the single records For each of the possible measurement parameters the space oc cupied by a single record in continuous recording 1s given in the following table a PA s HEADER or aa 8 ERA ARA A ame in sec n ee FRESE CENERI TT LEQSHORT OB The storage of reports and events is made by units records stored corresponding to each report Menu gt gt Instruments gt gt Measurements gt gt Report or for each event Each unit consists of a header header followed by set of parameters enabled in Recording gt gt Reports and Event menu The table below shows the occupation of each block that comprises a unit record 2 The maximum sampling frequency has been taken into consideration corresponding to 8 samples s 149 Space occupied HEADER ed PARAMETERS OCTAVE SPECTRUM THIRD OCTAVE SPECTRUM E STATISTICS From the table it is possible to calculate the memory capacity in the following cases e Continuous recording of SLM PROFILE 1 8s THIRD OCTAVE SPECTRUM minimum each 10s 14 20 16 66 10 56 6 bytes s gt gt maximum duration 8MB 56 6 40 ore
246. was issued in 1998 The purpose of the standard is to establish the test procedures used for insulation of airborne sound of internal compartments which are either walls or ceilings in order to verify that the protec tion conditions desired are obtained and to identify possible construction faults For the on site measurements the standardized sound insulation can be calculated using the follow ing expression T D L L 10log AT 1 2 505 where Li and L are the respective average sound pressure levels in the disturbing room and the re ceiving room and T gt is the reverberation time measured in the receiving room The standard also prescribes the measurement of the normalized sound insulation as defined by the expression A D L L 10log2 0 where Az is the equivalent absorption area of the receiving room m and Ao is the reference area equal to 10 m Appendix B of the standard reports the procedures for measuring the sound insulation in octave bands instead of thirds of an octave For this purpose the range of frequencies considered starts from 125 Hz and goes up to 4000 Hz Appendix C of the standard reports the procedure to measure the lateral transmission and these can be of fundamental importance in the on site measurements 175 A7 3 IMPACT SOUND INSULATION MEASUREMENTS Structural borne propagation is the propagation of sound energy from the emission envi ronment the waves being generated by
247. when the trigger 1s not active so as to highlight the event s portion Displayed Parameter Acquisition time Trigger enabled Maximum Level Trigger disabled Scale Fact aed Analogue Bar Minimum Level Trigger enabled Sampling Interval Weighting Fig 27 Description of the Event trigger display 38 DESCRIPTION OF THE DIFFERENT INTEGRATION MODES The HD2110L makes measurements according to two different acquisition modes either single or multiple The single integration begins by resetting the integrated levels e g the Leq and ends when the set integration time Tint is elapsed or when the acquisition is manually interrupted by the RUN STOP key The following figure shows the Leq Short profile calculated twice per second and the inte grated Leq over a measurement time of 1 minute in single mode L4egs LAeg dB 90 80 FO 60 50 1042145 10 42 22 1042295 10 42 37 10 4244 5 10 42 52 10 42 59 5 10 43 07 Fig 28 In the measurement time span the Leq Short LAeqS shows three phases with high noise about 80dB and a variable 52 60dB background noise The Leq profile shows that the integration of the three high noise phases gives an equivalent level stabilizing at about 77dB at the end It is often necessary or convenient to divide the measurement time in equal duration intervals and calculate the integrated levels as Leq maximum and minimum levels etc on each interval sepa rately instead of on th
248. while if you press it for the third time both cursors will be activated in tracking Use the LEFT and RIGHT arrows of the keypad to shift the selected cur sors into the desired position to indicate the measured level and the corresponding acquisition time Press CURSOR again to disable cursors Press PRINT at any time to print the on screen data To activate the continuous printing Monitor press and hold down PRINT for at least 2 seconds The flashing letter M over the status indicator indicates that the Monitor function has been activated The Monitor function remains ac tive even when jumping to other measuring views and can be disabled pressing PRINT again or START STOP RESET to stop measurement Spectrum by octave and optionally third octave bands See also the description on page 22 Press MODE to view the SPECTRUM screen by octave or third octave bands where the frequency spectrum by constant percentage bandwidths 1s displayed Use SELECT to set the type of spectral analysis the integration or sampling time the type of mean and the respective weight as well as the frequency weighting of the wideband auxiliary channel as described in the paragraph Spectrum mode by octave and third octave bands on page 22 Alternatively measuring parameters can be set from menu as described in DESCRIPTION OF THE MENU FUNCTIONS on page 49 Once parameters have been set via the START STOP RESET key the execution is started I
249. without moving the device or without using a notebook The maximum storage capacity of the card is 2GB the formatting is FAT 16 type The reader is powered by the sound level meter and doesn t require any external power supply PREPARATION OF A NEW MEMORY CARD Every new memory card needs to be formatted before use by means of the appropriate function of the Noise Studio software The formatting function requires the PC on which the Noise studio Software has been installed to be equipped with a PC Memory card reader not included in supply Those are typically included in most recent laptops and desktop computers Optionally it is possible to use an external memory card to be connected to an USB port How to format a memory card 1 Ifthe PC isn t provided with a SD MMC card reader connect an external device to the USB port of the PC 2 Start up the Noise Studio software 3 Press the key Instrument management in Noise Studio press the key Memory Card Format ting 4 Select the path of the card to be formatted and confirm with ENTER 5 On the following screen ensure that the parameter File System FAT has been selected and press START the card will be formatted 109 6 When the message Formatting completed appears press OK for confirmation and CLOSE to exit 7 Close the Noise Studio software 8 The formatting has been accomplished and the card is ready for use CONNECTION OF HD2010MC TO THE SOUND LEVEL M
250. wned structure of the square wave signal harmon 1CS Before performing the FFT calculation to get a good frequency resolution the segment s samples to be analyzed must be multiplied by a function called window This function has values close to 1 in the central zone and decreasing values on the sides until zero at the ends Some commonly used windows are e Triangle e Cosine Bell Hanning e Hamming e Blackman e Kaiser 153 These functions differ in regard to spectrum resolution and amplitude and calculation com plexity The spectrum resolution must be assessed for the capacity to separate two signals with close frequencies or equal width or very different widths In the first case use the window with best reso lution on peaks Triangle or Cosine Bell in the second use the one with the best dynamic Black man or Kaiser The application of the windows introduces a particularly important problem in developing real time analyzers As the window gradually declines to zero at the ends only central samples have weight in FFT calculation The following figure shows the Cosine Bell application to the series of 48kHz samples for a sinusoidal signal at 2 kHz The samples it was applied to are highlighted Windowing plt wit plt wit 0 0 002 0 004 0 006 0 008 0 01 If the audio trace segments are used for real time FFT calculation the trace s
251. wo values the first one represents as in the standard case L L difference the second one provides the difference between the isophone and Lo The isophone is calculated to have the same level of the current spectrum in correspondence with the band selected by L cursor Activating the AL function you can using the LEFT and RIGHT arrows of the keypad move the L2 cursor to check numerically if the band corresponding to L is the most audible of the spectrum verifying that the isophone passing through the level cor responding to the L cursor is always higher than or equal to the other levels of the spectrum If the L cursor is positioned on the bands with 16 Hz 16 kHz and 20 kHz central frequencies where isophone curves are not defined or if the level of the selected band is lower than the mini mum audible the minimum audibility isophone MAF will be displayed The isophone display is not available for A or C weighted spectra THIRD OCTAVE FILTERS SHIFTED BY HALF BAND THIRD OCTAVE OPTION The spectrum by third octave band provides in rather all cases all information necessary to classify sound sources In some cases however this type of spectrum can provide wrong indica tions when not properly interpreted The most frequent example is the analysis of a sound source emitting a pure tone that is a noise with an energy located in a limited area of the spectrum around a precise frequency This source is correctly c
252. xiliary frequency weighting Spectral analysis normally unweighted can be also carried out using A or C frequency weightings A or C frequency weighted analysis can be used to evaluate the audibility of different spectral components Some parameters can be modified without accessing the menus but simply using the SELECT the four arrows UP DOWN LEFT and RIGHT and ENTER keys by press ing repeatedly the SELECT key can be selected in a sequence the type of analysis the integration or profile time the average type the broad band auxiliary weighting the A C or Z spectrum fre quency weighting and the temporal linear Leq or exponential FAST or SLOW average mode for more details see Selecting parameters on page 18 In this display mode the Continuous Recording and Monitor functions work as in the SLM mode The only difference concerns the multi spectrum also maximum or minimum MLT MAX and MIN analysis where the time interval with which data are recorded or sent to the serial inter face equals the programmed profile time The integration mode and the Auto Store function change the recording functioning as de scribed in the table below see the chapter DESCRIPTION OF THE DIFFERENT INTEGRA TION MODES on page 39 Auto Store OFF Auto Store ON Recording of OCTAVE and T OCTAVE spec Only AVR mode tra enabled by Recording menu The recording Automatic recording of OCTAVE interval is equal to the set spectrum profi
253. y CH20 Workers Protection module cod NS1 module is used to download and process the noise measurements performed in workplaces for health and safety applications Noise exposition analysis 1s made according to EN ISO 9612 2011 standard and UNI 9432 2011 Exposition levels are calculated taking into account uncertainties and PPE Personal Protective Equip ment efficiency as well as impulsivity of noise sources Acoustic Pollution module cod NS2A module for acoustic climate analysis on a daily weekly and annual basis including road railways and airport noise The software performs statistical and spectral analysis and automatically identifies noisy events The analyses are performed in compliance with the national and EU legislation regarding the acoustic pollution and the noise mapping 121 Acoustic Insulation module cod NS3 for evaluation of airborne sound insulation ac cording to national and international standards Calculation of reverberation time in rooms and calculation of partitions and facades insulation and tapping noise according to ISO140 standards Post processing of reverberation time decay curves Calculation of sound insulation indexes according to ISO 717 1 1996 and ISO 717 2 1996 This program requests the rever beration time option installed in the sound level meter Monitor module cod NS4 for the acoustic monitoring and remote control via PC or via modem
254. yed data can be stored in memory as a single record alternatively the Auto Store mode can be activated PAUSE CONTINUE key pauses integrated measurements From PAUSE mode integrated measurements can be resumed by pressing the same key In PAUSE mode press START STOP RESET to reset measurements SELECT key enables modification mode of displayed parameters by selecting them in se quence ENTER key It confirms the entered data or edited parameters LEFT key in the menu it 1s used when editing parameters with attribute In graphic mode it reduces the vertical scale M12 connector for multi standard serial port RS232C and USB Auxiliary power supply connector DC output connector 2 5mm jack DOWN key in the menu it selects the next line or decreases the selected parameter In graphic mode it increases the vertical scale levels the graph is shifted downwards RIGHT key in the menu it is used when editing parameters with attribute In graphic mode it extends the vertical scale MODE key Selects in circular order the instrument s different view modes from the display of 5 channels in numeric format to the time profile to the octave and third octave spectrum Third Octave option to the narrow band spectrum FFT option and to the statistics screens UP key in the menu it selects the previous line or increases the selected parameter In graphic mode it decreases the vertical scale levels the graph is

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