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LxT User Manual - PC Environmental Ltd
Contents
1. A 14 1 1 1 3 Octave Filters A 15 Frequency Range nennt neni A 15 Filter Shapes utar nor A 15 Position of Instrument and Operator A 18 Effect of Windscreen aper cac Eus A 18 Frequency 20 LxT With 377 02 Free Field Microphone PRMLxT1 Preamplifier 20 Directional Characteristics 22442 A 23 1 12 LxT Technical Reference Manual LxT With 375A02 Free Field Microphone and PRMLxT2 ERE Kad 27 Directional 29 Noise Levels 32 LxT1 PRMLXT1 with 377B02 sese A 33 LxT1 PRMLXT1L with 377 02 2222440 2 A 34 LxT2 PRMLXT2 with 375A02 sse A 35 LxT2 PRMLXxT2L with 375 02 2 2 A 36 Microphone Preamplifier Specifications A 37 Model ott A 37 Specifications io t e o A 38 Optional 41 Model 0 43 Specifications 43 Optional 46
2. 48 Specifications 48 Optional 51 Model 2 2 2 A 53 Specifications 2 etie bab A 53 Vibration Sensitivity esses A 58 Vibration Parallel to the Microphone Diaphragm A 58 Vibration Perpendicular to the Microphone Diaphragm A 59 M A 60 Chapter 20 Upgrade Firmware and Options B 1 SLEM Utility G3 1 Upgrading LxT Firmware eene B 2 Define Path to Firmware Upgrade File B 5 Upgrading Options eene B 7 Saving an Option Upgrade File B 7 Implementing the Option Upgrade B 7 Define Path to Option Upgrade File B 8 Appendix B Testing to IEC61672 1 C 1 Sections 5 6 7 and 9 except 9 3 C 1 LxT Technical Reference Manual 1 13 C 8 C 8 b Calibration C 8 Calibration C 8 d Frequency Response and Corrections
3. 8 Sound Exposure Level E 9 SEA ee ted ub E 9 Community Noise Descriptors E 11 LDN A auia 11 RENE ede 11 zr a and are are eet 12 Appendix E LIMITED PRODUCT WARRANTY 2 1 1 16 LxT Technical Reference Manual List of Figures INTRODUCTION tss 1 1 BOOKIMAIKS wed 1 4 Bookmarks 1 5 Tie hod 1 12 Lex TB OLLI VIEW uu eiet 1 13 OVervIQW 2 1 Data Display 0 2 0 2 1 Power Control View 2 6 2 8 Control Paligl 2 9 Main View Block 2 12 res Reo cher 2 12 Data Display Screens 2 0 00 2 14 Measurement Properties 2 16 Tools Sereen xiu is ci ore oir pr ad tria eq up Ded 2 16 Highlighting a Tools Icon dee tet OR cuales ede 2 17 System Property
4. 10 1 Measurement Time 10 2 Measurement Counter 10 3 Time History Display Current Page Section 1 10 5 Measurement Record Display Measurement Page Section One cT 10 6 Measurement History Displays 10 8 Profile Display Measurement Page Section 2 10 9 Link to Time History Display 10 10 Time History 1144112 10 10 Data Explorer 11 1 COMING PANG e 11 1 Data EXplOrer dn i te tec Ra ev aks 11 2 Data Explorer Meis iei itae 11 3 Data View Paga icem erudire 11 4 Delete 11 4 Delete AAU FIGS EE 11 5 Ce 11 5 11 6 Selection of File to be Overwritten 11 6 Overwrite Confirmation 11 6 System 1 1 1 12 1 Control Panel ci eid A Gd e i d ERES RE RE MEN 12 1
5. 7 4 Use of a Windscreen 7 5 Performing the 7 6 Starting the 7 6 Data Display 7 6 Measurement 2 2 7 8 Overload Under Range 7 8 Overload Indication 7 8 Under Range 7 8 Pausing the Measurement 7 9 Back Erase 7 10 Time History 7 12 Resetting the 7 13 Resetting When Running or 7 13 Resetting When Stopped 7 13 Starting a New 7 14 Stopping the 7 14 Storing the 1 1 42 7 14 Overwriting a Saved 7 15 Low Level Sound Fields 02 222 2 7 16 Recovery After Improper Shutdown 7 18 NOPE Er Se re 7 18 Normal
6. 12 6 Backlight Tilrie i eo eee re e on enun 12 6 1 8 LxT Technical Reference Manual Backlight Mode 2 12 6 Display Contrasti 12 7 Battery Dude e pa RET NER E 12 7 1 PERPE TE CETTE TTE 12 7 Microphone Correction 2 2 12 8 ie neice eed 12 8 epee Nisha ital creatine 12 8 Prompt hee A eed aed oi a o 12 9 SOLO ek eu TR Secs 12 9 Jack FURCHOM eoe etre 12 9 Reset Prompting canned 12 10 Takt Maximal D ate 12 10 x eset cas seers Ceo C eva 12 10 USB SlOrage 12 10 LEocalizatlof a ete eL e 12 11 Larigdages ioc pei 12 12 Decimal Symbol uice Seeds exe ies 12 12 Date FOItnal rectc et o bee re Pe ete teta les 12 13 UNIS decetero ta an ete 12 13 12 14 LaL d pM ELO ED 12 14 Selecting Displays to 12 14 Tab Page 12 15 Display eese 12 15 Chapter 13 Lock Unlock the LxT 13 1 Control Panel c one Ea eee Ae 13 1 LOCK MOOOS ai s soe c t
7. EE das decem 2 15 Octave Band Analyzer Page uar dated ule md ave ere eoi te tun 4 6 Settings In Use tee eere e e e e e eee nete hawt oa 4 2 Setup Pagesz docemus bienes meh em bee 4 3 SEM iiie tecti Nd oer DRE n dane 2 15 Time History toot te Reate oe IN Co HER SE ce qi beet ORE REPORTE ERG 2 15 Triggers ege dete el ee edad e eO Re e ds 2 15 Measurement Status 2 4 Pause le Oth 2 4 RESUS COM NEUE e 2 4 RUD 2 4 2 5 SOTE eee rio ed IRE ERE 2 5 MOM ONY scere ROSEO Nette DEO ete ban uscito 5 6 Memory Status osea eR Eq pU S 5 6 Memory Utilization sse ener 19 1 Measurement History eis med UR ee t EE gre tie deret 19 1 Out of Memory Stop ec ett vic eee eee e Ens 19 1 Overall Data cress eie eee ee ee 19 1 Session ET tutu stein 19 1 Tame History s 19 2 Voice oco e oe pe tte DOS VINO Hed o Conde v ipe eroe ch 19 2 Microphone Guidelines eie tenen D 12 What it measures ient Reti e e Ee eee pec Ede eds D 13 Microphone Extension sse nere 7 4 Microphone Preamplifier Specifications
8. Reed s 5 14 Eoad Settings Lene UR IEEE eue 11 7 UR OR UR OR RR OR RE ES 2 18 Lock Modes Fully Locked sk RR det e Re RC s 13 3 Lock With Auto Stote eese eei metere etin eei 13 3 Lock with Manual Store ert tr e D ERO EE ie 13 3 Unlocked tot etm tie o Re ee ende a onte c 13 3 13 1 Allow Cal when 4 nennen 13 4 Calibration when Locked 13 9 Control Parel ot iet e eic io t TH Ee RS 13 1 Fully Locked eere I deret et 13 5 Lock MOGES 51 tenni n oA a BU at BS Ato s En 13 1 13 3 Locked with Auto Store eet te vance edes 13 6 Locked with Manual Store ce ettet rero tee tro Ten P REY dS 13 8 Unlock Code RTI ee aee ris 13 4 EXT Hardware onere erroe eei eee 17 1 Batteries 17 6 Components 17 1 Connectors oe enm c eee 17 5 Displ y i nahe Meet 17 2 External Power ise eese etie ee Eee ioris 17 7 datos nis o ette SOIN atem ae DOES 17 4 cO E e 17 5 Keypad s dome meii iem ote ien Rs 17 3 Microphone 2 eie 17 2 17 2 Softkeys cec ser erede e ete 17 3 EZpeak max eot et eut e c perg
9. Voice Recorder Chapter3 First Use Unpacking and Inspection Record Serial Numbers of and Components Connecting the Microphone and Preamplifier Connecting the Preamplifier to the LxT Disconnecting the Preamplifier from the LxT Inserting Batteries eee Hardware Power Switch Using USB Power cerent Chapter 4 Basic Measurement Setup Measurement Properties Accessing the Measurement Properties Screen Settings In Use Setup Pages General 2 2 22 2 2 2 2 2 2 SUM Frequency Weighting sss Time Weighting i Integration Method 2 Octave Band Analyzer Page Optional OBA Parameter Selection OBA Time 1 1 2 2 2 1 40242 4144144 0 Dosimeter 1 and 2
10. 2 18 Softkey Selection of About Pages 2 19 First LI E 3 1 MIGTIODPIOFIG or Eee mie De one opas de 3 2 3 2 Preamplifier Connected 2 2 3 3 Push Button to Release Preamplifier 3 4 Disconnect The 3 4 Battery DOOR oiii neat i etcetera eo es 3 5 Insert Batteries o eoe tenes 3 6 Basic Measurement Setup 4 1 Settings In Use By SLM Utility G3 4 2 Tabbed Setup Pages eese 4 3 General soa Sollee tates 4 4 4 5 4 6 OBA Parameter 4 7 4 9 Predefined Dose 4 10 C Pm 4 10 Exchange Rate list ehe eter re 4 11 EN qudd CE 4 12 Control Page x SERO BENE 4 13 Run Mode aaro apii 4 14 Manual Fait prem eere ge 4 14 Timed Stop Run 2 2 1 4 15 Ente
11. ranges Frequency 31 5 Hz 1 kHz 4 kHz 8 kHz 12 5 kHz Weighting A 40 to 1014 40 to 140 dB 40 to 140 dB 40 to 139 dB 40 to 136 dB C 40 to 137 dB 40 to 140 dB 40 to 139 dB 40 to 137 dB 40 to 135 dB Z 45 to 140 dB 45 to 140 dB 45 to 140 dB 45 to 140 dB 45 to 140 dB LxT Technical Reference Manual LxTI C 11 f Linear Measurement Starting Level The starting point for measuring level linearity errors is 114 dB at all frequencies g Electrical Insert Signals The electrical design of the input device to insert electrical signals into the preamplifier for the 377B02 microphone is a series 12pF 5 capacitor The Larson Davis ADP076 is used for this purpose The ADP076 can be used for noise floor measurements by attaching the included short on the front of the ADP076 h Inherent Noise Highest anticipated self generated noise of the LxTI Weighting Total Noise Electrical Noise A 31 31 C 33 27 Z 39 35 combination of the electronic noise and the thermal noise of the microphone at 20 measured in a sealed cavity and vibration isolated with a time average of 60 seconds electronic noise of the instrument with an ADPO76 in place of the microphone i Highest Sound Pressure Level The highest sound pressure level at the microphone and the greatest peak to peak voltage at the electrical input facility for the microphones recommended for use with the LxT1 are as specified in the following
12. 7 18 Improper 7 18 GASB 2 7 19 Improper 7 19 Chapter 8 Voice Recording 8 1 Control Page Voice Recording 8 1 Voice Recorder heic eiie 8 2 Record AMD 8 3 1 6 LxT Technical Reference Manual Save Prompt etae atu ede Dg tad qe ntis 8 3 Playback Do D ENT 8 4 Chapter9 Time History 9 1 Parameters Logged eese 9 1 Acoustical Parameters 2 2 2 2 2 9 1 Sound Pressure Level 9 1 Instantaneous 9 2 Specialized Acoustic 9 2 1 1 and 1 3 Octave 9 2 Non Acoustical Parameters 9 3 Time 9 3 LxT 9 3 Time History Setup rere ne ener 9 3 Set Time History Period 9 4 Select Time History Parameters 9 5 Exiting Time History 9 5 Time History 01 9 6 Single
13. 12 2 NING tette dat eel 12 3 Month 12 4 Power m 12 5 Preferences PAGS 12 7 Microphone Correction Menu 12 8 Auto Store Preferences 2 2 12 8 Jack Function Preferences 12 9 USB Host Port On Off 12 10 USB Storage Preferences 222222214 12 11 Localization Page uere tte 12 11 Language Preferences 2 22 2 2 2 12 12 Decimal Symbol Preferences 12 12 Date Format Preferences 12 13 12 13 Displays ccc cy nu 12 14 Display Start Options iret reote ta n 12 14 Display Tab Page 12 15 Live Page Displays teo ladite en 12 15 Overall Page Displays 12 16 Session Log Displays 12 16 Time History Displays iter eee 12 17 Display Set to Appear or Hide 12 18 Lock Unlock the LXT 13 1 Control Panel ied Eos ot oes 13 1 13 2 Lock cea vies 13 2 OU 13 4 Ais Mesa ut tod tou Sg ee
14. 2 5 ON OFF Key 2 6 Turn ThE XT iili e boat iad te THERE 2 6 Turn O The eee RR DEA 2 6 Power Control 2 6 SES ESSO V one Capena nva 2 7 Resetting When Running or 2 8 Resetting When Stopped 2 8 Resetting When 2 9 Starting a New 2 9 copie De EE 2 9 LEFT and RIGHT KEYS i oo aed eres oc ane oit 2 10 UP and DOWN Keys e io ed ad 2 10 ENTER KEY to pi d a Bera ede Ta 2 10 RUNIPAUSE KG xai Ur Mr un 2 10 STOPISTORE ROY 2 11 CFEC INS 2 11 Data Display Screen 2 12 Measurement Properties Screen 2 12 TOOIS SCFECN 2 13 Power Control 2 13 Data Display 20200 2 13 1 2 LxT Technical Reference Manual Changing Data Scrolling Between Sections Measurement Properties Screen Changing Setup Tools Seren mec E Gallbrate 2
15. D 3 Criterion Sound Exposure D 3 Criterion Sound Level Lc D 3 Daily Personal Noise Exposure D 3 Day Night Average Sound Level DNL Ldn D 3 Decibel dB D 4 Department of Defense Level 0000 D 7 DOS saint heen wii utendi t D 7 Detector sc iar mer pip i E D 7 Eight Hour Time Weighted Average Sound Level L TWA 8 D 8 Energy Equivalent Sound Level D 8 Exchange Rate Q Exchange Rate Factor q Exposure Factor k Emm D 8 Feat Field E ot e Gotta D 8 Free Field rese teet tris D 9 Frequency Hz 0 9 Frequency Band Pass 0 9 Frequency Filter Weighted sse D 10 N D 11 tevel erp iet bee ae cece D 12 Measurement Duration T seem D 12 Microphone 0 12 Near ett toe but a be seem D 14 INOISG centu ERE RU D 15 otn C ME nq D 15 D 16 OSHA Level 5 0 D 16 Pre
16. 5 21 Normalize to a Live Spectrum 5 22 Normalizing using Frequency Weighting 5 23 Overall Display io tree Uo 5 24 Normalized using a Previously Measured Spectrum 5 25 Normalizing using Frequency Weighting 5 27 Graph Relative iecur eo nieto que uobis 5 28 Return to Standard Display 5 29 Chapter 6 Run Control 6 1 Run Control Setup utero t ndi Seu S esi a LS 6 1 Run Modes Without Measurement History 6 2 Manual Timed Stop or Stop When Stable 6 3 CONtMUOUS wis ero Eo mE entes 6 3 Single Block Time or Daily 6 4 Entering Delta Level 6 4 Entering Time reel e 6 4 Mode with Measurement 6 5 Chapter 7 Making a Measurement 7 1 Configuration of the 7 1 Switching On the 7 1 LxT Technical Reference Manual 1 5 7 3 Se 7 3 LET Pr HE 7 4 Calibrating the EXT 7 4 Positioning the EXT eor ete eee 7 4 Observer POSIMOM tse na ee eked 7 4 Microphone Extension Cable
17. sse 10 1 Initiate a Run eae tet tst ee edet a eae 2 10 Integrated Level Calculations sse E 1 Dose Calculations ccce ERE RR OR RR RSEN ERREUR E 5 Equivalent Continuous Sound sess E 1 Projected a esee Ae E 5 Sound EXpOoSUIre 7 e ever e RO OE E 8 Time Weiehted Averages ERRASSE E 2 Integration 2 aos dete P 4 5 Intrinsic Safe Batteries Ver 3 5 J Jump to Beginning File esses 11 7 Jump to End File os tenete teer ette bin ipe 11 7 L 5 2 LANGUAGES IA RO eee ee 12 12 nee uaa qae 5 4 a 5 8 LAS MIT E oy roe e ep 5 8 LUDEN P 4 18 11 eheu Tn Tudor 4 18 E 11 Leftand RIgh Keys aed 2 10 Leq Gi cia D 8 1 6 Index LxT Technical Reference Manual Dept of Defense sese rd t ER he RR RR D 7 LINKS nu ER 1 6 Display Page Do E ta ead 1 6 Return to Previous Vie W oh ance eee eee irre reader 1 6 Live Enforcement Sound Level 1 esee 5 3 Eive Page sieh etes entrer 5 2 LniPage 5 sone tentiae aret ane ote 4 12 Ev Percentiles
18. LxT Technical Reference Manual Predefined Setups aere 4 9 Parameters Individually Defined 4 11 5 1 or oe 4 11 Parameter Fields 2 ni edited ten 4 11 Exchange Rate nO d eit 4 11 Threshold and 4 12 Auto Calculate 4 12 EAE atele e gp 4 12 Control AGC csc teed dete tero ans 4 13 Manual Stop 4 14 Timed Stop Mode oeni e a a 4 14 Stop When Stable Mode 4 15 Triggers PSU i eei eta 4 17 eque ei patet qu Uude 4 18 Barco TU 4 18 EDEN us 4 18 4 19 Exiting Measurement Property Screens 4 20 Chapter5 Basic Data Display 5 1 n e Pm 5 1 Tabbed Page Structure esses 5 1 Live Page idees 5 2 Sound Level Profile 22 5 2 Enforcement Sound 5 3 1 1 Octave Band Analyzer Optional 5 4 Ee erai 5 4 1 3 Octave Band Analyzer Optional 5 5 TRIG QING
19. 1 Threshold ee e ete ee rp e EUG 4 12 5 6 Allowed Exposure time T1 esses eee D 1 Weighttig 22 Time 1 9 1 Display 9 6 Erequency 9 9 Link to Measurement History 9 11 Markers tees 9 12 Parameters 9 1 NEED 9 3 Time History Parameters e p ipi 9 5 TimetHistory Period 3 5 RN p HEREDES 9 4 Time e 12 3 Time Weighting ee 4 5 Tools SCree ER elei a a 2 11 Triggers Page issih Hit n EE Mr er 4 17 Tripods cete ee 1 12 TWAT O reete D 22 U Under Range Levels ire eee pee eee ee 7 8 15 13 Uner Range Indication 7 8 Units erue ep RE Oe egre 12 13 Unpacking and Inspection sss 3 1 Up and rere eem ien tet tete Geen ess 2 10 Upgrade Firmware 2 2 2 2 41 4 14 04 000000000000 000000000000 B 1 USB Host Port eerte tie er e rn ER Ee ete ere eene e ER Ee 12 10 USB POWeF tI bep e 3 75 6 USB Storage tne e qa e eO Ede 12 10 Ser hn
20. acra edes 13 4 Allow Cal Check essere 13 5 Fully EOCK60 ben 13 5 Are You SUIO 13 6 ce acc lo mM 13 6 Locked with Auto Store or Manual Store 13 7 Auto Store Stop 13 7 Auto Store nloCKu ss cep 13 7 Manual Store When 13 8 Locked with Calibration Permitted 13 9 Y 14 1 Control Panel i a oo deo no e erts 14 1 About ooi seen es Molle 14 2 Standards nee 14 2 Options eM 14 3 User TET 14 4 15 1 Control Pane atta tiat bee 15 2 Calibratiom P ages unice tto odi 15 3 New Calibrator 3 ode reins 15 8 Microphone Selection 15 9 Galibratingr EE 15 10 Save Calibrations 2 2 15 10 Outside Normal Sensitivity Range 15 11 0 5 dB From Previous Calibration Result 15 11 Sensitivity osc o desert 15 12 Sensitivity Page Without 15 14 Certification 4 15 15 System Utilities sc 16 1 Gontrol Parel uer ene ented 16 1 File Syste
21. ee 6 3 Setup of Continuous Daily Timer and Single Block Time Run Modes PPM T E E 6 4 Auto Store Report Start Time 6 5 Making a Measurement 7 1 Boot Graphic i n urs ccs tts deh ceeds 7 2 Data Display Screen Live 7 2 iat etd esie 7 3 Position of Windscreen 7 5 Placement of Windscreen 2 2 2 7 5 Leq and Running SPL 7 7 Multiple Sound Level 7 7 Five Second Back Erase 7 10 Back Erase Undo Indication 7 11 Ten Second Back Erase Label 7 12 Stop Required 2 2 2 2 2 7 13 Save File 88 7 14 saved Data Files 2 Ln necs 7 15 Overwriting a Saved 2 2222 2 1 7 15 Overwrite Confirmation 7 16 Improper Shutdown Sequence Case 2 7 20 Voice Recording 8 1 Control i edebat deed ete 8 1 ioo pepe a 8 2 Recording 8 3 Save Recording 2 2 adenine 8 3 dM OMIM 8 4 A e 9
22. sse enne 5 16 Octave Band Analyzer 4 6 Bandwidth Setting epi eee tec ee ec ere tice ds 4 7 Control oce e 4 13 Frequency Weighting eise ee Ree ie rete 4 7 Range Setting iso un ep iade Rt Dena ETUR bae e EA RO ARE SUN 4 7 Off usse ete mete eR er e ed 2 7 On Off sonent nes oett 2 6 Power Control Page cce reste e e d RR Ade decens 2 6 Turn On ERE tates oes it E 2 6 Optional Accessories Equivalent Electrical Impedance Adaptor sese 1 10 1 9 PEE EE MEE B 1 OSHA Level madent e IH nena iam taped n D 16 Output cte EMIL 12 9 ae ae 12 9 Overall Enforcement sse 5 7 Overload Level nte e se hie ed 7 8 15 13 tacts ETUDES 5 15 Overwrite Filt ede e eed 11 6 1 10 Index LxT Technical Reference Manual ett t ee 2 2 Parameters Measured sse eere nennen rentrer entres 18 1 Exceedanc Counters t eee ten OG 18 4 Miscellaneous Parameters seen eene enne 18 5 Sound Exposure one ht EURO be t AREE E 18 3 SOUNG Ae Vell Sets EP EM E 18 1 Sound Level Meterics 18 2
23. 16 3 Chapter 17 LxT Hardware 17 1 Components inc uU UEM CR UD EU 17 1 Microphone and Microphone Preamplifier 17 2 DISDI BV coii eA eee ner er NC 17 2 tC 17 3 lenem e reta T etaed 17 3 2 22 Le 17 4 Connectors and 17 5 M RCM 17 6 External Power 17 7 2 emen 17 8 Chapter 18 Parameters Measured 18 1 Basic Sound Level Measurements 18 1 Frequency Weighting 2 18 1 RMS Averaging 18 2 Sound Level Metrics 18 2 1 1 and or 1 3 Octave Frequency Spectra 18 2 Sound Exposure Metrics Measured 18 3 Statistical Metrics Measured 18 4 Community Noise 18 4 Exceedance Counters 18 4 Miscellaneous Parameters 18 5 DEus ette D ctor 18 5 C MINUSA EP RUNDE 18 5 lmpulsivity 18 5 LxT Technical Reference Manual 1 11 Chapter 19 Memory Utilization 19 1 Out O
24. 2 2 Power Indicator een e tete ape e o be PR REG es 2 2 R n Time Ree vet 2 3 abb T tope tens 2 2 Section Indicator eese ce e ORE 2 2 Stability Indicator ze ertet ro RE RE SERE MD PU HUE PU tenete 2 3 JL m 2 2 Displays Selecting Displays to Appear sse nnne 12 14 Displays Page Statt co eere nee onum 12 14 1 4 Index LxT Technical Reference Manual Dosimete r S eoe diee ERECTO 4 9 Auto Calcul te e D e teg itia edt re Rees 4 12 Criterton i uio CE et REOR e ee TERRAS 4 12 Exchange Rate eric usa oet e lette a ivi ceo OE RR 4 11 Name 4 11 Predefined Setups ttiam edet 4 9 Threshold uo deo ede ice RR ER C e eH de 4 12 Duration Measurement nieni nti e D 12 E Eight Hour TWA e NE IEEE D 8 End a Lest oon ttt UR 2 11 Enter ee eet putat te e eR 2 10 Equivalent Electrical Impedance 1 10 Event History Link to Measurement 1 eren eren 10 10 Link to Time History eiecit 10 10 eres aer CR TR EDU 4 11 GOS cia E D 8 Exchange Rate Factor AGIOS SAT Yes e Cn eate
25. C 9 Section c C 10 a Reference Sound Pressure C 10 b Reference Level C 10 Microphone Reference C 10 d Periodic 2 2 1 11 10 Linear Operating 11 f Linear Measurement Starting C 12 g Electrical Insert Signals see C 12 h Inherent Noise ssss mmn C 12 i Highest Sound Pressure C 12 j Battery Power Voltage C 13 Display Device nnne C 13 Typical Stabilization C 13 m Field Strength gt 10 C 13 n Radio Frequency C 13 AC Power and Radio Frequency Susceptibility C 13 qp C 14 Section 9 24 Am 14 a Call Vator e Ten Lee its C 14 b Calibrator Frequency sm C 14 Calibration 14 d Frequency Response and Corr
26. ewe A EN wee D 8 Exposure Factor GlOSSaby s xe ott RE heed RR TR en ee D 8 F Far Field one ER eR eR Rb EO n D 8 ue eeu dede D 9 SCONE TIC 65i bc D 9 NS 1 7 tete edi de e oie ER a nt eed 16 2 Filters 1 1 1 3 Octave Filter Shapes iue ite dd iet i tede tas A 15 Firmware Upgrade dte e S eae WR ARR Cei caedit B 1 Free D 9 Frequency Band Pass Eilter OR ee e Hee e ERR E EU REB e CR D 9 GIIOSSaby UR ie E ET Ha E EP Ne ne eee tete at tote D 9 Hz ec ee de Tete dd D 9 222 etes enre te nasi es D 21 Frequency Weighting n sese nere reet s 4 5 LxT Technical Reference Manual Index 1 5 G Graph Relatii V n aneno e aaae te o RR REDE UIN 5 28 Graph sse eene eret entente nnns 5 19 H Headset oi 1 11 USE tre E potest Gees eo NI aa teet 8 3 Headset Output eroe RU RP Rn 12 9 I Improper Shutdown sss enne 7 18 Imp ulsivity eme tod 5 17 Industrial Hygiene Dosimieter 5 11 d 5 13 Industrial Hygiene Measurements
27. RUN PAUSE key is pressed to begin another measurement Overwriting a Saved File LxT Technical Reference Manual To continue with the save ee use the right arrow key to highlight Yes and press the er key To abort the save operation use the right arrow key to highlight No and press the key If you wish to use this data to replace a data file already saved in the LxT instead of highlighting Yes or No highlight the box with the title and press the mer key This will open a window listing all the data files already saved in the LxT as shown in FIGURE 7 13 LxT Data 001 LxT Data 002 LxT Data 003 LxT Data 004 LxT Data 005 FIGURE 7 13 Saved Data Files Use the CI keys to select the file which is to be overwritten and press the key This will replace the file name and number which previously appeared with this one as shown in FIGURE 7 14 SoundTrack LxT Save File Yes No El LASmin 29 9 dB Run Time 0 00 00 9 FIGURE 7 14 Overwriting a Saved File Storing the Measurement 7 15 Low Level Sound Fields To continue with the overwrite operation use the key to highlight Yes and press the key This will open the Overwrite Confirmation menu shown in FIGURE 7 15 9 1 01 43 0 LxT_Data 001 LxT_Data 002 FIGURE 7 15 Overwrite Confirmation Highlight Yes and press the key to implement the overwrite operation To abort the overwrit
28. Standard Accessories Microphone and Preamplifier SOftWale 2 LR e erre HE TER Optional Accessories 2 2 7 0 22 Microphones dime iR reine LER ee e NIMM Microphone Microphone and Preamplifier Configurations Equivalent Electrical Impedance Adaptor Cables ed P deett aad Ee eL oa Power Supplies en Ei LxT Technical Reference Manual 1 1 Chapter 2 Overview 2 1 Display and 2 1 Display Sections and lcons 2 2 amp ER 2 2 CREE 2 2 ETE 2 2 Scroll Bar and Section 2 2 Power 2 2 Measurement 2 2 2119 2 3 ant sed 2 3 Input Overload 2 3 Under Range CON si 2 3 OBA Overload 2 4 Measurement 2 4 SOfIKGyS ioco ere ele Er cece eben een 2 5 Changing Views emm 2 5 MC DLE
29. L ypeak max Lxsmin Lyxtmin Table 18 1 Sound Level Metrics Measured 1 1 and or 1 3 Octave Frequency Spectra The LxT can perform just 1 1 or 1 3 octave real time frequency spectra measurements or they can both be measured simultaneously These spectra will be made using a user selected frequency weighting A C or Z The averaging time is the same as that selected for the sound level measurements Fast Slow or Impulse Spectral data is displayed on both the Live and Overall Pages but only the Overall Data can be stored 18 2 Basic Sound Level Measurements LxT Technical Reference Manual Live Page From the Live Page the graphic shows the instantaneous SPL value for all frequencies and the bar to the far right shows the summation value for the entire frequency band The value corresponding to the cursor position is displayed numerically beneath the graph Overall Page From the Overall Page the graphic shows the energy equivalent level calculated over the measurement time period at each frequency band and at the far right for the summation of all frequency bands The values displayed digitally beneath the graph represent the following data for the frequency band at the cursor position Leq Lmax Lmin Sound Exposure Metrics Measured See Chapter 9 Industrial Hygiene on page 9 1 The LxT measures two separate and independent sets of sound exposure metrics The following parameters
30. Specifications Note that all electroacoustic values are at 23 C 50 RH 7 5 Volt supply 3 m 10 cable and equivalent microphone of 18pF unless otherwise stated Frequency response with respect to the response at 1 kHz with 1 1 Volts rms input and 18 pF equivalent microphone 4 Hz to 10 Hz 0 1 0 5 dB 10 Hz to 20 kHz 0 1 0 18 dB Lower 3 dB limit lt 1 5 Hz Attenuation 1 2 dB typical Input Impedance 10 G Ohm 3 pF Output Impedance 50 Ohm Maximum Output With LxT SLM 2 Vpp 126 dB peak for microphones with 20 mV Pa sensitivity Maximum Output Current 10 mA peak LxT Technical Reference Manual Technical Specifications A 53 Distortion Harmonics lt 62 dBc with 1 1 Volts rms input at 1 kHz Output Slew Rate 2 V uS typical Electronic Noise with 18pF equivalent microphone 1 8 uV typical A weighted 2 5 uV max 3 2 uV typical Flat 20 Hz to 20 kHz 5 max Power Supply Voltage 6 to 15 Volts DC Output Level 1 2 power supply voltage Power Supply Current 1 3 mA typical Temperature Sensitivity lt 0 05 dB from 10 to 50 C 14 to 122 F operating range to 60 140 F Humidity Sensitivity lt 0 05 dB from 0 to 90 RH non condensing at 40 C 104 F Dimensions 2 7 mm diameter x 125 mm length 0 50 dia x 4 92 length Microphone Thread 11 7 mm 60 UNS 0 4606 60 UNS A 54 Technical Specifications LxT Technical Reference Manual Cable Driving Capability
31. add numbers in this column to levels read on the LxT2 to correct the level at a specific frequency Section 9 3 a Reference Sound Pressure Level The reference sound pressure level is 114 dB re 20 p Pa C 16 LxT2 LxT Technical Reference Manual b Reference Level Range The reference level range is normal c Microphone Reference Point The microphone reference point is the center of the diaphragm of the 375A02 microphone d Periodic Testing See table 2 for values of Larson Davis LxT2 with PRMLxT2 and 375A02 Microphone adjustment data of A weighted levels used for periodic measurements Larson Davis LxT2 with PRMLxT2 and 375A02 Microphone adjustment data of A weighted levels used for periodic testing 0 Free Field Corrections from B amp K 4226 Calibrator dB 0 Free Field Corrections with WS from B amp K 4226 Calibrator dB 0 Free Field Corrections from B amp K UA0033 EA dB 0 Free Field Corrections with WS from B amp K UA0033 EA dB of Corrections 95 confidence add numbers in this column to levels read on the LxT to correct to the 0 Free Field level at a specific frequency EA Electrostatic Actuator WS Wind Screen LxT2 LxT Technical Reference Manual Linear Operating Range Weighted sound levels indicated on the LxT2 at the upper and lower limits of the linear operating ranges 31 5 Hz 1 kHz 4 kHz 8 kHz 12 5 kHz 40to1
32. 16 2 File System The File System page is used to repair or recover from file system problems The functions available on this page are similar to function that would be used to manage a hard drive See FIGURE 16 2 File System System Utilities Check File System Format Format Restore Defaults FIGURE 16 2 File System The three functions on the File System page are Check File System Format Format amp Restore Defaults Use the C and keys to select the desired function Press the key to initiate this operation The user should only activate these functions if there appears to be a problem These utilities will detect and repair file system problems When the Check File System button is selected the LxT will check the file system in the LxT similar to Check Disk on a PC If a problem is detected an attempt will be made to repair the problem LxT Technical Reference Manual Format Format amp Restore Defaults LxT Technical Reference Manual Selecting this function will format the internal data storage area in the memory of the LxT This operates similar to the Format function on a PC System and measurement properties are preserved Selecting this function formats the internal data storage area in the memory of the LxT The LxT is then restored to factory settings The Format and Format amp Restore Defaults function will erase all internal data files but it will not affect dat
33. 9 4 Time History Setup will add additional items to the Time History setup menu as shown in FIGURE 9 2 0 00 00 0 ings a Period ime History Options FIGURE 9 2 Time History Setup Menu Enabled To set the Time History Period use the C key to highlight the Period data field and press the ome key to list all the available values of time as shown partially in Figure 9 3 t 0 00 00 0 ttings Time History B Enable Time History FIGURE 9 3 Time History Period Menu The following values are available for selection as time increment for the Time History Milliseconds 100 200 500 LxT HSLOG firmware required LxT Technical Reference Manual Seconds 1 2 5 10 15 20 30 Minutes 1 2 5 10 15 20 30 Hours 1 24 Use the C and C keys to highlight the desired increment of time and press the key to make the selection Select Time History Parameters The parameters available selection are described Parameters Logged on page 9 1 Exiting Time History Options LxT Technical Reference Manual in The Time History Options Menu is used to select one by one the parameters to be stored for each time increment Use the 2 2 key to highlight the Time History Options window and press the key The first item in the options FIGURE 9 4 Time History Options Window Use the gt and C keys to move the highlight down or up respectively and use the Q Or 0 key
34. Standard ANSI 12 19 It is the logarithmic average of the sound during a Measurement Duration specific time period using the chosen Exchange Rate Factor Exposure to this sound level over the period would result in the same noise dose and the Glossary D 1 Community Noise Equivalent Level CNEL D 2 1 Lien 1010210 24 Glossary 0700 0000 actual unsteady sound levels If the Measurement Duration is the same as the Criterion Duration then Lave LTWA LC 1 Lus 410810 10 OY where the Measurement Duration specified time period is T T T and q is the Exchange Rate Factor Only sound levels above the Threshold Level are included in the integral Standard ANSI 12 19 A rating of community noise exposure to all sources of sound that differentiates between daytime evening and nighttime noise exposure The equation for it is 1900 2200 2400 L 10 10 L 10 1 5 10 L 10 10 DX 0700 1900 2200 The continuous equivalent sound level is generally calculated on an hourly basis and 1s shown in the equation as L The levels for the hourly periods from midnight to 7 a m have 10 added to them to represent less tolerance for noise during sleeping hours The same occurs from 10 p m to midnight The levels for the hourly periods between 7 p m and 10 p m have 5 added to them to represent a lessened tolerance for noise during evening activities They are
35. Urin R ie eei EC WM system Properties oes ee it de TR CR PUE ets Auto Sleepz x eet e op tee Ucet e re siete bend Backlight Mode eser per e e e e Backlight Time oet etie Fed eU D PUR REPE Battery Type eee ie c ETE as TG ER ie Control Panel xt te Sete Eos Device rite te reo de ot es Display Contrast ode ge en ae tet hu e TUE nee Display Customization iere ete etd eite e fee Rt USB e e Do rea a d n nana hawt System Properties Pages eene nennen nennen nns System Utilities oi rhe RR eee Rs Control File Systemi Een Format Internal eosar E ei Eea ae E S iE Format Internal Memory and Restore Defaults eese LxT Technical Reference Manual Index Tabs cede T eres 2 2 Hives A M MEA Ms 7 3 Overall b RR RR RR NIU e 7 3 Session Dog tse Dee Rt E tov e fien 7 3 Technical Specifications sees 1 Declaration of Conformity 1 2 REN RR ee Be es 1 Memory Retentions totu deb o deb ERIS A 12 Standards Met oce
36. is the sound pressure and T is the Measurement Duration specific time period When applied to hearing damage potential the equation 1s changed to SE where is the Exposure Factor See Exchange Rate Standard ANSI 51 25 The total sound energy in a specific time period The equation for it is Glossary D 17 Sound Pressure D 18 Glossary SEL 10Log 5 Pol The sound pressure is squared and integrated over a specific period of time this is called the sound exposure and has the units Pascal squared seconds or Pascal squared hours is the reference pressure of 20 uPa and is the reference time of 1 second It 1s then put into logarithmic form It is important to note that it is not an average since the reference time is not the same as the integration time The physical characteristic of sound that can be detected by microphones Not all pressure signals detected by a microphone are sound e g wind noise It is the amplitude of the oscillating sound pressure and is measured in Pascals Pa Newtons per square meter which is a metric equivalent of pounds per square inch To measure sound the oscillating pressure must be separated from the steady barometric pressure with a detector The detector takes out the steady pressure so only the oscillating pressure remains It then squares the pressure takes the time average and then takes th
37. A 33 Noise LxT1 with PRMLxT1L and 377 02 A 34 Noise LxT2 PRMLxT2 with 375 02 A 35 Noise LxT2 PRMLxT2L with 375A02 A 36 Output COTDngclor uou rero terat A 40 Optional Accessories 2 221 1 A 41 Input Connector dece e erui ck PIRE RC aaa etn go RN eR kes A 45 Optional Accessories A 46 INDUE SONNE CON ee A 50 Optional Accessories 51 Input Connector 55 Optional Accessories 56 Axis of Vibration Parallel to the Microphone Diaphragm A 59 Axis of Vibration Perpendicular to the Microphone Diaphragm cm WT ID A 60 Upgrade Firmware and Options B 1 Testing to IEC61672 1 C 1 e D 1 Integrated Level Calculations E 1 LIMITED PRODUCT WARRANTY 2 1 Introduction Welcome to the Larson Davis SoundTrack LxT This versatile instrument with graphic display performs the functions of several instruments It puts the combined features of a precision sound level meter and a real time frequency analyzer in the palm of your hand About This Manual This manual has 18 chapters and 5 app
38. A 37 PRMEUEXLDID AS Sors captu o E b pe A 43 crate ai eon eene ainsi A 37 48 PRM X P I a Iu A 53 Microphone Preamplifier Connecting i cie Dt ere 3 3 Connecting Together e PEOR e qud 3 2 Disconne ting eee eee iret e Nala te e Ord e eB 3 4 Microphones C apacltoEs i ec e DIR I REN eite be e e rem e etd D 12 Electret i ata dta OS t te n teet m o stets D 12 MISES p D 12 Move Horizontally sesenta 2 10 Move Vertically ile avn dee ne ee eed EUR 2 10 LxT Technical Reference Manual Index 1 9 N Near Field E 14 ns 14 GIIOSSAEY cette atis D 14 Noise e NOU RW RE D 15 Background encen D 15 Daily personal 2 2 1 2 2 1 nnne nnne nennen D 3 ee D 15 EX BOTAO TE HE D 16 Ghz D 2 D 15 LEE D 15 Projected noise dose ud dete D 16 Single event exposure 1 nennen D 16 unice D 15 Normalized Live sse ener nnns 5 20 Normalized Overall Display sess 5 24 Normalized Spectrum Display essere 5 20 Number of Measurements
39. FIGURE B 6 Loading Firmware Screen for Firmware Upgrade Upgrading Options Saving an Option Upgrade File Before modifying the options you will need to contact Larson Davis and arrange to have an option upgrade file sent to you via email This will be a opt file Save this file on your PC and make note of the location Implementing the Option Upgrade LxT Technical Reference Manual The procedure for changing the options to the LxT is very similar to upgrading the firmware as described in Upgrading LxT Firmware on page B 2 Follow the instructions up until the Select File Menu shown in FIGURE B 4 Select File Menu appears Upgrading Options B 7 Note that upgrades of both options Left click the check box corresponding to the text and firmware can be performed Changing installed options using a OPT file simultaneously by checking the check boxes for both and defining the paths to the files accordingly Define Path to Option Upgrade File Left click Browse and use the browser to define the path to the opt file you downloaded as described in Saving an Option Upgrade File on page B 7 Left click Next to display the Confirm Choices Menu If the choice is correct left click Finish to initiate the firmware upgrade Otherwise press Back to modify the choices or Cancel to abort the procedure When option upgrade is in progress the status of the upgrade process will be indicated dynamically on the screen which
40. Integration 8 Dosimeter 1 and 2 Pages L Predefined Setups Parameters Individually Defined iL Name Field Parameter Fields Exchange Rate Threshold and Criterion Bookmarks 2 n 2 8 7 FIGURE 1 2 Bookmarks Expanded Left click on any text field Chapter name Appendix name Table of Contents Index or any sub heading and the page displayed on the right will jump to the page associated with that text field To return to the page which was displayed previous to clicking on a bookmark text line click the View Menu in the menu bar Click the Goto and then Previous View on the pop up menus LxT Technical Reference Manual Special Features of the Electronic Version 1 5 Links Click a Link to Display a Page Return to Previous View Cross References Click Cross Reference Return To Previous View 1 6 The Table of Contents and the Index have a page number associated with each item For the Table of Contents left click on the text line and that page will be displayed For the Index left click on the page number itself to display the page associated with that entry To return to the page which was displayed previous to clicking on an item in the Table of Contents or a page number in the Index click the View Menu in the menu bar Click the Go to and then Previous View on the pop up menus Thr
41. Prompt Store Jack Function The jack function setting becomes active as soon as it is selected LxT Technical Reference Manual When the gt STOP STORE key is pressed to stop measurement the user will be prompted to save the data file See Storing the Measurement on page 7 14 If the user responds Yes then a data file is saved If No is selected a data file is not saved If data was stored when the amp RUN PAUSE key is pressed the instrument is automatically reset so new measurement may begin In this mode when the 32 STOP STORE key is pressed a data file is automatically saved The default file name is assigned to the file There is no user interaction in this process Pressing the RUN PAUSE key the instrument will automatically reset so a new measurement may begin The AC DC Out Headset Jack on the bottom of the instrument can be configured to provide one of the following Asan AC DC output of the signal from the detector Use with the optional AC DC Output Cable CLBL139 AC signal is output via the red BNC and DC signal via the white BNC The AC output is typically directed to a frequency analyzer or oscilloscope and the DC output is typically directed to a strip chart recorder Asamicrophone and speaker connection when used with the optional headset for voice recording playback ACC003 It can also be set to Off Use the 7 and C S keys to highlight the Jack Function fie
42. Standards lists the standards that the Lx T meets Options shows the options that are available in this instrument e User user entered instrument identification Softkey Selection of About Pages p Standards Options FIGURE 2 12 Softkey Selection of About Pages The Right and Left Softkeys are used to scroll between the About Pages Tools Screen 2 19 2 20 Tools Screen LxT Technical Reference Manual First Use This chapter outlines the steps to unpack the LxT and prepare it for first use The following topics are covered Unpacking and Inspection Connecting the microphone and preamplifier Installing 4 AA batteries Using USB power You will then be ready to use the LxT for actual measurements Unpacking and Inspection Your LxT has been shipped in protective packaging Please verify that the package contains the items listed below Retain the packaging for safe shipment for calibration service Report any damage or shortage immediately to PCB Piezotronics Inc at 888 258 3222 U S toll free or 716 926 8243 LxT Technical Reference Manual LxT PRMLxT Microphone Preamplifier Microphone Lanyard 4 AA Alkaline Batteries Hex Driver and 4 replacement screws used to secure the battery door to prevent battery exchange in explosive atmospheres User Manual 1770 01 First Use 3 1 Record Serial Numbers of LxT and Components If you have not already done
43. The labels for sound metrics in the LxT are designated by international standards For many displayed values the frequency and time weighting are indicate in the name of the metric Example Lag is the A weighted sound pressure level measured using the Slow detector Sound pressure level is often referred to as SPL Tabbed Page Structure Only a few of these horizontally arranged tab pages three in Figure 5 1 can be seen at one time To see those off screen to the right use the Right Softkey beneath the display To scroll back to the left use the Left Softkey beneath the display LxT Technical Reference Manual Measured data are displayed using a number of tabbed pages arranged horizontally across the screen as shown in Figure 5 1 Depending on the firmware options loaded in the LxT there may be as many as eleven different data display pages in the Data Display Screen each identified by a title on a tab at the top FIGURE 5 1 Tabbed Page Structure Basic Data Display 5 1 Live Page When the LxT is turned ON the user is presented with the Live Page The measurements displayed on the Live Page are always active real time measurements The displayed values are not controlled by the RUN PAUSE key This allows you to view the current SPL without disrupting any overall data For example suppose you are making a measurement and an unwanted event takes place causing you to stop the measurement With the measureme
44. near field effect of source geometry is significant Sound sources often have a variety of specific sources within them such as exhaust and intake noise When in the near field the sound of a weaker but close source can be louder than that of a more distant but stronger source Therefore measurements made here can be used to separate the various sources of sound but are not useful in predicting the sound levels and sound spectrum far from the source Typically it is unwanted sound This word adds the response of humans to the physical phenomenon of sound The descriptor should be used only when negative effects on people are known to occur Unfortunately this word is used also to describe sounds with no tonal content random Ambient The all encompassing sound at a given location caused by all sources of sound It is generally random but need not be Background The all encompassing sound at a given location caused by all sources of sound but excluding the source to be measured It is essentially the sound that interferes with a measurement Pink It is a random sound that maintains constant energy per octave Pink light is similar to pink noise in that it has a higher level at the lower frequencies red end of the spectrum White It is a random sound that contains equal energy at each frequency In this respect it is similar to white light It is the percentage of time a person is exposed to noise that is potentially dam
45. 0 10 016 0 10 0 10 6309 60 00 016 0 10 0 10 016 0 10 0 10 7943 30 00 016 0 10 0 10 016 0 10 0 10 10000 00 00 016 0 10 0 10 016 0 10 0 10 12589 00 00 016 0 10 0 10 016 0 10 0 10 15849 00 00 016 0 10 0 10 016 0 10 0 10 19953 00 00 016 0 10 0 10 016 0 10 0 10 25250 00 00 022 0 10 0 10 016 0 10 0 10 31500 00 00 022 0 10 0 10 016 0 10 0 10 39750 00 00 022 0 10 0 10 016 0 10 0 10 50000 00 00 022 0 12 0 12 016 0 10 0 10 63000 00 00 047 0 14 0 14 016 0 10 0 10 79500 00 01 047 0 16 0 16 016 0 10 0 10 100000 00 02 047 0 18 0 18 016 0 10 0 10 126000 00 03 063 0 20 0 20 Noise floor data 1 2 1 3 Octave 0 17 uV 15 3 dBuV uncertainty 0 47 dB Flat 20Hz 20kHz 1 6 uV 3 9 dBuV uncertainty 0 47 dB Awt 1 0 uV 0 2 dBuV uncertainty 0 46 dB Uncertainties are given as expanded uncertainty at 95 confidence level k 2 Technician Ron Harris Test Date 20JAN2006 FIGURE A 21 Certificate of Conformance PRMLxT2 A 52 Technical Specifications LxT Technical Reference Manual Model PRMLxT2L The Larson Davis PRMLxT2L is an electret microphone preamplifier It requires very little supply current and will drive 100 feet of cable The preamplifier operates over wide temperature and humidity ranges It is for use with 20 mV Pa sensitivity microphones up to 126 dBSPL
46. 43 0 01 016 0 09 0 11 19953 00 01 016 0 10 0 10 00 0 01 016 0 09 0 11 25250 00 01 022 0 10 0 10 89 0 01 016 0 09 0 11 31500 00 02 022 0 10 0 10 49 0 01 016 0 09 0 11 39750 00 02 022 0 10 0 10 53 0 01 016 0 09 0 10 50000 00 03 022 0 12 0 12 19 0 01 016 0 10 0 10 63000 00 04 047 0 14 0 14 23 0 00 016 0 10 0 10 79500 00 06 047 0 16 0 16 0 00 016 0 10 0 10 100000 00 07 047 0 18 0 18 19 0 00 016 0 10 0 10 126000 00 09 063 0 20 0 20 Noise floor data 1 2 1 3 Octave 0 37 uV 8 6 dBuV uncertainty 0 47 dB Flat 20Hz 20kHz 3 7 uV 11 3 dBuV uncertainty 0 47 dB Awt 2 3 uV 7 4 dBuV uncertainty 0 46 dB Uncertainties are given as expanded uncertainty at 95 confidence level k 2 Technician Jason Grace Test Date 09 2005 FIGURE A 22 Certificate of Conformance PRMLxT2L LxT Technical Reference Manual Technical Specifications 57 Vibration Sensitivity In these tests the LxT is mounted on an electrodynamic exciter and vibrated sinusoidally at an amplitude of 1 0 m s at the following frequencies 35 5 63 125 250 500 630 800 and 1 000 Hz The tests are performed with the meter oriented such that vibrations are producted in two different directions parallel to the microphone diaphragm and perpendicular to the diaphragm The resulting sound levels are measured using two different microphones The microphone c
47. Calculations 22 cea unie teret ee rt REP ber Rose E 1 Calibrate 2 18 15 1 15 1 gt 0 5 dB From Previous Calibration enne 15 11 SE e 15 1 Calibratom d EON d 15 5 Certification sce t REO aaa 15 15 Control 15 2 Direct Data Inp tz zu suc RR b ias NIRE IE MIS SIR RR Ri etian 15 13 Noise FLOOR he Tp 15 12 Outside Range of Normal Sensitivity 15 10 Overload Level eene b RR t tot do 15 13 Performing the Calibration eee ten 15 10 Sensitivity Page sh M E hs t cM dte E E dus 15 12 Under Range 15 13 Warning Messages a a nennen nnne ntn ener 15 10 EE 15 5 Recommended une rr t me Ut EDEN S 15 5 Changing Data Pages OON REPE RSEN 2 15 CHANGING VIEWS ee EDS egt 2 5 oie ttti epe TRE RO adi nete 2 11 Glose 2 7 oet 4 19 E 12 Community Noise 5 16 Community Noise Equivalent sss 4 19 E 12 Complete an 2 10 RUM 2 10 1 2 Index LxT Technical Reference Manual Contrast CONT OM Control Page eet RR eret D HR RENTES UR ERE US Control Panel ERE GSP ROTER ERREUR EORR Cali Dr
48. Certificate of Electrical Conformance Frequency response of this model PRMLxT2L preamplifier was tested at a level of 1 157 Vrms with 18pF microphone capacitance and driving a short cable Output level at 1KHz is 1 0018 Vrms 0 016 dBV uncertainty 0 035 dB Output is 3 586 V DC uncertainty 0 001 Results are displayed relative to the level at 1kHz 0 5 50 100 200 501 1000 1995 5012 10000 19953 50000 100000 Frequency Hz Freq Hz Measured dB Uncert dB Tolerance dB Freq Hz Measured dB Uncert dB Tolerance dB 16 0 51 058 0 32 0 73 794 33 00 016 0 10 0 10 98 0 35 058 0 22 0 50 1000 00 00 016 0 10 0 10 01 0 23 036 0 12 0 36 1258 90 00 016 0 10 0 10 31 0 16 036 0 04 0 28 1584 90 00 016 0 10 0 10 94 0 11 036 0 01 0 21 1995 30 00 016 0 10 0 10 00 0 07 016 0 03 0 17 2511 90 00 016 0 10 0 10 59 0 05 016 0 05 0 15 3162 30 00 016 0 10 0 10 85 0 04 016 0 06 0 14 3981 10 01 016 0 10 0 10 95 0 03 016 0 07 0 13 5011 90 00 016 0 10 0 10 12 0 02 016 0 08 0 12 6309 60 00 016 0 10 0 10 62 0 02 016 0 08 0 12 7943 30 00 016 0 10 0 10 81 0 02 016 0 08 0 12 10000 00 00 016 0 10 0 10 12 0 01 016 0 09 0 11 12589 00 01 016 0 10 0 10 10 0 01 016 0 09 0 11 15849 00 01 016 0 10 0 10
49. Data on page 12 10 Liwa and time weighted averages associated with Dose 1 and Dose 2 exchange rates and thresholds See Dosimeter 1 and 2 on page 5 11 LCSeq LASeq LXleq LXeq where X is the user selected frequency weighting for the sound level measurement This is the impulsivity metric where the LXeq value is always taken from a linear integration When the LxT OB1 firmware is enabled the following frequency spectra can be logged OBA 1 1 Leq OBA 1 1 max OBA 1 1 min When the LxT OB3 firmware 1s enabled the following frequency spectra can be logged OBA 1 1 Leq OBA 1 1 max e OBA 1 1 min OBA 1 3 Leq LxT Technical Reference Manual OBA 1 3 max OBA 1 3 min Non Acoustical Parameters Time in Milliseconds Tms will display the time in units of milliseconds LxT Battery Time Battery Level Internal Temperature Time History Setup Time History is setup using the Time History tab page of the Measurement Setup View as shown in Figure 9 1 Settings 70 Time History Enable Time Histor FIGURE 9 1 Time History Setup Menu Press ens key to enable the Time History functionality and to place a check in the Enable Time History check box This LxT Technical Reference Manual Time History Setup 9 3 Set Time History Period As you scroll downwards when the highlight reaches the bottom of the window the list will scroll upwards to reveal additional values
50. Displays Profile Enforcement Market 1 1 Octave FIGURE 12 17 Displays Page Start The user can select to have one of the following displays appear when the LxT is switched On With the Start field highlighted press the key to obtain a list of options as shown in FIGURE 12 18 Display Start Options Use the 7 and keys to highlight the Display Start option and press the key to make the selection Selecting Displays to Appear When there are measurement functions not being used or data displays which are not of interest for a measurement the instrument operation can be streamlined by hiding 12 14 Displays LxT Technical Reference Manual Tab Page Selection Display Selection LxT Technical Reference Manual selected displays As a default all available displays are set to appear Use the C key to highlight the Tabs field to list the tab pages for which displays can be set to appear or be hidden as shown in FIGURE 12 19 Live Overall Session Log Time Histor FIGURE 12 19 Display Tab Page Options Use the 7 and keys to highlight the desired Tab Page and press the key to make the selection The displays which can be set to appear or be hidden are shown below for each of the possible Tab Page selections Live Page Displays 6 System Properties Enforcement Market 1 1 Octave FIGURE 12 20 Live Page Displays Displays 12 15 Overall Page Displays 15 Profile Enforce
51. F Dimensions 12 7 mm diameter x 73 mm length 0 50 dia x 2 88 length Microphone Thread 11 7 mm 60 UNS 0 4606 60 UNS Cable Driving Capability LxT SLM 1 V rms output signal To 20 kHz with 200 61 m cable A 44 Technical Specifications LxT Technical Reference Manual Output Connector Switchcraft TASM 5 Pin male Pin Signal 1 Signal Ground 2 Signal Output 3 Power Supply 7 Volts 4 Preamp sense 5 No Connection Shell Connected to preamp housing Table A 25 Input Connector Compatibility Use with Larson Davis 377B02 or any 4 electret microphone having about 50 mV Pa sensitivity and meeting the mechanical requirements of IEC 61094 4 It can be used with either the Larson Davis ADP043 or ADPO008 adapters for 1 4 or 1 electret microphones In the interest of constant product improvement specifications are subject to change without notice LxT Technical Reference Manual Technical Specifications 45 Optional Accessories 010 Extension cable 5 pin Switchcraft male to 5 Switchcraft female 10 feet long 020 Extension cable 5 Switchcraft male to 5 Pin Switchcraft female 20 feet long 050 Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 50 feet long EXC100 Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 100 feet long EXC200 Extension cable 5 pin Switchcraft male to 5 Pin Swit
52. FIGURE 4 3 General Page The General Page is used to enter a file name and a measurement description for the measurement being defined Upon opening the Default File Name LxT Data may appear in the file name field To enter a new file name highlight the Default File Name text box and press the en key Use t D C J7 and keys to enter a new name The key is pressed to complete the entry process LxT Technical Reference Manual SLM Page Frequency Weighting Time Weighting Integration Method Note that the LxT can be set to run for a preset integration time as described in Manual Timed Stop or Stop When Stable on page 6 3 LxT Technical Reference Manual E SLM Frequency Weighting oc oz Detector amp Slow OFast Impl Peak Weighting oc 7 Integration Method Linear Exponential Close FIGURE 4 4 SLM Page Selections of Frequency Weighting Detector Peak Weighting and Integration Method are made one at a time using the and CY keys to move the highlight to the desired section prior to making the selection Use the V keys to highlight appropriate item for the selected parameters Press the key to make the selection A C and Z frequency weightings are provided for the RMS and peak detectors These are selected separately Available time weightings for the RMS detector are Slow Fast and Impulse Two Integration methods are available Linear
53. Glossary Low Pass A frequency filter that permits signals to pass through that have frequencies below a certain fixed frequency called a cutoff frequency It is used to discriminate against higher frequencies High Pass A frequency filter that permits signals to pass through that have frequencies above a certain fixed frequency called a cutoff frequency It is used to discriminate against lower frequencies Bandpass A frequency filter that permits signals to pass through that have frequencies above a certain fixed frequency called a lower cutoff frequency and below a certain fixed frequency called an upper cutoff frequency The difference between the two cutoff frequencies is called the bandwidth It is used to discriminate against both lower and higher frequencies so it passes only a band of frequencies Octave band A bandpass frequency filter that permits signals to pass through that have a bandwidth based on octaves An octave is a doubling of frequency so the upper cutoff frequency is twice the lower cutoff frequency This filter is often further subdivided in 1 3 and 1 12 octaves 3 and 12 bands per octave for finer frequency resolution Instruments with these filters have a sufficient number of them to cover the usual range of frequencies encountered in sound and vibration measurements The frequency chosen to describe the band is that of the center frequency Note table in Frequency Filter Frequency Weighting A specia
54. Measurement History is implemented from the Control Page of the Measurement Settings Screen by placing a check in the Enable Measurement History check box When the Run Mode has been set to Continuous this will produce a display as shown in FIGURE 10 1 ld Control Run Made Enable Measurement Histor Time 01 00 hh mm O Interval Time Sync Daily O Auto Store FIGURE 10 1 Measurement History Setup Measurement History 10 1 Continuous and Timer Modes The Continuous Single Block Timer and Daily Timer run modes are only available when the optional firmware LXT ENV is enabled Interval Time Sync Valid Measurement Times When other values are selected the interval time sync will still function but the time for which the first measurement is cut short will be different See Other Measurement Times below for further detail 10 2 Continuous and Timer Modes For these run modes when the Measurement History is enabled a series of measurements will be performed and stored automatically each running for a user defined time interval At the time the check mark is placed in the Measurement History check box to enable it a window such as shown in Figure 10 2 will appear to define a time duration for each measurement x Enable Measurement History hh mm _ Interval Time Sync FIGURE 10 2 Measurement Time Menu Highlight the Time data field and press the key Enter the desired
55. Microphone and electrical self noise included 2 Electrical Measurements Table A 4 LxT Performance Specifications Technical Specifications LxT Technical Reference Manual Physical Characteristics Length with microphone 11 35 inches 29 cm and preamplifier Length instrument body 8 80 inches 22 4 Width 2 80 inches 7 10 cm Depth 1 60 inches 4 10 cm Weight with batteries 1 0 Ib 471g no preamplifer or microphone Weight with batteries 1 1 Ib 513g preamplifer and microphone Table A 5 Physical Characteristics General Specifications Reference level 114 0 dB SPL Reference level range Single large Range for SLM Normal for OBA option Reference frequency 1000 Hz Reference direction 0 is perpendicular to the microphone diaphragm Temperature X 0 5 dB error between 10 C and 50 Storage temperature 20 C to 70 C Humidity lt 0 5 dB error from 30 and 90 relative humidity at 40 C Equivalent microphone 12 pF for Larson Davis 1 2 microphone impedance Table A 6 General Specifications LxT Technical Reference Manual Technical Specifications A 5 Range level error OBA option lt 0 1 dB relative to the reference range Digital Display Update Rate Four times per second 0 25 sec between updates First display indication is available 0 25 seconds after initiation of a measurement Effect of an exte
56. and keys to move the cursor left and right respectively LxT Technical Reference Manual 1 3 Octave Band Analyzer Optional The 1 3 Octave Band Analyzer display appears only when the Fa instrument is loaded with the LxT_Data optional LxT OB3 firmware ne Overall Session Log cA 50 TERA 1 14 1 3 Octave 1 00kHz z Slow L 1 00kHz S 46 0 dB Las 78 9 dB tarted 2007 Apr 16 13 28 33 FIGURE 5 5 Live Page Section 4 Note that the graph scaling can be Section 3 is similar to FIGURE 5 4 Live Page Section 3 modified as described in section The graph and data are presented for 1 3 octave bands Adjust Graph Scale on page 5 19 Triggering 43 4 dB 85 0 dB 115 0 dB 63 1 dB 135 0 dB 137 0 dB 140 0 dB tarted 2007 Apr 16 13 28 33 FIGURE 5 6 Live Page Section 5 For a description of the setup of Section 4 displays the sound level and peak level with their these trigger values see Triggers associated trigger points Exceedances of these trigger points Page on page 4 17 will be indicated by a check mark appearing to the right of LxT Technical Reference Manual Live Page 5 5 each The check mark will appear only as long as measured level remains above the trigger point Time Battery Voltage and Memory Note If there is USB power the estimated battery time will not be a true representation of the available battery life Check this when operating on batter
57. in sequence in the user created list of metrics to log For example in FIGURE 9 8 we have pressed the 0 twice to select Lpeak the third metric in the selection sequence at the same cursor position used to graph and display Leq in FIGURE 9 6 Graph Enter gt Change Record FIGURE 9 9 Time History Graph and Value of LApeak at Same Time as FIGURE 9 6 Frequency Spectra When the LxT is equipped with the optional firmware LXT OBA and either the 1 1 octave spectra or the 1 3 octave spectra or both have been selected for the measurement then frequency spectra will appear in the list of metrics which can be logged LxT Technical Reference Manual When frequency spectra have been included in the list of metrics to be measured in the setup as described in 1 1 and 1 3 Octave Spectra on page 9 2 there will be additional displays as follows One additional display if all frequency spectra metrics are either 1 1 or 1 3 octave spectra Press the key to show the spectrum display as shown FIGURE 9 10 Time History Display 9 9 Two additional displays if frequency spectra metrics include both 1 1 and 1 3 octave spectra Press the C key once to display metrics having the 1 1 octave format and press it a second time to display metrics having the 1 3 octave format Except for the bandwidth these displays are identical so we will use a 1 1 octave spectrum as an example Cursor Position Freque
58. when complete will look as shown in FIGURE B 6 Loading Firmware Restarting instrument OK Waiting for response OK Invalidating RAM OK Waiting for response OK Writing RAM to flash sector 1 of 1 Restarting instrument OK Waiting for response OK Reformatting file system OK Waiting for response OK Firmware upload complete FIGURE B 7 Loading Firmware Screen for Modification of Options B 8 Upgrading Options LxT Technical Reference Manual APPENDIX Testing to IEC61672 1 This appendix presents information for measuring the sound level meter functionality of the LxT according to IEC61672 1 Sections 5 6 7 and 9 except 9 3 The following table references sections and tables in this manual where information called for in specific sections of IEC61672 1 can be found In certain instances the requested information 1s not applicable as noted in the Comments column Further information called for in section 9 3 for testing as appropriate for a sound level meter can be found in Section 9 3 on page C 10 Section LxT Manual Comments 5 1 4 LxT Components on page 1 12 5 1 6 Microphone and Preamplifier on page 1 9 and Chapter 7 Making a Measurement on page 7 1 5 1 7 Connecting the Microphone and Preampli fier on page 3 2 and Connecting the Pream plifier to the LxT on page 3 3 5 1 8 Computer software is not an integral
59. 0 0 16 1 0 2 0 5 0 5 1 0 160 158 50 0 0 13 4 0 1 0 2 0 5 1 0 200 199 50 0 0 10 9 0 0 0 2 0 5 1 0 250 251 20 0 0 8 6 0 0 0 2 0 5 1 0 315 316 20 0 0 6 6 0 0 0 2 0 5 1 0 400 398 10 0 0 4 8 0 0 0 2 0 5 1 0 500 501 20 0 0 3 2 0 0 0 2 0 5 1 0 630 631 00 0 0 1 9 0 0 0 2 0 5 1 0 800 794 30 0 0 0 8 0 0 0 2 0 5 1 0 Table 8 Frequency Weightings LxT Technical Reference Manual Technical Specifications A 7 Nominal Rance Z A Electrical Microphone Microphone Frequency Frequency Weight Weight Weight Limits Limits Limits Ideal Ideal Ideal Class 1 Class 1 Class 2 1000 1000 00 0 0 0 0 0 0 0 2 0 5 1 0 1250 1259 00 0 0 0 6 0 0 0 2 0 5 1 0 1600 1585 00 0 0 1 0 0 1 0 2 0 5 1 3 2000 1995 00 0 0 1 2 0 2 0 2 0 5 1 3 2500 2512 00 0 0 1 3 0 3 0 2 0 5 1 7 3150 3162 00 0 0 1 2 0 5 0 2 0 5 1 7 4000 3981 00 0 0 1 0 0 8 0 2 0 5 2 0 5000 5012 00 0 0 0 5 1 3 0 2 0 75 2 3 6300 6310 00 0 0 0 1 2 0 0 2 1 0 3 0 8000 7943 00 0 0 1 1 3 0 0 2 1 25 3 3 10000 10000 00 0 0 2 5 44 0 2 1 50 3 3 12500 12590 00 0 0 4 3 6 2 0 2 1 75 3 3 16000 15850 00 0 0 6 6 8 5 0 3 2 0 3 3 20000 19950 00 0 0 9 3 11 2 0 5 2 0 3 3 Table 8 Frequency Weightings A 8 Technical Specifications LxT Technical Reference Manual AC DC Output The purpose of the AC output is to drive a headset
60. 0 0 0 0 0 0 316 23 0 1 0 1 0 0 0 1 0 1 398 11 0 1 0 1 0 1 0 0 0 0 501 19 0 0 0 0 0 1 0 1 0 1 630 96 0 0 0 0 0 1 0 1 0 1 794 33 0 1 0 1 0 0 0 1 0 1 1000 00 0 2 0 2 0 1 0 1 0 1 1059 25 0 2 0 2 0 1 0 1 0 1 1122 02 0 3 0 3 0 2 0 1 0 1 1188 50 0 4 0 4 0 2 0 2 0 2 1258 93 0 4 0 4 0 3 0 1 0 1 1333 52 0 4 0 4 0 3 0 1 0 1 1412 54 0 3 0 3 0 2 0 1 0 1 1496 24 0 4 0 4 0 3 0 1 0 1 1584 89 0 2 0 2 0 2 0 0 0 0 1678 80 0 3 0 3 0 3 0 0 0 0 1778 28 0 1 0 1 0 3 0 2 0 2 1883 65 0 1 0 1 0 3 0 2 0 2 1995 26 0 1 0 1 0 4 0 5 0 5 2113 49 0 2 0 2 0 4 0 6 0 6 2238 72 0 2 0 2 0 4 0 6 0 6 2371 37 0 0 0 0 0 5 0 5 0 5 2511 89 0 0 0 0 0 4 0 4 0 4 2660 73 0 0 0 0 0 5 0 5 0 5 2818 38 2985 38 3162 28 3349 65 3548 13 Continued on next page LxT Technical Reference Manual LxT2 C 15 Larson Davis LxT2 with PRMLxT2 and typical 375A02 Microphone average frequency responses and corrections Required by IEC 61672 1 Sections 5 2 4 5 2 5 5 2 6 and 9 2 4 d 0 Free Field expanded Wind Screen Corrections with uncertainty 0 Free Field 0 Free Field Effect of onLxT2 Wind Screen of Corrections Response Corrections Wind Screen 0 Free Field on LxT2 3758 37 3981 07 4216 97 4466 84 4731 51 5011 87 5308 84 5623 41 5956 62 6309 57 6683 44 7079 46 7498 94 7943 28 8413 95 8912 51 9440 61 10000 00 10592 54 11220 18 11885 02 12589 25 13335 21 14125 38 14962 36 15848 93 16788 04 17782 79 18836 49 19952 62
61. 0 2 0 2 0 6 4250 4216 97 0 3 0 3 0 0 0 3 0 3 0 6 4500 4466 84 0 0 0 0 0 0 0 0 0 0 0 6 4750 4731 51 0 4 0 4 0 2 0 5 0 5 0 6 5000 5011 87 0 5 0 5 0 1 0 6 0 6 0 6 5300 5308 84 0 3 0 3 0 0 0 4 0 4 0 6 5600 5623 41 0 5 0 5 0 1 0 4 0 4 0 6 6000 5956 62 0 5 0 5 0 2 0 4 0 4 0 6 6300 6309 57 0 0 0 0 0 2 0 3 0 3 0 6 Continued on next page LxT Technical Reference Manual C 9 Larson Davis LxT1 with PRMLxT1 and typical 377A02 Microphone average frequency responses and corrections Required by IEC 61672 1 Sections 5 2 4 5 2 5 5 2 6 and 9 2 4 d 0 Free Field expanded Wind Screen Corrections with uncertainty 0 Free Field 0 Free Field Effect of on LxT1 Wind Screen of Corrections Nominal Exact Frequency Frequency Response Corrections Wind Screen 0 Free Field on LxT1 Hz Hz dB 6300 6309 57 0 0 6700 6683 44 0 2 7100 7079 46 0 2 7500 7498 94 0 4 8000 7943 28 0 4 8500 8413 95 0 1 9000 8912 51 0 1 9500 9440 61 10000 10000 00 10600 10592 54 11200 11220 18 11800 11885 02 12500 12589 25 13200 13335 21 14000 14125 38 15000 14962 36 16000 15848 93 17000 16788 04 18000 17782 79 19000 18836 49 s E 20000 19952 62 2 1 6 1 2 0 4 add numbers in this column to levels read on the LxT1 to correct the level at a specific frequency Section 9 3 a Reference Sound Pressure Level The reference sound pressure level is 114 dB re 20 pu Pa b Reference Level Range The reference level rang
62. 1 Time History Setup Menu eere 9 3 Time History Setup Menu 9 4 Time History Period 9 4 Time History Options Window 9 5 Time History Display First Point Keypress 9 6 Measured Data at Cursor Position First Parameter 9 7 Left Right Arrow Change 9 7 Left Right Arrow Change 9 8 Time History Graph and Value of LApeak at Same Time as FIGURE 9 Gece ie c AM 9 9 Time History Display Spectra Metrics Section 2 and 3 9 10 Left Right Arrow Change 9 11 Left Right Arrow Change Frequency 9 11 Link to Measurement History Display 9 11 Markers Setup Window Markers 1 5 9 12 Markers Setup Window Markers 6 10 9 13 Marker Name Field eee 9 13 Menu ODLOFIS eode act pot Ced an t tup 9 13 Time History Display with 9 14 Marker Indication on 9 15 Measurement History 10 1 Measurement History
63. 12 Overall Page paragraph the ProjTWA for that ten minute measurement represents the value of TWA which would be measured if the noise measured during the ten minute period had continued for eight hours Lep d The Daily Personal Noise Exposure Lep q is calculated from data measured during the run time of the measurement DOSE Dose is based on data measured during the run time calculated for the user defined Criterion Time and Criterion Level 100 definition As as example suppose a measurement was performed over a time period of ten minutes The value of Dose would be the same as the Dose measured over an eight hour period if there had been no other sound exposure other than that which occurred during that ten minute period ProjDOSE Projected Dose is based on data measured during the run time and calculated for the user defined Criterion Time and Criterion Level 100 definition Continuing with the example in the above paragraph the Projected Dose for that ten minute measurement represents the value of Dose which would be measured if the noise measured during the ten minute period had continued for eight hours The remainder of the display shows the parameters used for the measurement Frequency Weighting Exchange Rate Threshold and Criterion time and level LxT Technical Reference Manual Sound Exposure SEA The SEA parameter is used mainly in the Canadian province of Quebec LxT Technical Reference Ma
64. 2 5 5 2 6 and 9 2 4 d 0 Free Field expanded Wind Screen Corrections with uncertainty 0 Free Field 0 Free Field Effect of on LxT1 Wind Screen of Corrections Nominal Exact Frequency Frequency Response Corrections Wind Screen 0 Free Field on LxT1 95 Hz Hz dB dB dB dB dB dB 250 251 19 0 0 0 0 0 0 0 0 0 0 0 4 315 316 23 0 0 0 0 0 0 0 0 0 0 0 4 400 398 11 0 0 0 0 0 0 0 0 0 0 0 4 500 501 19 0 1 0 1 0 1 0 0 0 0 0 4 630 630 96 0 0 0 0 0 0 0 0 0 0 0 4 800 794 33 0 1 0 1 0 1 0 0 0 0 0 4 1000 1000 00 0 2 0 2 0 1 0 1 0 1 0 4 1060 1059 25 0 2 0 2 0 1 0 1 0 1 0 4 1120 1122 02 0 4 0 4 0 2 0 2 0 2 0 4 1180 1188 50 0 4 0 4 0 2 0 2 0 2 0 4 1250 1258 93 0 4 0 4 0 2 0 2 0 2 0 4 1320 1333 52 0 3 0 3 0 2 0 1 0 1 0 4 1400 1412 54 0 4 0 4 0 3 0 1 0 1 0 5 1500 1496 24 0 4 0 4 0 3 0 1 0 1 0 5 1600 1584 89 0 2 0 2 0 3 0 1 0 1 0 6 1700 1678 80 0 2 0 2 0 4 0 1 0 1 0 6 1800 1778 28 0 2 0 2 0 4 0 2 0 2 0 6 1900 1883 65 0 1 0 1 0 4 0 3 0 3 0 6 2000 1995 26 0 1 0 1 0 4 0 5 0 5 0 6 2120 2113 49 0 1 0 1 0 5 0 6 0 6 0 6 2240 2238 72 0 1 0 1 0 5 0 6 0 6 0 6 2360 2371 37 0 1 0 1 0 6 0 5 0 5 0 6 2500 2511 89 0 2 0 2 0 6 0 4 0 4 0 6 2650 2660 73 0 1 0 1 0 5 0 4 0 4 0 6 2800 2818 38 0 2 0 2 0 6 0 4 0 4 0 6 3000 2985 38 0 4 0 4 0 5 0 1 0 1 0 6 3150 3162 28 0 5 0 5 0 4 0 1 0 1 0 6 3350 3349 65 0 4 0 4 0 3 0 0 0 0 0 6 3550 3548 13 0 6 0 6 0 3 0 3 0 3 0 6 3750 3758 37 0 3 0 3 0 2 0 1 0 1 0 6 4000 3981 07 0 3 0 3 0 1
65. 2 dB 12 6 Hz to 40 kHz 0 1 0 1 dB Lower 3 dB limit lt 1 Hz Attenuation 22 8 dB typical Input Impedance 10 G Ohm 5 3 pF Output Impedance 50 Ohm Maximum Output 2 8 Vpp 143 dB peak for microphones with 50 mV Pa sensitivity Maximum Output Current 10 mA peak Distortion Harmonics lt 60 dBC with 0 7 Volt rms output at 1 kHz Output Slew Rate 2 V uS typical A 38 Technical Specifications LxT Technical Reference Manual Electronic Noise with 18pF equivalent microphone 1 1 pV typical A weighted 1 4 uV max 1 6 uV typical Flat 20 Hz to 20 kHz 2 1 nV max Power Supply Voltage 6 to 10 Volts DC Output Level 1 2 power supply voltage Power Supply Current 1 3 mA typical Temperature Sensitivity 0 05 dB from 10 to 50 C 14 to 122 F operating range to 60 C 140 F Humidity Sensitivity lt 0 05 dB from 0 to 90 RH non condensing at 40 C 104 F Dimensions 12 7 mm diameter x 73 mm length 0 50 dia x 2 88 length Microphone Thread 11 7 mm 60 UNS 0 4606 60 UNS Cable Driving Capability LxT SLM 1 V rms output signal To 20 kHz with 200 61 m cable LxT Technical Reference Manual Technical Specifications A 39 Output Connector Switchcraft TASM 5 Pin male Pin Signal 1 Signal Ground 2 Signal Output 3 Power Supply 7 Volts 4 Preamp sense 5 No Connection Shell Connect to preamp housing Table A 23 Output Connector Compatibility
66. 87 18 0 10 00 inf 1188 50 0 00 0 10 0 30 0 60 81 81 10 00 inf 1295 69 0 01 10 0 30 1 30 67 18 10 50 inf 1412 54 3 15 10 2 00 5 00 3411 10 00 5 00 1995 26 91 94 10 17 50 inf 0 21 10 30 1 30 3981 07 291 92 10 42 00 inf 0 00 10 30 0 60 7943 28 90 84 10 61 00 inf 0 00 10 30 0 40 15848 93 91 27 12 00 inf 0 00 10 30 0 30 Table A 16 Passband of 1kHz 1 1 Octave Filter Technical Specifications LxT Technical Reference Manual lt Sound Level Meter Model LxT Serial Number 0000033 Certificate of 1000 0 Hz Third Octave Filter Shape Larson Davis This Class 1 Sound Level Meter including attached PRMLXT1 preamplifier and ADPOO05 18pF input adapter was calibrated with a reference 1kHz sine wave The instrument s 1000 0 Hz filter response was then electrically tested using a 137 00 dBSPL sinewave at selected frequencies as specified in IEC 61260 am1 2001 09 10 00 0 00 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90 00 100 00 1000 Frequency Hz Freq Measured Uncert Limits Measured Uncert Limits Hz 185 46 90 61 0 10 00 inf 0 00 0 10 0 30 0 40 327 48 82 27 10 00 inf 0 00 10 0 30 0 60 531 43 68 01 10 00 inf 0 14 10 0 30 1 30 772 57 75 25 10 50 inf A 2 56 10 2 00 5 00 891 25 2 50 10 00 5 00 93 15 10 17 50 inf 919 58 0 29 10 30 1 30 E 97 6
67. Adjust Graph Scale on page 5 19 for the duration of the measurement The right most bar on the graph is the sum of the Leq values for the total spectrum The bar for the displayed is highlighted The highlight can be moved using the and 2 keys Leq Leq is the energy average sound level of the frequency band for the duration of the measurement Lmin Lmin 18 the minimum sound level of the frequency band for the duration of the measurement Lmax The value of Lmax for each frequency band is the maximum value which occurred in that band during the entire measurement period Since individual frequency bands may LxT Technical Reference Manual Overall Page 5 9 reach their maximum levels at different times this spectrum might be one which never occurred at any instant during the measurement period 1 3 Octave Band Analyzer Optional The 1 3 Octave Band Analyzer display appears only when the instrument is loaded with the optional LxT OB3 firmware and this measurement mode has been selected in the setup 3 60 ili 1 3 Octave 1 00kHz L2Seq 55 5 dB 125 64 6 L2Smin 26 8 dB Run Time 0 00 04 9 FIGURE 5 12 Overall Page Section 5 Note that the graph scaling can be data displayed in Section 4 is similar to that displayed modified as described in section for a 1 1 octave spectrum measurement described in 1 1 Adjust Graph Scale on page 5 19 Octave Band Analyzer Optional on
68. As the battery nears end of life the empty battery symbol will begin to flash The unit will shut down in a short time because the battery voltage is too low When the battery is at the end of life the LxT will stop running save all data and instrument status then turn off When the unit is turned on again with fresh batteries or an external power supply the unit will return to the state it was in when it shut down FIGURE 17 5 External Power Icon If external power is supplied through the USB connector the battery icon is replaced with the External Power icon When external power is connected to the LxT the unit is not dependant on batteries The Estimated Run Time calculation is valid only if there is no external power External Power Supply The LxT cannot be operated under external power USB or from an external power supply if the internal batteries are discharged flat for reasons described in this section If there are no batteries installed the LxT external power via USB or an external power supply will be utilized without host permission Thus you can remove depleted batteries and run on USB power only or power from an external power supply However LxT Technical Reference Manual The LxT can be powered from batteries or if available from the USB host portion of your computer It can also be powered externally using the PSA029 power supply as described in the section External Power Supply on pa
69. Ee ove 1 9 Add Obptloris t oceans sheesh tt Ut eT B 1 ein p d t ead e ih 12 5 Auto StoFre cU er n RENE PRA RAR 12 8 B Backlight Display DO e aO e UR ote di a dit 2 11 2 7 NEL 12 6 Basic Data Display eie ER RE REIR TRUE 5 1 eoe ce doe TOR UR OR UO E Met ve REN re qe eque Rea 17 6 Alignment ena mere tiet ete eet o RP Ces 3 5 POOR sete assiette obe tenenti 3 5 Inserting Re RT RR e e Sek Heec EAR ee tss 3 5 Intrinsic Safes c ente cette n 3 5 Battery osos eee NI e RR TU E E s 5 6 Battery Door 3 5 ite ott ted etel nete 3 5 Battery Power LxT Technical Reference Manual Index Battery Type sesta eesonm edit ate odi e s 12 7 Battery Voltage co RR RC REIR RES 5 6 Bookmarks aduer ERE DO E Ep DEREN R 1 3 oe e e T 1 4 Display a at te 1 5 Expanding soe se cae tee de e UR UR e RR HEAR E e eredi 1 4 Opening E 1 3 Ret rn to Previous View oie ie irii eer ete eae e Beers 1 5 C LX UII 5 17 Cables ACDC cies cates E a ters AR 1 11 Direct Input io ote e rk 1 11 Microphone Extension eSI S han NE eet E YE 1 11 USB cetero te tes t 1 11
70. From the Control Panel Keypad 2 9 LEFT and RIGHT Keys UP and DOWN Keys ENTER Key RUN PAUSE Key 2 10 Keypad Function Chapter Number About 14 System Utilities 16 Table 2 1 Chapters Describing Functions From the Control Panel The Left and Right Softkeys and the 7 keys allow selection of the desired function To activate the desired function press the key Pressing the Center Softkey labeled Close will return to the Data View The keys are used for moving horizontally screen This includes moving the highlight from one property to the next The C 7 and keys are used for moving vertically on a screen This includes moving the highlight from one property to the next and to move to a previous or next data page section These keys are also used for character entry by scrolling through a list of characters in a text box The key is typically used for completing an action or accepting a value The CX RUN PAUSE key will initiate a run If a measurement is running this key will pause the run It will not end the run the 82 STOP STORE key is used for that Pressing the RUN PAUSE key when the unit is PAUSED will continue the run This key is only active on Data View screen LxT Technical Reference Manual STOP STORE Key Note Pressing the RUN PAUSE key when the unit is in STOP mode will continue previous ru
71. HSLOG also enabled the time interval for automatic logging is extended down to 100 milliseconds RMS Levels The following RMS sound pressure level values measured using the frequency weighting and averaging selected during the measurement setup as described in SLM Page on page 4 5 can be logged Leq Lmax Lmin Peak Level Values of Lpeak measured using the frequency weighting selected during the measurement setup as described in SLM Page on page 4 5 can be logged Time History 9 1 Instantaneous Values Specialized Acoustic Parameters The LAFTMS parameter will only be displayed when it has been enabled in the System Properties menu as described in Takt Maximal Data on page 12 10 and when the the time history period is greater than five seconds 1 1 and 1 3 Octave Spectra The optional firmware LxT OB1 or LxT OB3 15 required for these parameters to be measured 9 2 Parameters Logged When the LxT HSLOG firmware is enabled three instantaneous values are available These are continuously varying sound levels based on Slow S Fast F and Impulse I detectors and the user selected frequency weighting measured at the each time interval Lys Lxp Lx where X is the user selected frequency weighting for the sound level measurement LAFTMS Taktmaximal 5 utilized in Germany using A weighting and Fast detector This also requires selection from the Preferences page Takt Maximal
72. History Data 10 5 Current Page ss ste 10 5 Measurement 10 6 Record Profile 10 9 Changing Displayed Record 10 9 Storing a Time History Measurement 10 10 Link to Time History eese 10 10 Chapter 11 Data Explorer 11 1 Control Panel Data Explorer 11 1 Data Explore e 11 2 Scrolling Modes aii ar a A 11 2 11 3 11 4 Delete 11 4 Delete All i dA RIS IMs 11 5 CE 11 5 Refresh t ER hae lie 11 6 Load Settings cece dida eade 11 7 Jump to 11 7 Jump to End dad haere 11 7 Chapter 12 System Properties 12 1 Control Panel System Properties 12 1 lup 12 2 DEN LC E 12 3 Setting Day and 2 12 3 Selecting the 12 3 Sync Data Time with 12 4 POWOE ence eMe IE 12 5 Aut Off TIME tna droht bra cdd 12 5 Power Save
73. Levening 5 Lnight 10 12 10 4 10 9 8 10 0 In the default form the day has twelve hours the evening has four hours and the night has eight hours as can be seen in the equation The default times for these periods are as follows Day 07 00 to 19 00 Evening 19 00 to 23 00 Night 23 00 to 07 00 Lday Levening and Lnight are A weighted long term average sound levels measured during the day evening and night respectively To account for the increased impact of environmental noise during the evening and night penalties are added to the measured level 5 dB for evening and 10 dB for night as can be seen in the equation The Directive 2002 49 EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment of environmental noise permits member states to shorten the evening period by one or two hours and lengthen the day and or the night accordingly and also to choose the time for the start of the day To accommodate these and other possible modifications the Day Night page permits the user to modify the times for the beginning of the Day Evening and Night periods and the penalties to be utilized when calculating 24 hour integrated values In the state of California a commonly used community noise descriptor is Community Noise Equivalent Level CNEL defined by the following formula This is essentially the same as the using default values with the exception that the e
74. Lifetime Battery Operating Life Hours Alkaline cells 16 NiMH rechargeable cells 2500 mAH 16 external charger required Energizer L91 e Lithium cells 30 Table A 13 Battery Operating Lifetime Battery Life Test Conditions Continuous run until instrument shuts off due to low battery Measuring 1 3 octave data Power Save feature set to Never Memory Retention Data Memory Permanently stored in non volatile flash memory every one minute If power failure maximum data loss will be less than one minute Real time Clock gt 10 minutes Table A 14 Memory Retention Without Batteries or External Power 12 Technical Specifications LxT Technical Reference Manual PSA029 AC to DC USB Power Adapter Specifications DC Output Regulation Line 5 Load 5 DC Output Load Minimum 0 A Maximum 0 5 A DC Output Connector USB Type A Jack USB Cable type A to mini B supplied AC Input Voltage 90 to 264 Vac AC Input Frequency 47 to 63 Hz AC Input Current 0 15 Arms 120 Vac at maximum load 0 08 Arms 230 Vac at maximum load Ac Inrush Current 30 A for 120 Vac at maximum load 60 A for 240 Vac at maximum load Efficiency 55 typical 0 3 W maximum no load 230 Vac 50 Hz Temperature Operation 0 to 45 C Storage 40 C to 85 Humidity Operation 10 to 90 Storage 5 to 85 Emissions FCC Part 15 Class B EN55022 Class N 61000 4 2 Level 4 N61000 4 3 Level 2 N61000 4 4 Level 2 N6100
75. LxT Manual Comments 7 4 Octave Band Analyzer Page Optional on page 4 6 9 2 1 General a Standards Met by LxT on page A 1 b Configuration of the System on page 7 1 Microphone Extension Cable on page 7 4 and Use of a Windscreen on page 7 5 Standard Accessories on page 1 9 d No microphone extension or microphone extension cable is required to meet specified standards e The LxT is a single channel instrument 9 2 2 Design Features a Parameters Measured on page 18 1 b Frequency Response on page A 20 Frequency Weightings on page 7 d Sound Level Meter Specifications on page A 3 e LxT Performance Specifications on page A 4 f The LxT measures sound level using a single range g Features on page A 2 and General Speci fications on page A 5 h Performance Specifications on page A 4 i Performance Specifications on page A 4 j Computer software is not an integral part of the LxT LxT Technical Reference Manual Sections 5 6 7 and 9 except 9 3 C 5 Section LxT Manual Comments k Additional metrics measured not spectified by the IEC61672 standard perform to their respective standards published elsewhere for example Takt Maximal and SEA 9 2 3 Power Supply a Battery Operating Lifetime on page A 12 b Power Indicator on page 2 2 and j Battery Power Voltage Range on
76. LxT is fully started the Data Display Screen will refer to Live Overall and Session appear as shown in FIGURE 7 2 Data Display Screen Live Log Pages Page Overload Icons Power Indicator 0 00 09 5 tea 2 4 LxT_Data Measurement Status Live Page Section indicator Scroll Bar Stability Indicator FIGURE 7 2 Data Display Screen Live Page 7 2 Switching On the LxT LxT Technical Reference Manual Views Softkeys LxT Technical Reference Manual The STOP STORE key will produce a steady red light to indicate that the LxT is in the stopped state with no data yet measured In this screen there are three tabs labeled Live Overall and Session Log each of which is associated with a page Because the Live Tab is selected the Live Page is seen in FIGURE 7 2 The Left and Right Softkeys defined below are used to select these tab pages There are three buttons beneath the display aligned with the left arrow Menu and right arrow keys as shown in FIGURE 7 3 Softkeys 4 gt FIGURE 7 3 Softkeys These buttons are called softkeys because pressing any one will invoke the action associated with the text or symbol directly above it on the screen In this instance pressing the Left or Right Softkey will display the tab page to the left or right respectively of the tab page presently displayed The Center Softkey will open a menu associated with this screen Thes
77. Ration of Value to Reference p Ratio 1 10 0 10 10 20 100 10 40 200 107 46 1 000 10 60 10 000 10 80 100 000 10 100 1000 000 10 120 Department of Defense Level Lpop Dose Detector LxT Technical Reference Manual The Average Sound Level calculated in accordance with Department of Defense Exchange Rate and Threshold Level See Average Sound Level See Noise Dose The part of a sound level meter that converts the actual fluctuating sound or vibration signal from the microphone to one that indicates its amplitude It first squares the signal then averages it in accordance with the time weighting Glossary D 7 Eight Hour Time Weighted Average Sound Level L Energy Equivalent Sound Level eq Exchange Rate Q Exchange Rate Factor q Exposure Factor k Far Field characteristic and then takes the square root This results in an amplitude described as rms root mean square It is the constant sound level that would expose a person to the same Noise Dose as the actual unsteady sound levels The equation for it is D Let aLogy 7 gt NOTE This definition applies only for a Criterion Duration of 8 hours Standard ANSI 12 19 The level of a constant sound over a specific time period that has the same sound energy as the actual unsteady sound over the same period 159 pp oat 2 L m 1020210 Pot where is the sound pressure an
78. Reference Manual Time of Day Drift The LxT displays the time of day and also time stamps various single events i e maximum level Two different time reference sources are used in the LxT depending on whether the unit is power on or off as described in Table A 11 Instrument Power Ambient Temperature Nominal Drift in 24 hours State 25 C tolerance 2 6 s 30 ppm 10 C to 50 C stability 55 50 ppm Unit Off 25 C tolerance 2 20 ppm 10 C to 50 C stability 0 5 s 50 ppm See FIGURE 1 Table A 11 Time of Day Drift Parabolic Temperature Curve 20 10 0 10 20 3040 50 60 70 EM d N 10 30 40 50 60 amp VT PPM To determine frequency stability use parabolic curvature K For example What is stability at 4st 1 Change in T 45 25 20 2 Change in frequency 0 04 PPM A 0 04 PPM 20 16 0 PPM FIGURE A 1 Temperature Stability vs Temperature LxT Technical Reference Manual Technical Specifications Power Supply Batteries 4 AA LR6 Alkaline NiMH or Energizer L91 e Lithium cells supplied with Alkaline cells External Power Powered through USB interface from computer or from PSA029 AC to DC Power Adapter 5 Volt 5 required Applying a voltage greater than specified can damage the instrument and void the warranty Table A 12 Power Supply Specifications Battery Operating
79. Use with Larson Davis 377B02 or any electret microphone having about 50 mV Pa sensitivity and meeting the mechanical requirements of IEC 61094 4 It can be used with either the Larson Davis ADP043 ADP008 adapters for 1 4 or 1 electret microphones A 40 Technical Specifications LxT Technical Reference Manual Optional Accessories 010 EXC020 EXC050 EXC100 EXC200 Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 10 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 20 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 50 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 100 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 200 feet long ADP076 12 pF equivalent 2 Microphone with BNC Connector input ADP008 Adapter for 1 microphones ADP040 Microphone Signal Tee ADP043 Adapter for 1 4 microphones ADP068 Preamplifier holder for 2 preamplifiers on microphone stand Table A 24 Optional Accessories In the interest of constant product improvement specifications are subject to change without notice Larson Davis provides a complete line of acoustic measurement tools including dosimeters sound level meters real time analyzers preamps calibrators and microphones LxT Technical Reference Manual Technical Specifica
80. add additional parameter fields to the display as it does with Continuous Single Block Timer and Daily Timer modes With the Measurement History enabled sequentially pressing the amp Stop and 274 Run Pause keys will store the measurement and initiate another measurement eliminating the need to perform a separate data store operation LxT Technical Reference Manual Display of Measurement History Data Current Page Leq using Frequency Weighting and Detector from Setup User selected There are two pages in the Data Display View which are used to display the data measured with the Measurement History the Current Page and the Measurement Page These pages are located to the right of the Session Log Page When a measurement is in progress the data will appear on the Current Page the first section of which is shown in FIGURE 10 4 e 0 01 44 2 G LxT_Data 20 Laseq 53 6 dBEJ Sound Las 52 7 dB Level Parameter btarted 2007 Apr 16 15 39 08 FIGURE 10 4 Time History Display Current Page Section 1 LxT Technical Reference Manual When that measurement 1s complete its data will then be available for display on the Measurement Page The Current Page is then reset and begins displaying data for the next measurement in progress As a result at any time the Current Page displays the measurement in progress The Current page can display as many as thirteen different data displays depending on the firmw
81. and f Linear Measurements Starting Level on page C 18 5 5 11 k Display Device on page C 13 and k Display Device on page C 19 LxT Technical Reference Manual Sections 5 6 7 and 9 except 9 3 Section LxT Manual Comments 5 6 1 h Inherent Noise on page C 12 and h Inherent Noise on page C 18 5 6 2 h Inherent Noise on page C 12 and h Inherent Noise on page C 18 5 6 3 h Inherent Noise on page C 12 and h Inherent Noise on page C 18 5 6 4 LxT Performance Specifications on page A 4 5 6 5 Low Level Sound Fields on page 7 16 5 7 1 Features on page A 2 5 10 1 Overload Indication on page 7 8 5 11 1 See comment for section 5 11 2 5 11 2 LxT measures sound level using a single range The lower limit for level linearity error is caused by the inherent noise from the microphone and electronic ele ments within the sound level meter 5 12 1 LxT Performance Specifications on page A 4 5 14 Threshold and Criterion on page 4 12 5 15 2 Chapter 5 Basic Data Display on page 5 1 5 15 3 Chapter 5 Basic Data Display on page 5 1 5 15 4 Chapter 5 Basic Data Display on page 5 1 5 15 5 General Specifications on page A 5 5 15 6 Integration Method on page 4 5 5 15 7 Software on page 1 9 5 15 8 The LxT uses no alternative dis play devices 5 16 1 AC DC Output on page A 9 and Jack Function on page 12 9 LxT Technica
82. are user selectable Exchange Rate 3 4 5 or 6 dB Threshold Enable Yes or No Threshold Level Numeric entry Criterion Level and Hours Numeric entries In Table 18 2 Sound Exposure Metrics Measured the symbol X is used to represent the user selected RMS and Impulse frequency weighting A C or Z and the symbol Y is used to represent the user selected peak frequency weighting A C or Z LxT Technical Reference Manual Sound Exposure Metrics Measured 18 3 The symbol is used to represent the user selected time weighting S or I Metric Symbol Sound Exposure Level SEL LxvE Average Sound Level Lavg Lxavg Time Weighted Average Level TWA x 8 Noise Dose DOSE Projected Noise Dose ProjDose Daily Personal Noise Exposure Lep d LXep 8 Sound Exposure E Exy Projected 8 Hour Sound Exposure Projected 40 Hour Sound Exposure Exvao SEA SEA Table 18 2 Sound Exposure Metrics Measured Statistical Metrics Measured See Ln Page on page 4 12 Six Ln statistical parameters are measured using the frequency weighting A C or Z and exponential averaging Slow or Fast selected when setting up the LxT for a sound level measurement These six values are user selected over the range Lo to Log 99 Community Noise Parameters Exceedance Counters See Triggers Page on page 4 17 When the optional firmware LXT ENV is e
83. bands may have occurred at different times the ensemble of frequency band maximum levels may represent a spectrum which never existed at any single instant during the measurement The time averaging used for the 1 1 and 1 3 octave frequency analysis depends upon the integration method selected for the sound level meter function described in Integration Method on page 4 5 Exponential SLM Integration When using exponential integration for the sound level meter all 1 1 and 1 3 octave spectrum values are based on the same exponential time weighting Slow or Fast selected for the sound level measurement Linear Integration When using linear integration for the sound level meter the Leq value is determined digitally there is no exponential averaging However the Lmax and Lmin values are determined using the same exponential weighting Slow or Fast selected for the sound level measurement LxT Technical Reference Manual Dosimeter 1 and 2 Pages Predefined Setups 0 00 00 0 Dosimetert Name OSHA 1 I Exchange Rate Threshold X Enabled 090 0 dB Criterion 090 0 dB h O Auto Calculate 4 Close FIGURE 4 7 Dosimeter 1 The Dosimeter 1 and Dosimeter 2 Pages are provided to permit the evaluation of two independent noise dose data sets Other than being on separate pages they are identical In most cases measurements of this type are setup to conform to a specific standard The LxT permit
84. can change depending upon how it is programmed as indicated by the label Components 17 3 Hardkeys The ten push button hardkeys have fixed functionalities as defined below The Power button is used to turn the Lx T ON and OFF when the Hardware Power Switch on the base of the unit is in the position The Navigation buttons Up Down Left and Right are multipurpose keys used to highlight icons and defined areas on the display make a selection from multiple options scroll through sections of multi section Data Views and to input alphanumeric characters into data fields 17 4 The Enter button is used to implement data entry associated with selections from multiple options or the input of alphanumeric characters into data fields The Run Pause Button is used to initiate and pause a measurement and to con tinue a paused measurement The Stop Store Button is used to stop a measurement and to store a measure ment when the measurement is stopped The Reset Button is used to reset a measurement The Tools Button is used to set a number of parameters not associated with a specific measurement such as setting date and time managing power options and setting personal preferences 1 e language decimal and date formats etc Table 17 1 Keypad Hardkeys Components LxT Technical Reference Manual Connectors and Interfaces Hardware Power Switch USB Interface AUX Connec
85. constant See the explanation for q on the previous page Integrated Level Calculations LxT Technical Reference Manual LxT Technical Reference Manual n is the total number of samples taken in the measurement The sample rate is 32 samples per second T is the criterion sound duration as set by the LxT s Criterion Time Hours setting which by default is set to 8 hours L is the criterion sound level as set by the LxT s Overall Criterion or Current Criterion settings Addition of the term log 100 was used to implement the 100 multiplier of the ANSI equation that creates the percentage Subtracting the log of the Criterion Time was used to implement the division of Criterion Time of the ANSI equation Projected Dose in the analyzer is obtained with an equation similar to that of Dose except that the actual duration time of the measurement is used rather than a Criterion Time as thus 6 iu k Lc gt 5 1 PROJDOSE 10 where the log 7 is the actual time factor being the total number of samples taken Integrated Level Calculations E 7 LD 0 08 03 9 il 831_Data 4 Overall ene 49 7 67 4 dB Projected DOSE 62 6 dB pos 0 03 The currently selected Frequency Weighting A 1 76 and Detector Response Slow for SPL ign Km The currently selected Exchange Rate rest 80 0 dB 8 0 h 85 0 dB Criterion Time and Level Elapsed measureme
86. d tutorem tel 9 14 Setting On Off ied ito n 9 14 SEUD cas om E 9 12 Fas 9 13 Measurement 0 0 811122 10 3 Measurement History iste 10 1 Continuous Mode dvi eid e ire ipei iD chan e Rae 10 2 D ta Display ee Ree gei e n Bet eR RR IER Pe d 10 5 Link to Time History ie rue et ee tee d Ree E aai s 10 10 Manual Mode ize eet ee e ete rd ete ee dd 10 4 Measurement Counte ts serene E D ERE S UR MEHR ERIS 10 3 Rui Control en eed ee pede te E t ede i edis 10 1 Stop When Stable Mode sse eene 10 4 Storing Measurement eie eee ee P e E eie ER RED 10 10 Timed Stop Mode ted ve eth behead etii ailes leer e e 10 3 Timer Mode ener Wette e eere CP EE rs 10 2 Measurement ipe s 2 2 Measurement Properties rennes 2 12 2 15 4 2 ACCeSSITI itte enu obra eee ad rop veda 4 2 Control eR ROW eme eee e D ed eats 2 15 Dosimeter 2 15 Dosimeter 2 eb HI Y p ee Ee es 2 15 Generals e Sette we ie dp e iet pen en ERR ew UNS 2 15 Lieu amate PUn eat m es 2 15 1 8 Index LxT Technical Reference Manual Markets o bn emm eta mo auris udin ets 2 15
87. energy summed and converted to an average noise exposure rating LxT Technical Reference Manual Criterion Duration Criterion Sound Exposure CSE Criterion Sound Level L Daily Personal Noise Exposure LEP a Day Night Average Sound Level DNL Lan LxT Technical Reference Manual It is the time required for a constant sound level equal to the Criterion Level to produce a Noise Dose of 100 Criterion Duration is typically 8 hours Example If the Criterion Level 90 dB and the Criterion Duration is 8 hours then a sound level of 90 dB for 8 hours will produce a 100 Noise Dose See Noise Dose Standard ANSI S12 19 The product of the Criterion Duration and the mean square sound pressure associated with the Criterion Sound Level when adjusted for the Exchange Rate It is expressed in Pascals squared seconds when the exchange rate is 3 dB where q is the Exchange Rate Factor See Exchange Rate 9 CSE 7 10 Standard ANSI 1 25 It is the sound level which if continually applied for the Criterion Duration will produce a Noise Dose of 100 The current OSHA Criterion Level is 90 dB Standard ANSI 12 19 It is the level of a constant sound over the Criterion Duration that contains the same sound energy as the actual unsteady sound over a specific period The period is generally shorter so the sound energy is spread out over the Criterion Duration period Example the Criterion Duration 8 hours and
88. from that determine the under range levels for A C and Z weighting sound level measurements The overload level is also determined Peak Overload Level belf Moise dB Dverload Level 144 1 dBpl nder Range Level Under Range Levels B7 1dBA 35 1dBC 43 1 dB 7 gt Noise Floor P4 3dBA 24 9dBC 32 3464 Close FIGURE 15 9 Sensitivity Page Sensitivity Page The noise floor is calculated as the energy sum of the microphone self noise preamplifier self noise and instrument self noise When using one of the following preamplifiers identified automatically when plugged into the LxT Direct PRMLxT1 e PRMLxT2 PRMLxTIL PRMLxT2L ICP 426A12 LxT Technical Reference Manual Direct Data Input Overload Level Under Range Level LxT Technical Reference Manual and one of the five most commonly used microphones for that type of preamplifier user selected a database in the LxT provides the nominal sensitivity and the self noise of the preamplifier and microphone pair When a calibration has been performed using any of the four preamplifiers listed above that calibration information is saved for that preamplifier If the preamplifier is switched from one of these types to another then the calibration information already saved for that new preamplifier type is recalled As long as the same microphone is being used with that preamplifier the calibration should be correct Self noise values can a
89. in the Run Mode data field to open the Run Mode Menu Manual Stop Timed Stop Stop When Stable Continuous Single Block Timer Daily Timer FIGURE 4 13 Run Mode Menu set the mode use the C 7 C keys to highlight the mode desired and press the key to make the selection The screen will then look as shown in Figure 4 14 Figure 4 15 or Figure 4 17 depending upon the mode selected For the Timed Stop and Stop When Stable modes further information must be entered Manual Stop Mode 0 00 00 0 eee Control Run Mode Manual Stop Y O Enable Measurement History FIGURE 4 14 Manual Run Mode The run mode is indicated as Manual Stop no further information is required Timed Stop Mode 0 00 00 0 Control Run Mode Timed Stop Time 00 00 20 hh mm ss O Enable Measurement History 4 14 Dosimeter 1 and 2 Pages LxT Technical Reference Manual Stop When Stable Mode LxT Technical Reference Manual FIGURE 4 15 Timed Stop Run Mode The run mode is indicated as Timed Stop Timed Stop has only 1 parameter time The measurement will run for the duration specified after which it will be stopped The range of time values which can be entered is 00 00 01 to 99 59 59 in the format hh mm ss Entering Run Time To enter the Run Time use the C 7 and C keys to highlight the Time data field and press the 9 key This will produce a cursor whic
90. lt chapnum gt 9 Non Specta Displays With the exception of frequency spectra displays the D and keys are used to step the selected measurement record number up or down respectively Frequency Spectra Displays When a frequency spectrum 15 displayed the 0 6 keys are used to move the cursor to the right and left respectively so that the levels can be displayed for different frequency bands To change the displayed record shift to a non spectrum display to make the change then return to the frequency spectrum display LxT Technical Reference Manual Display of Measurement History Data 10 9 Storing a Time History Measurement Although the time history data can be displayed during a measurement and after it has been stopped the data has not been stored to memory To store the data press the Stop Store key Link to Time History When Time History has also been enabled a link is provided to make a rapid transition from any of the Measurement History displays to the Time History display To implement this link press the Menu softkey which will produce the display shown in FIGURE 10 8 Settings Link Time History Adi FIGURE 10 8 Link to Time History Display Highlight Link Time History and press the key to obtain the display shown in FIGURE 10 9 92 0 01 rd 1 128 2007 Apr 18 14 33 19 Enter gt Change Metrics FIGURE 10 9 Time History Display 10 10 Storing a Time History Mea
91. mista 14 4 1 14 Index LxT Technical Reference Manual ie oV ORI qe D 22 View A enne nnne nennt tnter entente nnne rennes 11 4 View Spectrum 5 20 Views Chan Ging x2 ete i eit ties tete ie tee ten esa een Shae eae 2 5 Voice nnne eere 2 18 reo 2 18 8 2 Voice Recording 8 1 Playa 8 4 8 3 Recorder um eee RU to p ie Ute E 8 2 Voltage isch eoe ti Ah ve er RU ITO d eiecit 5 6 W Warranty eene E E C 12 1 Wavelength l GOS cia EE EE D 22 Wavenumber ee at amu n t e veg EROR AVE D MG OE RUSO EN RENE d D 23 Weighting PErequency ipe Ee Ee epe ies Ic Ute AUR ete eM oec D 10 J M D 22 LxT Technical Reference Manual Index 1 15 Index LxT Technical Reference Manual APPENDIX LIMITED PRODUCT WARRANTY PCB PIEZOTRONICS INC A Total Customer Satisfaction PCB Piezotronics Inc PCB guarantees Total Customer Satisfaction If at any time you are not completely satisfied with any PCB product PCB will repair replace or exchange it at no charge except as otherwise provided in this Limited Warranty The employ
92. observation t T 1s the averaging time interval amp is A weighted sound pressure Po is the reference sound pressure of 20 LxT Technical Reference Manual Integrated Level Calculations E 1 Note that the format used by the LxT to display equivalent continuous sound pressure level is Leg where X is the frequency weighting X C or Z Time Weighted Averages In the equation the numerator of the argument of the logarithm is the root mean square frequency weighted sound pressure level over the averaging time interval T When a frequency weighting other than A is used the frequency weighting used shall be included explicitly in the title and the formula of the quantity for example equivalent continuous C weighted sound pressure level 1 2 Ler 2016 qs If no frequency weighting is used the quantity is simply called equivalent continuous sound pressure level The Larson Davis LxT calculates many time integrated levels or time weighted averages TWA based on different parameters and time intervals They are all designed and programmed to perform the equation specified in IEC 61672 1 with allowances for the following A C and Flat frequency weighting characteristics Various interval times both fixed interval TWAs and variable interval event TWAs Exchange rates or doubling rates can be entered that effect certain TWA measurements Certain TWA measurements in
93. page B 1 Unless you saved it to a different location this file will be located in the default location C Program Files PCB Piezotronics Slm Utility G3 Left click Next to display the Confirm Choices Menu shown in FIGURE 5 LxT Technical Reference Manual Upgrading LxT Firmware B 5 Confirm Step 2 Confirm Choices If the following choices are correct press the Finish button to begin uploading the firmware into the instrument Firmware Filename C Program Files PCB Piezotronics Sim Utility G3 Firmw Options Filename none selected Instrument Serial Number 0001152 Cancel FIGURE B 5 Confirm Choices Menu If the choice is correct left click Finish to initiate the firmware upgrade Otherwise press Back to modify the choices or Cancel to abort the procedure When the firmware upgrade is in progress the status of the upgrade process will be indicated dynamically on the screen which when complete will look as shown in FIGURE B 6 Upgrading LxT Firmware LxT Technical Reference Manual oading Firmware Unpacking file OK Reading mode number OK Verifying file contents OK Restarting instrument OK Waiting for response OK Invalidating RAM OK Waiting for response OK Writing sector 2695 of 2695 Writing RAM to flash sector 2695 of 2695 Restarting instrument OK Waiting for response OK Reformatting file system OK Waiting for response OK Firmware upload complete
94. page C 13 c PSA029 AC to DC USB Power Adapter Specifications on page A 13 d PSA029 AC to DC USB Power Adapter Specifications on page A 13 9 2 4 Adjustments to Indicated Levels a Recommended Calibrator on page 15 5 b Recommended Calibrator on page 15 5 c Calibration on page 15 1 d See d Frequency Response and Corrections on page C 9 9 2 5 Operating the Sound Level Meter a General Specifications on page 5 b Positioning the LxT on page 7 4 The LxT measures sound level using a single range d Low Level Sound Fields on page 7 16 e Start up Period on page 7 2 f Integration Method on page 4 5 g Control Page on page 4 13 and Time on page 12 3 h Min Max Integration Time on page A 10 Sections 5 6 7 and 9 except 9 3 LxT Technical Reference Manual Section LxT Manual Comments i RUN PAUSE Key on page 2 10 and Maxi mum Minimum and Peak Sound Levels on page 5 8 and RESET Key on page 2 7 j Overload Indication on page 7 8 and Max imum Minimum and Peak Sound Levels on page 5 8 and Run Next Icon on page 2 4 k Measurement Range on page 7 8 1 Parameters Individually Defined on page 4 11 m Software on page 1 11 and Connectors and Interfaces on page 17 5 n Connectors and Interfaces on page 17 5 h Inherent Noise on page C 12 AC DC Output on pa
95. part of the LxT 5 1 10 Frequency Weightings on page A 7 5 1 12 The Model LxT measures sound level using a single range 5 1 13 Section 9 3 on page C 10 and Section 9 3 on page C 16 LxT Technical Reference Manual Testing to IEC61672 1 C 1 Section LxT Manual Comments 5 1 14 RESET Key on page 2 7 and Maximum Minimum and Peak Sound Levels on page 5 8 5 1 15 g Electrical Insert Signals on page C 12 and g Electrical Insert Signals on page C 18 5 1 16 i Highest Sound Pressure Level on page C 12 and i Highest Sound Pressure Level on page C 19 5 1 17 The Model LxT is a single chan nel instrument 5 1 18 Start up Period on page 7 2 52 1 Calibrator on page 15 5 5 2 3 Calibrating the LxT1 377B02 micro phone on page 15 5 and Calibrating the LxT2 and 375A02 microphone on page 15 6 5 2 4 d Frequency Response and Corrections on page C 9 and d Frequency Response and Corrections on page C 15 52 5 d Frequency Response and Corrections on page C 9 and d Frequency Response and Corrections on page C 15 52 7 d Periodic Testing on page C 10 and d Periodic Testing on page C 17 52 8 d Periodic Testing on page C 10 and d Periodic Testing on page C 17 5 4 12 No optional frequency responses 5 5 9 e Linear Operating Range on page C 11 and e Linear Operating Range on page C 18 5 5 10 f Linear Measurement Starting Level on page C 12
96. selected frequency weighting are shown in Table A 4 LxT Performance Specifications on page A 4 Measurements which include levels outside this range should not be considered accurate An overload indication will appear when levels above the range appear However the user should take care not to rely on measurements whose levels are below the lower limit of the specified range As part of the calibration procedure an overload level dB Peak and under range sound pressure levels for A C and Z weighting are determined for the instrument setup and microphone preamplifier combination being used These are displayed on the Sensitivity Page as shown in FIGURE 17 7 Microphone Page on page 17 12 When a signal from the preamplifier exceeds the calibrated input range of the LxT the Input Overload Icon will appear at the top of the display il SLH While the overload is present the icon will flash on and off When the overload is removed the icon will be removed from the display If a measurement is running and an overload occurs the icon will flash on and off for as long as the overload condition exists or one second minimum When the overload has been removed the icon will still be present not flashing to indicate that an overload has occurred during the measurement A reset will clear the icon from the display When the signal from the preamplifier drops to the point where the noise level of the instrument and the p
97. sequence By page pressing the up or down arrow key moves the highlight to the first or last respectively data file displayed on the page Pressing the left softkey labeled By page in FIGURE 11 2 toggles between the two modes Since the softkey is used to change the scrolling mode to that indicated by the softkey label the mode active is not the one whose name appears in the lable LxT Technical Reference Manual When there are many data files use the By page mode to select a data file near the one desired then switch to the By item mode to select the specific file Menu Softkey LxT Technical Reference Manual Use the 7 and C keys to scroll the list of data files As each file is selected you get an expanded view of the directory entry showing File name Description of measurement Start date and time of measurement End date and time of measurement Run time of measurement Press the key to view the data file or press the Right Softkey labeled Menu for more options Delete Delete All Internal Rename Refresh List Load Settings Jump to Beginning FIGURE 11 3 Data Explorer Menu Using the C 7 and keys select the desired menu item Press the key to execute the function selected To leave this menu without taking any action press the Close Softkey Data Explorer 11 3 View Delete 11 4 Data Explorer The View function opens a data view of the selected data file e 0
98. so please record the purchase date the model and serial numbers for your instrument preamplifier and microphone in the spaces provided on the copyright page Record of Serial Number and Purchase and Serial numbers printed on the label on the instrument s back panel The microphone s model and serial numbers are engraved on the outside of the microphone as shown in FIGURE 3 1 Microphone The preamplifier s model and serial numbers are engraved on the outside surface of the preamplifier You may be asked to provide this information during any future communications with PCB Piezotronics Inc FIGURE 3 1 Microphone Connecting the Microphone and Preamplifier Take care when handling the bottom end of the microphone attaches to the top end of preamplifier as the pogo is senstive the preamplifier The top end of the preamplifier has a single to electrostatic discharge ESD gold pin and threads on the preamplifier body The model and serial number of the microphone are engraved on the side FIGURE 3 2 Microphone Preamplifier 3 2 Connecting the Microphone and Preamplifier LxT Technical Reference Manual Carefully place the bottom end of the microphone over the top end of the preamplifier and gently screw the assembly together The microphone body will seat smoothly against the preamplifier body DO NOT use excessive force When removing the microphone turn while gripping the microphone body not the grid cap
99. than the largest dimension of the sound source In the far field the effect of source geometry is negligible Sound sources often have a variety of specific sources within them such as exhaust and intake noise When in the far field the sources have all merged into one so that measurements made even further away will be no different See the definition of Geometric Near Field for the advantages of being in the geometric far field A sound field that is free of reflections This does not mean that the sound is all coming from one direction as is often assumed since the source of sound may be spatially extensive See the definitions of near and far fields for more detail This definition is often used in conjunction with reverberant field The rate at which an oscillating signal completes a complete cycle by returning to the original value It can be expressed in cycles per second and the value has the unit symbol Hz Hertz added and the letter f is used for a universal descriptor It can also be expressed in radians per second which has no symbol and the greek letter is used for a universal descriptor The two expressions are related through the expression w 2ITf The part of certain sound level meters that divides the frequency spectrum on the sound or vibration into a part that is unchanged and a part that is filtered out It can be composed of one or more of the following types Glossary D 9 Frequency Filter Weighted D 10
100. that was exceeded percent of the time LxT Technical Reference Manual Events D 0 00 15 9 LAS gt 85 0 dB 2 0 00 08 5 LAS gt 115 0 dB 0 0 00 00 0 LZpeak gt 135 0 dB 0 0 00 00 0 LZpeak gt 137 0 dB 0 0 00 00 0 LZpeak gt 140 0 dB 0 0 00 00 0 Run Time 0 00 15 9 FIGURE 5 17 Overall Page Section 11 Section 10 shows the number of exceedances that have occurred during the measurement and the total duration of exceedances Exceedances are shown for two threshold levels of the RMS detector and three for the peak detector Overloads KD 0 00 15 9 zN LxT_Data TA Overall Dverloads FIGURE 5 18 Overall Page Section 12 Section 11 shows the overloads which have occurred during the measurement LxT Technical Reference Manual Overall Page 5 15 Number of Measurements D 0 00 15 9 2 LxT_Data TA Overall 50100709 2007 Apr 16 13 44 18 50951kB of 51061kB 1 Data Files Btarted 2007 Apr 16 13 37 02 FIGURE 5 19 Overall Page Number of Measurements by Type Section 13 Section 12 presents the quantity of each type of measurement which has been made and also the memory status Community Noise 0 00 15 9 Community Noise LDN LDay 0700 2300 LNight 2300 0700 LDEN LDay 0700 1900 dB LEve 1900 2300 dB LNight 2300 0700 dB FIGURE 5 20 Community Noise Section 14 Overall Page LxT Technical Refere
101. the automatic logging of up to xxx parameters as a function of time Triggers used to setup the triggers which define noise exceedance events Markers optional Use in conjunction with time history measurements this feature permits the user to annotate portions of a time history record to identify noise sources or make other notes Screens 2 15 Day Night optional Defines hours for day night and evening periods for 24 hour noise monitoring 4 General SLM OBA Control Time History Triggers Markers Day Night Optional Feature FIGURE 2 8 Measurement Properties Screen Changing Setup Pages As indicated in the diagram to switch between setup pages use the Left and Right Softkeys Since each page has only one section vertical scrolling is not required Tools Screen For a detailed description of the The Tools Screen uses icons to represent the different Tools Screen see Control Panel functions available as shown in FIGURE 2 9 Tools System Properties on page 12 1 Screen QD 0 00 00 0 Control Panel Data Calibrate Explorer Setup Manager Voice Recorder System About Properties FIGURE 2 9 Tools Screen Selection of an item is done by highlighting the icon representing the desired function and pressing the D key 2 16 Tools Screen LxT Technical Reference Manual Data Explorer For a detai
102. the specific period is 4 hours and the average level during the 4 hours is 86 dB then the 83 dB A rating of community noise exposure to all sources of sound that differentiates between daytime and nighttime noise exposure The equation for it 1s The continuous equivalent sound level See definition 1s generally calculated on an hourly basis and 1s shown in the equation as L Glossary D 3 Decibel dB D 4 Lan 1010510 Glossary 0700 2200 2400 1 L 10 10 L 10 L 10 10 54 gt 10 10 v 10 0000 0700 2200 The values for the hourly periods from midnight to 7 a m have 10 added to them to represent less tolerance for noise during sleeping hours The same occurs from 10 p m to midnight They are energy summed and converted to an average noise exposure rating A logarithmic form of any measured physical quantity and commonly used in the measurement of sound and vibration Whenever the word level is used this logarithmic form is implied The decibel provides us with the possibility of representing a large span of signal levels in a simple manner as opposed to using the basic unit Pascal for acoustic measurements It is not possible to directly add or subtract physical quantities when expressed in decibel form since the addition of logarithmic values correspond to multiplication of the original quantity The word evel is normally attached to a physical quantity when expressed in decibels fo
103. to different digit positions in the data field using the 4 2 keys as shown in Figure 9 16 View 1 5 46 10 Record FIGURE 9 16 Marker Name Field Enter a marker name and press the er key to conclude the process The Time History page of the Data Display View is used to display the data as shown in FIGURE 9 5 Time History Display First Point Keypress After the measurement is begun press the Menu key to bring up the display shown in Figure 9 17 Settings Mark Sound Type Adjust Graph FIGURE 9 17 Menu Options Markers 9 13 Highlight Mark Sound and press the key which will modify the Time History display as shown in Figure 9 18 Automobile dB Motorcycle Aircraft Exclude 6 FIGURE 9 18 Time History Display with Markers Setting Markers On Off At any time during a measurement any of the markers can be set On or Off Highlight the field of the desired marker Pressing the 0 key will toggle the marker status between Off and On Setting All Markers Off To set all markers to Off press the right softkey labeled None Close Marker Control Window Press the left softkey labeled Close to close the marker control window and return the display to the standard Time History display 9 14 Markers LxT Technical Reference Manual Markers Display LxT Technical Reference Manual When any type of marker has been active during a time history measur
104. to prevent damage to the microphone diaphragm Connecting the Preamplifier to the LxT Note The connectors are keyed for correct alignment Caution Do not attempt to unscrew the collar ring at the top of the LxT body The bottom end of the preamplifier has a 5 pin connector that fits snugly into the top of the LxT Insert the preamplifier into the mating connector on the LxT Rotate the preamplifier until the keyways line up Press the assemblies together until a small click is heard The microphone preamplifier assembly is now securely attached to the LxT If the LxT is ON when the preamplifier is connected to the LxT the Preamp Connected message box will appear for several seconds oY 0 00 00 0 _Data Live ema P PRMLxT2 Preamp Connected Check Calibration FIGURE 3 3 Preamplifier Connected Press the key to clear the message box LxT Technical Reference Manual Connecting the Preamplifier to the LxT 3 3 Disconnecting the Preamplifier from the LxT When transporting the LxT it is On the front surface of the LxT just below the preamplifier recommended that the preamplifier connector is a small button Press and hold this button while and microphone be detached and pulling the microphone preamplifier assembly out of the placed in a secure location the carrying case Preamplifier Release Button If the LxT is switched ON when the preamplifier is disconnected the Preamp D
105. to select an option and place a check in the check box Use the same keys to deselect a box already checked en the options have been designated as desired press the key to exit from the Time History Options Menu You will then be able to display other pages of the Measurement Setup Menu or exit from the Measurement Setup Menu by pressing the center softkey labeled Close Time History Setup 9 5 Time History Display Single Value Metrics When the LxT is not equipped with the optional firmware LXT OB3 or if it is equipped with this option but the measurement of 1 1 and 1 3 octave spectra has been set to Off in the measurement setup all measured parameters will be single value parameters In this section we discuss the time history graph which appears for single value metrics such as sound levels and non acoustic parameters Time History data is displayed on the Time History tab page of the Data Display View as shown in Figure 9 5 Time History Graph Data measurement time of keypress beginning the 2007 May 22 14 42 26 Enter Change Metrics FIGURE 9 5 Time History Display First Point Keypress Note that the graph scaling can be modified as described in section Adjust Graph Scale on page 5 19 Data Display at Cursor Position The first display labeled Run represents the keypress initiating the measurement with the corresponding data and time There will be no measured data associated wit
106. unlock the LxT press the A TOOLS key the key or the Right or Left Softkey Enter your 4 digit code then press the key Enter 4 digit code 000 FIGURE 13 12 Auto Store Unlock Locked With Auto Store 13 7 The LxT is unlocked and all functions are available to the user Locked With Manual Store Unlock If the Locked w Manual Store mode has been selected upon accepting the changes on the Lock Page the view would be as shown in FIGURE 13 10 Locked with Auto Store or Manual Store In this mode a measurement is started by pressing the RUN PAUSE key Pressing the RUN PAUSE key a second time will pause the measurement and pressing it again will continue the measurement The STOP STORE key will stop a measurement and a pressing it a second time will initiate the storage process by displaying the Save File prompt as shown in FIGURE 13 13 831 Save File FIGURE 13 13 Manual Store When Locked Left click Yes to store into the file number indicated No to abort the storage operation or to overwrite a file into which data has already been stored To unlock the LxT press the A TOOLS key the key or the Right or Left Softkey Enter your 4 digit code then press the 9 key See FIGURE 13 10 Locked with Auto Store or Manual Store The LxT is unlocked and all functions are available to the user The measurement may be stored Locked With Manual Store LxT Technic
107. 0 0 07 0 10 0 0 08 1 2 5 h 0 Ay 0 08 12 23 y a 0 0 0 08 x lad 0 0 0 09 2 y 0 0 0 09 x 5 4 0 0 0 09 0 0 0 09 0 0 0 09 k 022 0 0 0 09 r 022 0 0 0 09 x lt A 0 0 0 10 0 0 0 10 0 0 0 10 x 100000 0 0 0 126000 n 0 0 2 Noise floor data 1kHz 1 3 Octave 0 45 uV 7 0 dBuV uncertainty 0 47 dB Flat 20Hz 20kHz 3 5 uV 10 9 dBuV uncertainty 0 47 dB 1 7 uV 4 8 dBuV uncertainty 0 46 dB Uncertainties are given as expanded uncertainty at 95 confidence level 2 Technician Jason Grace Test Date 050 2005 FIGURE A 20 Certificate of Conformance PRMLxT1L LxT Technical Reference Manual Technical Specifications Tolerance dB 47 Model PRMLxT2 The Larson Davis PRMLxT2 is an electret microphone preamplifier for use with Larson Davis LxT Sound Level Meters It requires very little supply current and will drive 200 feet of cable The preamplifier operates over wide temperature and humidity ranges It has a built in attenuation of 15 dB for use with 20 mV Pa sensitivity microphones up to 140 dBSPL Specifications Note that all electroacoustic values are at 23 50 RH 7 5 Volt supply 3 m 10 cable and equivalent microphone of 18pF unless otherwise stated Frequency response with respect to the respons
108. 0 C to 39 14 F to 102 F Table 15 2 Environmental Parameter Ranges for Calibration LxT Technical Reference Manual Set the CAL200 level switch to 94 or 114 dB Acoustic Calibration 15 7 Adding a Calibrator 15 8 When adding a calibrator to the list the following information may be entered Calibration Level Calibration Frequency e Calibrator Description The calibration level and frequency values are as specified in section Recommended Calibrators for Use with LxT1 and LxT2 on page 15 5 Looking at FIGURE 15 2 Calibration Pages on page 15 3 highlight each text box in the Calibrator section of the Calibrate Page and enter the correct information about a calibrator enter the information and press the key to complete the entry When the calibration level calibration frequency and calibrator description have been entered highlight the Save button and press the key to save the information to the list of calibrators 1 35 06 2 Calibrate Tool Calibrate Calibrate Calibrator aa oola 0004 Save Description LD CAL200 114 00dB 1kHz LD CAL200 114 00dB 1kHz LD CAL200 94 00dB 1kHz OLD CAL150 114 00dB 1kHz o 114 00dB 1kHz FIGURE 15 3 New Calibrator If the desired calibrator is already in the list highlight the calibrator and press the key The radio button next to the selected calibrator will be filled in and the calibration information will appea
109. 0 4 5 Level 3 N61000 4 6 Level 3 N61000 4 11 Table A 15 PSA029 AC to DC USB Power Adapter Specifications Immunity LxT Technical Reference Manual Technical Specifications A 13 Dielectric Withstand Hipot AC Input Plugs supplied USA RPA Europe RPE UK RPK Australia RPS Dimensions Weight Length 75 32 mm 2 97 in Height 31 67 mm 1 25 in Width 45 96 mm 1 81 in Weight 61 1 g 2 16 02 Table A 15 PSA029 AC to DC USB Power Adapter Specifications Electromagnetic Emission Declaration of Conformity PCB Piezotronics Inc declares that LxT Sound Level Meter has been measured in representative configuration with PRMLxT1 preamplifier 377B02 microphone and the following cables 010 microphone extension cable CBL138 USB interface cable and CBL139 AC DC output cable with an applied acoustic field of 74 dB at 1 kHz in accordance with the following directives 89 336 EEC The Electromagnetic Compatibility Directive and its amending directives has been designed and manufactured to the following specifications EN 50081 1 1992 Electromagnetic compatibility Generic emission standard Part 1 Residen tial commercial and light industry EN 50082 2 1995 Electromagnetic compatibility Generic immunity standard Part 2 Industrial environment A 14 Technical Specifications LxT Technical Reference Manual 1 1 and 1 3 Octave Filters The 1 1 and 1 3 octave filters OB1 and OB3 Opt
110. 00 6 2 Run ICON BT etr e TV ERER 2 4 RUN robe ub mcns Pa ro E LEE T 2 3 5 6 Run Pause Keys ea e d eerte s 2 10 LxT Technical Reference Manual Index 1 11 S SCleelS 2 2 2 11 2 13 CR RR ERE GEGEN 2 11 Measurement Properties 5 use ER e RES ER EATER EIUS 2 11 Power oet eere OR EORR RU qM 2 11 Fo P 2 11 Scroll Bat ete 2 2 Scrolling Between 2 15 Section Indicator eoe eee pter there dr 2 2 SEE Calculations o aont atid awa E 4 Session Log eren enne entente nne 5 18 Settings Screen Day Night Page ee gite utendi 4 18 Triggers Page cente eR trece ten IRI 4 17 Setup Key 2 7 Setup Pages ote ee vete UNE 4 3 Shutdown 1 enne ener nnne nnne nnns 7 18 ooftkeys o Aa a ce tpe 2 5 7 3 Softwate eee Et ee E e RH Seiten 1 11 2 Vet bh dederit 1 11 Sound Average level eh se ied D 1 Day night average nennen D 3 Energy average E8q dete e ESSAIS EVE EUNT D 20 benc PE D 17 Exposure ede
111. 00 34 7 LxT_Data 000 LaSeq 65 1 dBEZI Las 65 1 dB Close FIGURE 11 4 Data View Page The Data View screen is similar to the Data Display screen See Overall Page on page 5 6 The file name of the data file being displayed is found in the title bar near the top of the screen For information on the Session Log Page see Session Log Page on page 5 18 Pressing the Center Softkey labeled Close returns the screen to the Data Explorer view This deletes the selected stored data file When the Delete menu item is highlighted and the eer Enter key is pressed a message box appears asking you to confirm the request to delete the file Delete File FIGURE 11 5 Delete File Highlight the appropriate response using the keys and the Enter key LxT Technical Reference Manual Delete All Rename LxT Technical Reference Manual This deletes all of the stored data files SS the Delete All menu item is highlighted and the Enter key is pressed a message box appears asking you to confirm the request to delete all files Delete All Files FIGURE 11 6 Delete All Files Highlight the appropriate response using the keys and the er Enter key The Rename menu item enables you change the name of the selected data file Pressing the eer Enter key brings up a message box for editing the file name ESI Rename File LxT 001 FIGURE 11 7 Rename Fil
112. 01dB 40 140 40to140dB 40to 139 dB 40 to 136 dB c 40t0137dB 40tol40dB 40to139dB 40to137dB 40 to 135 dB 2 451014048 4514048 45to140dB 45 140 45 to 140 dB f Linear Measurements Starting Level The starting point for measuring the level linearity errors is 114 dB at all frequencies g Electrical Insert Signals The electrical design of the input device to insert electrical signals into the preamplifier for the 375A02 microphone is a series 18pF 5 capacitor The Larson Davis ADP005 is used for this purpose The 005 can be used for noise floor measurements by attaching the included short on the front of the ADP00S h Inherent Noise Highest anticipated self generated noise of the LxT2 Weighting Total Noise Electrical Noise A 27 26 C 30 26 Fit 41 30 combination of the electronic noise and the thermal noise of the microphone at 20 C measured in a sealed cavity and vibration isolated 2 electronic noise of the instrument with an ADPO05 in place LxT2 LxT Technical Reference Manual i Highest Sound Pressure Level The highest sound pressure level at the microphone and the greatest peak to peak voltage at the electrical input facility for the microphone recommended for use with the LxT2 are as specified in the following table Mi h Damage Level Overload Level Preamplifier Sound Pressure Level dB El
113. 1 87 Hz Mic 10000 00 Hz FIGURE A 8 LxT with 377B02 Microphone 1258 93 Hz 2511 89 Hz 5011 87 Hz and 10000 00 Hz LxT Technical Reference Manual Technical Specifications A 25 LD Model 1 1 Serial 0010 Normalized to 251 19Hz 8 0 sted 11 23 05 12 25 57 by Alex PRMLxT1 0155 and 377B02 100650 Reference Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 0 6 0 Mic 1584 89 Hz Mic 3162 28 Hz Mic 6309 57 Hz Mic 12589 25 Hz FIGURE A 9 LxT with 377B02 Microphone 1584 89 Hz 3162 28 Hz 6309 57 Hz and 12589 25 Hz A 26 Technical Specifications LxT Technical Reference Manual LxT With 375A02 Free Field Microphone and PRMLxT2 Preamplifier LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 4 0 dB 2 0 dB 0 0 dB Mic 120 LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 4 0 Mic 135 FIGURE A 11 LxT with 375A02 Microphone 15 75 and 135 degrees LxT Technical Reference Manual Technical Speci
114. 10 microphone extension cable used to connect the PRMLxTI to the LxT1 Adding the USB cable did not emit more radio frequencies levels AC Power and Radio Frequency Susceptibility The mode of operation of the LxT1 that produced the greatest measurement susceptibility to A C power frequency and radio frequency fields was with the Lx T1 set to run USB cable attached and with an 010 10 microphone extension cable between the and the LxTI LxT Technical Reference Manual LxTl C 13 LxT2 Section 9 2 4 a Calibrator The calibrator to be used with the LxT2 is the Larson Davis Model CAL150 b Calibrator Frequency The calibration check frequency is 1000 Hz c Calibration Procedure For calibration refer to the chapter Calibration on page 15 1 C 14 LxT2 LxT Technical Reference Manual d Frequency Response and Corrections Larson Davis LxT2 with PRMLxT2 and typical 375A02 Microphone average frequency responses and corrections Required by IEC 61672 1 Sections 5 2 4 5 2 5 5 2 6 and 9 2 4 d 0 Free Field expanded Wind Screen Corrections with uncertainty 0 Free Field 0 Free Field Effect of on LxT2 Wind Screen of Corrections Frequency Response Corrections Wind Screen 0 Free Field on LxT2 95 Hz dB dB dB dB dB dB 63 10 0 0 0 0 0 0 0 0 0 0 79 43 0 0 0 0 0 0 0 0 0 0 100 00 0 0 0 0 0 0 0 0 0 0 125 89 0 0 0 0 0 0 0 0 0 0 158 49 0 0 0 0 0 0 0 0 0 0 199 53 0 0 0 0 0 0 0 0 0 0 251 19 0 0 0 0
115. 1672 1 C 1 Glossary D 1 Integrated Level Calculations E 1 TWA DPA S E 3 Sound Exposure Level and Sound Exposure E 5 DOSE and Projected DOSE E 8 LIMITED PRODUCT WARRANTY 2 1 List of Tables INtFOGUIGEION 1 1 Microphone and 1 9 OVER VIG Wiss DAR LERRA 2 1 Chapters Describing Functions From the Control Panel 2 9 3 1 Basic Measurement 4 1 Predefined Noise Dosimeter Setups 4 9 Basic Data Display 5 1 Run cca 6 1 Making a Measurement 7 1 VOICE Recording 8 1 Uude 9 1 Measurement History 10 1 Examples of Displays on Measurement Page 10 7 Data Explorer 11 1 System Properties 2 12 1 Lock Unlock the EXT iicet erba EP tn 13 1 14 1 Calibration d nent 15 1 Recommended Calibrators for Use with LxT1 and LxT2 15 5 Environmental Parameter Ranges for Calibration 15 7 System Utilities sse 16 1 EXT Har
116. 200 114 00dB 1kHz 114 00dB 1kHz Calibrate Page 0 00 00 0 Calibrate Tool Sensitivity 622211 PRMLxT1 377802 Preamp p4 3dBA 24 9dBC 32 3987 Close Sensitivity Page e 0 00 00 0 Calibrate Tool fey History Preamp PRMLxTi1 History Date Time 55 0 007 1816 43 58 1 1 50 History Page e 0 00 00 0 Calibrate Tool Certification Performed 2007 Apr 10 Due 2008 Apr 09 actory Certification 681 West 820 North Provo LIT 84601 y15 926 8243 Certification Page FIGURE 15 2 Calibration Pages Calibrate Page The Calibrate Page is used when performing an acoustic calibration including the selection of the sound level calibrator to be used and the implementation of the calibration procedure History Page The History Page lists the results along with the date and time of the ten most recent calibrations performed using the same type of preamplifier as presently connected to the LxT whose name appears at the top of the page PRMLxTI in this example The preamplifier type is read automatically LxT Technical Reference Manual Control Panel Calibrate 15 3 when the instrument is booted up or following a change in preamplifier The value of sensitivity in dB re 1 V Pa and the variation of the sensitivity determined from that calibration relative to the calibration prior to that A dB are presented for each calibration Se
117. 27 0 33 0 20 0 17 1778 28 0 43 0 37 0 33 0 40 0 37 0 33 0 40 0 13 1883 65 i i 0 43 0 37 0 37 0 40 0 37 0 33 0 30 0 23 1995 26 B 0 43 0 47 0 47 0 40 0 37 0 37 0 40 0 23 2113 49 0 53 0 47 0 47 0 40 0 47 0 43 0 37 0 33 2238 72 0 53 0 47 0 47 0 50 0 47 0 47 0 40 0 30 2371 37 0 53 0 47 a 0 47 0 50 0 47 0 53 0 50 0 33 2511 89 0 53 0 57 i 0 57 0 53 0 53 0 53 0 50 0 37 2660 73 5 0 57 0 57 0 50 0 60 0 50 0 53 0 50 0 43 2818 38 0 57 0 60 E 0 50 0 53 0 53 0 57 0 57 0 43 2985 38 0 43 0 57 a 0 50 0 57 0 53 0 57 0 57 0 37 3162 28 0 53 0 50 0 57 0 50 0 47 0 53 0 50 0 43 3349 65 0 40 0 43 3548 13 0 33 0 37 Continued next page 18 Technical Specifications LxT Technical Reference Manual Angle from Reference direction degrees 3758 37 3981 07 4216 97 4466 84 4731 51 5011 87 5308 84 5623 41 5956 62 6309 57 6683 44 7079 46 7498 94 7943 28 8413 95 8912 51 9440 61 10000 00 10592 54 11220 18 11885 02 12589 25 13335 21 14125 38 14962 36 15848 93 16788 04 17782 79 18836 49 19952 62 Table A 18 Directional Response 3 1 2 Windscreen LxT Technical Reference Manual 75 90 105 Technical Specifications 120 A 19 Frequency Response LxT With 377B02 Free Field Microphone and PRMLxT1 Preamplifier A 20 LD Model LxT1 Serial 0010 Normalized to 251 19Hz 0 Tested 11 23 05 12 25 57 by Alex T Note PRMLxT1 0155 and 3
118. 3 10 42 00 inf 947 19 0 01 10 30 0 60 96 71 10 61 00 inf 974 02 0 00 10 30 0 40 97 53 10 70 00 inf 1000 00 0 00 10 30 0 30 Table A 17 Filter Skirts of 1kHz 1 3 Octave Filter LxT Technical Reference Manual Technical Specifications A 17 Position of Instrument and Operator When making a measurement it is recommended that the observer be positioned as far behind and to the right of the instrument as possible to minimize interference of the sound field at the microphone resulting from body reflections When using the LxT the meter is held in one hand with the arm extended away from the body Better results can be obtained by using a tripod Effect of Windscreen The corrections which should be subtracted from the measured data when using the Larson Davis Model WS001 3 inch diameter windscreen with 1 2 inch Larson Davis microphone are as indicated in the following table Directional Response Effect of 3 Inch Wind Screen 377B02 Microphone Attached to LxT1 Frequency Angle from Reference direction degrees Hz 15 30 45 75 90 105 120 135 150 251 19 T 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 266 07 0 00 0 03 0 03 0 00 0 00 0 03 0 03 0 00 0 03 281 84 0 10 0 07 0 03 0 00 0 03 0 00 0 07 0 00 0 03 298 54 0 07 0 00 0 00 0 00 0 03 0 03 0 03 0 03 0 10 316 23 0 03 0 07 0 00 0 03 0 00 0 03 0 03 0 03 0 10 334 97 0 00 0 03 0 00 i 0 03 0 07 0 13 0 00 0 00 0 07 354 81 0 0
119. 400 1 L 10 10 1 10 L 10 10 Lan 1010810 54 10 gt 10 gt 10 0000 0700 2200 The day evening night level Lpgw is defined by the following formula 1 Lday Levening 5 Lnight 10 boa toig 12 10 4 10 48 0 5 In the default form the day has eight hours the evening has four hours and the night has eight hours as can be seen in the equation The default times for these periods are as follows e Day 07 00 to 19 00 Evening 19 00 to 23 00 Night 23 00 to 07 00 Lday Levening and Lnight are A weighted long term average sound levels measured during the day evening and night respectively LxT Technical Reference Manual Integrated Level Calculations E 11 CNEL E 12 To account for the increased impact of environmental noise during the evening and night penalties are added to the measured level 5 dB for evening and 10 dB for night as can be seen in the equation The Directive 2002 49 EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment of environmental noise permits member states to shorten the evening period by one or two hours and lengthen the day and or the night accordingly and also to choose the time for the start of the day To accommodate these and other possible modifications the Day Night page permits the user to modify the times for the beginning of the Day Evening and Night periods and the penalties to be utilized when calculati
120. 5 5 Time Battery Voltage and Memory 5 6 Overall Page iine ODE Ue o 5 6 Overall Leq with Profile 5 7 Overall Enforcement Sound Level 5 7 Maximum Minimum and Peak Sound Levels 5 8 1 1 Octave Band Analyzer Optional 5 9 ES E 5 9 a genie 5 9 cd e 5 9 1 3 Octave Band Analyzer Optional 5 10 1 4 LxT Technical Reference Manual SOUNA EX DOS US 5 13 S Eid siio deque dt ce ea Sa Out 5 13 Ln Percentiles Reel eee n 5 14 EVENTS era eee 5 15 OVerloads si aac MM 5 15 Number of 5 16 Community tenerent 5 16 C A and Impulsivity dae inns Dic dE 5 17 session Log 5 18 Adjust Graph Scale eene ettet 5 19 View Spectrum Normalized 5 20 Live DISDISV biet ete eret na euer aen S Pee etd 5 20 Selecting the Spectrum Type 5 21 Selecting the Reference
121. 5A02 A 36 Technical Specifications LxT Technical Reference Manual Microphone Preamplifier Specifications The general specifications for the LxT microphone preamplifiers are shown in Table A 22 Noise LxT2 PRMLxT2L with 375A02 Nominal Nominal Preamp Mic Microphone Preamplifier Nominal Sensitivity at Type Type Sensitivity Attenuation LxT Input Sensitivity Limits High dB Low dB 50 0 _ _ 45 00 510 37 62 43 6 ee FIGURE A 18 LxT Preamplifiers The following sections present the specifications for the four different microphone preamplifiers which can be used with the LxT Model PRMLxT1 The Larson Davis is an electret microphone preamplifier for use with a Larson Davis LxT Sound Level Meter It requires very little supply current and will drive 200 feet of cable The preamplifier operates over wide temperature and humidity ranges It has a built in attenuation of 23 dB for use with 50 mV Pa sensitivity microphones up to 140 dBSPL LxT Technical Reference Manual Technical Specifications A 37 Specifications Note that all electroacoustic values are at 23 C 50 RH 7 5 Volt supply 3 m 10 cable and equivalent microphone of 18pF unless otherwise stated Frequency response with respect to the response at 1 kHz with 13 Volts rms input and 18 pF equivalent microphone 4 Hz to 10 Hz 0 1 0
122. 6 Refresh 2 en oet Net s a a ten 11 6 Rename Files e te e DR ded decns 11 5 Start Date anid Tames ict et e t OT ERROR een 11 3 Test Descriptiori 4 eee e e it ee aee cedet t 11 3 Test Run TIT dose dH P ROO UR ERES UOI 11 3 View Files siccis e Ce e UR C ERI E NETT RESET 11 4 Data Labels tet ep E io aee ie etti p aD 5 1 Data View Screen sse 11 4 Date Fortmat oe cete eripiet Pelea ien atit tenir 12 13 Day Night rere 4 18 Day Evening Night Level sse 4 18 E 11 Day Night Level UR RI deep be E HE 4 18 E 11 DC obla eit ite erts PRO NEN 12 9 bIldalme D 4 Decimal Symbol eee e ode ed 12 12 Declaration of 2 Delete Files 11 5 Delete 11 4 Department of Defense 7 Detector Tesserini an a Ea D 7 Device Page o We ERO ec te 12 2 Display Backlight one tede 2 11 Display Contrast esi tane ete D pen 2 7 12 7 Display Customization sese 12 14 Display Sections Icons rete tette ente tee metet et 2 2 Meas rement eor tede e e EEG ied er eee ere 2 2 Measurement tere tree EDO DERE 2 4 RERO
123. 60 13 4 3 0 0 1 200 10 9 2 0 0 250 250 8 6 1 3 0 315 6 6 0 8 0 400 4 8 0 5 0 500 500 3 2 0 3 0 630 1 9 0 1 0 800 0 8 0 0 1000 1000 0 0 0 1250 0 6 0 0 1600 1 0 0 0 1 2000 2000 1 2 0 1 0 2 2500 1 3 0 2 0 3 3150 1 2 0 4 0 5 4000 4000 1 0 0 7 0 8 5000 0 5 1 2 1 3 6300 0 1 1 9 2 0 8000 8000 1 1 2 9 3 0 10000 2 5 4 3 4 4 12500 4 3 6 1 6 2 16000 16000 6 6 8 4 8 5 20000 9 3 11 1 11 2 See Energy Equivalent Sound Level Sound Level Energy Average and Time Weighted Average Glossary D 11 Level dB Measurement Duration T Microphone Guidelines D 12 Glossary A descriptor of a measured physical quantity typically used in sound and vibration measurements It is attached to the name of the physical quantity to denote that it is a logarithmic measure of the quantity and not the quantity itself The word decibel is often added after the number to express the same thing When frequency weighting is used the annotation is often expressed as dB A or dB C The time period of measurement It applies to hearing damage risk and is generally expressed in hours Standard ANSI 812 19 Microphone Types A device for detecting the presence of sound Most often it converts the changing pressure associated with sound into an electrical voltage that duplicates the changes It can be composed of one of the following types Capacitor Condenser A microphone tha
124. 7 0 10 0 03 A 0 00 0 00 0 03 0 03 0 03 0 03 375 84 0 07 0 03 0 00 0 03 0 00 0 03 0 03 0 00 0 10 398 11 0 00 0 10 0 03 A 0 00 0 00 0 03 0 07 0 03 0 07 421 70 0 00 0 07 0 03 0 03 0 00 0 03 0 03 0 00 0 07 446 68 0 03 0 03 0 03 X 0 03 0 10 0 03 0 03 0 00 0 00 473 15 0 03 0 03 0 00 E 0 03 0 07 0 00 0 03 0 00 0 07 501 19 0 10 0 13 0 07 0 07 0 00 0 00 0 13 0 10 0 07 530 88 k 0 10 0 13 0 07 0 07 0 03 0 03 0 07 0 00 0 03 562 34 0 10 0 13 0 07 0 07 0 00 0 03 0 13 0 10 0 03 595 66 0 10 0 13 0 07 0 03 0 00 0 00 0 10 0 07 0 03 630 96 0 00 0 07 0 03 i 0 07 0 10 0 07 0 13 0 10 0 03 668 34 3 0 10 0 13 0 07 0 00 0 03 0 03 0 07 0 00 0 03 707 95 d 0 10 0 13 0 07 A 0 07 0 10 0 07 0 03 0 10 0 03 749 89 5 0 10 0 13 0 07 i 0 03 0 10 0 07 0 13 0 10 0 03 794 33 d 0 10 0 13 0 07 A 0 13 0 10 0 07 0 13 0 10 0 03 841 40 0 07 0 10 0 07 0 07 0 10 0 10 0 03 0 10 0 03 891 25 E 0 07 0 10 0 00 T 0 07 0 03 0 07 0 13 0 07 0 03 944 06 0 20 0 07 0 07 0 13 0 17 0 20 0 17 0 03 1000 00 0 13 0 07 0 17 0 10 0 17 0 23 0 10 0 03 1059 25 0 23 0 17 0 07 0 10 0 07 0 13 0 10 0 03 1122 02 0 23 0 13 0 17 0 10 0 17 0 23 0 20 0 13 1188 50 0 23 0 07 0 17 0 10 0 17 0 13 0 20 0 13 1258 93 0 23 0 17 0 17 0 23 0 13 0 23 0 17 0 13 1333 52 0 33 0 27 0 17 0 20 0 23 0 23 0 20 0 13 1412 54 0 23 0 17 0 17 0 20 0 27 0 23 0 20 0 13 1496 24 0 23 0 17 0 17 0 20 0 27 0 23 0 27 0 13 1584 89 0 37 0 30 0 27 0 33 0 27 0 30 0 27 0 20 1678 80 0 40 0 37 0 27 0 30 0
125. 77B02 100650 Reference Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 FIGURE 2 LxT with 377B02 Microphone 0 60 120 and 180 degree Technical Specifications LxT Technical Reference Manual LD Model LxT1 Serial 0010 Normalized to 251 19Hz 0 Tested 11 23 05 12 25 57 by Alex T Note PRMLxT1 0155 and 377B02 100650 Reference Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 6 0 dB 2 0 dB 2 0 dB 6 0 dB 10 dB 14 dB 18 dB Mic 135 FIGURE A 3 LxT with 377B02 Microphone 15 75 and 135 degrees LD Model LxT1 Serial 4 0010 Normalized to 251 19Hz 0 Tested 11 23 05 12 25 57 by Alex T Note PRMLxT1 0155 and 377B02 100650 Reference Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 6 0 dB Mic 150 FIGURE A 4 LxT with 377B02 Microphone 30 90 and 150 degrees LxT Technical Reference Manual Technical Specifications A 21 LD Model LxT1 Serial 0010 Normalized to 251 19Hz 0 Tested 11 23 05 12 25 57 by Alex T Note PRMLxT1 0155 and 3
126. 77B02 100650 Reference Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 6 0 dB 2 0 dB 2 0 6 0 A0 dB 14 dB 18 22 26 FIGURE 5 LxT with 377B02 Microphone 45 105 and 165 degrees A 22 Technical Specifications LxT Technical Reference Manual Directional Characteristics LD Model LxT1 Serial 4 0010 Normalized to 251 19Hz 0 Tested 11 23 05 12 25 57 by LD Note PRMLxT1 0155 and 377B02 100650 Reference Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 2 0 Mic 251 19 Hz FIGURE A 6 LxT with 377B02 250 19 Hz LxT Technical Reference Manual Technical Specifications A 23 del LxT1 Serial 0010 Normalized to 251 19Hz 8 0 d 11 23 05 12 25 57 by Alex T PRMLxT1 0155 an 6 ce Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 0 6 0 dB 2 0 dB 2 0 dB 6 0 dB 10 0 dB 14 0 dB 18 0 dB Mic 1000 00 Hz Mic 1995 26 Hz Mic 3981 07 Hz Mic 7943 28 Hz FIGURE A 7 LxT with 377B02 1000 00 Hz 1995 26 Hz 3981 07 and 7943 28 Hz A 24 Technical Specifications LxT Technical Reference Manual PRMLxT1 0155 and 377B02 100650 once Mic B amp K Model 4189 Serial Number 2440346 Tested 11 23 05 08 44 02 0 Mic 1258 93 Hz Mic 2511 89 Hz Mic 501
127. E o E 2 m c Sn e FE E E Ej EE EE EE EFE EFE FE EFE FE FE FE EE ES 1 FIGURE 1 1 Bookmarks In the unexpanded view bookmarks lists the names and page numbers of chapters and appendixes in order of appearance as well as the Table of Contents and the Index To close bookmarks simply left click the tab once more For any entry if there is a within the rectangle to the left there are sub entries which can be displayed upon expanding the tree by clicking the rectangle For example clicking the to the left of any chapter will expand it into major headings and by clicking all the symbols the complete tree for that chapter will be shown In the following figure we can see the entry Measurement Setup completely expanded Special Features of the Electronic Version LxT Techncial Reference Click to Display a Page Return to Previous View There are several methods to return to a previous view These methods differ in the various version of Adobe Reader Refer to Help in your version of Adobe Reader amp bookmark L List of Figures L List of Tables L Introduction L First Use L Overview L Basic Measurement Setup Measurement Properties Screen L Accessing the Measurement Properties Screen i L Settings In Use Message J L Setup Pages General Page 5 1 SLM Page L Frequency Weighting L Time Weighting
128. E 12 1 Control Panel System Properties FIGURE 12 1 Control Panel Press the key to open the System Property Pages There are four System Property Pages that may be selected using the Right and Left Softkeys All System Property Pages have one section LxT Technical Reference Manual System Properties 12 1 Device It is easier to enter the text information for these three fields using the Blaze software or the SLM Utility G3 software 12 2 Device The Device Page has three fields in which the user may enter information about the instrument This can identify the owners company name and address Information may be easily placed in these fields using Blaze software oY 0 40 37 2 System Properties FIGURE 12 2 Device Page Using the 7 keys select one of the three fields to edit Press the key to highlight the 1st character position in the field The 7 and keys are used to scroll through a list of characters and change character positions in the field When the information is complete press the key to accept the information and move the highlight out of the field At this point another field could be selected and the above process repeated LxT Technical Reference Manual Time The time and date for the LxT may be adjusted on the time page o 0 40 37 2 System Properties ES Time System Date System Time Sync Date Time with FIGURE 12 3 Time Page Setting Day and Ye
129. GURE A 15 LxT with 375A02 Microphone 1000 00 Hz 1995 26 Hz 3981 07 and 7943 28 Hz A 30 Technical Specifications LxT Technical Reference Manual LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 4 0 dB Mic 1258 93 Hz Mic 2511 89 Hz Mic 5011 87 Hz Mic 10000 00 Hz FIGURE A 16 LxT with 375A02 Microphone 1258 93 Hz 2511 89 Hz 5011 87 Hz and 10000 00 Hz LxT Technical Reference Manual Technical Specifications A 31 LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 4 0 0 0 4 0 8 0 12 0 16 0 20 0 Mic 1584 89 Hz Mic 3162 28 Hz Mic 6309 57 Hz Mic 12589 25 Hz FIGURE A 17 LxT with 375A02 Microphone 1584 89 Hz 3162 28 Hz 6309 57 Hz and 12589 25 Hz Noise Levels The noise of the LxT includes contributions from the following components Instrument and preamplifier Microphone In the following sections the noise levels for each component and the total are presented as a function of frequency A 32 Technical Specifications LxT Technical Reference Manual LxT1 PRMLxT1 with 377B02 17 Nov 05 377B02 PRMLxT1L and LxT1 Noise LxT1 amp PRMLxT1L 377B02 PRMLxT1L and 377B02 Frequency Noise
130. LxT SLM 1 Vrms output signal To 20 kHz with 200 60 m cable Output Connector Switchcraft TASM 5 Pin male Pin Signal 1 Signal Ground 2 Signal Output 3 Power Supply 7 Volts 4 Preamp sense 5 No Connection Shell Connect to preamp housing Table A 29 Input Connector Compatibility Use with ACO 375A02 or any electret microphone having about 20 mV Pa sensitivity and meeting the mechanical requirements of IEC 61094 4 It can be used with either the Larson Davis ADP043 or ADP008 adapters for 1 4 or 1 electret microphones LxT Technical Reference Manual Technical Specifications A 55 Optional Accessories EXCXXX Extension Cable 5 Pin Switchcraft male to 5 Pin Switchcraft female XXX feet long ADPO005 18 pF equivalent gt Microphone with BNC Connector input ADP008 Adapter for 1 microphones ADP040 Microphone Signal Tee ADP043 Adapter for 1 4 microphones ADP068 Preamplifier holder for 2 preamplifiers on microphone stand Table A 30 Optional Accessories In the interest of constant product improvement specifications are subject to change without notice Larson Davis provides a complete line of acoustic measurement tools including dosimeters sound level meters real time analyzers preamps calibrators and microphones A 56 Technical Specifications LxT Technical Reference Manual Preamplifier Model PRMLxT2L Serial Number 0104 Larson Davis
131. MAIA JO Koxyos FIGURE 2 7 Data Display Screens LxT Technical Reference Manual Screens 2 14 Changing Data Pages Scrolling Between Sections To switch between tab pages use the Left and Right Softkeys To display different sections Data Views use the C 7 and C keys Measurement Properties Screen Note that the screen is not wide enough to show the tabs for all thirteen setup pages at the same time Use the Right and Left Sofikeys to scroll the view to the right or left respectively For a more detailed description of the Measurement Properties Screen and its associated pages see Chapter 4 Basic Measurement Setup on page 4 1 LxT Technical Reference Manual There are ten Measurement Property Pages the Measurement Properties Screen identified by their titles on the tabs at the top of the page as follows General used to create a file name and a measurement description SLM used to setup the parameters for the measurement of sound levels OBA optional used to setup the real time octave band frequency analysis Dosimeter 1 used to setup the parameters for the measurement of sound exposure and noise dose Dosimeter 2 used to setup the parameters for the measurement of sound exposure and noise dose Ln used to define the parameters for the measurement of Ln statistics Control use to setup the mode of measurement timing Time History optional Permits
132. No Store only to internal memory Auto Store data to USB memory if available otherwise store to internal memory LxT Technical Reference Manual Localization Note that the default values for these parameters are as shown FIGURE 12 12 LxT Technical Reference Manual in Highlight the USB Storage field and press the key to obtain a listing of the choices as shown in FIGURE 12 9 No No FIGURE 12 11 USB Storage Preferences Highlight the desired USB Storage and press the key to make the selection When data is stored to USB memory it is first stored to internal flash memory a process which is much more rapid than storing directly to USB memory Following that the data is then copied to USB memory without interfering with the operation of the instrument When the data file has been successfully copied the original data file in internal memory is deleted The Localization Page shown in is used to select formats for parameters which may vary from one country or region to another FIGURE 12 12 gt 0 40 37 2 System Properties Localization ffi Language Decimal Symbol FIGURE 12 12 Localization Page Highlight the parameter to be set and left click the key to view a list of options Localization 12 11 Languages Decimal Symbol 12 12 The LxT supports the following languages English French German Italian Portuguese Spanish Swedish English is the default langu
133. Noise Noise Hz dB SPL dB SPL dB SPL 6 3 10 3 21 2 10 3 7 9 9 2 20 2 9 2 10 0 8 2 19 2 8 2 12 6 7 2 18 2 7 2 15 8 6 1 17 2 6 1 20 0 5 1 16 2 5 1 25 1 4 4 15 2 4 4 31 6 3 4 14 2 3 5 39 8 2 6 13 2 2 7 50 1 1 4 12 2 1 6 63 1 0 1 11 2 0 4 79 4 1 0 10 2 0 5 100 0 1 8 9 2 1 1 125 9 2 7 8 2 1 6 158 5 3 6 7 2 2 0 199 5 4 1 6 2 2 0 251 2 4 8 5 2 2 0 316 2 5 4 4 2 1 8 398 1 5 8 3 2 1 3 501 2 6 1 2 6 1 0 631 0 6 5 1 8 0 5 794 3 6 5 0 8 0 2 1000 0 6 6 0 1 0 8 1258 9 6 6 0 8 1 5 1584 9 6 2 1 5 2 2 1995 3 5 8 2 5 3 1 2511 9 5 3 3 2 3 8 3162 3 4 6 3 9 4 5 3981 1 3 9 4 4 5 0 5011 9 3 2 4 9 5 5 6309 6 2 3 5 1 5 8 7943 3 1 4 5 6 0 10000 0 0 5 4 8 5 9 12589 3 0 4 4 3 5 8 15848 9 1 4 3 4 5 5 19952 6 2 3 2 1 5 2 Awt 8 0 16 7 17 3 Cwt 11 7 17 8 18 8 Zwt 18 0 22 9 24 1 Table A 19 Noise LxT1 PRMLxT1 with 377B02 LxT Technical Reference Manual Technical Specifications A 33 LxT1 PRMLxT1L with 377B02 17 Nov 05 377B02 PRMLxT1L and LxT1 Noise LxT1 amp PRMLXxT1L 377B02 LxT1 PRMLxT1L and 377B02 Frequency Noise Noise Noise dB SPL dB SPL 10 3 21 2 9 2 20 2 8 2 19 2 7 2 18 2 6 1 17 2 5 1 16 2 4 4 15 2 3 4 14 2 2 6 13 2 1 4 12 2 0 1 11 2 10 2 9 2 8 2 Table A 20 Noise LxT1 with PRMLxT1L and 377B02 A 34 Technical Specifications LxT Technical Reference Manual LxT2 PRMLxT2 with 375A02 375A02 PRMLxT2 and LxT2 Noise Frequency H
134. Overall Page Number of Measurements by Type Section 13 5 16 Community Noise Section 14 5 16 C A Level and Impulsivity Section 15 5 17 Session Log Page leen 5 18 MGR pnr EE 5 19 Adjust Graph NIertl ioo 5 19 Standard Live Spectrum Display 5 20 21g 10 HTC VS 5 20 Normalized Live Spectrum Display 5 21 Live Reference 5 21 Live Spectrum Normalized to Reference Spectrum 1 5 22 Spectrum From FIGURE 5 25 Normalized using A 5 23 Overall ooi a xod aiia 5 24 eint laetis uin edis 5 24 Normalized Overall Spectrum No Reference Selected 5 25 Spectrum 20222222 272222 5 25 Overall Reference 22 224 021 5 25 Lmin Spectrum Normalized to Lmin Spectrum 5 26 Lmax Lmin peel Briss 5 27 Leq Spectrum Normalized by 5 27 Lmin Normalized by Lmax Standard Display Scale 5 28 Lmin Normalized by Lmax Graph Relative Display Scale5 29 t ts 6 1 6 1 Mode Menu 6 2 Setup of Manual Stop Timed Stop and Stop When Stable Run Modes eM
135. Overview When the LxT is first switched on the Data Display Screen will appear When a measurement is in progress it will look similar to FIGURE 2 1 Data Display Screen Run Time OBA Overload Icon Input Overload Measurement Name Live Page ASeq 1s 75 1 dK LxT Technical Reference Manual Icon Power Indicator Measurement Status Section Indicator Scroll Bar Stability Indicator Las 75 1 dB 2 97 2 dB 1 Center Right Softkeys FIGURE 2 1 Data Display Screen Overview 2 1 Display Sections and Icons Screens Tabs Page Scroll Bar and Section Indicator Power Indicator Measurement Name A Screen comprises everything which can be seen on the display at one time There are four different screens available with the LxT which are described in more detail in the section Screens on page 2 11 The tabs indicate the active page as well as any other possible pages available in this view This is the main body of the screen The page contains the data to be viewed There may be more than 1 section for a page This is indicated on the scroll bar The scroll bar represents the complete page The section indicator shows the location on the page you are viewing One of the three possible images indicating the state of the battery charge or the external power connection icon will be displayed to indicate that the batteries or power supply are providing sufficient power to oper
136. PL1 Trigger Level Indication of Current Exceedance of SPL1 Trigger Level FIGURE 5 3 Live Page Section 2 In addition to displaying the current value of Leq this display uses a check mark to indicate a current exceedance of the SPL trigger level which is user defined as described in section Triggers Page on page 4 17 LxT Technical Reference Manual Live Page 5 3 1 1 Octave Band Analyzer Optional The 1 1 Octave Band Analyzer display appears only when the instrument is loaded with the optional LxT OB3 firmware Frequency Spectrum Bandwidth Frequency Frequency Band Level at Cursor Position Weighting and Averaging for Spectrum Measurement TERIS 0 00 28 1 Live aa 140 Time 100 60 20 1 1 Octave 1 00kHz z Slow L 1 00kHz S 53 0 dB Las 82 0 dB Sound Pressure Level Frequency Weighting and Averaging as Indicted by Subscripts FIGURE 5 4 Live Page Section 3 Note that the graph scaling can be modified as described in section Adjust Graph Scale on page 5 19 Cursor 5 4 Live Page Started 2007 Apr 16 13 21 32 Section 2 shows a bar graph of sound level in 1 1 octave frequency bands The right most bar on the graph is the Las The spectrum frequency weighting is selected independently from that of the sound level measurement as described in OBA Frequency Weighting on page 4 7 The detector is the same as that of the sound level measurement Use the
137. Percent Of Measurement SPL1 Trigger Level Time Above SPL1 Trigger Level Maximum Level using Frequency Weighting and Detector from Setup LASmax 78 9 dB Peak Level using Frequency LZpeak 79 3 dB Weighting from Setup Run Time 0 01 50 2 Measurement Duration FIGURE 5 9 Overall Page Section 2 Note that the graph scaling can be The graph in Section 1 presents a data compressed profile of modified as described in section the sound level for the run time of the measurement The run Adjust Graph Scale on page 5 19 time for the average calculation 1s shown at the top of the screen The graph is updated once per second and the calculation of the average sound level is updated approximately four times a second The process is continuous throughout the run time LxT Technical Reference Manual Overall Page 5 7 Maximum Minimum and Peak Sound Levels Leq using Frequency Weighting and Detector from Setup Lpeak using Frequency Weighting from Setup Measurement Run Time See Chapter 2 RESET Key on page 2 7 5 8 Overall Page KD 0 01 45 3 TA Overall Current SPL using Frequency Weighting and Detector from Setup Laseq 65 0 dB 4 Maximum SPL Measurement with Date Time Occurrence Las 1 2 1 2007 Apr 16 13 35 14 Minimum SPL During Measurement with Date Time of Occurrence FIGURE 5 10 Overall Page Section 3 The L7peak
138. Record to Change Metrics FIGURE 9 7 Left Right Arrow Change Record 9 7 When the left right arrow symbols appear to the left of Record as they did in FIGURE 9 6 pressing the left or right arrow key will move the cursor left or right respectively selecting a different record to be displayed The text message Enter gt Change Metrics indicates that pressing the key will change the role of these keys to stepping through the metrics while the record number remains the same Doing so will change the lower portion of the display to that shown in FIGURE 9 8 eq 200 ms 85 0 dB Left and Right Arrow key gt Leg 85 0 dB Step through Metrics The time history graphs for Leq x and the selected time history parameter are overlaid the display not visible in FIGURE 9 6 because the selected parameter is the same as the Leq x rd 2 134 2007 May 22 14 42 26 Enter gt Change Record Switch role of left right arrow keys from Change Metrics to Change Record FIGURE 9 8 Left Right Arrow Change Metrics When the left right arrow symbols appear to the left of one of the user selected metrics pressing the left or right arrow key will step sequentially backward or forward through the list of measured metrics and change the display accordingly The text message Enter gt Change Record indicates that pressing the key will change the role of these keys to moving the cursor left or right respecti
139. Serial Number Recycling PCB Piezotronics Inc is an environmentally friendly organization and encourages our customers to be environmentally conscious When this product reaches its end of life please recycle the product through a local recycling center or return the product to PCB Piezotronics Inc Attn Recycling Coordinator 1681 West 820 North Provo Utah USA 84601 1341 where it will be accepted for disposal Table of Contents Chapter 1 Introduction About This Special Features of the Electronic BOOKITBr ed eto oso fie Pa Opening Bookmarks sse Closing Bookmarks Expanding Bookmarks Click to Display a Page Return to Previous em Click a Link to Display a Return to Previous VieW cccccccccccccceeeceseeaeaeseasseaeeeeeseeess Cross References 00 0 Click Cross Return To Previous t PH 9 Basic Basic cuni Dt Available O PONS
140. SoundTrack Sound Level Meter Operation Manual Larson Davis SoundTrack LxT Technical Reference Manual 1770 01 Rev F Supporting Firmware Version 1 3 Copyright Copyright 2006 2007 by PCB Piezotronics Inc This manual is copyrighted with all rights reserved The manual may not be copied in whole or in part for any use without prior written consent of PCB Piezotronics Inc Trademark SoundTrack and Blaze are registered trademarks of PCB Piezotronics Inc Disclaimer The following paragraph does not apply in any state or country where such statements are not agreeable with local law Even though PCB Piezotronics Inc has reviewed its documentation PCB Piezotronics Inc makes no warranty or representation either expressed or implied with respect to this instrument and documentation its quality performance merchantability or fitness for a particular purpose This documentation is subject to change without notice and should not be construed as a commitment or representation by PCB Piezotronics Inc This publication may contain inaccuracies or typographical errors PCB Piezotronics Inc will periodically update the material for inclusion in new editions Changes and improvements to the information described in this manual may be made at any time Record of Serial Number and Purchase Date LxT Model LxT1 LxT2 Serial Number Preamplifier Model Serial Number Microphone Model
141. Statistical sirsie sikeee rao nennen nennen 18 4 Pause a Rule ee ete e ce 2 10 o E ESI t TRO EA T AE t EOD ET ecu 2 4 Power Control Screen eene eere 2 11 Power Indicator 2 2 Power Save 12 6 Power Suppli s 1 11 Power Supply aet aa epi rna an et der PALE MU alot 17 7 5 020 0 M 17 8 E 3 7 Power Switch Hardware 2 2 22 2 01 6 000000000000000000000 81 3 6 Preamplifier Definition err D 16 Preferences Page s Ree ERRARE ape Se 12 7 PAISES REP rH ED 12 8 uoi 12 13 Decimal Symbol SERERE IER ET AUI EB TORRE Noui 12 12 eee RE ER e e AS NE VE uen e SPEO ree ues 12 10 R Refresh File List ore o ER ee ree eer petes 11 6 Rename File 5 ovi tsi ron etie ape tav anis 11 5 Reset Icon dnte demone eat tee io p Wh e TRE d 2 4 Reset Prompt soe ertet em Werte te work cose RTI bb 12 10 Run Control Measurement History 11 2 2 40002002111000000000000000000000000000000000 000000000003 10 5 ND 6 1 Without Measurement History 1 0000410 100 00400000000000000000000000000000000000000
142. Value Metrics 222222 9 6 Data Display at Cursor Position 9 6 Left Right Arrow eem 9 7 Displaying Other Single Value Metrics 9 8 Frequency Spectra ou perdere cesa chos evo Ebr papi 9 9 Left Right Arrow 9 10 Link to Measurement History Display 9 11 Markers Mee M 9 12 Markers ascen cui oce 9 12 Naming a 9 13 Using Markers epi end ege 9 13 Setting Markers 9 14 Setting All Markers 9 14 Close Marker Control Window eene 9 14 Markers Display eerte 9 15 Chapter 10 Measurement History 10 1 Run Control with Measurement History 10 1 Continuous and Timer Modes 10 2 LxT Technical Reference Manual 1 7 Interval Time Sync enne 10 2 Valid Measurement Times ssee em 10 2 Other Measurement Times 10 3 Timed Stop Mode 4 rrr xe ca eua so to nena natare 10 3 Measurement 10 3 Example tnde teet eld a eat bolo 10 4 Manual and Stop When Stable Modes 10 4 Display of Measurement
143. a s 0 15 T t tj the time interval for measurement in seconds for sound exposure level and time average sound level The SEA parameter used mainly in the Canadian provence of Quebec It is based on the theory that impulsive sounds Integrated Level Calculations E 9 above 120 dBC have an effect on hearing loss which is in addition to the that caused by non impulsive noises It calls for the calculation of the parameter Leq peak value which is calculated as follows N L 10 Leq peak value 10 logio 1 2 10 The value of SEA is then determined as follows SEA Leq peak value 10 10910 Where SEA Acoustical Energy Sum Leq peak value Equivalent level of impact noises Ln PeakC level of the nth impact noise N Total number of seconds with an impact noises to which the worker is exposed during one working day number of impact noises for each level of impact noise over 120 dBC evaluated once per second impact noise below 120 dBC are not considered Examples of results SEA 160 dB for 100 impact noises at 140 dBC SEA 160 dB for 200 impact noises at 137 dBC SEA 137 78 dB for 6 impact noises at 130 dBC The formula implemented in the LxT is a simplification of the above N L 10 SEA 10 10910 10 n 0 Integrated Level Calculations LxT Technical Reference Manual Community Noise Descriptors Lon The day night level Lpy defined by the following formula 0700 2200 2
144. a stored in USB memory File System 16 3 16 4 File System LxT Technical Reference Manual LxT Hardware Components Microphone Microphone Preamplifier 160 240 Graphic LCD Display Context Sensitive Softkeys Fixed Function Hardkeys FIGURE 17 1 LxT Front View LxT Technical Reference Manual LxT Hardware 17 1 Microphone and Microphone Preamplifier Display 17 2 Components There are three models of microphone four preamplifiers available for use with the LxT There are three equivalent electrical impedance adaptors available These are discussed in Chapter 1 Optional Accessories on page 1 10 The LxT has a 160 x 240 graphic liquid crystal display The display is backlit to provide comfortable viewing in most ambient light situations Controls are provided for contrast and backlight adjustments These controls are discussed in Chapter 2 Power Control Page on page 2 6 and Chapter 12 Power on page 12 5 LxT Technical Reference Manual STOP STORE ENTER Softkeys LxT Technical Reference Manual SOFTKEYS Center Right RUN PAUSE FIGURE 17 2 LxT Keys The three push button keys just beneath the display on the body of the LxT are called Softkeys Above each Softkey on the bottom of the display is an icon that may contain a label The label indicates the action which will take place when the key is pressed Softkeys are so named because the role of each key
145. adio frequencies levels AC Power and Radio Frequency Susceptibility The mode of operation of the LxT2 that produced the greatest measurement susceptibility to A C power frequency and radio frequency fields was with the LxT2 set to run USB cable attached and with an 010 10 microphone extension cable between the PRMLxT2 and the LxT2 C 20 LxT2 LxT Technical Reference Manual APPENDIX Allowed Exposure Time Average Sound Level Layg LxT Technical Reference Manual Glossary This appendix contains technical definitions of key acoustical and vibration terms commonly used with Larson Davis instruments The reader is referred to American National Standards Institute document 51 1 1994 for additional definitions Specific use of the terms defined are in the main body of the text It is the allowed time of exposure to sound of a constant A weighted sound level given a chosen Criterion Level Criterion Duration and Exchange Rate The equation for it is T T C C 1079 1974 where L is the Criterion Level T is Criterion Duration Q is the Exchange Rate K is the Exchange Rate Factor and Layg is the Average Sound Level Example If L 90 T 8 3 and L 95 then A 8 1905 9510 5095 90773 5 656 5 39 This means that if a person is in this area for 5 hours and 39 minutes he will have accumulated a Noise Dose of 100
146. age Highlight the Language field and press the key to obtain a listing ofthe language choices as shown in FIGURE 12 13 English FIGURE 12 13 Language Preferences Highlight the desired language and press the key to make a selection The LxT supports two formats for the decimal symbol Period Comma Highlight the Decimal Symbol field and press the key to obtain a listing of the choices as shown FIGURE 12 14 Comma FIGURE 12 14 Decimal Symbol Preferences LxT Technical Reference Manual Highlight the desired symbol and press the key to make the selection Date Format The LxT supports two formats for expressing dates e day month year year month day Highlight the Date Format field and press the key to obtain a listing of the choices as shown in FIGURE 12 15 FIGURE 12 15 Date Format Preferences Highlight the desired Date Format and press the key to make the selection Units The LxT supports both English and SI units Highlight the Units field and press the key to display the Units Menu as shown in FIGURE 12 16 SI FIGURE 12 16 Units Menu Highlight the desired Units and press the key to make the selection LxT Technical Reference Manual Localization 12 13 Displays Note that the default values for these Displays page shown in FIGURE 12 17 permits some parameters are as shown in customization of the displays FIGURE 12 17 010437 System Properties
147. aging to hearing Zero represents no exposure and 100 or more represents complete exposure It is calculated by dividing the actual time of exposure by the allowed time of exposure The allowed time of exposure 15 determined by the Criterion Duration and by the sound level the higher the level the shorter the allowed time The sound levels must be measured with A frequency weighting and slow exponential time weighting See Projected Noise Dose where T is Measurement Duration T 1s Criteria Time Glossary D 15 Noise Exposure OSHA Level LosuA Preamplifier Projected Noise Dose Single Event Noise Exposure Level SENEL Lax Sound D 16 Glossary _ 1007 1 12 4 0 is TWA L is Criteria Level q is exchange rate factor see page D 8 Exchange Rate Q Exchange Rate Factor q Exposure Factor k Standard ANSI 12 19 See Sound Exposure The Average Sound Level calculated in accordance with the Occupational Safety and Health Administration Exchange Rate and Threshold Level A part of the sound level meter that matches a particular model of microphone to the meter It must be chosen in conjunction with a microphone and a cable that connects them It is the Noise Dose expected if the current rate of noise exposure continues for the full Criterion Duration period The total sound energy over a specific period It is a special form of the Sound Exposure Level where the time period is
148. al Reference Manual Calibration When The LxT Is Locked When the LxT is in any of the lock modes and is stopped the unit may be calibrated This is only possible if the Allow Cal When Locked check box on the Lock Page has been checked previous to entering Lock mode See FIGURE 13 6 Allow Cal Check Box If the Center Softkey indicating CAL is active as shown in FIGURE 13 14 press this key This will bring up the calibration screen See Chapter 15 Calibration on page 15 1 for complete details on calibrating the LxT 0 10 43 7 Date 2007 Apr 16 17 08 46 This instrument has been LOCKED Press the Tools key to UNLOCK FIGURE 13 14 Locked with Calibration Permitted LxT Technical Reference Manual Calibration When The LxT Is Locked 13 9 13 10 Calibration When The LxT Is Locked LxT Technical Reference Manual CHAPTER About The About Pages give summary information concerning the instrument available options and instrument identification Control Panel About To activate the About Pages press the A TOOLS key Use the C or keys to highlight the About icon as shown in FIGURE 14 1 Control Panel 037438 Control Panel Setup Manager Voice Recorder Properties Close FIGURE 14 1 Control Panel Press the key to open the About Pages There are three About Pages that may be selected using the Right and Left Softkeys All About Pages have one section There is no u
149. al Reference Manual Voice Recording 8 1 Voice Recorder 8 2 Voice Recorder 0 00 00 9 oice Recorder gt Voice 1 2007 Apr 16 15 23 44 Keypress Measurement gt 2007 Apr 16 15 23 52 gt 2007 Apr 16 15 26 35 FIGURE 8 2 Voice Recorder The Voice Recorder Page will present a list of existing voice records The scroll bar and section indicator depict where you are in the list of files Using the C 7 and keys scroll through the list of voice records You may playback the highlighted voice record through a headset speaker by pressing the Right Softkey When measurement data is stored all voice records that are shown on the list will be stored in the data file The voice records list will then be empty LxT Technical Reference Manual Save Prompt LxT Technical Reference Manual With a headset and microphone attached to the headset jack on the bottom of the LxT a voice record can be made Record Button Press the Left Softkey to begin recording The Recording message box will appear The meter indicates the relative signal level from the recording microphone and the progress bar shows the elapsed time of the measurement The progress bar length represents 20 seconds which is the maximum time for a voice recording FIGURE 8 3 Recording Press the key to stop recording if 20 seconds has not elapsed At the end of 20 seconds recording will stop automatically When the reco
150. ambplifl r rere ite eet ae e en D 16 Projected Noise D 16 LxT Technical Reference Manual 1 15 oec aeter 0 16 Sound Exposure SE sese D 17 Sound Exposure Level SEL D 17 Sourid PressUres is eset o i tei D 18 Sound Pressure Level SPL D 19 Sound Power W centena D 21 Sound Power Level PWL D 21 Sound Speed D 21 Spectrum Frequency D 21 Threshold Sound Level Lt D 21 Time Weighted Average Sound Level TWA LTWA TC D 22 Time Weighting 44000 a D 22 bleu E P D 22 Wavelength 2222 2 2 1 4 2 0 nnns D 22 Wavenumber k eiie teen nnns D 23 Appendix D Integrated Level Calculations 1 Basic Integrated Level Calculations E 1 Equivalent Continuous Sound Level E 1 Time Weighted E 2 SEL Galculations 2 erected endl E 4 Dose and Projected Dose Calculations E 5 Sound Exposure Calculations E 8 Sound
151. and Exponential Exponential Integration Exponential integration would typically be selected to provide compatibility with older analog instruments in Setup Pages 4 5 which all measurements involve exponential time weighting of signals Exponential detectors have a tendency to hide small events in the long decay of a loud impulsive event Linear Integration Linear integration integrates only energy that occurs during a given time period and therefore does not exhibit the decay slope of a Fast Slow or Impulse exponential detector The value of the integrated level is displayed immediately following the end of the integration time For long duration measurements both integration methods report the same value in that they both have equivalent energy under the curve although short term metrics may vary Octave Band Analyzer Page Optional The default values for these parameters are as shown in OBA Parameter Selection 4 6 Setup Pages This page will only appear when the LxT has the optional LxT OBI or Lx T OB3 firmware enabled 001190 s Max Spec Close FIGURE 4 5 OBA Page The OBA parameters are selected as shown in LxT Technical Reference Manual Left Click to Select lt 0 01 19 0 4 4 Settings METI obs OBA Range B Normal O Low Bandwidth Freq Wt Max Spec FIGURE 4 6 OBA Parameter Selection Turning off the frequency analysis will reduce
152. ar Using the 7 0 keys highlight the data field of the numerical parameter to modify Press the key to highlight the 1st character position in the date year or time field The C7 y eys are used to modify the parameter Press the key when modifications are complete Selecting the Month When the Month box is highlighted pressing the key will drop down a list of months See FIGURE 12 4 Month List LxT Technical Reference Manual Time 12 3 Sync Data Time with 12 4 Time FIGURE 12 4 Month List Use the 7 and keys to highlight the desired month Press the eer key to accept the selection and exit the field Selecting the Sync Date Time with PC check box enables the LxT time to be set to the PC time when the unit is connected to the SLM Utility G3 software This function is enabled if there is an X in the check box To modify the state of the Co box move the highlight to the check box and press key The state of the check box will change LxT Technical Reference Manual Power Auto Off Time LxT Technical Reference Manual D 0 40 37 2 System Properties Power Save Time Backlight Time Backlight Display Contrast Battery Type FIGURE 12 5 Power Page There are five drop down list fields and one scrollable value field on the Power Page These fields are selected and modified as discussed in the previous sections Auto Off time is the duration of time the in
153. are options enabled and the setup used Use the C 7 and keys to page sequentially through these different data displays With the exception of the first display these displays are similar to those displayed on the Measurement Page as described in the next section The main difference is that there is no reference to a record number In the first display shown in FIGURE 10 4 the Ist numerical value displayed Lageg in this example is Leq Display of Measurement History Data 10 5 Measurement Page Selected Measurement Record Number Cursor Position Graph of Leq Values for each Record in sequence by time Leq and Max Values at Cursor Position using the frequency weighting and detector from the setup The 2nd numerical value displayed As in this example is a user selected parameter This parameter is selected the same as for the Live SLM Display described in User Selected SLM Parameter on page 5 3 The Measurement Page can display data for any one of the previously completed measurements These measurement records are numbered in sequence from the first to the last The data displayed in the first section of the Measurement Page is shown in Figure 10 5 History Number of Records Measured Measurement Duration Date and Time of Measurement 53 7 dB 65 2 dB M LASeq LASmax FIGURE 10 5 Measurement Record Display Measurement Page Section One During the first measurement the same data will appear
154. asured parameter is in an under range condition it s numeric display will not appear Display Sections and Icons 2 3 OBA Overload Icon Measurement Status 2 4 If the input to the Octave Band Analyzer optional firmware LxT OBA required becomes overloaded the icon shown will appear to indicate the overload This icon operates similar to the Input Overload Icon shown in the above section Input Overload Icon When the OBA Range property is set to Low the OBA Overload Icon will activate at a level 30 dB lower than it would had the OBA Range been set to Normal Reset Icon The Reset Icon indicates that a reset has occurred Run Next Icon The Run Next icon appears when the CA RUN PAUSE key is pressed and the LxT is waiting for filters and detector initialization to complete The LxT will automatically start the run after the wait or warm up state is completed less than 10 seconds Run Icon The Run Icon moves from left to right to indicate that a measurement is running Pause Icon The Pause Icon indicates that the present run has been paused Display Sections and Icons LxT Technical Reference Manual Softkeys Changing Views Keypad LxT Technical Reference Manual Stop Icon A Stop Icon is displayed when a measurement has been stopped Store Icon When a data file has been stored the Store Icon is displayed Beneath the display on the body of the LxT there are three Softkeys as show
155. asurement will consist of data measured over different blocks of time between the start date and time and the end date and time The selection and setting of appropriate parameters for the Continuer Single Block Time and Daily Timer run modes is shown in FIGURE 6 4 0 00 00 0 Settings Stop When Stable Control gt Continuous Run Mode Single Block Timer Single Block Timer Enable Measurement History Daily Timer btart Time End Time e009 ettings EE Control Run Mode LJ Enable Measurement History btart Time End Time open z roce Click to open data fields for blocks 2 12 and 3 Close FIGURE 6 4 Setup of Continuous Daily Timer and Single Block Time Run Modes Entering Delta Level Entering Time The Delta level is the maximum one minute change in overall average level ie Laeg allowed for the measurement to be considered stable The Time is the duration that the measurement must run before the measurement can stop If the time were set to 0 the measurement would run until the stability condition was met 6 4 Run Modes Without Measurement History LxT Technical Reference Manual If a duration is set the measurement would run for the duration specified and then continue until the stability condition was met For each use highlight the desired data field and_press the key Enter the desired values and press the key When the Auto St
156. ate Griterlon mate tse SA Dist DEED Data Display II Octave Band Analyzet NECI Re 1 3 Octave Band 1 Data Live En P rcentiles est Re UE Reti itte eie t tute e De d us Max Min and Peak Sound Levels sss eee 0 oft Meas rementsz cene rond WE ORT RN GRE Ti LER Number of Measurement cccccccccsccsssecsecessecsseecsseceseeceeeeseceesesseseseeceeseseseeseceseees Octave Band Analyzer dan tee t eet tei Re OR se ceo Overallu Overall Enforcement Levels Overloads ist E CRT m tetti Session de iate Sound Level Profile A E T erret ter enne Tabbed Page Time Battery Voltage and TAS EE Display Screen cece dte ee ED Data Explor t e eee tirer imde iv ed ista foe Cette ote mta dte LxT Technical Reference Manual Index 1 3 File Ga Eu 11 3 Jump to Beginning File eren 11 7 Jump to End teer tee ete es Ne hee 11 7 Toad Set ngs iue tee OH ER Eb i ROME e on A 11 7 Oyerwtite File 5 nne eee pepe eH edis 11
157. ate the meter within specifications This is the file name to be used for the data file 2 2 Display Sections and Icons LxT Technical Reference Manual Stability Indicator Run Time Input Overload Icon Under Range Icon LxT Technical Reference Manual For certain measurement modes and for calibration an indication of the stability of the measured signal is presented in the following icon This is the amount of time the measurement has been running When a signal from the preamplifier exceeds the calibrated input range of the LxT the Input Overload Icon will appear While the overload is present the icon will flash on and off When the overload is removed the icon will be removed from the display If a measurement is running and an overload occurs the icon shown below will flash during the overload SLH When the overload has been removed the icon will still be present not flashing to indicate that an overload has occurred during the measurement A reset will clear the icon from the display When the signal from the preamplifier drops to the point where the noise level of the instrument and the preamplifier influence the measurement an under range condition exists When this happens the Under Range Icon will appear As long as the under range condition exists the icon will flash When the measured level no longer produces an under range condition the icon will be removed from the display Whenever a me
158. begin the measurement A measurement cannot be Paused Stopped or Stored in the Fully Locked mode To unlock the LxT press the A TOOLS key Unlock Enter 4 digit code 000 FIGURE 13 9 Unlock The key or the Right or Left Softkey may also be used The CY CCS keys are used to enter your 4 digit code then press the E key The Model LxT is unlocked and all functions are available to the user Locked With Auto Store If the Locked w Auto Store mode has been selected upon accepting the changes on the Lock Page the view would 13 6 Locked With Auto Store LxT Technical Reference Manual Unlock LxT Technical Reference Manual look as shown in FIGURE 13 10 Locked with Auto Store or Manual Store 9 0 01 53 1 Date 2007 May 18 16 23 34 LOCKED 473 Laseq 49 4 Las 43 4 dB Started2007 May 18 16 22 03 FIGURE 13 10 Locked with Auto Store or Manual Store In this mode measurements may be started by pressing the CA RUN PAUSE key A measurement may not be Paused or Stopped Pressing the STOP STORE key will initiate storing the data file Measurement OK FIGURE 13 11 Auto Store Stop Use the keys to select the desired response If Yes is selected the data file will be saved The unit is still locked and a new measurement may be started by pressing the RUN PAUSE key If No is selected the data is reset and a new measurement may be made To
159. chcraft female 200 feet long ADP076 12 pF equivalent Microphone with BNC Connector input ADP008 Adapter for 1 microphones ADP040 Microphone Signal Tee ADP043 Adapter for 1 4 microphones ADP068 Preamplifier holder for preamplifiers on microphone stand Table A 26 Optional Accessories Larson Davis provides a complete line of acoustic measurement tools including dosimeters sound level meters real time analyzers preamps calibrators and microphones A 46 Technical Specifications LxT Technical Reference Manual Preamplifier Model PRMLxT1L Serial Number 0102 Larson Davis Certificate of Electrical Conformance Frequency response of this model PRMLxT1L preamplifier was tested at a level of 1 157 Vrms with 18pF microphone capacitance and driving a short cable Output level at 1kHz is 1 0167 Vrms 0 144 dBV uncertainty 0 035 dB Output is 3 664 V DC uncertainty 0 001 Results are displayed relative to the level at 1kHz 0 5 50 100 200 501 1000 1995 5012 10000 19953 50000 100000 Frequency Hz Measured dB Uncert dB Tolerance dB 075 0 49 gt 2 0 10 0 0 32 a 43 5 0 10 0 0 22 x A 0 10 0 0 12 36 2 5 0 10 0 0 04 3 5 0 10 0 0 01 0 10 0 0 03 2 y 0 10 0 0 05 y 0 10 0 0 06 5 0 10
160. ck LxT Technical Reference Manual Lock Unlock the LxT To prevent unauthorized use or tampering with measurements and data the LxT has a lock feature When this is enabled the LxT is tamper proof to a level selected by the user There are 4 levels of security provided by this feature To activate the Lock Page press the A TOOLS key Use the 7 keys to highlight the Lock icon as shown in FIGURE 13 1 Control Panel v 0 10 43 7 Control Panel Setup Manager Voice Recorder System Properties System Lltilities FIGURE 13 1 Control Panel Press the key to open the Lock Page There is one Lock Page There are three items on this page the user may configure Lock Unlock the LxT 13 1 13 2 0 10 43 7 Lock Mode Unlock Code Enter a 4 digit code to use when unlocking this unit O Allow Cal When Locked FIGURE 13 2 Lock Page Using the 7 aa C keys highlight the Lock Mode list box Press the key to drop down the list 0 10 43 7 i Lock Mode Unlocked Unlock C Lock w Auto Store Enter a dLock w Manual Store when un Fully Locked O Allow Cal When Locked FIGURE 13 3 Lock Mode List Use the 7 or keys to highlight the desired lock mode Press the key to accept the selection Control Panel Lock LxT Technical Reference Manual Lock Modes Unlocked Lock w Auto Store Lock w Manual Store In this mode the Auto Store preference is disabled see C
161. clude a programmable threshold with only levels above this threshold contributing to the measurement No attempt is made to meet the IEC 61672 1 requirement to title the TWA by frequency weighting and time interval within the analyzer s display or report system The E 2 Integrated Level Calculations LxT Technical Reference Manual Frequency Weighting and Time Interval are both displayed in the same view to meet this requirement The following figure indicates how the requirements are met in the LxT 0 00 15 9 LxT_Data TA Overall 501007109 The numerical value for the TWA and Proj TWA 41 4 dB 95 5 dB 66 5 dB 0 12 213 75 The currently selected Frequency Weighting A and 9 Weighting A Slow xchange Rate 5 dB Detector Response Slow for SPL LE dinde 90 0 dB Ud riterion 8 0 h 90 0 dB The currently selected Exchange Rate Run Time 0 00 15 9 Threshold Level Elapsed measurement time shown as h mm ss s FIGURE E 1 TWA Note that the LxT displays the time actual equations used within the LxT are based those weighted average as TWA Hr for IEC 61672 1 and are implemented according to this where Hr is the time in hours over equation which the average is performed n Loy Leart ke log gt 10 log n s l where Lis is the current SPL at sample s for measurements that include a threshold L is set to x if Lc is less than the Threshold Level L LxT Technical Ref
162. con on the toolbar of the SLM Utility G3 software After communication has been established the Instrument Manager shown in FIGURE B 1 will appear sound Track LxT Instrument Manager Instrument Status Settings Manual Control Download Calibrate System Model LxT1 Serial Number 0001152 Firmware Version 1 210 2006 Jun 23610 50 10 50 Power 5 2 Volts Battery 5 0 Volts USB Free Memory 20657 out of 21007 kB remaining Records 8 Files Instrument Time 22 March 2007 16 03 18 Computer Time 22 March 2007 16 03 51 FIGURE B 1 Instrument Manager B 2 Upgrading LxT Firmware LxT Technical Reference Manual Left click the Manual Control Tab to open the Manual Control page shown in FIGURE B 2 SoundTrack LxT amp Instrument Manager n Instrument Status Settings Manual Control Download Calibrate System Run Control Data Files Reset Click Reset Current Data to reset Run Status STOPPED overall data Reset Current Data Lock Control Refresh Lock Status Unlocked Browse SoundTrack LxT Files UnLock Upgrade SoundTrack LxT Restore SoundTrack LxT FIGURE B 2 Manual Control Page LxT Technical Reference Manual Upgrading LxT Firmware B 3 Left click the Upgrade SoundTrack LxT box to run the SLMFirmwareProgrammer software which will produce the display shown in FIGURE B 3 SLMFirmwareProgrammer Welcome This software allows you to upgrade the firmwa
163. coustic Calibration 2 4 1 15 4 Frequency Weighting 15 4 15 5 Recommended 15 5 Calibrating the LxT1 and 377 02 15 5 Calibrating the LxT2 and 375A02 15 6 Environmental Parameter 15 7 Adding a 15 8 Microphone 15 9 Performing the 15 10 Warning 15 10 Calibration Results 15 11 Sensitivity Page 15 12 NOISE 5 ators 15 12 Direct Data Input tod ote nea rentre aae 15 13 pyerload 15 13 Under Range 15 13 1 10 LxT Technical Reference Manual Calibration Without 15 14 C rtificati N ETE 15 15 Chapter 16 System Utilities 16 1 Control Panel System Utilities 16 1 File SY Ste PC 16 2 Check File System 4 4 16 2 Format PE 16 3 Format amp Restore Defaults
164. ction Shell Connect to preamp housing Table A 27 Input Connector Compatibility Use with ACO 375A02 or any 4 electret microphone having about 20 mV Pa sensitivity and meeting the mechanical requirements of IEC 61094 4 It can be used with either the Larson Davis ADP043 or ADP008 adapters for or 1 electret microphones A 50 Technical Specifications LxT Technical Reference Manual Optional Accessories 010 EXC020 EXC050 EXC100 EXC200 Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 10 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 20 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 50 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 100 feet long Extension cable 5 pin Switchcraft male to 5 Pin Switchcraft female 200 feet long ADP005 18 pF equivalent 2 Microphone with BNC Connector input ADP008 Adapter for 1 microphones ADP040 Microphone Signal Tee ADP043 Adapter for 1 4 microphones ADP068 Preamplifier holder for 2 preamplifiers on microphone stand Table A 28 Optional Accessories In the interest of constant product improvement specifications are subject to change without notice Larson Davis provides a complete line of acoustic measurement tools including dosimeters sound level meters real time analyzers pream
165. d 4 can be defined Once defined the user can chose to display the live SPL spectrum normalized to any one of these four reference spectra by using the Ref field to select the one desired 5 22 View Spectrum Normalized LxT Technical Reference Manual Normalizing using Frequency Weighting Note that normalized displays can be rescaled using the Graph Relative feature described in section Graph Relative on page 5 28 or adjusted as described in section Adjust Graph Scale on page 5 19 LxT Technical Reference Manual When normalizing using positively signed A and C this normalization subtracts a spectrum which is the inverse of the spectrum representing the corrections Thus by selecting A or C this will negate the frequency weighting effect on spectra which had originally been measured using A or C frequency weighting To obtain an A or C weighted spectrum when the measurement had been made without frequency weighting select A or C for the reference For example when the measured spectrum is similar to Figure 5 25 on page 20 by selecting A the normalized view displays an A weighted version of this spectrum as shown in FIGURE 5 30 Q 0 00 00 0 40 LxT_Data Normalized Spectrum moque 110 70 in gt l n 13 10 30 10 05 O Graph Relative 2007 30 12 03 56 Close FIGURE 5 30 Spectrum From FIGURE 5 25 Normalized using A View Spectrum Normalized 5 23 Overall Display 5 24 In g
166. d press the key to bring up the cursor Enter descriptive text to define the microphone and press the key to accept the input Acoustic Calibration 15 9 Performing the Calibration Refer to the calibrators operating instruction for more information You can simply verify the calibration by selecting No Also if no significant changes are seen you may choose to answer No also Warning Messages Carefully insert the microphone into the microphone opening in the top of the calibrator Turn on the calibrator Highlight the Calibrate button on the LxT and press the re key alibrating 113 2 dB EH 0 8 dB Cancel FIGURE 15 5 Calibrating The Calibrating message box appears The present sound level 114 0 dB the difference between the calibration level and the present sound level A and an indication of stability are displayed in this message box When the pointer in the stability indicator is vertical the sound level is stable The Cancel button is highlighted Pressing the key will abort the calibration Save Results Wes FIGURE 15 6 Save Calibration When the calibration is completed a message box appears Selecting Yes will save the results of the calibration and No will cancel the results of the calibration Highlight the desired button and press the key After selecting Yes to save the results of the calibration there are two warning messages which may appear Outside Range o
167. d the Measurement Duration specific time period See Sound Exposure Level It is defined in ANSI S1 25 as the change in sound level corresponding to a doubling or halving of the duration of a sound level while a constant percentage of criterion exposure is maintained The rate and the factors are given in the table below Standard ANSI 12 19 Exchange Rate Q Exchange Rate Exposure Factor k Factor q 3 01 10 1 4 13 333 75 5 16 667 60 6 02 20 50 There are two types of far fields the acoustic far field and the geometric far field LxT Technical Reference Manual Free Field Frequency Hz rad sec Frequency Band Pass Filter LxT Technical Reference Manual Acoustic Far Field The distance from a source of sound is greater than an acoustic wavelength In the far field the effect of the type of sound source is negligible Since the wavelength varies with frequency See the definition of Wavelength the distance will vary with frequency To be in the far field for all frequencies measured the lowest frequency should be chosen for determining the distance For example if the lowest frequency is 20 Hz the wavelength at normal temperatures is near 56 ft 17 m at 1000 Hz the wavelength is near 1 1 ft 1 3 m See the definition of Acoustic Near Field for the advantages of in the acoustic far field Geometric Far Field The distance from a source of sound is greater
168. defined as the start and end times of a noise event such as an aircraft or automobile passby The rapid oscillatory compressional changes in a medium solid liquid or gas that propagate to distant points It is characterized by changes in density pressure motion and temperature as well as other physical quantities Not all rapid changes in the medium are sound wind noise since they do not propagate The auditory sensation evoked by the oscillatory changes LxT Technical Reference Manual Sound Exposure SE Sound Exposure Level SEL Le LxT Technical Reference Manual Difference between sound and noise Sound is the physical phenomenon associated with acoustic small pressure waves Use of the word sound provides a neutral description of some acoustic event Generally noise is defined as unwanted sound It can also be defined as sound that causes adverse effects on people such as hearing loss or annoyance It can also be defined as the sound made by other people In every case noise involves the judgment of someone and puts noise in the realm of psychology not physics Rules 1 Use word sound to describe measurements to remove the emotional overtones associated with the word noise Some sound metrics use noise in their name and it is proper to use the name as it is It is the total sound energy of the actual sound during a specific time period It is expressed in Pascals squared seconds T SE where
169. description of the Data Display Screen and its associated Views see Chapter 5 Basic Data Display on page 5 1 LxT Technical Reference Manual Highlight Settings and press the key to open the Measurement Properties Screen Closing When in the Measurement Properties Screen pressing the Center Softkey now labeled Close will bring back the Data Display Screen The Tools Screen is accessed by pressing the A TOOLS key at the lower right of the LxT front panel To exit from the Tools Screen and return to the Data Display Screen press the Center Softkey now labeled Close The Power Control Screen is opened by pressing the ON OFF key while in a Data View screen To exit from the Power Control screen press the Center Softkey labeled Close There are four Data Views in the Data Display Screen identified by their titles on the tabs at the top of the screen as follows Live Data is continuously displayed in this view whether there is a measurement in progress or not Overall The data displayed in this view represents data measured and averaged beginning from the time the measurement was started by pressing the Run key until the elapsed time indicated above the display If the Pause or Stop key is pressed the elapsed time will be stopped However pressing the Run key again will continue this overall measurement as shown by the elapsed time restarting from the time when it had previously been paused or stopped S
170. detector response reduces the stabilization time required before calibration 15 4 Acoustic Calibration LxT Technical Reference Manual Calibrator Recommended Calibrator After calibration the LxT returns to the original frequency and time weighting set by the user The calibrator section of the Calibrate Page shown in FIGURE 15 2 Calibration Pages on page 15 3 includes an area to enter information about a calibrator and a list of calibrators The user may select a calibrator from the list or enter new information about a calibrator Table 15 1 Recommended Calibrators for Use with LxT1 and LxT2 lists the sound level calibrators which Larson Davis recommends for calibrating the LxT1 and LxT2 When using a 1 4 microphone the adaptor ADP024 a 1 4 microphone adaptor for the 1 2 opening in the CAL150 and CAL 200 calibrators is also required Calibrator Instrument or Output Frequency Precision CAL200 LxTI LxT2 Class 1 94 114 dB 1 kHz CAL150 LxT2 Class 2 94 114 dB 1 kHz Table 15 1 Recommended Calibrators for Use with LxT1 and LxT2 Calibrating the LxT1 and 377B02 microphone LxT Technical Reference Manual The CAL200 provides a nominal pressure level of 94 dB or 114 dB The exact levels are printed on the Larson Davis calibration sheet that came with the calibrator When using a free field microphone the pressure level at the microphone diaphragm will be slightly different T
171. dly switch from a Time History display to a Measurement History display press the Menu softkey which will produce the display shown in FIGURE 9 13 Link Measurement History Mark Sound Type FIGURE 9 13 Link to Measurement History Display LxT Technical Reference Manual Link to Measurement History Display 9 11 Markers Markers Setup Note that the default values for these parameters as shown FIGURE 9 14 9 12 Markers Markers are used to annotate portions of the time history especially for the purpose of identifying sound sources as they become dominant in the measurement The LxT offers ten separate user definable markers Markers are setup using the Markers tab page of the Measurement Setup View as shown in Figure 9 14 FIGURE 9 14 Markers Setup Window Markers 1 5 There are five markers with names predefined for convenience shown in this figure Any of these names can be changed by the user To view markers 6 10 highlight the 6 10 text line and radio buttons and press the key to obtain the display shown in Figure 9 15 LxT Technical Reference Manual Naming a Marker The process of naming markers is simplified by using the SLM Utility G3 software Using Markers LxT Technical Reference Manual 0 00 26 4 FIGURE 9 15 Markers Setup Window Markers 6 10 Highlight the field of the marker to be named and press the key This will produce a cursor which can be moved left and right
172. dware uoo edidi 17 1 Keypad Hardkeys 17 4 Parameters Measured 18 1 Sound Level Metrics Measured 18 2 Sound Exposure Metrics Measured 18 4 Memory 19 1 Technical Specifications 1 Standards Met by 1 Eu RR A 2 Sound Level Meter Specifications A 3 LxT Performance Specifications A 4 Physical A 5 General 2 2 A 5 Resolution A 6 Frequency Weightings 7 eee te ea es A 9 Min Max Integration Time A 10 Time of Day DL A 11 Power Supply A 12 Battery Operating Lifetime A 12 Memory Retention Without Batteries or External Power A 12 PSA029 AC to DC USB Power Adapter Specifications A 13 Directional Response 1 2 Windscreen A 19 Noise LxT1 PRMLxT1 with 377 02
173. e Highlight the text box with the file name Press the Enter key and the first character in the file name will be highlighted Using the C _ and keys modified the file name Press the Enter key to complete the changes Highlight the Yes button to accept the changes or the No button to discard the changes the press the Enter key If your new file name is the same as a file already in the directory Overwrite message box will appear See FIGURE 11 10 Overwrite Confirmation If you select Yes then the old file will be over written with the newly named file A response of No will return the Rename message box Use the 5 or keys to make a selection and press the eer Enter key Data Explorer 11 5 Refresh List 11 6 Data Explorer Overwrite an Existing File Another method of renaming a file is to overwrite a stored file Highlight the button and press the eer Enter key to display a list of file names as shown in FIGURE 11 8 LxT Data D01 LxT Data 002 LxT Data 003 LxT Data 004 LxT Data 005 LxT Data 006 LxT Data 007 LxT Data 008 LxT Data 009 LxT_Data 010 FIGURE 11 8 File Name List Select a name from the list and press the Enter key The Rename File will now open again with the name of the file which is to be overwritten in the file name field as shown in FIGURE 11 9 Rename File Yes FIGURE 11 9 Selection of File to be Overwritt
174. e LxT will be stopped automatically when the amount of available memory drops to 100 KB Each overall data block stored when performing a Save File operation will utilize 27 kB of memory The amount of memory utilized in bytes when storing a session log is calculated as follows 52 12 Number of records where Number of records includes all Run Pause Stop Voice Message and Marker events The amount of memory utilized in bytes when storing a measurement history is calculated as follows 52 Number of Measurement Histories Base Measurement History Size Optional Metrics Base Measurement History Size LxT Technical Reference Manual Base Measurement History Size 752 Bytes Memory Utilization 19 1 Optional Metrics 1 1 Octave 192 Bytes 1 3 Octave 576 Bytes Dose 68 Bytes Takt 4 Bytes Time History The amount of memory utilized in bytes when storing a time history block is calculated as follows 52 16 4 Number of parameters enabled Number of records where Number of Records Number of Samples Number of Run Pause and Stop events Voice Messages The amount of memory utilized in bytes when storing each voice message is calculated as follows 24 16000 Record Length where Record Length is in seconds 19 2 Time History LxT Technical Reference Manual APPENDIX Technical Specifications The specifications contained in this chapter are subject to change without notice P
175. e 5 8 M Making a Measurement sss eene enne nennen 7 1 Calibrating eee hae tenent A A hh a i a ESA 7 4 Low Level Sound 1 1 nnne 7 16 EXT SOUP C M 7 4 LxT Technical Reference Manual Index Measurement Display risen 7 6 Measurement Range a sod Er nire 7 8 Microphone Extension Cable sss eene 7 4 Observer at leitet 7 4 Overload Indication o eet nene tere ehe e e uere dt 7 8 Pausing the enne 7 9 Performing the Measurement 7 6 7 4 Recovery from Improper 7 18 Resetting the 7 13 SOPK 7 3 Start up 5 eu ertt e epe TO Se EO E OT He de t eate ft 7 2 Stopping the Measurement 5 ede ee eerie dede 7 14 Storing the Measurement sss ener nennen nnne nnn nnne 7 14 eos he De ot e UO RR EE RERO Lade 7 1 Under Range Indication usi teet RO ian E RN 7 8 Use of Windscreen ist eee ROI RU p e ede 7 5 oe iig nitet eon nm 7 3 Markers o ene od ER ER PROC ER ORE 9 12 Close Window sac ge Re ERI iet Re ihe eR ire ated 9 14 Naming dee re ac ep e qe e EE 9 13 Set ng ATEFORF
176. e are context sensitive meaning that the text or symbol above each Softkey and the associated action can change depending upon the page appearing at that time See Chapter 2 Softkeys on page 2 5 Switching On the LxT 7 3 LxT Setup Calibrating the LxT Positioning the LxT Observer Position Microphone Extension Cable Note that the electromagnetic emission conformity testing was performed using only 010 microphone extension cable which has length of 10 ft See Electromagnetic Emission page A 14 for further details 7 4 LxT Setup Set the measurement parameters of the LxT as described in Chapter 4 Basic Measurement Setup on page 4 1 The LxT must be calibrated using a sound level calibrator prior to performing a measurement The procedure for calibration is described in Chapter 15 Calibration on page 15 1 The meter will be either mounted upon a tripod or held in the hand In order to avoid the effect of sound reflections from the body of the operator interfering with the measurement the meter should be located as far as possible from the body Thus when actually performing the measurement the operator should place himself at a distance behind the tripod mounted meter or extend the hand held meter as far from the body as is comfortable If desired a microphone extension cable may be placed between the meter and the preamplifier microphone No correction is required when using Lar
177. e at 1 kHz with 5 3 Volts rms input and 18 pF equivalent microphone 2 5 Hz to 10 Hz 0 1 0 25 dB 10 Hz to 40 kHz 0 1 0 1 dB Lower 3 dB limit 1 Hz Attenuation 14 6 dB typical Input Impedance 10 G Ohm 40 pF Output Impedance 50 Ohm Maximum Output 2 8 Vpp 143 dB peak for microphones with 20 mV Pa sensitivity A 48 Technical Specifications LxT Technical Reference Manual Maximum Output Current 10 mA peak Distortion Harmonics lt 67 dBc with 0 7 Volt rms output at 1 kHz Output Slew Rate 2 V uS typical Electronic Noise with 18pF equivalent microphone 1 0 typical A weighted 1 4 uV max 1 4 pV typical Flat 20 Hz to 20 kHz 2 2 uV max Power Supply Voltage 6 to 15 Volts DC Output Level 1 2 power supply voltage Power Supply Current 1 3 mA typical Temperature Sensitivity lt 0 05 dB from 10 to 50 C 14 to 122 F operating range to 60 C 140 F Humidity Sensitivity 0 05 dB from 0 to 90 RH non condensing at 40 C 104 F Dimensions 12 7 mm diameter x 73 mm length 0 50 dia x 2 88 length LxT Technical Reference Manual Technical Specifications A 49 Microphone Thread 11 7 mm 60 UNS 0 4606 60 UNS Cable Driving Capability LxT SLM 1 V rms output signal To 20 kHz with 200 61 m cable Output Connector Switchcraft TASM 5 Pin male Pin Signal 1 Signal Ground 2 Signal Output 3 Power Supply 7 Volts 4 Preamp sense 5 No Conne
178. e is normal c Microphone Reference Point The microphone reference point is the center of the diaphragm of the 377B02 microphone d Periodic Testing Table 2 lists values of Larson Davis LxT1 with PRMLxTI 377B02 Microphone adjustment data of A weighted levels used for periodic measurements C 10 LxT Technical Reference Manual Table 2 Larson Davis LxT1 with PRMLxT1 and 377B02 Microphone adjustment data of A weighted levels used for periodic testing WS Wind Screen EA Electrostatic Actuator at a specific frequency 0 Free Field 0 Free Field 0 Free Field Corrections 0 Free Field Corrections expanded Corrections with WS Corrections with WS uncertainty from from from from of Corrections B amp K 4226 B amp K 4226 B amp K UA0033 B amp K UA0033 95 Frequency Calibrator Calibrator EA EA confidence Hz dB dB dB dB dB 31 62 0 2 0 2 0 0 0 1 0 25 63 10 0 1 0 2 0 0 0 1 0 25 125 89 0 0 0 1 0 0 0 1 0 25 251 19 0 1 0 1 0 0 0 1 0 25 501 19 0 0 0 0 0 1 0 1 0 25 1000 00 0 0 0 0 0 0 0 0 0 25 1995 26 0 6 0 9 0 6 0 9 0 30 3981 07 1 1 1 1 1 0 1 0 0 35 7943 28 2 3 1 9 2 9 2 6 0 40 12589 25 5 2 4 4 6 8 6 0 0 50 15848 93 5 4 4 3 8 1 7 0 0 60 add numbers in this column to levels read on the LxT to correct to the 0 Free Field level e Linear Operating Range Weighted sound levels indicated on the at the upper and lower limits of the linear operating
179. e operation use the key to highlight No and press the er key To select a different previously saved file to overwrite use the R key to highlight the box with the title and press the key to repeat the overwrite procedure As long as the sound level being measured is within the measurement range shown in Frequency Weightings on page A 7 inherent self generated noise and linearity problems can be ignored It is possible to correct the measured RMS sound pressure levels for the typical inherent noise levels see the noise floor specifications in Table A 4 LxT Performance Specifications on page A 4 as long as the difference between the measured sound level and the inherent noise level is greater than 3 dB This is done by subtracting the inherent sound level from the total sound level using the following formula 7 16 Storing the Measurement LxT Technical Reference Manual LxT Technical Reference Manual Lcorr idles 9 oe where Lcorr corrected sound level Lmeas measured sound level Linh inherent noise level Storing the Measurement 7 17 Recovery After Improper Shutdown Case 1 Normal Operation Improper Shutdown 7 18 When the LxT has been shutdown improperly for example a loss of power during a measurement the procedure for handling data depend upon the setup being used at the time If the Run Mode is Continuous or Single Block Timer or Daily and Daily Autosto
180. e square root this is called rms for root mean square There are several ways this can be done Moving Average The averaging process is continually accepting new data so it 1s similar to an exponential moving average The equation for it is 1 5 t Pins t 45 5 LxT Technical Reference Manual Sound Pressure Level SPL L LxT Technical Reference Manual p The sound pressure is squared and multiplied by a exponential decay factor so that when the time of integration is near the current time t it is essentially undiminished For times older less than the current time the value is diminished and so becomes less important The rate at which older data are made less influential is expressed by the constant T The larger is it the slower the decay factor reduces and the slower the response of the system to rapid changes These are standardized into three values called Time Weighting See the values below Fixed Average The averaging process is over a fixed time period The equation for it is The sound pressure is squared and averaged over a fixed time period Unlike the moving average the sound pressures in all time intervals are equally weighted The logarithmic form of sound pressure It is also expressed by attachment of the word decibel to the number The logarithm is taken of the ratio of the actual sound pressure to a reference sound pressure which is 20 MicroPascals Pa There are
181. e the C 7 and C keys to highlight the preference to be selected and left click the key to view a list of options Preferences 12 7 Microphone Correction The random incidence correction should only be selected when using a free field microphone to make measurements in a random incidence acoustic field Auto Store None 12 8 Preferences Use the 0 7 and keys to highlight the desired language and press the key to make a selection When using a free field microphone a correction can be applied to provide a random incidence response Highlight the Mic Corr field and press the key to open the Microphone Correction menu shown in FIGURE 12 7 7 FIGURE 12 7 Microphone Correction Menu Highlight FF gt IR and press the key to make the random incidence correction active The default mode is Off The LxT provides three Auto Store options to enhance your data gathering activities None Prompt Store Use the 7 CS keys to highlight the Auto Store field and press the key to obtain a listing of the choices as shown in FIGURE 12 8 FIGURE 12 8 Auto Store Preferences Use the 7 keys to highlight the desired Auto Store option and press the CD key to make the selection The user must press the 2 STOP STORE key to Stop the measurement Press it again to store the data and also assign a filename See Storing the Measurement on page 7 14 LxT Technical Reference Manual
182. ections C 15 Section tiunt LUE o d C 16 a Reference Sound Pressure C 16 b Reference Level C 17 Microphone Reference C 17 d Periodic Testing ii C 17 Linear Operating 18 f Linear Measurements Starting C 18 9 Electrical Insert Signals see C 18 h Inherent C 18 i Highest Sound Pressure C 19 j Battery Power Voltage C 19 Display Device 1 44 40000 10 000 tnnt nnne C 19 1 14 LxT Technical Reference Manual 1 Typical Stabilization Time e C 19 m Field Strength gt 10 C 19 n Radio Frequency Emission C 20 AC Power and Radio Frequency Susceptibility C 20 Appendix C Glossary D 1 Allowed Exposure Time Ti D 1 Average Sound Level D 1 Community Noise Equivalent Level CNEL Lden D 2 Criterion Duration
183. ectrical Input Sound Pressure Level dB Electrical Input Facility Vpeak Facility Vpeak 375A02 159 60 139 5 6 PRMLxT2 j Battery Power Voltage Range The battery power supply voltage range for which the LxT2 conform to this standard 6 4 Volts maximum The LxT will shut down if the battery is below 4 0 Volts when used with alkaline batteries Therefore from 4 0 to 6 4 Volts is the usable range of battery voltages The instrument will shut off to ensure that no data is taken that would not meet the requirements of the IEC61672 1 standard k Display Device The display device will display all levels over the entire linear operating range Typical Stabilization Time The typical time interval needed to stabilize after changes in environmental conditions For a temperature change of 5 C then 30 minutes are required For a static pressure change of 5 kPa then 15 seconds are required For a humidity change of 30 non condensing then 30 minutes are required Field Strength gt 10 V m The Larson Davis model LxT2 was not measured for field strengths greater than 10 V m LxT Technical Reference Manual LxT2 C 19 Radio Frequency Emission The mode of operation of the LxT2 that produced the greatest measurement radio frequency emission levels was with the LxT2 set to run and with an 010 10 microphone extension cable used to connect the PRMLxT2 to the LxT2 Adding the USB cable did not emit more r
184. ed to automatically adjust the contrast of the display to compensate for temperature changes Press the Left Softkey labeled Off to turn off the LxT Pressing the Right Softkey labeled Setup takes you to the System Properties Device Page See Chapter 12 System Properties on page 12 1 Pressing the Center Softkey labeled Close will close this screen and return to the Data View screens To reset a measurement in progress press the D RESET key This will erase all data previously measured and reset the run time clock to zero A reset will not reset stored data files A reset can be initiated when the LxT is running paused or stopped However it must be stopped for the reset operation to be performed Keypad 2 7 Resetting When Running or Paused Resetting When Stopped 2 8 Keypad If it is running or paused when the 2 RESET key is pressed a Stop Required Menu will be displayed as shown in FIGURE 2 3 Stop Required ESO Laseq 47 1 dB LAS 43 9 dB Started 2007 Apr 16 13 13 02 FIGURE 2 3 Stop Required Prompt The OK response will already be highlighted so simply press the ENTER key to continue Otherwise press the 0 key to highlight Cancel and then the ENTER key to cancel both the Stop and the Reset operations After selecting to Stop the measurement the Save File Menu shown in FIGURE 7 12 Save File Menu on page 7 14 will appear to provide a choice of saving the measured data
185. ees of PCB strive to provide superior unmatched customer service Should you find yourself dissatisfied with any PCB product for any reason consult a PCB Application engineer or local representative distributor to discuss your situation If there are any questions regarding power intended application or general usage please consult with your local sales contact or distributor B Purchase Price Refund Limited Warranty PCB warrants to the original purchaser the Buyer that unless otherwise expressly specified in writing by PCB all PCB products or repairs shall be free of defects in material and workmanship for a period of one 1 year from date of original purchase In furtherance of PCB s commitment to Total Customer Satisfaction PCB will refund 100 of the customer s purchase price for any PCB product or repair with which you are not completely satisfied The option of a refund may be selected in lieu of the repair replacement or exchange of the product Shipping Charges PCB will pay all shipping charges in connection with the fulfillment by PCB of its obligations under this Limited Warranty i at any time with respect to a defective product and ii during the first year only if the product is not defective Products Manufactured by Others This Limited Warranty does not cover any products manufactured by others Such products are subject to the warranty if any of their respective manufacturers and to be repaired on
186. egrees 28 LxT with 375A02 Microphone 45 105 and 165 degrees A 28 LxT with 375A02 Microphone 251 19 2 A 29 LxT with 375A02 Microphone 1000 00 Hz 1995 26 Hz 3981 07 and 1943 29 HE uc tati i kb EE CERES SH cud A 30 LxT with 375A02 Microphone 1258 93 Hz 2511 89 Hz 5011 87 Hz 10000 00 HZ caso ae eee A 31 LxT with 375A02 Microphone 1584 89 Hz 3162 28 Hz 6309 57 Hz and 125892512 caos teca te te tet Ur d A 32 ll Preamplifiers tute dug A 37 Certificate of Conformance PRMLXTI1 A 42 Certificate of Conformance PRMLXTIAL A 47 Certificate of Conformance 2 A 52 Certificate of Conformance PRMLXT2L A 57 Vibration Parallel to Microphone Diaphragm A 58 Vibration Perpendicular to Microphone Diaphragm A 59 Upgrade Firmware and Options B 1 Instrument 4 4 4 4 4 4 2 4 B 2 Manual Control Page toe of oic rp ete Een B 3 4 File 5 Confirm Choices Menu nn B 6 Loading Firmware Screen for Firmware Upgrade B 7 Loading Firmware Screen for Modification of Options B 8 Testing to IEC6
187. ement this will be indicated by a solid horizontal line at the top of the screen as shown in Marker Indication on Time on page 9 15 52 0 01 02 2 gt Record 1 65 2007 May 22 15 10 42 Enter gt Change Metrics FIGURE 9 19 Marker Indication on Time Note that the graph scaling can be modified as described in section Adjust Graph Menu on page 5 19 The first display labeled Run represents the keypress initiating the measurement with the corresponding data and time There will be no measured data associated with this sample point Markers 9 15 9 16 Markers LxT Technical Reference Manual CHAPTER Measurement History Measurement History is used to perform a sequence of measurements using the same setup either manually or automatically which provide the same data as is obtained from the basic measurement described in Chapter 5 Basic Data Display on page 5 1 The optional firmware LXT ENV must be enabled for to obtain the measurement history capability Timed Stop and Continuous Run Modes This chapter presents a detailed description of the setup and use of the Measurement History feature and the data displays which it provides Run Control with Measurement History It is recommended that the user become familiar with the setup of Run Modes described in Chapter 6 Run Control on page 6 1 before beginning to work with the Measurement History LxT Technical Reference Manual
188. en Highlight Yes and press the Enter key to display the Overwrite Confirmation menu shown in FIGURE 11 10 LxT Data 002 av FIGURE 11 10 Overwrite Confirmation Select the desired response and press the Enter key If you select Yes then the old file will be over written with the selected file A response of No will return to the Rename message box The Refresh List menu item will refresh the file list on the Data Explorer Page LxT Technical Reference Manual Load Settings Jump to Beginning Jump to End LxT Technical Reference Manual Using the Load Settings menu item a new measurement may be run with the exact same parameters as the selected measurement When the eer Enter key is pressed the parameters from the selected measurement are loaded so a new measurement may be made This is a convenient method to duplicate a previous measurement The Jump to Beginning menu item will select the first data file listed The Jump to End menu item will select the last data file listed Data Explorer 11 7 Data Explorer LxT Technical Reference Manual System Properties The System Property Pages are used to identify and or control functions of the LxT that are not related to sound measurement or calculations Control Panel System Properties To activate the System Property Pages press the A TOOLS key Use the V keys to highlight the System Properties icon as shown in FIGUR
189. endices covering the following topics Chapters LxT Technical Reference Manual Chapter 1 Introduction Orients the user to the contents of this user manual and the LxT features functions and measurement capabilities Chapter 2 First Use Describes the process of unpacking the LxT and preparing for first use Chapter 3 Overview A brief discussion of the displayed views the keypad and navigation through the various functions of the LxT Chapter 4 Basic Measurement Setup A detailed description of setting up the LxT for the measurement of basic sound level parameters Chapter 5 Basic Data Display A detailed look at the various metrics and information presented on these screens during and following a basic sound level measurement Chapter 6 Run Control The LxT provides a number of run modes to control the time duration of a measurement These include Manual Stop Timed Stop Stop when Stable Continuous Single Block Time and Daily Timer modes Chapter 7 Making a Measurement Describes the important steps in making an accurate sound level measurement Introduction 1 1 Chapter 8 Voice Recording The user is instructed in the process of recording reviewing and saving voice messages Chapter 9 Time History Describes the use of the optional firmware LxT LOG and LxT HSLOG for measuring time history data Chapter 10 Data Explorer Learn to use the Data Explorer to view stored data files load s
190. eneral obtaining a normalized display of 1 1 and 1 3 octave spectra appearing on the Overall Page is the same as for Live Displays described in Live Display on page 5 20 The major difference is that spectra appearing on the Overall Page display Leq Lmax and Lmin data simultaneously as shown in FIGURE 5 31 Lmax Spectrum SSeS Overall 0 Leq Spectrum Lmin Spectrum FIGURE 5 31 Overall Spectrum To access the View Normalized display press the center software Menu to display the menu shown in FIGURE 5 32 Settings View Normalized Adjust Graph FIGURE 5 32 Menu Highlight View Normalized and press the key to make the selection This will display the spectrum in the normalized view as shown in FIGURE 5 27 View Spectrum Normalized LxT Technical Reference Manual Normalized Spectrum 70 Leq Spectrum Displayed 2007 30 10 17 15 Close Edit FIGURE 5 33 Normalized Overall Spectrum No Reference Selected The Leq in the data field shown highlighted above indicates that the spectrum being displayed is Leq With this data field highlighted press the key to open the menu shown in FIGURE 5 34 FIGURE 5 34 Spectrum Type Menu Using this menu the user can select from the three spectrum types Leq Lmax and Lmin Highlight the desired parameter and press the key to make a selection If no reference spectrum has yet been defined the displayed spectrum will correspond to the se
191. enu will not appear but the Save File Menu will appear to provide a choice of saving the measured data prior to the reset or not Performing the Measurement 7 13 Starting a New Measurement Stopping the Measurement Note that the LxT can be stopped when either running or paused The Q key RUN PAUSE key must be pressed to start a new measurement Press the STOP STORE key to suspend the overall measurement Pressing the key RUN PAUSE key afterwards will continue the overall measurement which had been stopped Storing the Measurement Note a measurement can only be stored when the measurement has been stopped To store the measurement press the eS STOP STORE key one more time The Save File menu will then be displayed as shown in FIGURE 7 12 Save File Menu 0 00 22 9 Save File No AG LASmin 30 0 dB Run Time 0 00 22 9 FIGURE 7 12 Save File Menu The data will be stored under the file name defined in the section General Page on page 4 4 TEST 3 in FIGURE 7 12 along with a file number The file number automatically begins at 000 for the first measurement stored and will index so that whenever a measurement 15 stored the file number assigned will be the next in sequence following the measurement previously stored 7 14 Storing the Measurement LxT Technical Reference Manual After a file has been successfully stored the LxT will automatically reset when the
192. er describes the procedure for upgrading the LxT firmware and or options SLM Utility G3 The software program SLM Utility G3 is used to install firmware and option upgrades as well as providing remote control of the LxT and downloading data to the PC Access the Larson Davis website to see if you are using the most recent version of this program If not download the latest version from the website or call technical support The firmware will be in a zip format Unzip the file and copy the folder CD to the desktop and run setup exe in the CD folder Follow the instructions to install the upgrade The default location is C Program Files PCB Piezotronics Slm Utility G3 When the installation has been completed an SLM Utility G3 shortcut will be placed on the desktop Sim Utility G Double click this shortcut to initiate the SLM Utility G3 software LxT Technical Reference Manual Upgrade Firmware and Options B 1 Upgrading LxT Firmware The SLM Utility G3 software is used to implement the firmware upgrade The section SLM Utility G3 page B 1 describes how to determine the latest version of the software and how to update the software if you are not using the latest version Connect the LxT to the PC or laptop via the USB cable CBL 138 which is part of the PSA029 power supply and run the SLM Utility G3 software Initiate communication between the LxT and the PC or laptop by clicking the connect i
193. erence Manual Integrated Level Calculations E 3 SEL Calculations Note that the LxT displays SEL as Lxp where X is the frequency weighting X A C or Z k is the exchange rate constant which is equal to 10 00 for an exchange rate of 3dB Leq 13 29 for an exchange rate of 4dB Lpop 16 61 for an exchange rate of 5dB 20 00 for an exchange rate of 6dB L Avg n is the total number of samples taken in the measurement The sample rate is 32 samples per second is the calibration offset that corrects for various sensitivities of microphones SEL is available for the overall measurement and is calculated using this formula Lo SEL Leat ke log y 10 log 32 5 1 All of the SEL energy values in the analyzer utilize the Threshold and Exchange Rate settings Care should be taken when modifying these settings since some standards or governments require SEL to be taken without a Threshold set it to zero and with an Exchange Rate of 3 dB E 4 Integrated Level Calculations LxT Technical Reference Manual iy 0 00 19 0 i TA Overall bound Exposure Level i Sound Exposure Level 9 LASE 103 1 dB bound Exposure EAS 2 290m Pa h Sound Exposure in hours 58 3 3826 Pa h EAS40 16 913 Pa h Eas 8 2452 Pa s Sound Exposure in seconds gt 8 12177 Pa s EAS40 60887 Pa s Run Time 0 00 19 0 FIGURE E 2 Sound Exposu
194. es e AUX Connector for USB for use with USB mass storage cellular amp dialup modems GPS and future devices The installation of batteries into the LxT is discussed in Chapter 3 Inserting Batteries on page 3 5 The LxT is compatible with AA alkaline nickel metal hydride batteries and e2 Lithium batteries Energizer Duracell and other nationally recognized brands are the preferred suppliers of alkaline batteries These will provide the user with the best battery life estimation Energizer and Ray O Vac 2500 mAH AA NiMH batteries and their respective fast chargers are also recommended CAUTION NiMH batteries cannot be charged in the LxT Do not mix alkaline and NiMH batteries in the LxT Do not mix batteries from different manufacturers Replace all four batteries when installing fresh cells NiMH batteries may not be used in areas requiring Intrinsic Safety Approval Battery Voltage and Estimated Run Time are displayed on the Power Control screen and the last section of the Live Pages FIGURE 17 4 Battery Status Icons A battery icon is always available in the status bar at the top of the screen The icon shows the state of the battery charge as a full icon with fresh batteries decaying to an empty battery near the end of the battery life The battery voltage and the state of the battery icon directly reflect the remaining Estimated Run Time as displayed by the instrument LxT Technical Reference Manual
195. ession Log The Session Log is a record of data accumulation actions A time stamped record is made for every Run Pause Stop or Voice Message action Screens 2 13 with conjuction in optional using Current Measurement History This view displays data measured using the time history measurement feature Measurement History optional This view displays data measured using the time history measurement feature History optional Time suonoes 2 10 sKay C 5 pue c 5 320 A10 S1H 390 L L A10 SIH puegpeoig suonoes sjua 3 UT ensodx3 punos z 19jeuisog L jueuia240jJu3 A10 S1H A sjue 3 vas eunsodx3 punog z 19jeuusog L V80O L L juauio210Ju3 A suoljoas se suonoes vas aunsodxy punos z JajawWISOg L V8O L L jueuia240jJu3 A suonoes 5 5 V80O L V80O L L jueuie2Joju3 aloud 9 JUSIIND uoisseg S
196. ettings from a saved data file and other operations Chapter 11 System Properties A discussion of instrument related functions Chapter 12 Lock and Unlock The LxT A discussion of the various scenarios to lock or unlock the LxT and the interaction with running a measurement Chapter 13 Calibration Describes the process of calibrating an LxT Chapter 14 About A look at basic LxT system related information Chapter 15 System Utilities A description of the utilities available within the LxT Chapter 16 Hardware A description of the major hardware related features of the LxT Chapter 17 Parameters Measured An overview of the many parameters measured and recorded by the LxT Chapter 18 Memory Utilization Presents formulas to determine the memory used when saving parameters to internal memory Chapter 19 Upgrade Firmware Add Options Describes the procedure for upgrading firmware versions and adding options to the LxT Appendices Appendix A Technical Specifications Provides a listing of acoustic electronic environmental and physical characteristics of the LxT About This Manual LxT Techncial Reference Manual Appendix B Measuring to IEC61672 1 Provides specifications and information specifically required to appear in the manual by this standard Appendix C Integrated Level Calculations provides information on TWA Leq SEL Dose and Projected Dose calculations Append
197. evel Measurements Frequency Weighting See SLM Page on page 4 5 Each of the sound level parameters measured at one time will be frequency weighted as set by the user from the Measurement Properties Pages The frequency weighting for RMS and Impulse averaged sound levels will be the same selected independent from the frequency weighting for peak detection RMS and Impulse Weighting The LxT measures RMS and Impulse averaged sound level values using one of the following user selected frequency weightings A Weighting e C Weighting e Z Weighting Peak Weighting The LxT measures peak sound level values using one of the following user selected frequency weightings A Weighting e C Weighting e Z Weighting LxT Technical Reference Manual Parameters Measured 18 1 RMS Averaging The exponential averaging time for RMS sound levels is set to one of the following Slow Fast An impulse detector is also available Sound Level Metrics Measured Metric Instantaneous Sound Level Selected RMS Averaging In Table 18 1 Sound Level Metrics Measured the symbol X is used to represent the user selected RMS and Impulse frequency weighting A C or Z and the symbol Y is used to represent the user selected peak frequency weighting A C or Z The symbol V represents the time weighting Fast Slow or Impulse Impulse Integrated Lypeak Maximum Sound Level Minimum Sound Level Equivalent Level
198. f Memory Stop eese 19 1 Overall nisi 19 1 KIDCIII NE Mo 19 1 Measurement History 4 0 19 1 Base Measurement History 5 2 19 1 Optional Metrics 2 a 19 2 lectus 19 2 eec cm 19 2 Appendix A Technical Specifications A 1 Standards Met by LxT eee A 1 UXT Specifications Gasssssidececectcstenene A 2 sce NH E acti A 2 Sound Level Meter Specifications A 3 Performance 4 Physical Characteristics 5 General SpecillcallOris ueniret xa Rr 5 Resolution Specifications A 6 Frequency 68 2 222 A 7 AGI DGOUIDUE A 9 Min Max Integration A 10 Time of Day hence bien ead tees A 11 Power Supply x draco cocta cel sus A 12 Memory Retention esee nter A 12 5 029 AC to DC USB Power Adapter Specifications A 13 Electromagnetic Emission eene A 14 Declaration of
199. f Normal Sensitivity When the results of the calibration correspond to a sensitivity outside the range of the nominal sensitivity for 15 10 Acoustic Calibration LxT Technical Reference Manual that microphone the message shown in FIGURE 15 7 will appear SoundTrack LxT Calibration outside normal range Save anyway FIGURE 15 7 Outside Normal Sensitivity Range 0 5 dB From Previous Calibration Result When the results of the calibration indicate a change in sensivity greater than 0 5 dB from the previous calibration results the message shown in FIGURE 15 8 will appear SoundTrack LXT Calibration change more than 0 598 Save anyway FIGURE 15 8 0 5 dB From Previous Calibration Result The choice of whether or not to save the calibration 1s up to the descretion of the user Calibration Results When the calibration results are saved the History Page shown in section FIGURE 15 2 on page 3 is updated The parameters for this most recent calibration appear at the top of the list LxT Technical Reference Manual Acoustic Calibration 15 11 Sensitivity Page Preamplifier Presently Connected Selected Microphone Self Noise of Selected Microphone Unless Value Entered Manualfy Noise Floor Levels Noise Floor 15 12 The Sensitivity Page shown in FIGURE 15 9 is used primarily to establish the noise floor of the instrument with the preamplifier and microphone presently being used and
200. ff to turn off the LxT Method 2 Press and hold the ON OFF key Method 3 Press the ON OFF key twice If the LxT is ON pressing the ON OFF key will bring up the Power Control screen 0 00 00 0 Estimated Run Time Battery Voltage 0 0 USB Powered 5 0 Backlight Bright lt gt Display Contrast T internal 91 6 F FIGURE 2 2 Power Control View Located on the first section of this screen is the Estimated Battery Run Time calculated using the voltage of the installed batteries Battery Voltage and the USB Power voltage LxT Technical Reference Manual Note that the Backlight and Display Contrast can also be adjusted from the Power Page as described in the section Power on page 12 5 The Center Softkey provides an exit escape or cancel function as well as the function displayed above it on the display RESET Key If desired the LxT can be set to display a Reset Prompt menu prior to the completion of reset operation as described in Reset Prompting on page 12 10 LxT Technical Reference Manual In the next section of this display Backlight Mode and Display Contrast are adjusted using the 5 2 C J and keys There are 3 choices for Backlight Mode Off Dim and Bright which are adjusted using the and keys The Display Contrast has a range of 9 to 9 which is adjusted using 7 keys The last section displays the LxT temperature that is us
201. fications A 27 LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 FIGURE A 12 LxT with 375A02 Microphone 30 90 and 150 degrees LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 4 0 Mic 165 FIGURE A 13 LxT with 375 02 Microphone 45 105 and 165 degrees 28 Technical Specifications LxT Technical Reference Manual Directional Characteristics LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375A02 Mic and PRMLxT2 Preamp Reference Mic 4189 Serial Number 2440346 4 0 Mic 251 19 Hz FIGURE A 14 LxT with 375A02 Microphone 251 19 Hz LxT Technical Reference Manual Technical Specifications A 29 LD Model LxT2 SLM Serial 001093 Normalized to 251 19Hz 0 Tested 12 27 04 15 58 03 by LD Note 375 02 Mic and PRMLxT2 Preat Reference Mic 4189 Serial Number 2440346 4 0 dB Mic 1000 00 Hz Mic 1995 26 Hz Mic 3981 07 Hz Mic 7943 28 Hz FI
202. for the reference as described in Normalizing using Frequency Weighting on page 5 23 A standard spectrum displayed on the Live Page will appear as shown in FIGURE 5 25 L 1 00kHz S 27 6 dB LAS 35 4 dB Started 2007 Apr 26 15 40 11 FIGURE 5 25 Standard Live Spectrum Display To access the View Normalized display press the center software Menu to display the menu shown in FIGURE 5 25 nu Settings View Normalized Adjust Graph FIGURE 5 26 Menu Highlight View Normalized and press the key to make the selection This will display the spectrum in the normalized view as shown in FIGURE 5 27 5 20 View Spectrum Normalized LxT Technical Reference Manual Normalized Spectrum Selected Spectrum Type only SPL 1 1 for Live Spectrum Re O Graph Relative 2007 Apr 30 10 08 00 b Close Edit FIGURE 5 27 Normalized Live Spectrum Display Note that normalized displays can be default the display will represent a spectrum normalized rescaled using the Graph Relative reference spectrum 1 If reference spectrum 1 has not been feature described in section Graph previously defined the display will show the actual live SPL Relative on page 5 28 or adjusted spectrum Otherwise it will show the live SPL spectrum as described in section Adjust normalized to the previously defined reference spectrum 1 Graph Scale on page 5 19 Selecting the Spectrum Type In the live display it is not necessary to select a spectru
203. ge 9 and Jack Function on page 12 9 9 2 6 Accessories a Effect of Windscreen on page A 18 d Frequency Response and Corrections on page C 9 and d Frequency Response and Corrections on page C 15 b Microphone Extension Cable on page 7 4 c Octave Band Analyzer Page Optional on page 4 6 d No manufacturer provided auxiliary devices are provided 9 2 7 Influence of variations in environmental conditions a No components of the LxT are intended to be operated only in an environmentally controlled enclosure b General Specifications on page A 5 c Electromagnetic Emission on page A 14 LxT Technical Reference Manual Sections 5 6 7 and 9 except 9 3 C 7 The following two sections are related to the LxT1 and the LxT2 configurations respectively In each information is provided which corresponds to the specific item number in this standard LxT1 Section 9 2 4 a Calibrator The calibrator to be used with the LxT1 is the Larson Davis Model CAL200 b Calibration Frequency The calibration check frequency is 1000 Hz c Calibration Procedure For calibration refer to the chapter Calibration on page 15 1 C 8 LxTI LxT Technical Reference Manual d Frequency Response and Corrections Larson Davis LxT1 with PRMLxT1 and typical 377A02 Microphone average frequency responses and corrections Required by IEC 61672 1 Sections 5 2 4 5
204. ge 17 7 External power whether provided via USB or an external power supply is negotiated with the host and cannot be utilized until permission is granted by the host This means that the LxT must run on batteries until allowed by the host to run on USB or external power If the batteries cannot provide sufficient power flat cells the LxT will not power on Ensure that the LxT has good batteries in order to turn on External Power Supply 17 7 PSA029 The PSA029 is supplied with mains power adaptors for most areas of the world Locate the plug adapter for your locality and install it by sliding it onto the supply case The PSA029 external power supply for the LxT has an input operating voltage range of 90 to 274 VAC and a power line frequency range of 47 to 63 Hz The output voltage from the supply is 5 VDC The external power supply connects to the USB connector on the bottom of the LxT With the power supply connected and operating at rated conditions the LxT will operate properly with or without batteries installed If the LxT is operated on external power only no batteries installed there is a possibility of instrument malfunction if there is an interruption of power to the LxT for any reason 17 8 External Power Supply LxT Technical Reference Manual CHAPTER Parameters Measured This chapter describes the different acoustic parameters which can be measured displayed and stored using the LxT Basic Sound L
205. gradeable firmware WS001 windscreen Features 1 7 Basic Measurements Basic Operation 1 8 SPL Leq Lmax Lmin SEL Lpeak Lpeak max 2 Sets of hygiene metrics Lavg TWA x Dose ProjDose Lep d E8 E40 SEA peak exposure 2 RMS event counters and 3 Peak event counters Ly table displays 6 user selected Ly metrics Auto Store with Auto Reset Run Timer and Stop When Stable Control Real time clock Start time elapsed time and paused time Time stamping for Lmax Lmin Lpeak max metrics Session Log Lock functions Calibration with calibration history and list of calibrators Power management Status bar and About display Multiple languages Data files and Data Explorer Automatic data backup to prevent data loss on power failure Overall measurement Features LxT Techncial Reference Manual Available Options Standard Accessories Real time 1 1 Octave Frequency Analysis LXT OB1 Real time 1 3 amp 1 1 Octave Frequency Analysis LXT OB3 Automatic Data Logging with intervals from 1 second to 24 hours LXT LOG Add LXT HSLOG as well to obtain intervals down to 100 milliseconds Measurement History Environmental Data Logging LXT ENV Community Noise LXT CN Digital Voice Annotation LXT DVA includes SLM LxT Headset LXT IH 256 MB Memory LXT MEM256 The LxT is delivered with the standard accessories described below Microphone and Preamplifier The LxT is delive
206. h can be moved left and right to different digit positions in the data field using the V 5 and keys as shown in Figure 4 16 Time 10 00 20 hh mm ss FIGURE 4 16 Entering Time in Timed Stop Run Mode At any digit position use the 7 C keys to adjust the value over the range 0 to 9 When the desired value of time has been entered press the key to conclude the process D 0 00 00 0 em IM Run Mode Stop When Stable v dB hh mm ss Enable Measurement History FIGURE 4 17 Stop When Stable Run Mode The run mode is indicated as Stop When Stable Data fields are provided to define Delta and Time Entering Delta Level The Delta level is the maximum one minute change in overall average level ie allowed for the measurement to be considered stable Dosimeter 1 and 2 Pages 4 15 4 16 Entering Time The Time is the duration that the measurement must run before the measurement can stop If the time were set to 0 the measurement would run until the stability condition was met If a duration is set the measurement would run for the duration specified and then continue until the stability condition was met For each use the C3 and keys to highlight the desired data field and press the key Use the and keys to position the cursor and the C3 and keys to set the digit for that position When the desired value has been entered press the key Dosimeter 1 and 2 Pages LxT Techn
207. h this sample point Press the 0 key once to display data measured during the first time interval as shown in FIGURE 9 6 Once data are displayed use the and keys to move the cursor right or 9 6 Time History Display LxT Technical Reference Manual left respectively in increments equal to the time history period Time History Graph Leq x where x is the time ps history interval Leq x calculated using Cursor position the ome multiples of time history interval at cursor i period position eq Ist Time History W gt Record 1 Parameter at cursor 2007 May 22 14 42 26 P Enter gt Change Metrics Total number of data ane in this points measured instance Date and time a cursor position FIGURE 9 6 Measured Data at Cursor Position First Parameter Left Right Arrow Keys LxT Technical Reference Manual Time History Display For the display shown in FIGURE 9 6 the 6 0 arrow keys have dual roles as listed below Use the key to toggle between them Move cursor and change displayed record Step through metrics At any time the role of the left and right arrow keys as well as the means to change it are indicated in the lower portion of the display as shown in FIGURE 9 7 and FIGURE 9 8 Left and Right Arrow keys ord 2 134 Step through Records 2007 May 22 14 42 26 Enter gt Change Metrics Switch role of left right arrow keys from Change
208. hange Rate List Use the C 7 keys to highlight the desired value and press the key to make the selection Dosimeter 1 and 2 Pages 4 11 Threshold and Criterion Note that when setting the Threshold value the Enabled check box must be checked before data can be entered into the numeric field Use the Left Softkey to highlight the box and press the key Auto Calculate Ln Page To set these parameters after highlighting the appropriate section press the key use the 4 2 7 and keys to enter the numeric value desired then press the key As described above the Criterion Level and Time are set independently However in the standards there is a linear relationship between the Criterion Level and the Time When Auto Calculate is activated by checking the check box to the left then only one of these need be entered and the other will be automatically set to follow the standard Ln Percentiles 1 5 10 00 33 30 66 60 2 3 4 50 00 95 5 6 90 00 95 FIGURE 4 11 Ln Page The Ln value is the measured sound level which was exceeded n of the measurement time For example a value of Log 35 dB means that the measured sound level was above 35 dB for 90 of the measurement period These statistical values are commonly used to describe the characteristics of non steady sound such as environmental noise 4 12 Dosimeter 1 and 2 Pages LxT Technical Reference Manual A de
209. hapter 12 Preferences on page 12 7 Fully Locked LxT Technical Reference Manual The user has complete access to the features of the instrument The user cannot change the data view in this mode Only the status line at the top of the screen is updated A measurement may be running when this mode is enabled or pressing the RUN PAUSE key will begin measurement A measurement cannot be paused Pressing the STOP STORE key stops the run and stores the data but does not reset the measurement See Chapter 13 Locked With Auto Store on page 13 6 The user cannot change the data view in this mode Only the status line at the top of the screen is updated Measurements may be run paused and stopped See Chapter 13 Locked With Manual Store on page 13 8 The user has no access to the instrument except to start a run Auto Store preferences are enabled in this mode See Chapter 13 Fully Locked on page 13 5 A measurement cannot be reset when the Model LxT is locked in any mode Control Panel Lock 13 3 Unlock Code Allow Cal When Locked Move the highlight to the Unlock Code Field Lock Mode Fully Locked Y Unlock Code Enter a 4 digit code to use when unlocking this unit O Allow Cal When Locked FIGURE 13 4 Unlock Code Press the key The 1st character in the field will be highlighted Use the C 7 or keys to select the desired unlock code To accept the new unlock code pres
210. he measurement time seconds minutes or hours For example suppose the measurement time is set to three minutes Based on the unit of minutes the time intervals per hour are xx 00 00 xx 01 00 xx 02 00 etc If the measurement were begun at 08 14 23 the first measurement would be cut short at the next measurement interval so subsequent measurements would be started at 08 15 00 08 18 00 08 21 00 etc Timed Stop Mode Measurement Counter Note that the measurement counter will be set to one and the selection field disabled when the measurement time has been set to less than one minute LxT Technical Reference Manual The Time Stop Mode with Measurement History has a feature not included for the other run modes the ability to automatically measure and store a user defined number of records then stop Subsequent runs each manually initiated will produce the same number of stored measurements When the Measurement History has been enabled for the Time Stop Mode the Measurement Counter field will appear as shown in Figure 10 3 Enable Measurement Histor easurement Counter 00000 FIGURE 10 3 Measurement Counter Measurement Counter is used to set the number of measurements to be made during each manually initiated measurement sequence To enter the a value into the Measurement Counter field time highlight the Measurement Counter data field and press the ere key Enter the desired value and press the key to c
211. heck mark next to an option indicates that the option is enabled See FIGURE 14 4 Options Page e 0 39 41 5 About About Standards Enabled Option Name 1 1 Octave 1 3 Octave Voice Annotation Time History Industrial Hygiene Community Noise Close FIGURE 14 4 Options Page Options 14 3 User 14 4 User This page displays any identifying information the user may have entered on the System Properties Device Page or using Blaze software See FIGURE 14 5 User Page About Instrument Identification FIGURE 14 5 User Page LxT Technical Reference Manual Calibration Calibration Overview Sensitivity Determination The primary role of sound level meter calibration is to establish a numerical relationship between the sound level at the diaphragm of the microphone and the voltage measured by the meter so that the sound pressure level can be read directly from the display of the meter in units of dB The result of a calibration is the determination of the sensitivity of the meter including microphone and preamplifier typically in units of dB re 1 V Pa or mV Pa Overload Under Range Conditions A secondary role of calibration is to determine the sound level which would overload the instrument and the minimum sound level which can be accurately measured referred to as the under range level This requires a knowledge of the electrical noise levels of the microphone preamplifier and the instr
212. hus a free field correction of 0 12 dB 0 03 dB uncertainty at 95 confidence level should be applied to either of these levels If the calibrator and instrument are near room temperature 23 C and near sea level 101 3 kPa then no other corrections need to be made For example if the calibration sheet for the CAL200 indicates 113 98 dB for its level when set to 114 dB then set the Cal Level in the LxT to 113 86 dB and 1000 Hz Acoustic Calibration 15 5 When the microphone and instrument are at a temperature other than near room temperature or static pressures not near sea level then corrections will need to be added for the ambient temperature and the prevailing static pressure Check the calibration data shipped from Larson Davis with the CAL200 to get these corrections The corrections can be added to the level obtained in the previous paragraph to get the actual level of the CAL200 The 377B02 microphone s sensitivity varies with static pressure If the instrument is calibrated in one environment and moved to another then the sensitivity will change after stabilization depending on the change of temperature and pressure The coefficient of static pressure is 0 01 dB kPa If the system is calibrated at 85 kPa for instance then it will be 0 16 dB less sensitive at sea level 101 3 kPa The sensitivity of the 377B02 and LxT vary slightly with temperature also The coefficient of temperature is 0 009 dB C If the system is cal
213. ibrated at 18 C then it will be 0 045 dB more sensitive at 23 C The Larson Davis 3 Wind Screen has less than 0 05dB effect on the system response at 1 kHz Set the CAL200 level switch to 94 or 114 dB Calibrating the LxT2 and 375A02 microphone 15 6 The CAL200 and CAL150 provide a nominal pressure level of 94 dB or 114 dB The exact levels are printed on the Larson Davis calibration sheet that came with the calibrator When using a free field microphone the pressure level at the microphone diaphragm will be slightly different Thus a free field correction of 0 12 dB 0 03 dB uncertainty at 95 confidence level should be applied to either of these levels If the calibrator and instrument are near room temperature 23 C and near sea level 101 3 kPa then no other corrections need to be made For example if the calibration sheet for the CAL200 or CAL150 indicates 113 98 dB for it s level when set to 114 dB then set the Cal Level in the LxT to 113 86 dB and 1000 Hz When the microphone and instrument are at a temperature other than near room temperature or static pressures not near sea level then corrections will need to be added for the ambient temperature and the prevailing static pressure Check the calibration data shipped from Larson Davis with Acoustic Calibration LxT Technical Reference Manual Environmental Parameter Ranges the CAL200 or CAL150 to get these corrections The corrections can be added to the level ob
214. ical Reference Manual Triggers Page Note that the default values for these parameters are as shown in Table 4 1 MEER Triagers CEAN Trigger Levels SPL 1 dB SPL 2 dB Peak 1 dB Peak 2 137 0 dB Peak 3 140 0 dB FIGURE 4 18 Triggers Page The Triggers Page is used to define trigger levels which can than be used to detect when the measured sound level SPL or Peak exceeds one of these trigger levels LxT Technical Reference Manual Dosimeter 1 and 2 Pages 4 17 Day Night The Day Night parameters are used in conjunction with Community Noise Measurements which require that the optional firmware LXT ENV be enabled Note that the default values for these Among the parameters measured and displayed as part of a parameters are as shown in Table 4 basic sound level measurement are the community noise 1 descriptors Lpy and The Day Night page is used to define the times and penalties to be used e 0 19 33 8 5 Settings MEUS Day Night hh mm hhimm 05 0 hh mm Penalty dB FIGURE 4 19 Day Evening Night Definition Lon The day night level Lpy defined by the following formula 0700 2200 2400 1 L 10 10 L 10 Lj 10 10 Lan 1010810 54 gt 10 gt 10 gt 10 0000 0700 2200 LpEN The day evening night level is defined by the following formula 4 18 Dosimeter 1 and 2 Pages LxT Technical Reference Manual Lyy 10 CNEL LxT Technical Reference Manual 1 Lday
215. ied by the manufacturer to increase the frequency response choose smaller microphones 2 Choose a microphone for free field or random incidence to minimize the influence of orientation A microphone influences the sound being measured The microphone measures very small forces low level sound can run about one billionth of a PSI Every measurement instrument changes the thing being measured and for very small forces that effect can be significant When sound impinges directly on a microphone the incident wave must be reflected since it cannot pass through the microphone This results in the extra force required to reflect the sound and a microphone output that is higher than would exist if Glossary D 13 Near Field D 14 Glossary the microphone were not there This is more important at high frequencies and when the microphone is facing the sound source Rules 1 Do not use a microphone at frequencies higher than specified by the manufacturer to increase the frequency response choose smaller microphones 2 Choose a microphone for free field or random incidence to minimize the influence of orientation A microphone measures what is there from any direction Most measurements are intended to measure the sound level of a specific source but most microphones are not directional so they measure whatever is there regardless of source Rules 1 When making hand held measurements keep your body at right angles to the directio
216. ilters 64 MB standard data memory 256 MB optional High contrast 1 8th VGA LCD display with white LED backlight sunlight readable Icon driven graphic user interface Soft rubber keys Large dynamic range Time weightings Slow Fast Impulse Integration and Peak Frequency weightings A C Z 1 1 and 1 3 octave frequency analysis available Voice message annotation available which includes headset L Statistics L0 01 through L99 9 available Blaze software available for setup control high speed data download analysis and reporting Multi tasking processor allows measuring while viewing data or transferring data Data Secure Feature saves data to permanent memory every minute AC DC outputs to recorder Long battery life 16 hours continuous measurement Field upgradable firmware keeps instrument current with the latest measurement features Two year limited warranty Class 1 Precision Integrating Sound Level Meter with real time 1 3 Octave Filters classified as group X for the emission of and susceptibility to radio frequency fields Table A 2 LxT Features A 2 Technical Specifications LxT Technical Reference Manual Sound Level Meter Specifications LxT Technical Reference Manual RMS Time Slow Fast or Impulse weighting Frequency A CorZ Weightings See Frequency Weightings on page A 7 Peak detector A CorZ Frequenc
217. inuously from start time to end time The selection and setting of appropriate parameters for these run modes is shown in FIGURE 6 3 KD 0 00 00 0 zn Settings Control Ei Run Mode Timed Stop Run Stop When Stable v ime 00 00 20 hh mm ss Delta dB C Enable Measurement History ime 00 00 20 hh mm ss KD 0 00 00 0 4 0 Settings Control gt Run Mode Manual Stop Y l Enable Measurement History Enable Measurement History Manual stop v Manual Stop Timed Stop Stop When Stable Continuous Single Block Timer Daily Timer FIGURE 6 3 Setup of Manual Stop Timed Stop and Stop When Stable Run Modes Continuous Daily Auto Store The Continuous run mode is similar to the Manual Stop mode except that Daily Auto Store can also be enabled in which case daily measurement reports for 24 hour time periods beginning at a user specified time will be automatically stored assuming that the measurement time period encompasses at least one 24 hour time period as programmed The parameter Time defines the start time for the 24 hour time period to be used for the report LxT Technical Reference Manual Run Modes Without Measurement History 6 3 Single Block Time or Daily Timer KD 0 00 00 0 0 Settings Control Run Mode Continuous Y LJ Enable Measurement History Daily O Auto Store I 5 When the run mode is Single Block Timer or Daily Timer this single me
218. ions comply with all requirements of IEC 61260 1995 including amendment 1 2001 for Class 1 These digital filters are sampled at a rate of 51 200 samples per second with base X10 center frequencies and having real time performance for all filters The 0 dB gain setting is the reference range and the reference input signal is 1 Volt rms at 1 kHz Frequency Range 1 1 Octave Filters 8 Hz to 16 kHz 1 3 Octave Filters 6 3 Hz to 20 kHz Filter Shapes The following figures present the filter shapes for the 1 1 and 1 3 octave bands centered at 1 kHz Overlaid with these curves are the limit curves associated with IEC 61260 1995 Class 1 LxT Technical Reference Manual Technical Specifications A 15 16 lt gt Sound Level Meter Model LxT Serial Number 0000033 Certificate of 1000 0 Hz Full Octave Filter Shape Larson Davis This Class 1 Sound Level Meter including attached PRMLXT1 preamplifier and ADP005 18pF input adapter was calibrated with a reference 1kHz sine wave The instrument s 1000 0 Hz filter response was then electrically tested using a 137 00 dBSPL sinewave at selected frequencies as specified in IEC 61260 am1 2001 09 10 00 0 00 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90 00 100 00 1000 100000 Frequency Hz Measured Uncert Limits Freq Measured Uncert Limits Hz 88 46 0 10 00 inf 1090 18 0 00 0 10 0 30 0 40
219. isconnected message box will Preamp Disconnected FIGURE 3 5 Disconnect The Preamplifier Press the key to clear the message box 3 4 Disconnecting the Preamplifier from the LxT LxT Technical Reference Manual Inserting Batteries Note There are 2 tabs on the bottom of the battery door that engage the case of the LxT LxT Technical Reference Manual The LxT can use Alkline NiMH or gi Lithium cells See Power Supply on page A 12 for details The LxT 15 designed for use in areas requiring Intrinsic Safety approval as well as use in safe atmospheres By the standards it is required that access to the battery compartment be secured to deter opening in a hazardous atmosphere and batteries cannot be changed in a hazardous atmosphere hex screw is provided to secure the battery door in these uses Extra screws were provided when the unit was shipped The battery compartment of the LxT is located on the back of the unit There is a clip on the battery door and a hex screw holding the door in place To remove the battery door first remove the screw if installed Then pull the clip towards the battery door while lifting The battery door will pivot away from the unit v m a gt gt 73A37 GNNOS 1x7 4284Lpunos m 5 a FIGURE 3 6 Battery Door Insert 4 fresh AA batteries as shown in FIGURE 3 7 Ensure correct alignment of the ba
220. ith no attenuation PRMLxT2L Low Level Type 2 with no attenuation Microphone and Preamplifier Configurations PRMLxTI or PRMLXxTIL with 377B02 PRMLxT2 or PRMLxT2L with 375A02 or PRMLXTIL with 377A01 including ADP043 adapter Equivalent Electrical Impedance Adaptor An equivalent electrical impedance adapter can be used in place of the microphone when the instrument is being 1 10 Features LxT Techncial Reference Manual Cables Power Supplies Software Other LxT Technical Reference Manual measured electrically The adapter is simply a series capacitor with the same capacitance as the microphone it is replacing The following adapters will be available for sale ADP002 6 8pF Adaptor for 1 4 in 7pF microphone 377B01 ADP005 18pF for 1 2 in 18pF microphone 375A02 ADP076 12pF for 1 2 in 12 pF microphone 377B02 Direct Input Cable or Adaptor Microphone Extension Cable shielded EXCXXX where XXX is the length in feet 010 020 050 066 100 and 200 available USB Cable CBL138 AC DC Output Cable CBL139 Universal AC Power Adaptor PSA029 12 Volt DC to USB Power Adaptor PSA031 Blaze software SWW BLAZE LXT for setup control and high speed data download DNA Data Navigation and Analysis software for instrument control high speed data download data streaming with real time data display on PC advanced data graphic presentations and powerful report generation featu
221. ix D Glossary Contains technical definitions of key acoustic and vibration terms Appendix E Warranty Customer Satisfaction A presentation of warranty and customer satisfaction policies Special Features of the Electronic Version Bookmarks Opening Bookmarks LxT Technical Reference Manual There are a variety of special techniques for navigating through pdf documents which can greatly simplify finding specific items in this manual Three of these bookmarks links and cross references are discussed below Bookmarks are clickable navigation tools in pdf files To open a bookmark left click the upper tab on the left of the screen labeled Bookmarks These will appear as shown FIGURE 1 1 Special Features of the Electronic Version 1 3 Closing Bookmarks Expanding Bookmarks L Table of Contents L List of Figures L List of Tables L Introduction L First Use Overview Basic Measurement Setup L Basic Data Display Run Control Making a Measurement L Voice Recording Time History L Data Explorer L System Properties L Lock Unlock the LxT Calibration 7 About L System Utilities L LxT Hardware L Parameters Measured L Technical Specifications L Testing to IEC61672 1 L Integrated Level Calculations L Glossary Cana L Bookmar L 7 2 m m 2 E 3 7 P
222. l Reference Manual Sections 5 6 7 and 9 except 9 3 Section LxT Manual Comments 5 17 1 Control Page on page 4 13 and Time on page 12 3 5 17 1 NOTE 2 Time of Day Drift on page A 11 5 17 2 Min Max Integration Time on page A 10 5 18 1 Microphone Extension Cable on page 7 4 5 18 2 n Radio Frequency Emission on page C 13 and n Radio Frequency Emission on page C 20 5 19 2 The LxT is a single channel instrument 5 20 2 j Battery Power Voltage Range on page C 13 and j Battery Power Voltage Range on page C 19 5 20 3 Battery Operating Lifetime on page A 12 5 20 4 External Power Supply on page 17 7 5 20 5 Power Supply on page A 12 6 12 Typical Stabilization Time on page C 13 and I Typical Stabilization Time on page C 19 6 2 2 Calibrating the LxT1 and 377 02 micro phone on page 15 5 and Calibrating the LxT2 and 375A02 microphone on page 15 6 6 5 2 General Specifications on page A 5 6 6 1 AC Power and Radio Frequency Suscepti bility on page C 13 6 6 3 No detectable increase in any direction with application of 74 dB A weighted sound level 6 6 9 AC Power and Radio Frequency Suscepti bility on page C 13 7 1 Microphone Extension Cable on page 7 4 7 2 Effect of Windscreen page A 18 7 3 Optional Accessories on page 1 10 Sections 5 6 7 and 9 except 9 3 LxT Technical Reference Manual Section
223. l Reference Manual The LxT can be powered from batteries or if available from the USB host portion of your computer It can also be powered externally using the PSA029 power supply as described in the section External Power Supply on page 17 7 When batteries are installed USB power is negotiated with the host and cannot be utilized until permission is granted by the host This means that the LxT must run on batteries until allowed to run on USB power by the host If there are no batteries installed in the LxT USB power will be utilized without host permission Thus make sure that the batteries can provide sufficient power for the LxT to turn On Otherwise remove the batteries and turn on the LxT using USB power Using USB Power 3 7 Using USB Power LxT Technical Reference Manual Basic Measurement Setup This chapter describes the setup of the LxT to perform basic sound level measurements These measurements may include the following Leq Lmax Lmin corresponding to user selected values of frequency weighting and detector Lpeak and Lpeak max corresponding to a user selected value of frequency weighting 1 1 and or 1 3 Octave real time spectra LxT OB3 required Six values of Ln based on six user selected values of the parameter n Count of the number of times the levels RMS and Peak exceeded user selected threshold values Sound exposure and sound exposure level da
224. l frequency filter that adjusts the amplitude of all parts of the frequency spectrum of the sound or vibration unlike band pass filters It can be composed of one or more of the following types A Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to low levels of sound This weighting is most often used for evaluation of environmental sounds See table below B Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to higher levels of sound This weighting is seldom used See table below C Weighting A filter that adjusts the levels of a frequency LxT Technical Reference Manual LxT Technical Reference Manual spectrum in the same way the human ear does when exposed to high levels of sound This weighting is most often used for evaluation of equipment sounds See table below Flat Weighting A filter that does not adjust the levels of a frequency spectrum It is usually an alternative selection for the frequency weighting selection Center Frequencies Hz Weighting Network Frequency Response 1 3 Octave 1 Octave A B C 20 50 4 24 2 6 2 25 44 7 20 4 4 4 31 5 31 5 39 4 17 1 3 0 40 34 6 14 2 2 0 50 30 2 11 6 1 3 63 63 26 2 9 3 0 8 80 22 5 7 4 0 5 100 19 1 5 6 0 3 125 125 16 1 4 2 0 2 1
225. ld and press the emen key to obtain a listing of the choices as shown in FIGURE 12 9 FIGURE 12 9 Jack Function Preferences Preferences 12 9 Reset Prompting Takt Maximal Data USB Host Port Note that this must be On in order to utilize the USB Port with peripheral devices USB Storage 12 10 Preferences Use the 7 and keys to highlight the desired Jack Function press the key to make the selection If the Reset Prompting check box is checked the user will be prompted with an Are You Sure message box whenever the 2 RESET key is pressed If it is not checked this prompt will not appear prior to the reset action taking place Use the CI and keys a the Reset Prompting check box Pressing the een key toggles the state of the check box When this is checked the parameter LAFTMS is also measured and displayed on the Community Noise Page of the Overall Screen and as a parameter of a Time History measurement This function controls the power to the USB Port so it must be set to On in order to utilize it with peripheral devices Highlight the USB Host Port field and press the er key to obtain a listing of the choices as shown in FIGURE 12 9 Off FIGURE 12 10 USB Host Port On Off Menu Highlight the desired USB Host Port Status and press the oe key to make the selection Data can be stored to internal memory or to an external memory device connected to the USB Port The options are
226. lease refer to calibration and measurement results for data on a specific unit Standards Met by LxT The LxT meets the specifications of the following standards Instrument Sound Level Meter Standards LxT1 IEC61672 1 2002 05 Class 1 Group X IEC60651 1979 plus Amendment 1 1993 02 and Amendment 2 2000 10 Type 1 Group X IEC60804 2000 10 Type 1 Group X ANSI S1 4 1983 R 2006 plus Amendment 51 4 1985 R 2006 Type 1 ANSI S1 43 1997 1 LxT2 IEC61672 1 2002 Class 2 Group X IEC60651 1979 plus Amendment 1 1993 02 and Amendment 2 2000 10 Type 2 Group X IEC60804 2000 10 2 Group X ANSI 1 4 1983 R 2006 plus Amendment 1 4A 1985 R 2006 Type 2 ANSI 1 43 1997 Type 2 Octave Filter Standards Options OBI or OB3 only IEC61260 1995 07 Ed 1 0 plus Amendment 1 2001 09 1 1 and 1 3 octave Bands Class 0 Group X all filters ANSI S1 11 2004 Class 0 IEC61260 1995 07 plus Amendment 1 2001 09 1 1 and 1 3 octave Bands Class 0 Group X all filters ANSI S1 11 2004 Class 0 Personal Noise Dosimeter Standards TEC61252 Ed 1 1 2002 Type 1 ANSI 61 25 1991 Class 1 IEC61252 Ed 1 1 2002 Type 2 ANSI 1 25 1991 Class 2 LxT Technical Reference Manual Table A 1 Standards Met by LxT Technical Specifications 1 LxT Specifications Features Class 1 Precision Integrating Sound Level Meter with real time 1 3 Octave F
227. lected parameter Normalized using a Previously Measured Spectrum Provided with a choice of spectrum types the user can create a spectrum display where one type of spectrum 1s normalized by another For example let us use the spectrum type data field to select Lmin Then highlight the Reference field and press the key to display the options for reference as shown in FIGURE 5 35 10207 Eo FIGURE 5 35 Overall Reference Menu LxT Technical Reference Manual View Spectrum Normalized 5 25 The items listed in this menu are as follows 1 2 3 4 e A e C The first four items permit the user to define four reference spectra based on the spectrum being displayed Press the left softkey SET to make the Lmin spectrum the reference spectrum for reference 1 The resulting spectrum will look like FIGURE 5 34 0 00 24 9 _Data Normalized Spectrum Selected Spectrum Type 2007 Apr 30 10 47 01 Close FIGURE 5 36 Lmin Spectrum Normalized to Lmin Spectrum Note that normalized displays can be This display now shows the Lmin spectrum presently being rescaled using the Graph Relative measured normalized by the Lmin spectrum which which feature described in section Graph existed at the time the normalization was performed Of Relative on page 5 28 or adjusted course the values are all zero as the spectrum is normalized as described in section Adjust with itself 1419 If the LxT has not been not running
228. led description of the Data Explorer see Chapter 11 Data Explorer on page 11 1 System Properties For a detailed description of the System Properties Pages see Chapter 12 System Properties on page 12 1 LxT Technical Reference Manual To highlight a particular icon the Left and Right Softkeys and the 4 I C keys are used as indicated by the arrows in FIGURE 2 10 Highlighting a Tools Icon 0 00 00 0 40 Control Panel C C Keys or Left and Right Softkeys Setup Manager Voice Recorder Q and FIGURE 2 10 Highlighting a Tools Icon The Data Explorer is used to examine data which had been stored following previous measurements It is also used to manage stored measurements such as rename or delete files System Property Pages are used for general instrument bookkeeping Functions such as setting the instrument date and time display contrast adjustment date format etc are located here These are single section pages There are six System Property Pages Device instrument identification is entered here Time the date and time are set on this page Power controls that affect power consumption are located here Tools Screen 2 17 Preferences a variety of system parameters such as microphone correction auto store jack function reset prompting takt maximal and USB port are configured here Localization regional characteristics such as language decimal symbol da
229. lso be entered manually when using preamplifiers and or microphones not included in the LxT data base See also Direct Data Input on page 15 13 The overload level is the highest peak level which can be measured without overloading the input of the LxT The Under Range Level is the higher of the following 1 Noise Floor plus 10 dB 2 Actual point where the log linearity exceeds maximum permitted value Except for very low noise level microphones the under range level is usually determined by 1 Sensitivity Page 15 13 Calibration Without Preamplifier There may be situations where the microphone preamplifier provided with the LxT is not being used For example when a hydrophone is being used no level calibrator is available so the sensitivity must be input directly by the user When the preamplifer has been disconnected the Sensitivity Page will appear as shown in FIGURE 15 10 Q 000016 Direct ther e mia Sensitivity mvjPa Self Noise dB Overload Level 119 8 dBpl Under Range Level 40 1 48 39 1dBC 40 8dBZ Noise Floor 30 1 dBA 29 1dBC 30 8982 FIGURE 15 10 Sensitivity Page Without Preamplifier In this situation the sensitivity of the transducer and the self noise if know can be input directly 15 14 Calibration Without Preamplifier LxT Technical Reference Manual Certification A certification interval of one year is recommended but this can be lengthened or disabled depending o
230. ly by a respective authorized service person for such products PCB shall have no obligation to undertake repairs of products manufactured by others E No Special Incidental or Consequential Damages PCB s sole obligations under this limited warranty are set forth above in paragraphs A B and C In no event shall PCB be liable to the buyer or any other person for any indirect special incidental or consequential losses or damages connected with the use of the product under this limited warranty Such damages for which PCB shall not be responsible include but are not limited to lost time and convenience loss of use of the product the cost of a product rental costs of gasoline telephone travel or lodging the loss of personal or commercial property and the loss of revenue F No Liability in excess of Purchase Price In no event shall PCB s obligations under this limited warranty exceed the purchase price of the product plus any shipping charges that PCB may be obligated to pay pursuant to paragraph C above LxT Technical Reference Manual Limited Product Warranty 2 1 No Extension of Statute of Limitations Any repairs performed under this limited warranty shall not in any way extend the statues of limitations for claims under this limited warranty H Waiver of other Warranties The express warranties set forth in this limited warranty are in lieu of and exclude any and all other warranties express or implied including but not li
231. m type since only SPL is available Selecting the Reference Spectrum Highlight the Ref data field and press the key to open the Reference Menu shown in FIGURE 5 28 il 3 FIGURE 5 28 Live Reference Menu The items listed in this menu are as follows gt N m LxT Technical Reference Manual View Spectrum Normalized 5 21 Normalize to Live Spectrum Note that normalized displays can be rescaled using the Graph Relative feature described in section Graph Relative on page 5 28 or adjusted as described in section Adjust Graph Scale on page 5 19 e C C The first four items permit the user to define four reference spectra based on the spectrum being displayed The last four items permit the user to use add positive or negative A or C frequency weightings to the displayed spectrum See Normalizing using Frequency Weighting on page 5 23 If normalizing to a reference spectrum highlight 1 2 3 or 4 and press the key to make a selection The live spectrum is continually changing with the sound field being measured By pressing the Set softkey the live spectrum measured at that instant 1s defined as the reference spectrum for that selection 1 2 3 or 4 The display will continue to change but the display will be normalized to that reference spectrum as shown in FIGURE 5 29 FIGURE 5 29 Live Spectrum Normalized to Reference Spectrum 1 Following this procedure reference spectra 1 2 3 an
232. m oai obe a eed UM MEN UN UE UE 16 2 LXT 17 1 LXT Front P 17 1 ema 17 3 ExT Bottom Panli 17 5 Battery Status 17 6 External Power COM ehe ee ees 17 7 Parameters Measured 18 1 Memory Utilization 19 1 Technical Specifications 1 Temperature Stability vs Temperature A 11 Passband of 1kHz 1 1 Octave Filter A 16 Filter Skirts of 1 2 1 3 Octave Filter A 17 LxT with 377B02 Microphone 0 60 120 and 180 degreeA 20 LxT with 377B02 Microphone 15 75 and 135 degrees A 21 LxT with 377B02 Microphone 30 90 and 150 degrees 21 LxT with 377B02 Microphone 45 105 and 165 degrees A 22 LxT with 377B02 250 19 Hz iiu iicet ettet A 23 LxT with 377B02 1000 00 Hz 1995 26 Hz 3981 07 and 7943 28 Hz mE A 24 LxT with 377B02 Microphone 1258 93 Hz 2511 89 Hz 5011 87 Hz aid T0000 00 HZ esce tette Prot sie o bte A 25 LxT with 377B02 Microphone 1584 89 Hz 3162 28 Hz 6309 57 Hz 12589 25 Hz eon sates os A 26 LxT with 375A02 Microphone 0 60 and 120 degree A 27 LxT with 375A02 Microphone 15 75 and 135 degrees A 27 LxT with 375A02 Microphone 30 90 and 150 d
233. max 15 the highest level the peak detector has measured during the run time of the measurement A date and time of occurrence is recorded with this event The L7peak max i also considered the peak hold Whenever data is reset this parameter is cleared To reset data press the 2 RESET key The LAsmax is the highest level the RMS detector has measured during the run time of the measurement A date and time of occurrence is recorded with this event The L Asmax is also considered the max hold Whenever data is reset this parameter is cleared To reset data press the 5 RESET key The Lasmin is the lowest level the RMS detector has measured during the run time of the measurement A date and time of occurrence is recorded with this event LxT Technical Reference Manual 1 1 Octave Band Analyzer Optional The 1 1 Octave Band Analyzer display appears only when the optional firmware LxT OB1I or LxT OB3 has been enabled and this measurement mode has been selected in the setup 0 00 04 9 5 Lmax Values LxT Data Overall Leq Values Lmin Values Frequency Spectrum Bandwidth Spectral Measurements Leq Lmax Lmin m an min Run Time 0 00 04 9 FIGURE 5 11 Overall Page Section 4 Note that the graph scaling can be The data displayed in in Section 3 shows Leq Lmax and modified as described in section Lmin sound levels in 1 1 octave frequency bands calculated
234. measurement select the Live View You can now see a live display of the instantaneously measured data The data available for display from the Live View is distributed over three pages four or five pages with the optional OBA feature Use the CI and keys to change pages Take a minute or so to examine these different displays before continuing with this example Use the softkeys to select the Overall View Note that the measurement and display of data has not yet begun and that the measurement run time displayed at the very top of the screen indicates 00 00 00 0 Performing the Measurement Starting the Measurement The LxT uses a single range for sound level measurements so there is no need to select a range as part of making a measurement Data Display See Overall on page 5 6 The Live Display provides a running sound level measurement whether or not the LxT is actually performing a measurement while the Overall Display provides the measurement actually being made Select the Overall Display in order to observe the measurement in progress Press the 7 RUN PAUSE key to start the measurement which will start the run clock and initiate the measurement and display of overall data The measured data are available for display from the Overall View These data are distributed over thirteen sections with the LxT LOG and LxT OBA options Use the 0 2 keys to change sections The first two secti
235. ment 2007 Apr 16 14 08 29 2007 Apr 16 14 08 32 2007 Apr 16 14 08 37 2007 Apr 16 14 08 43 2007 Apr 16 14 08 51 FIGURE 5 22 Session Log Page The Session Log is a record of data accumulation actions A time stamped record is made for every Run Pause Stop Voice Message or Marker action The source responsible for each action is also recorded which may be any of the following Key press USB command e Run timer compete Low battery Outof memory e Preamplifier disconnect The icons in the left column of the display indicate the action Run Pause Voice Recording etc The date and time of the action is displayed next to the icon Each measurement segment from Run to Stop is numbered as is each voice message 5 18 Session Log Page LxT Technical Reference Manual Adjust Graph Scale Note that when the OBA Range for frequency spectra has been set to Low the value actually used for the baseline of the display will be 30 dB less than the number indicated for Bottom in the Adjust Graph menu LxT Technical Reference Manual Using the 7 and keys the user may scroll the list and expand each item In the upper right corner of the expanded item the number indicates which item is being viewed out of how many total items are in the list The default amplitude dB settings for the graphic display of sound pressure level versus time and frequency spectra 1 1 and 1 3 octave are as indicated below Level v
236. ment Market Leq 1 1 Octave 1 3 Octave Dose 1 Dose 2 FIGURE 12 21 Overall Page Displays Session Log Display abs Session Log Pages Session Log FIGURE 12 22 Session Log Displays 12 16 Displays LxT Technical Reference Manual LxT Technical Reference Manual Current Display 14 Displays Live Enforcement Market Leq 1 1 Octave 1 3 Octave History Profile Enforcement Market Metrics 1 1 Octave 1 3 Octave Dose 1 Time History Displays 3 Tabs Time Histor Pages Time History 1 1 Octave 1 3 Octave FIGURE 12 23 Time History Displays displays which have a check in their check box will appear on the LxT To modify any of the displays associated with one of the Tab Pages use the 2 2 or C keys to highlight the field listing Displays 12 17 12 18 Displays those displays and press the key to obtain the display shown in FIGURE 12 24 FIGURE 12 24 Display Set to Appear or Hide Pressing the key will toggle the state of the highlighted display between Appear checked and Hide unchecked Use the C keys to highlight different displays and set them as desired When finished setting the display types for this Tab Page press the er key When all desired modifications have been made to the displays for all Tab Pages press the center softkey Close to return to the Control Panel LxT Technical Reference Manual Control Panel Lo
237. meter 1 and 2 Pages LxT Technical Reference Manual Parameters Individually Defined Name Field If predefined setup has been selected and any of the preset parameters are modified the user should consider changing the name of the setup Parameter Fields Exchange Rate LxT Technical Reference Manual In the Dosimeter Page there are two fields Name and Exchange Rate and two sections Threshold and Criterion The Name field is optional although many users will enter text associated with the measurement to be performed such as a specific company Dose standard My Dose or the name of a standard not in the list To enter a name use the CC and C keys to highlight the Name field Use the key to highlight the name portion of the highlighted box Then press the key Use the M CI gud 42 2 keys to enter the desired characters Press the key to complete your entry The titles of the second field Exchange Rate and the two sections at the lower portion of the display Threshold and Criterion correspond to the three parameters we wish to set Within each is a numeric field into which the user can enter the value desired Use the 7 and keys to highlight the desired section and proceed as described below To set the exchange rate highlight the data field and press the key to open a drop down list of values as shown in FIGURE 4 10 Exchange Rate List Exchange Rate Threshold FIGURE 4 10 Exc
238. mited to the implied warranties or merchantability and fitness for a particular purpose I Procedure for Warranty Performance If the product fails to perform to PCB s specifications the Buyer must provide PCB with the applicable model and serial numbers the date of purchase and the nature of the problem J Authority to Alter This Limited Warranty No agent representative or distributor of PCB has any authority to alter the terms of this Limited Warranty in any way This Limited Warranty may be altered only in writing by an authorized officer of PCB 2 2 Limited Product Warranty LxT Technical Reference Manual Total Customer Satisfaction Guaranteed 3425 Walden Avenue Depew NY USA 14043 ARSON DAVIS Phone 716 926 8243 Toll Free 888 258 3222 A PCB PIEZOTRONICS DIV LarsonDavis com FAX 716 926 8215
239. n Screens LxT Technical Reference Manual The STOP STORE key will end run Pressing the key a second time will store the data in a file This key is only active on a Data View screen There are four different screens available on the LxT Data Display Screen used to display measured data Measurement Properties Screen used to set the parameters for a measurement Tools Screen used to set non measurement related parameters and to implement calibration Power Control Screen used to check battery power control the contrast and backlight of the display and other features Screens 2 11 The diagram shown in FIGURE 2 5 Main View Block Diagram illustrates the manner in which the user can move between these four screens Data Display Screen A Close Measurement h Tools Screen Properties Screen Power Control Screen FIGURE 2 5 Main View Block Diagram Data Display Screen When the ON OFF key is pressed to switch ON the LxT the Data Display Screen appears Measurement Properties Screen Opening From the Data Display Screen pressing the Center Softkey labeled Menu will bring up the menu shown in FIGURE 2 6 FIGURE 2 6 Menu 2 12 Screens LxT Technical Reference Manual Tools Screen Power Control Screen Data Display Screen For a more detailed
240. n applicable requirements LxT Technical Reference Manual D 0 00 00 0 Calibrate Tool Performed 2007 Apr 10 Due 2008 Apr 09 actory Certification arson Davis Inc 681 West 820 North Provo LIT 84601 156 926 8243 FIGURE 15 11 Certification Page The user has the opportunity to set the calibration interval and a calibration reminder Highlight the desired drop down list box and press the key A list of available times will appear Highlight the desired duration and press the key Available Certification Intervals are 1 year 2 years 3 years and 4 years Available Certification Reminder times are 15 days and 30 days Certification 15 15 15 16 Certification LxT Technical Reference Manual CHAPTER System Utilities Control Panel System Utilities Note It is necessary to press the To activate the System Utilities Page press the A key one time in order to see the TOOLS key Use the Q keys to highlight System Utilities icon on the Control the System Utilities icon as shown in FIGURE 16 Panel 1 Control Panel System Properties System Utilities FIGURE 16 1 Control Panel Press key to open the System Utilities Page There is one System Utilities Page File System LxT Technical Reference Manual System Utilities 16 1 File System Warning Using these functions may cause loss of data and restoration of the LxT to default conditions Check File System
241. n at the bottom of FIGURE 2 1 Data Display Screen Above each Softkey is a label which in this case will look as shown below The label indicates the action which will take place when the key is pressed Softkeys are so named because the role of each key can change depending upon the screen being displayed as indicated by the label In the Data Views the labels of the Left and Right Softkeys are left and right arrow symbols respectively These indicate that the Left and Right Softkeys are used to scroll the selection of the tab page being displayed in the corresponding direction One press of the Right Softkey will bring up the Overall Page and a second press will bring up the Session Log View Then sequential presses of the Left Softkey will bring up the Overall Page then the Live Page The LxT has a 13 button keypad The upper 3 keys are discussed in the section titled Softkeys on page 2 5 Keypad 2 5 Turn On The LxT Turn Off The LxT See Chapter 2 Power Control View on page 2 6 Power Control Page 2 6 Keypad The ON OFF key is used to turn the LxT ON and OFF If the instrument is OFF pressing this key will turn ON the instrument There will be a slight delay from pressing the button until a start up screen is displayed There are three methods to turn off the LxT Method 1 Press the 9 ON OFF key to bring the Power Control Page into view Press the Left Softkey labeled O
242. n of the sound you are interested in and hold the meter as far from your body as possible Use a tripod whenever possible 2 Measure the influence of other sources by measuring the background sound level without the source of interest You may have to correct for the background There are two types of near fields the acoustic near field and the geometric near field Acoustic Near Field The distance from a source of sound is less than an acoustic wavelength In the near field the effect of the type of sound source is significant Since the wavelength varies with frequency See the definition of Wavelength the distance will vary with frequency The most common example of a near field is driving an automobile with an open window As you move your ear to the plane of the window the sound pressure level builds up rapidly wind noise since most of the pressure changes are to move the air and very little of it compresses the air to create sound Persons not far way can hardly hear what you hear The acoustic near field is characterized by pressures that do not create sound that can be measured in the far field Therefore measurements made here are not useful in predicting the sound levels far way or the sound power of the source Geometric Near Field The distance from a source of sound is less than the largest dimension of the sound source In the LxT Technical Reference Manual Noise Noise Dose D LxT Technical Reference Manual
243. nabled the community noise parameters Lpy and are measured and displayed The LxT has three exceedance event counters two RMS event counters and three peak event counters For each exceedance there is a threshold level event counter and duration 18 4 Statistical Metrics Measured LxT Technical Reference Manual The thresholds Lyy Lypeak are the levels that the parameter must exceed to increment the counter and duration X is RMS frequency weighting Y is peak frequency weighting and V is time weighting The Count is the number of times each parameter has exceed the preset level The duration is the total accumulated duration of all exceedances for a specific parameter Miscellaneous Parameters S E A C minus A Impulsivity LxT Technical Reference Manual SEA is a time integration of peak levels that exceed 120 dB This measurement represents the difference between the C weighted and the A weighted measurements taken simultaneously The values and Lateg LAeq are measured and displayed Miscellaneous Parameters 18 5 18 6 Miscellaneous Parameters LxT Technical Reference Manual CHAPTER Out Of Memory Stop Overall Data Session Log Measurement History Memory Utilization This chapter presents formulas to calculate the amount of memory used by the parameters which can be stored to internal memory In order to ensure that all measured data can be stored th
244. nce Manual Note that the times intervals associated with the Day Evening and Night periods are set as described in Triggers Page on page 4 17 Section 13 displays three equivalent levels calculated for the total measurement time Legeg and Lageg are equivalent levels measured using Slow RMS averaging and using frequency weightings of C and A respectively The difference between them Legeg Lageg is often used as indicator of the amount of low frequency content in a sound It is also used as a parameter for the selection of hearing protectors since noise fields having a large amount of low frequency sound can require more effective hearing protectors than would otherwise be indicated by the measured Ls level alone The parameter LAFTMS will only appear when Takt Maximal Data has been selected on the Preferences Page as shown in Takt Maximal Data on page 12 10 C A and Impulsivity LxT Technical Reference Manual 0 03 41 2 Overall LCSeq LASeq LCSeq LASeq Impulsivity LAIeq LAeq LAIeq LAeq Run Time 0 03 41 2 FIGURE 5 21 C A Level and Impulsivity Section 15 The integrated levels for LAeq are always calculated using the linear detector regardless of the value selected in the SLM Setup The LAlIeq value is from the impulse detector C A and Impulsivity 5 17 Session Log Page 0 00 24 2 TASEEN Session Loa E gt Run 1 6 2007 Apr 16 14 08 17 Keypress Measure
245. ncel the attempt to access the Measurement Properties Screen highlight No and press the key 4 2 Measurement Properties Screen LxT Technical Reference Manual Setup Pages Only a few of these horizontally arranged tab pages three in Figure 4 2 can be seen at one time To see those off screen to the right use the Right Softkey beneath the display To scroll back to the left use the Left Softkey beneath the display LxT Technical Reference Manual Depending on the firmware options loaded in the LxT there may be as many as ten different setup pages in the Measurement Properties Screen each identified by a title on a tab at the top as shown in Figure 4 2 e 0 00 00 0 4L Settings General OBA Dosimet FIGURE 4 2 Tabbed Setup Pages For basic measurements we will only be concerned with the following pages General e SLM OBA Dosimeter 1 Dosimeter 2 Ln Control Triggers e Day Night The Right and Left Softkeys are used to scroll through the available pages to the right and left respectively in the order they are listed above Each of these is described in detail in the sections which follow Setup Pages 4 3 Note The SLM Utility G3 Software can be used to easily enter both the file name and the measurement description 4 4 Setup Pages 5 0 00 00 0 Settings General Default Data File LxT Data Measurement Description
246. ncy at Cursor Position Leq Lmax and Lmin Values at Cursor Position Data and time at cursor position rd 2007 May 22 14 42 Total Number of Records Enter gt Change Measured Record Number at Cursor Position FIGURE 9 10 Time History Display Spectra Metrics Section 2 and 3 Left Right Arrow Keys For the display shown in FIGURE 9 10 the 0 arrow keys have dual roles as listed below Use the key to toggle between them Step through records Move cursor along frequency axis 9 10 Time History Display LxT Technical Reference Manual At any time the role of the left and right arrow keys as well as the means to change it are indicated in the lower portion of the display as shown in Left and Right Arrow keys 2152 Step through Records 2006 Oct 03 09 24 52 Switch role of left right arrow keys from Change Record to Change Frequency FIGURE 9 11 Left Right Arrow Change Record Left and Right Arrow keys 5 L25 2 00kHz eq 80 3 dB to Move Cursor 80 5 d Enter Change Record Switch role of left right arrow keys from Change Frequency to Change Record FIGURE 9 12 Left Right Arrow Change Frequency Thus be redefining the role of the and keys these keys can be used to either scroll through record numbers displaying the spectra for each or to move the cursor in the the spectrum displays Link to Measurement History Display To rapi
247. ncy weighting and a peak detector LxT Technical Reference Manual Sound Power W Sound Power Level PWL Ly Sound Speed c Spectrum Frequency Spectrum Threshold Sound Level Lt LxT Technical Reference Manual Weighted Peak The peak value of a sound with a meter that has a frequency weighting other than flat and a peak detector The sound power emitted by a sound source It is measured in Watts The logarithmic form of sound power It is also expressed by attachment of the word decibel to the number The logarithm is taken of the ratio of the actual sound power to a reference sound power which is 1 pico watt Sound power level cannot be measured directly but can only be deduced through measurements of sound intensity or sound pressure around the source The equation for it is L 101 W 10 0 The speed at which sound waves propagate It is measured in meters per second It should not be confused with sound or particle velocity which relates to the physical motion of the medium itself 20 05 degC 273 m sec 49 03 degF 460 ft sec The amplitude of sound or vibration at various frequencies It is given by a set of numbers that describe the amplitude at each frequency or band of frequencies It is often prefixed with a descriptor that identifies it such as sound pressure spectrum It is generally expressed as a spectrum level The A weighted sound level below which the sound prod
248. nd Exposure LASmax EAS 1 558u Pa h EAS8 748 0u Pa h EAS40 3 740 Pa h 5 610m Pa s 2 6927 Pa s 13 464 Pa s 1 00kHz 49 9 dB 59 2 dB EAS EAS8 26 5 dB 8 0 h 90 0 dB 8 0 h 90 0 dB Lass Lasio LAS33 3 Lasso LAS66 6 14590 LASmin 2007 Apr 16 15 44 08 0 2007 Apr 16 15 44 08 2007 Apr 16 15 44 08 8 2007 Apr 16 15 44 08 2007 Apr 16 15 44 08 KD 010437 E mm Measurement mA 0 10 43 7 5 ETTE 0 00 00 0 2007 Apr 16 15 44 08 FIGURE 10 6 Measurement History Displays 10 8 Display of Measurement History Data LxT Technical Reference Manual Record Profile Display Note that there is no cursor on this The second section on the Measurement Page presents a graph nor a numerical display of Profile Level versus Time for the selected measurement amplitude or time record as shown in FIGURE 10 7 Level versus Time Graph for the Selected Record Leq and Maximum Minimum Levels for the Selected Measurement Record Selected Record Number 95 2007 Apr 16 15 44 08 FIGURE 10 7 Profile Display Measurement Page Section 2 Changing Displayed Record For the Measurement Record Display shown in Figure 10 5 on page lt chapnum gt 6 the selected record number for which data 1s being displayed in indicated at the upper right For all other displays the selected record number is indicated below the graph as shown in Figure 10 7 on page
249. ng 24 hour integrated values In the state of California a commonly used community noise descriptor is Community Noise Equivalent Level CNEL defined by the following formula 1900 2200 2400 1 L 10 10 1 10 1 5 10 L 10 10 CNEL way 54 0700 1900 2200 This is essentially the same as the using default values with the exception that the evening period begins at 22 00 instead of 23 00 Thus by making this change in the Lpgw formula the measured value will represent CNEL Integrated Level Calculations LxT Technical Reference Manual 2 d Taine et enu eai ab d 11 1 14 1 About sa ite e utat pte Oa diee hte I es ire S 14 2 14 1 14 3 Standards PEENE A EREN E E A EEE ETTE E 14 2 E A EE 14 4 About Pages d tite oU Nae ett 2 19 S o t Retina 2 19 o cette detect edere NUR nav uere OUS 2 19 p E E Aas sees 2 19 2 19 AC DC Output rete erre ETN ERE 12 9 Accessories M icroplione Re d ttd UR A ete dta A ard ae 1 9 Microphone 1 9 Microphone Preamplifiers ee eee 1 10 1 10 Optional Hh ce Asad Cee 1 10 Du 1 10 Standard e RE
250. nsion cable on calibration None up to 200 feet Electrostatic Discharges The instrument is not adversely affected by electrostatic discharges Table A 6 General Specifications Resolution Specifications Resolution of data shown on the instrument s display is specified in Table 7 Higher resolution level dose and elapsed time data are available via I O commands and data file downloads Levels 0 1dB Dose 0 01 Elapsed time 0 1 second Real time clock 1 second Calendar 01 Jan 2005 31 Dec 2038 Table A 7 Resolution Specifications A 6 Technical Specifications LxT Technical Reference Manual Frequency Weightings Nominal Exact Z A C Electrical Microphone Microphone Frequency Frequency Weight Weight Weight Limits Limits Limits Ideal Ideal Ideal Class 1 Class 1 Class 2 10 10 00 0 0 70 4 14 3 1 4 0 7 1 5 2 0 12 5 12 59 0 0 63 4 11 2 0 5 0 6 x13 1 8 16 15 85 0 0 56 7 8 5 0 4 0 5 1 0 1 7 20 19 95 0 0 50 5 6 2 0 3 0 4 0 5 1 5 25 25 12 0 0 44 7 4 4 0 2 0 5 1 5 31 5 31 62 0 0 39 4 3 0 0 2 0 5 1 5 40 39 81 0 0 34 6 2 0 0 2 0 5 1 0 50 50 12 0 0 30 2 1 3 0 5 0 5 1 0 63 63 10 0 0 26 2 0 8 0 5 0 5 1 0 80 79 43 0 0 22 5 0 5 0 5 0 5 1 0 100 100 00 0 0 19 1 0 3 0 5 0 5 1 0 125 125 00
251. nsitivity Page When performing an acoustic calibration the Sensitivity Page is used to select the microphone being used Certification Page The Certification Page shows the date of the last certification and the due date for the next certification Information about the calibration facility The user can enter their own certification interval and certification reminder from this page Exiting from the Calibration Function Press the Close Softkey to exit from any of the calibration pages to the Control Panel Acoustic Calibration This is the most commonly used calibration method and the one required by most national and international standards prior to performing a measurement A sound level calibrator is used to apply an acoustical signal of a known amplitude and frequency to the microphone From the voltage level measured by the meter the sensitivity can be determined In this technique one is obviously assuming that the calibrator is functioning correctly any variation in level from that expected will result in an improper calibration and an erroneous value of sensitivity For this reason the user is advised to compare the newly determined sensitivity with the previous sensitivity to ensure that significant variations have not occurred Frequency Weighting The LxT automatically switches to C frequency weighting and Fast detector response for calibration This permits 250 Hz and 1000 Hz calibrators to be used The Fast
252. nt but that an action can now be taken to delete the last five second segment 7 10 Performing the Measurement The back erase function permits the user to rapidly delete from the measurement the effects of acoustical events which have occurred during the previous five or ten seconds The back erase can be implemented when the measurement is paused as described in the preceding section When the measurement is paused the center softkey will be labeled Back 5s as shown in FIGURE 7 8 0 00 25 0 LxT_Data ASeq 1s Las 40 9 dB LZpeak 66 3 dB 5 Second Back Erase Label FIGURE 7 8 Five Second Back Erase Label Press the center softkey to implement the five second back erase lt Ten Seconds Since Last Stop or Pause After pressing the center softkey if the measurement duration since the last Stop or Pause has been less the ten LxT Technical Reference Manual seconds the center softkey will be labeled Undo as shown in FIGURE 7 9 69 0 03 27 9 Laseq 49 9 Las 49 1dB Back Erase Undo Indication FIGURE 7 9 Back Erase Undo Indication The user can take one of the following actions Press the 24 RUN PAUSE key to continue the measurement with the five second segment removed Press the center softkey to implement the Undo action and then press the amp RUN PAUSE key to continue the measurement without removing the previous five second time segment gt Ten Second
253. nt stopped you can monitor the actual level on the Live Page to be certain that the residue effects of the unwanted event have died down before beginning a new measurement There are six sections to the Live Page To scroll between sections use the 0 7 keys The Right and Softkeys beneath the display scroll between pages Sound Level Profile Profile of 1 Sec Leq using Frequency Weighting from Setup Current Value of 1 Sec Leq using Frequency Weighting from Setup Current SPL using Frequency Weighting and Detector from Setup 2007 Apr 16 13 21 32 Value of Lpeak using Frequency Weighting from Setup Reset Every Second Note that the graph scaling can be Section 1 presents a recent graphic history of L Data and Time Measurement Began FIGURE 5 2 Live Page Section 1 eq using the modified as described in section user selected frequency weighting calculated for each Adjust Graph Scale on page 5 19 5 2 Live Page LxT Technical Reference Manual second The graph presents the last 120 seconds of the measurement The time at the bottom of the page is the date and time the measurement was started Enforcement Sound Level This display is provided to make it easier for the user to observe both the instantaneous sound level and along with the value of the user selected SPL1 Trigger Level Current Value of Leq using Frequency Weighting and Detector from Setup Updated Once per Second S
254. nt time shown as h mm ss s FIGURE E 3 DOSE and Projected DOSE Sound Exposure Calculations Note that the LxT displays Sound Exposure as Ex where X is the fre quency weighting X A C or Z Sound Exposure See FIGURE E 2 Sound Exposure Level and Sound Exposure Sound exposure and sound exposure level are calculated as specified in IEC 61672 1 The A weighted sound exposure of a specified event is represented by t2 f p dt where P t is the square of the A weighted instantaneous sound pressure during an integration time starting at and ending at t E 8 Integrated Level Calculations LxT Technical Reference Manual Note that the LxT displays Sound Exposure Level as Lyp where X is the frequency weighting X A C or Z Sound Exposure Level The unit of A weighted sound exposure is pascal squared seconds if A weighted sound pressure is in pascals and running time is in seconds However it is sometimes expressed in pascal squared hours for measurements of noise exposure in the workplace The A weighted sound exposure level Lap is related to a corresponding measurement of time average A weighted sound level Lay or LAgeqr by 12 Lac 101 p3 e dt E La 101g 7 7 tl SEA LxT Technical Reference Manual where is the A weighted sound exposure in pascal squared seconds Ep is the reference sound exposure of 20 x 1s 400 x 10 P
255. nual 0 00 15 LxT_Data TA Overall 11709 Sound Exposure Level LASE 111 1 dB Sound Exposure EAS 14 34m Pa h EAS8 25 967 Pa h EAS40 129 83 Pa h EAS 51 609 Pa s EAS8 93481 Pa s EAS40 467 4k Pa s Run Time 0 00 15 9 FIGURE 5 14 Overall Page Section 8 Section 7 shows the Sound Exposure metrics in this instance for A weighted Slow L sg is the sound exposure level previously known as SEL The Sound Exposure metrics indicate the actual and extrapolated 8 and 40 hours exposure accumulated in terms of hours and seconds These are discussed in Sound Exposure SE on page D 17 and Sound Exposure Level SEL LE on page D 17 Frequency Weighting Z Start Time 2007 Apr 16 13 37 02 End Time 2007 Apr 16 13 40 17 Run Time 0 00 15 9 Overall Page 5 13 Ln Percentiles 5 14 Overall Page SEA is an integration of 1 second peaks that exceeded 120 dB Both the SEA value and the frequency weighting used for the measurement are displayed See section SEA on page E 9 for a detailed description 000153 EAL Ln Percentiles LASmax 108 2 dB LASS 106 8 dB 14510 105 3 dB LAS33 3 93 6 dB LAS50 85 8 dB LAS66 6 55 5 dB LAS90 33 0 dB LASmin 30 5 dB Run Time 0 00 15 9 FIGURE 5 16 Overall Page Section 10 Section 9 displays the Ln statistics for the measurement based on the run time Also shown are the maximum and minimum sound levels measured An Ln is the level
256. nually by pressing the Run Pause key and it is stopped by pressing the amp 2 Stop key Measurements are made only during the separate time blocks defined by the setup When the Control Page is opened the Run Mode field will already be highlighted Press the Enter key to open the Run Mode Menu Manual Stop FIGURE 6 2 Run Mode Menu set the mode use the C 7 C keys to highlight the mode desired and press the Enter key to make the selection Each of the Run Modes is described in the following sections Run Modes Without Measurement History For descriptions of setup procedures of the six Run Modes have a check box to enable the for Run Modes with Measurement Measurement History feature as is shown in the figures History enabled see Run Mode with appearng in the sections which follow The setup Measurement History on page 6 5 6 2 Run Modes Without Measurement History LxT Technical Reference Manual descriptions presented in the following sections are for setups without the Measurement History enabled When Measurement History is not enabled at the conclusion of the measurement there will be a single measurement which must be manually stored Since there is only a single measurement the data displayed on the Overall and Current pages will be identical Manual Timed Stop or Stop When Stable When the run mode used is Manual Timed Stop or Stop When Stable a single measurement will run cont
257. of which are we interested sound Non sound forces are 1 direct physical contact such as that with a finger or a raindrop 2 those caused by the movement of air over the diaphragm such as environmental wind or blowing 3 those caused by vibration of the microphone housing and 4 those caused by strong electrostatic fields Rules 1 Do not permit any solid or liquid to touch the microphone diaphragm Keep a protective grid over the diaphragm 2 Do not blow on a microphone and use a wind screen over the microphone to reduce the effect of wind noise 3 Mount microphones so their body is not subject to vibration particularly in direction at right angles to the plane of the diaphragm 4 Keep microphones away from strong electrical fields A microphone measures forces not pressures We would like the microphone to measure sound pressure force per unit area instead of sound force If the pressure is applied uniformly over the microphone diaphragm a simple constant the diaphragm area relates the two but if the pressure varies across the diaphragm the relationship is more complex For example if a negative pressure is applied on one half the diaphragm and an equal positive pressure is applied to the other half the net force is zero and essentially no motion of the diaphragm occurs This occurs at high frequencies and for specific orientations of the microphone Rules 1 Do not use a microphone at frequencies higher than specif
258. on the Overall Page and Current Pages After that the overall measurement will continue while new current measurements will be made as the measurement sequence proceeds 10 6 Display of Measurement History Data Figure 10 5 shows the first or section one data display appearing on the Measurement Page There are as many as fifteen different data displays which might appear on that page as shown in FIGURE 10 6 Measurement History Displays on page 10 8 depending on the firmware options enabled and the setup used Use the C 7 and C keys to page sequentially through these different data displays LxT Technical Reference Manual TABLE 10 1 lists these displays by name and indicates the position of that display in FIGURE 10 6 Location in Section Display Type Comments EE FIGURE 10 6 1 Measurement Record Display Row 1 See Figure 10 5 for detailed view Column 1 2 Sound Level Display Row 1 Column 2 3 Records Profile Display with Row 1 See Figure 10 7 for detailed view Lemay and Lsmin Column 3 4 Max Min and Peak Levels Row 1 Column 4 5 1 1 Octave Spectrum Row 1 Option LXT OB3 Required Column 5 6 1 3 Octave Spectrum Row 2 Option LXT OB3 Required Column 1 7 Noise Dose 1 Row 2 Column 3 7 Noise Dose 2 Row 2 Column 3 9 Sound Exposure Row 2 Column 4 10 Ln Percentiles Row 2 If the user were to manually change Column 5 the Ln values to be displayed during a meas
259. onclude the process Timed Stop Mode 10 3 The Continuos Mode described Continuous and Timer Modes on page 10 2 can be used to make an automatic Time History Measurement of number of records but the measurement process would need to be stopped manually when the desired number of records have been measured An example of the use of this would be when the user wishes to make a fixed number of separate measurements each for the same run time then stop By setting the measurement counter to 4 for example pressing the Run Pause key would initiate a measurement sequence which would conclude when four measurements have been completed each using the value of Run Time set as described in Manual Timed Stop or Stop When Stable on page 6 3 These data are displayed on the Measurement History tab page as described in Measurement Page on page 10 6 and can be saved by pressing the 2 key Manual and Stop When Stable Modes For these modes the Measurement History does not automate the measurement and storage of data as it does for the Continuous Single Block Timer and Daily Timer modes However it does simplify the number of key presses required when making multiple measurements 10 4 Manual and Stop When Stable Modes For these run modes at the conclusion of a measurement the data must be manually saved Checking the Enable Measurement History checkbox does not
260. onnected to the instrurment which is moving A reference microphone at a fixed position A diagram showing the test setup and and the data measured are presented in the following two sections Vibration Parallel to the Microphone Diaphragm REFERENCE MICROPHONE Vibration Exciter VIBRATION PARALLEL TO MICROPHONE DIAPHRAGM FIGURE A 23 Vibration Parallel to Microphone Diaphragm A 58 Technical Specifications LxT Technical Reference Manual Frequency Lacq Ref 31 5 35 7 35 4 63 35 5 34 8 125 35 8 36 8 250 47 7 47 9 500 52 6 51 4 630 60 5 50 4 800 61 0 54 4 1 000 62 2 60 0 Table A 31 Axis of Vibration Parallel to the Microphone Diaphragm Vibration Perpendicular to the Microphone Diaphragm REFERENCE Vibration Exciter VIBRATION PERPENDICULAR TO MICROPHONE DIAPHRAM FIGURE A 24 Vibration Perpendicular to Microphone Diaphragm LxT Technical Reference Manual Technical Specifications A 59 Frequency Leg Ref 31 5 35 9 35 6 63 38 6 34 5 125 46 0 355 250 54 1 39 4 500 67 1 44 2 630 82 6 70 0 800 69 7 45 7 1 000 69 2 51 7 Table A 32 Axis of Vibration Perpendicular to the Microphone Diaphragm Technical Specifications LxT Technical Reference Manual CHAPTER Upgrade Firmware and Options This chapt
261. ons from the top present basic sound level parameters as shown in FIGURE 7 6 and FIGURE 7 7 7 6 Performing the Measurement LxT Technical Reference Manual Measurement Duration Leq Running SPL ASeq 64 6 37 0 Date and Time of Initiation Started 2007 4 16 15 14 04 of Measurement FIGURE 7 6 Leq and Running SPL The two digital displays present the Leq value 72 2 dB and the running SPL 33 5 dB Both of these were measured using A weighting and Slow detector as indicated by the AS The duration of the measurement is indicated at the top of the display and the data and time that the measurement was initiated are indicated at the bottom of the display The graph represents the value of Leq as a function of time during the measurement Leq using Frequency Weighting and Detector from Setup Percent Above SPLI Trigger LAS gt 85 0 dB Trigger Level 9 LaSmin 30 0 dB Maximum and Minimum Levels Run Time man using Frequency Weighting and Detector from Setup easurement Duration FIGURE 7 7 Multiple Sound Level Parameters LxT Technical Reference Manual Performing the Measurement 7 7 Measurement Range Overload Under Range Levels For further detail on determination of overload level and under range levels see section on page 12 Overload Indication Under Range Indication The measurement ranges over which the LxT meets the standards which depend upon the
262. oot 13 3 WMO CK OG E 13 3 Lock w Auto Store 2000100 0 13 3 Lock w Manual 13 3 Fully LOCKE pua 13 3 Unlock Goo eO ren eren t 13 4 Allow Cal When Locked 13 4 F lly ord CG rA 13 5 Locked With Auto Store e 13 6 LxT Technical Reference Manual 1 9 Locked With Manual Store s 13 8 WM OC dee UE 13 8 Calibration When The LxT Is Locked 13 9 Chapter 14 About 14 1 Control Panel About eene 14 1 en 14 2 Slandaruis suco I I MM DELE 14 2 TONS oeste uM UICE 14 3 rl p 14 4 Chapter 15 Calibration 15 1 Calibration Overview 15 1 Sensitivity 15 1 Overload Under Range Conditions 15 1 Calibration 15 1 Control Panel Calibrate 15 2 Calibrate Page 2 ec racer tene 15 3 History ertet tet t ter fore rea 15 3 Sensitivity 15 4 Certification 15 4 Exiting from the Calibration Function 15 4 A
263. ore check box in the Daily Section is checked daily measurement reports for 24 hour time periods beginning at a user specified time will be automatically stored assuming that the measurement time period encompasses at least one 24 hour time period as programmed Highlight the Auto Store field and press the key to insert a check mark repeat the procedure to remove a check mark When the check mark is inserted a data field will be opened as shown in FIGURE 6 5 to define the start time for the 24 hour time period to be used for the report esee FIGURE 6 5 Auto Store Report Start Time Highlight the data field below and press the err key Enter the desired values and press the key Run Mode with Measurement History Measurement History requires that the optional firmware LXT ENV be enabled LxT Technical Reference Manual There are many applications where it is desirable to measure and store a sequence of measurements using the same setup either manually or automatically With the LxT this is facilitated using the Measurement History feature which is described in detail in Chapter 11 Measurement History on page 11 1 Run Mode with Measurement History 6 5 Run Mode with Measurement History LxT Technical Reference Manual Making a Measurement In this chapter we describe how to make and store an accurate sound level measurement Before doing this make sure that the LxT has been setup to meet the
264. orming the Measurement LxT Technical Reference Manual Resetting the Measurement A measurement is most often reset when a noise event which is not typical of the measurement desired takes place For example an aircraft passing overhead when attempting to measure the background noise in a normally quiet area To reset a measurement in progress press the 5 RESET key This will erase all data previously measured and reset the run time clock to zero A reset will not reset stored data files A reset can be initiated when the LxT is running paused or stopped However it must be stopped for the reset operation to be performed Resetting When Running or Paused Resetting When Stopped LxT Technical Reference Manual If it is running or paused when the amp RESET key is pressed a Stop Required Menu will be displayed as shown in FIGURE 7 11 Stop Required FIGURE 7 11 Stop Required Prompt The OK response will already be highlighted so simply press the ENTER key to continue Otherwise press the 0 key to highlight Cancel and then the ENTER key to cancel both the Stop and the Reset operations After selecting to Stop the measurement the Save File Menu shown in Figure 7 12 on page 14 will appear to provide a choice of saving the measured data prior to the reset or not as described in Storing the Measurement on page 7 14 If the LxT is stopped when the 5 RESET key is pressed the Stop Required M
265. oughout this manual there are cross reference links to other chapters and figures The cross reference may appear similar to FIGURE 3 5 Measurement Properties Screen page 3 3 Left click on these text areas to display the page associated with that cross reference To return to the previously displayed page click the View Menu in the menu bar Click Goto and then Previous View on the pop up menus Special Features of the Electronic Version LxT Techncial Reference Features Hardware Features LxT Technical Reference Manual The Larson Davis SoundTrack LxT has the following features Precision integrating sound level meter 64 MB unformatted standard data memory 256 MB optional 160 X 240 graphic LCD display with backlight and icon driven user interface Silent Touch elastomeric keypad Large dynamic range providing single SLM display page RMS Detectors Slow Fast amp Impulse RMS Frequency Weighting A C amp Z Peak Frequency Weighting A C amp Z Ly Statistics 6 user selected values over the range 10 01 through Log 99 and Histogram tables Jack for AC DC output or headset microphone and speaker Compatible with 61 m 200 ft microphone extension cable full scale to 20 kHz 4 AA batteries provide 16 hour operating time USB 2 0 full speed peripheral connector and AC DC output Multiple language support English French German Italian Portuguese Spanish and Swedish Field up
266. page 5 4 except that it represents 1 3 octave data 5 10 Overall Page LxT Technical Reference Manual Dosimeter 1 and 2 LxT Technical Reference Manual 41 4 dB 95 5 dB 66 5 dB 0 12 213 75 4 Slow 5 dB 90 0 dB Criterion 8 0 h 90 0 dB Run Time 0 00 15 9 FIGURE 5 13 Dosimeter 1 amp 2 Display Sections 6 and 7 There are two separate but similar dosimeter data displays in sections 5 and 6 In this example we can see that the measurement parameters correspond to the setup named OSHA 1 TWA 8 The value of TWA 8 Time Weighted Average for 8 hours is based on data measured during the run time and calculated for the user defined Criterion Time in this case 8 hours The value of Criterion Time is set by selecting a predefined setup as described in Predefined Setups on page 4 9 or by entering a numerical value as described in Threshold and Criterion on page 4 12 As as example suppose a measurement was performed over a time period of ten minutes The value of TWA 8 would be the same as the TWA measured over an eight hour period if there had been no other sound exposure other than that which occurred during that ten minute period ProjTWA The ProjTWA Projected Time Weighted Average is calculated from data measured during the measurement run time and calculated for the user defined Criterion Time in this case 8 hours Continuing with the example in the above Overall Page 5 11 5
267. prior to the reset or not as described in Storing the Measurement on page 7 14 If the LxT is stopped when the 2 RESET key is pressed the Stop Required Menu will not appear but the Save File Menu will appear to provide a choice of saving the measured data prior to the reset or not After the reset has been performed the STOP STORE key will produce a steady red light to indicate the measurement state as Stopped Reset LxT Technical Reference Manual Resetting When Reset Starting a New Measurement TOOLS Key Note that there is one more icon System Utilities which does not appear in FIGURE 2 4 It is necessary to scroll down below the Lock and About icons in order to see it LxT Technical Reference Manual If the LxT has already been reset when the D RESET key is pressed the filters will be reset and a run can begin after a short delay less than 10 seconds The 574 key RUN PAUSE key must be pressed to start new measurement Pressing the A TOOLS key will bring you to the Control Panel screen D 0 00 00 0 0 Control Panel Data Calibrate Explorer Setup Manager Voice Recorder System About Properties FIGURE 2 4 Control Panel Table 2 2 lindicates the chapter in which each of these functions is described Function Chapter Number Voice Recorder 8 Data Explorer 11 System Properties 12 Lock 13 Calibrate 15 Table 2 1 Chapters Describing Functions
268. ps calibrators and microphones LxT Technical Reference Manual Technical Specifications A 51 Preamplifier Model PRMLxT2 Serial Number 0182 Larson Davis Certificate of Electrical Conformance Frequency response of this model PRMLxT2 preamplifier was tested at a level of 5 356 Vrms with 18pF microphone capacitance and driving a short cable Output level at 1kHz is 1 0039 Vrms 0 034 dBV uncertainty 0 035 dB Output is 3 454 V DC uncertainty 0 001 Results are displayed relative to the level at 1kHz 0 5 50 100 200 501 1000 1995 5012 10000 19953 50000 100000 Frequency Hz Freq Hz Measured dB Uncert dB Tolerance dB Freq Hz Measured dB Uncert dB Tolerance dB 16 0 06 98 0 04 01 0 03 31 0 02 94 0 01 00 0 01 489 0 00 85 0 00 295 0 00 12 0 00 62 0 00 81 0 00 12 0 00 10 0 00 43 0 00 00 0 00 89 0 00 49 0 00 93 0 00 19 0 00 223 0 00 11 0 00 19 0 00 058 0 09 0 21 794 33 00 016 0 10 0 10 058 0 10 0 18 1000 00 00 016 0 10 0 10 036 0 10 0 15 1258 90 00 016 0 10 0 10 036 0 10 0 13 1584 90 00 016 0 10 0 10 036 0 10 0 11 1995 30 00 016 0 10 0 10 016 0 10 0 10 2511 90 00 016 0 10 0 10 016 0 10 0 10 3162 30 00 016 0 10 0 10 016 0 10 0 10 3981 10 00 016 0 10 0 10 016 0 10 0 10 5011 90 00 016 0 10
269. r above Acoustic Calibration LxT Technical Reference Manual Microphone Selection In order for the Noise Floor and Under Range Levels to be determined when the microphone is not selected from the drop down list as described in Larson Davis Microphone on page 15 9 the user must manually enter a value into the Self Noise data field LxT Technical Reference Manual The microphone being used is selected from the Sensitivity Page shown in FIGURE 15 2 Larson Davis Microphone If using one of the Larson Davis microphones most frequently used with the LxT highlight the down arrow portion of the Type data field to obtain a list of microphones such as shown in FIGURE 15 4 FIGURE 15 4 Microphone Selection List Co the microphone type being used and press the key to make the selection The nominal value of sensitivity for that type of microphone will now appear in the Published data field and the Self Noise for that microphone and preamplifier combination will appear in the Self Noise data field Other Microphone If using a microphone from another manufacturer or if the Larson Davis microphone type being used does not appear in this list the name and parameters can be entered manually The Type data field is a combobox which means that the down arrow right portion can be used to open a drop down list while the left portion can be used for text entry Use the key to highlight the left portion of the data field an
270. r example Lp represents the sound pressure level The difference between the sound pressure for silence versus loud sounds is a factor of 1 000 000 1 or more and it is very unpractical to use these large numbers Therefore a measure that would relate to the number of zeros would help for example 100 000 would be equal to 50 and 1000 would be equal to 30 and so on This is the basic principal of the dB measure LxT Technical Reference Manual LxT Technical Reference Manual All dB values are unit free and therefore the dB value is not the value of the quantity itself but the ratio of that quantity to an actual reference quantity used Thus for every level in decibels there must be a well defined reference quantity Sound versus vibration uses different references but the dB principal is the same When the quantity equals the reference quantity the level is zero To keep dB values above zero the reference is generally set to be the lowest value of the quantity that we can imagine or normally wish to use Before explaining the calculation of dB values it is useful to remember the following rules of thumb when dB values are used for sound levels Doubling of the Sound Pressure 6 dB Doubling of the Sound Power 3 dB Doubling of the Perceived Sound Level approx 10 dB Note The latter is frequency and level dependent but the value 10 dB is a good rule of thumb especially around 1 kHz Table 1 shows the ac
271. rding has been stopped the Save Prompt shown in FIGURE 8 4 will appear Voice Recorder t Voice 1 2 2007 Apr 16 15 23 44 SoundTrack E AEG Save Recording FIGURE 8 4 Save Recording Prompt Voice Recorder 8 3 Playback 8 4 Select Yes to save the recording or No to close the recording session without saving the recording Playback Button Lb To playback a highlighted voice record press the Right Softkey With a headset attached to the headset jack on the bottom of the case you will hear the voice recording in the headset speaker FIGURE 8 5 Playback The meter indicates the relative amplitude of the recorded sound The progress bar indicates the elapsed time of the playback of the recording The progress bar length represents the actual recording time Press the key to stop the playback At the end of the voice record the playback will stop automatically LxT Technical Reference Manual CHAPTER Parameters Logged Acoustical Parameters Sound Pressure Level Values LxT Technical Reference Manual Time History This chapter describes the measurement features associated with the optional data logging firmware LxT LOG and LxT HSLOG With the optional firmware LxT LOG enabled the Time History mode permits the LxT to automatically log up to twenty parameters both acoustic and non acoustic at time intervals ranging from 1 second to twenty four hours With the optional firmware LxT
272. re Level and Sound Exposure Dose and Projected Dose Calculations Dose is a measure of Sound Exposure and is defined in ANSI 51 25 Section 4 7 as MT 29 fi a 0 See FIGURE E 3 DOSE and Pro where jected DOSE D Q is the percentage criterion exposure for exchange rate Q T is the criterion sound duration 8 hours T is the measurement duration in hours t is the time in hours L is the SLOW or FAST A weighted sound level a function of time when the sound level is greater than or LxT Technical Reference Manual Integrated Level Calculations E 5 equal to L or equals x when the A weighted sound level is less than Ly L is the threshold sound level specified by the manufacturer is the criterion sound level specified by the manufacturer is the exchange rate in dB and 4 the parameter that determines the exchange rate where q 10 for a 3dB exchange rate q 13 29 4 log 2 for a 4dB exchange rate q 16 61 5 log 2 for a 5 dB exchange rate q 20 6 log 2 for a 6dB exchange rate The factor of 100 in the equation produces a result that is a percentage Dose is obtained from the accumulations made for TWA and SEL using the formula where L is the current SPL at sample s for measurements that include a threshold Lis is set to x if Lis is less than the Threshold Level Ly 5 a 3 ye log T 115200 log 100 DOSE 10 k is the exchange rate
273. re and installed options in your Larson Davis SLM without sending it back to the factory Before beginning make sure your instrument is properly connected to your PC and that you have a firmware file on your computer When you re ready to begin click Next If at any time you want to change a previous selection click the Back button Back FIGURE B 3 SLMFirmwareProgrammer Upgrading LxT Firmware LxT Technical Reference Manual Left click Next to proceed with the upgrade which will display the Select File menu shown in FIGURE B 4 Select File Step 1 Select the file s to load into the instrument Select the type of file s you would like to load into the instrument Upgrade the firmware using ROM file C Program Files PCB Piezotronics Sim Utility G3 Firmware LxT Browse L Change installed options using a OPT file FIGURE B 4 Select File Menu Note that upgrades of both firmware click the check box corresponding to the text Upgrade and options can be performed the firmware using a ROM file simultaneously checking the check boxes for both and defining the paths to the files accordingly See section Upgrading Options on page B 7 for details on upgrading options Define Path to Firmware Upgrade File Left click Browse and use the browser to define the path to the LxT v rom file which was installed when you upgraded the SLM Utility G3 as described in SLM Utility G3 on
274. re is enabled Under normal operation the stored data files will be stored with the following name format yymmdd00 LD0 where is the date the file was stored Following an improper shutdown when the instrument 15 next turned On the data is automatically stored in the following name format yymmddxx LD0 where is the date the data was stored and xx is a number beginning at 01 which is automatically incremented for subsequent instances of improper shutdown Thus all data blocks stored with the 01 02 03 etc represent data which were being measured at the time of an improper shutdown Recovery After Improper Shutdown LxT Technical Reference Manual Case 2 Improper Shutdown When the user is present he she must eventually select to store the data reset the instrument or take no action in which case the instrument will be automatically reset LxT Technical Reference Manual This case covers all setups other than those described in Case 1 Following an improper shutdown when the instrument is next turned On Step 1 The user is prompted to save the data If the user responds by selecting to store the data the data is stored and the instrument is reset f there is no user response to the prompt within ten seconds the instrument is reset If the user responds by selecting not to store the data the sequence moves to Step 2 Step 2 The user is prompted to reset the inst
275. reamplifier influence the measurement an under range condition exists When this happens the Under Range Icon will appear 7 8 Performing the Measurement LxT Technical Reference Manual Pausing the Measurement Note that a measurement may be paused and then run again multiple times LxT Technical Reference Manual As long as the under range condition exists the icon will flash When the measured level no longer produces an under range condition the icon will be removed from the display Whenever a measured parameter is in an under range condition it s numeric display will not appear At any time the measurement of overall data can be temporarily suspended by pressing the 574 RUN PAUSE key Note that the run clock will also pause However instantaneous data will continue to be displayed in the Live View Pressing amp i RUN PAUSE key one more time will cause the measurement to begin again and overall data will continue to be accumulated The run clock will also begin again from the time indicated when the pause had occurred The overall data will not be affected by any acoustic events occurring during the time period that the LxT was paused Performing the Measurement 7 9 Back Erase Note that Back Erase is disabled when Measurement History has been enabled in the LxT setup as described in Chapter 10 Measurement History on page 10 1 Note that the Back 5s label does not indicate the state of the instrume
276. red with one of the following combinations of microphone and microphone preamplifer Microphone Microphone 61672 1 Measurement Instrument i Preamplifier Sensitivity Conformance Range PRMLxTI 377B02 50 mV Pa Class 1 38 dB to 140 dB LxT2 PRMLxT2 375A02 22 6mV Pa Class2 37 dB to 139 dB Table 1 1 Microphone and Preamplifier Software LxT Technical Reference Manual SLM Utility G3 software providing setup utilities calibration routines remote instrument control from PC data downloading and export of data to 3rd party software such as MS Excel CBL138 USB cable required for utilization e SLMScreengrabber software to capture and save screen displays as bitmap files 1 9 Features Other Optional Accessories Microphones Microphone Preamplifiers Windscreen 3 1 2 in diameter WS001 Alkaline Batteries 4 AA Lanyard Qty 4 SS button socket head screws 4 40 x 3 16 to secure access to battery door when using in an explosive atmosphere Larson Davis part number 5290 0185 Hex Driver 1 16 miniature for use with battery door access screw LxT User Manual 1770 01 1 2 in free field prepolarized microphone 50 mV Pa order 377B02 1 2 in free field prepolarized microphone 23 mV Pa order 375A02 1 with 23 dB capacitive attenuation PRMLxT2 2 with 15 dB capacitive attenuation PRMLxTIL Low Level Type 1 w
277. requirements for the measurement as described in Chapter 4 Basic Measurement Setup on page 4 1 Configuration of the System The use of the microphone extension cable EXCXXX where XXX is the length in feet XXX 010 020 025 035 050 060 100 and 200 available will not affect the ability of the LxT to comply with acoustic standards referenced in this manual The System LxT should be configured as shown in FIGURE 1 3 The LxT on pagel 12 with the preamplifier connected to the front of the instrument and the microphone connected to the end of the preamplifier If desired a microphone extension cable may be connected between the preamplifier and the body of the LxT For more details on the positioning of the LxT and the permitted length of the extension cable see Positioning the LxT on page 7 4 Switching On the LxT DO NOT use the hardware power switch to turn the LxT OFF This may cause data to be lost See Hardware Power Switch page 3 6 for additional information on the use of the hardware power switch LxT Technical Reference Manual With fresh batteries installed press the ON OFF key shown in ON OFF Key on page 2 6 to switch on the LxT Making a Measurement 7 1 Start up Period The start up period will be less than two minutes As the instrument is starting up the display will show the following screen FIGURE 7 1 Boot Graphic Data View and Data Display screen When the
278. res Headset with microphone for voice recording playback LXT HS Note this is included with the optional accessory LXT DVA Storage Case LX T CCS Environmental Protection EPS2106 2 Environmental Shroud Features 1 11 EPS2108 2 Environmental Shroud EPS029 LXT Environmental Case with two lead acid batteries and integrated microphone mast EPS030 LXT Environmental Case with one lead acid battery used with external microphone tripod Tripods TRP001 Instrument Camera Tripod with ADP032 1 2 in microphone clip TRP002 Microphone Stand with adjustable height and boom angle Calibrators CAL150 CAL200 LxT Components 1 12 Features lt a Microphone lt Preamplifier LCD Display FIGURE 1 3 The LxT LxT Techncial Reference Manual The SoundTrack LxT is a convenient hand held sound level meter real time analyzer with a simple user interface The standard LxT shown in FIGURE 1 3 includes the following 1 2 in diameter condenser microphone Backlit graphic 160 x 240 pixel LCD display 13 key soft rubber backlit keypad AC DC output control USB and external power connectors shown in FIGURE 1 4 True hand held instrument with sure grip pads Hardware Power Switch AC DC Output and Headset AUX Connector FIGURE 1 4 LxT Bottom View LxT Technical Reference Manual Features 1 13 Features LxT Techncial Reference Manual Display Softkeys
279. ring Time in Timed Stop Run Mode 4 15 Stop When Stable Run 4 15 Triggers Page xd essc cu o meet ou 4 17 Day Evening Night Definition 4 18 Apply Changes edocet e t 4 20 Basic Data Display 4 erre erret 5 1 Tabbed Page 5 2222222 2 5 1 Live Page Section 1 22 5 2 Live Page Section 2 5 3 Live Page Section 5 4 Live Page Section 4 222 5 5 live Page Section 5 5 5 Live Page Section 6 iia erede cec brand 5 6 Overall Page Section 5 7 Overall Page Section 2 2 2 5 7 Overall Page Section 5 8 Overall Page Section 4 2 2 5 9 Overall Page Section 5 2 1 5 10 Dosimeter 1 amp 2 Display Sections 7 5 11 Overall Page Section 8 5 13 SEA Display Section s Mob nth 5 13 Overall Page Section 10 5 14 Overall Page Section 11 2 2 tes 5 15 Overall Page Secliorni 12 2 iu 5 15
280. rument Ifthe user responds by selecting to reset the instrument the instrument is reset If there is no user response to the prompt within ten seconds the instrument is reset f the user responds by selecting not to reset the instrument the sequence moves back to Step 1 This sequence is diagramed below Recovery After Improper Shutdown 7 19 Save Data prompt Data Saved Y No Response for 10 seconds gt Reset Instrument prompt No Y Y No Response for 10 seconds Y Instrument Reset FIGURE 7 16 Improper Shutdown Sequence Case 2 7 20 Recovery After Improper Shutdown LxT Technical Reference Manual Voice Recording Control Page Voice Recording Voice recordings are made using a sample rate of 8 kHz To activate the Voice Recorder Page press the A TOOLS key Use the 7 keys to highlight the Voice Recorder icon as shown below Properties Close FIGURE 8 1 Control Panel Press the key to open the Voice Recorder Page Press the Close Softkey to exit from this page By connecting a headset to the headset jack on the bottom of the LxT voice annotation may be recorded using the headset microphone Voice records may be played back through the headset speaker With no headset plugged in a record may be made of the sound arriving at the measurement microphone LxT Technic
281. ry can be enabled the Run Control Setup Run Control Setup The Run Control is setup from the Control Page of the Measurement Setting Screen as shown in Figure 6 1 Run Mode Manual Stop Y O Enable Measurement History FIGURE 6 1 Control Page The Control Page is used to set the Run Mode for the measurement to be performed There are six modes of measurement duration available Manual Stop The measurement is initiated manually by pressing the Run Pause key and it is stopped by pressing the amp Stop key Timed Stop The measurement is initiated manually by pressing the Run Pause key and will be stopped automatically after a user defined time period LxT Technical Reference Manual Run Control 6 1 e Stop When Stable The measurement is initiated manually by pressing the Run Pause key The measurement will stop when the measured level has remained within a user defined range the measurement has run for a user defined time period Continuous The measurement is initiated manually by pressing the Run Pause key and it is stopped by pressing the gt Stop key Measurements are made continuously from start to stop Single Block Timer The measurement is initiated manually by pressing the Run Pause key it is stopped by pressing the amp 2 Stop key Measurements are made only during the time interval defined by the single block timer Daily Timer The measurement is initiated ma
282. s Time Graph 20 dB to 140 dB e Frequency Spectra Normal Range 20 dB to 140 dB Frequency Spectra Low Range 10 dB to 110 dB To change the scaling of any one of these graphs press the Menu softkey to obtain the display shown in FIGURE 5 23 FIGURE 5 23 Menu Use the C key to highlight Adjust Graph and press the key to obtain the Adjust Graph menu shown in FIGURE 5 24 Height Bottom FIGURE 5 24 Adjust Graph Menu Use the and 0 keys to change the baseline level and the C7 and 2 2 keys to adjust the height range between the baseline and the top of the display Press the key to implement the change Once one or more graphic displays have had their scalings changed they will remain that way until changed again or until the defaults settings are restored as described in Format amp Restore Defaults on page 19 3 Adjust Graph Scale 5 19 View Spectrum Normalized Note that the Live Spectrum will continue to change in time following the normalization whereas the Reference spectrum will remain the same Live Display The View Normalized function permits the display of the difference between two spectra by subtracting a user selected reference spectrum from the measured spectrum This function can be used with both 1 1 and 1 3 octave spectra although the measured spectrum and the reference spectrum must have the same bandwidth 1 1 or 1 3 octave A and C frequency weighting curves can also be used
283. s Since Last Stop or Pause After pressing the center softkey to implement a five second back erase if the measurement duration since the last Stop LxT Technical Reference Manual Performing the Measurement 7 11 Note that the Back 10 label does not indicate the state of the instrument but that an action can now be taken to delete the last ten second segment Time History Records or Pause has been more then ten seconds the center softkey will then be labeled Back 10s as shown in FIGURE 7 9 e 0 13 00 0 5 LxT_Data ASeq 1s 38 6 dBET Las 36 2 dB LZpeak 65 1 dB Started 2007 Apr 20 15 05 45 Back 10s Ten Second Back Erase Label FIGURE 7 10 Ten Second Back Erase Label Now the user can take one of the following actions Press the RUN PAUSE key to accept the five second back erase and continue the measurement Press the center softkey to extend the back erase to ten seconds The center softkey will then be labeled Undo as shown in FIGURE 7 9 The user can then take one of the following actions Press the RUN PAUSE key to accept the ten second back erase and continue the measurement Press the center softkey to implement the undo action and the press the amp RUN PAUSE key to continue the measurement without removing the previous ten second time segment The time history records from the point data were restored from to the last record will be marked as back erase records 7 12 Perf
284. s the key Press the Close soft key to exit the Lock Page LUI I gt Apply Changes FIGURE 13 5 Apply Changes Make the choice whether to accept the changes using the keys and then press the D key to complete the process Move the highlight to Allow Cal When Locked Pressing the key will toggle the state of the check boxes shown in FIGURE 13 6 Allow Cal Check Box If the box is 13 4 Control Panel Lock LxT Technical Reference Manual checked calibration will be allowed while the unit is locked but not running a measurement 0 10 43 7 Lock Made Unlock Code Enter 4 digit code to use when unlocking this unit Ix Allow Cal When Locked FIGURE 13 6 Allow Cal Check Box Fully Locked 0 10 43 7 5 Date 2007 Apr 16 17 04 31 This instrument has been LOCKED Press the Tools key to UNLOCK FIGURE 13 7 Fully Locked If you have selected Fully Locked for the Lock Mode upon accepting the changes FIGURE 13 7 Fully Locked represents the view you will have At this point the instrument is not running a measurement It is possible to select the Fully Locked mode while a measurement is in progress LxT Technical Reference Manual Fully Locked 13 5 Pressing the CA RUN PAUSE key will start a measurement by bring up the following message box Run Are you sure FIGURE 13 8 Are You Sure Use the 0 keys to select the desired response Selecting Yes will
285. s the user to create such a setup in a single step by simply selecting the applicable standard The standards addressed by the Lx T and the corresponding parameters are as shown in Table 4 1 Predefined Noise Dosimeter Setups Standard pxelianee Threshold Criterion Rate Level Hours OSHA 1 3 90 90 8 OSHA 2 5 80 90 8 ACGIH 3 80 85 8 Table 4 1 Predefined Noise Dosimeter Setups LxT Technical Reference Manual Dosimeter and 2 Pages 4 9 5 Standard Threshold Criterion Rate NIOSH 3 80 85 8 IEC 3 Not Enabled 85 8 Table 4 1 Predefined Noise Dosimeter Setups The Name field will already be highlighted when the Dosimeter View is opened If this has been changed use the 2 key to move the highlight back to the Name field The names of the predefined setups can be accessed from the Name field at the top of the display Press the key to drop down a list of predefined setups by name as shown in FIGURE 4 8 Predefined Dose Setups FIGURE 4 8 Predefined Dose Setups Use the C 7 keys to highlight the name of the desired setup and press the key to make the selection The name of this setup will now appear in the Name field and all parameters will be set according to the setup selected as shown in FIGURE 4 9 TEC Name ec ___ Exchange Rate Threshold O Enabled Criterion dB h O Auto Calculate FIGURE 4 9 IEC 4 10 Dosi
286. scale used by default for normalized spectrum displays is the same as used for the original spectrum as shown in FIGURE 5 31 When the normalized spectrum has negative components these cannot be seen on the display although the numeric level displayed at the cursor position will indicate the negative value For example the display shown in shows an Lmin spectrum normalized by an Lmax spectrum which has negative levels at all frequencies KD 0 00 24 9 2007 Apr 30 11 00 44 Close FIGURE 5 39 Lmin Normalized by Lmax Standard Display Scale By highlighting the Graph Relative check box and pressing the key to place a check in this box the display is rescaled to display both positive and negative components The spectrum displayed in FIGURE 5 39 will now appear as shown in FIGURE 5 40 5 28 View Spectrum Normalized LxT Technical Reference Manual Return to Standard Display LxT Technical Reference Manual 0 00 24 9 i n FIGURE 5 40 Lmin Normalized by Lmax Graph Relative Display Scale To return to the standard display highlight the Graph check box and press the key to remove the check View Spectrum Normalized 5 29 5 30 View Spectrum Normalized LxT Technical Reference Manual CHAPTER Run Control The LxT provides a number of run modes to control the time duration of a measurement These are all described in detail in this chapter When the optional firmware LXT ENV has been enabled Measurment Histo
287. ser input required on these pages LxT Technical Reference Manual About 14 1 About This page gives you important information such as Serial Number and Firmware Revision See FIGURE 14 2 About Page orresponds to Instrument About at Time of About Larson Davis LxT1 SoundTrack Precision Integrating Sound Level Meter Instrument Information Serial Number 0001580 Corresponds to Preamplifier Firmware Rev 1 300 Build 2 Presently Connected Dor Rev 0 3 Manufactured 2007 10 Preamp PRMLXT1 2007 PCB Piezotronics Inc FIGURE 14 2 About Page Standards The Standards Page lists the standards that the LxT meets See FIGURE 14 3 Standards Page About Standards 77010 This instrument conforms to the Following standards Standards ANSI 51 4 R2006 Type 1 ANSI 51 43 1997 Type 1 ANSI 51 25 1991 Type 1 IEC 60651 2001 Type 1 IEC 60804 2000 Type 1 IEC 61672 2002 Class 1 IEC 61252 2002 IEC 61260 2001 Class 0 ANSI 51 11 2004 Class 1 Se 4 Close gt FIGURE 14 3 Standards Page 14 2 About LxT Technical Reference Manual Options Options may be added at any time In the Field Just call one of the telephone numbers listed on the inside front cover or contact your local representative listed under Sales on the Larson Davis web site www LarsonDavis com LxT Technical Reference Manual The Options Page lists available options for the LxT A c
288. since the normalization was performed and we then change the selected spectrum type to Lmax the display will show a spectrum whose 5 26 View Spectrum Normalized LxT Technical Reference Manual amplitudes represent Lmax Lmin of original spectrum as shown in FIGURE 5 37 0 00 24 9 LxT_Data Normalized Spectrum 70 FIGURE 5 37 Lmax Lmin Spectrum The same procedure can be used to define each of the four different reference spectra and select them as desired using the Ref field Normalizing using Frequency Weighting Note that normalized displays canbe When using frequency weighting for normalization the rescaled using the Graph Relative display will be similar to that for Live Spectra described in feature described in section Graph Normalizing using Frequency Weighting on page 5 23 Relative on page 5 28 or adjusted except that the use will have the option of displaying any of as described in section Adjust the three spectra types Leq Lmax and Lmin normalized by Graph Scale on page 5 19 the frequency weighting used for the normalization as shown in FIGURE 5 38 0 00 24 9 LxT_Data 1 00kHz bs 63 1 dB Ref Z Slow O Graph Relative FIGURE 5 38 Leq Spectrum Normalized by A LxT Technical Reference Manual View Spectrum Normalized 5 27 Graph Relative Note that the spectrum display can also be rescaled as described in section Adjust Graph Scale on page 5 19 The vertical
289. son Davis Model EXCXXX shielded microphone extension cables in combined lengths up to 200 feet XXX is the length in feet XXX 010 020 025 035 050 060 100 and 200 available When doing so take care that the preamplifier microphone is held or mounted in such a way to minimize the effect of reflections on the sound field near the microphone LxT Technical Reference Manual Use of a Windscreen LxT Technical Reference Manual Wind blowing across the microphone generates pressure fluctuations on the microphone diaphragm which can produce errors in the measurement As a result when performing measurements in the presence of low level airflows it is recommended that a windscreen be placed over the microphone Larson Davis provides the WS001 windscreen a 3 1 2 diameter ball made of open cell foam which can be placed over the microphone and preamplifier as shown below FIGURE 7 4 Position of Windscreen To install the windscreen hold the meter in one hand and the windscreen in the other Insert the microphone preamplifier assembly into the opening in the windscreen as shown below and slide the windscreen completely down over the preamplifier FIGURE 7 5 Placement of Windscreen Positioning the LxT 7 5 The position of the vertical scroll bar on the right side of the display indicates the page being displayed relative to the available pages first page at the top last page at the bottom Prior to beginning the
290. strument will stay on when no activity is occurring button presses running a measurement USB communications etc Pressing the ON OFF key will return the instrument and the display to the state it was in when the Auto Off time expired If the instrument is connected to external power this feature is ignored Available durations are 5 min 10 min 30 min 60 min Never Power 12 5 Power Save Time Backlight Time Backlight Mode Note that using the backlight on bright setting will significantly increase power consumption and decrease battery life 12 6 Power The default value is Never The duration selected in the Power Save Time field sets the length of time the instrument will continue to measure sound level and update the display when the instrument is not in run mode and no other activity is taking place such as key presses or USB communication At the end of this time the display shut off To exit this mode press the RUN PAUSE key There will be a few seconds delay before the instrument starts recording data If the LxT is connected to external power this feature is ignored Available durations are 5 minute 10 minute 30 minute 60 minute and Never The default is Never This sets the duration of time the backlight remains on after the last key press Available choices are e 5 sec e 10 sec 30 sec 60 sec Alwa
291. surement LxT Technical Reference Manual Data Explorer Control Panel Data Explorer To activate the Data Explorer Page press the A TOOLS key Use the 7 C keys to highlight the Data Explorer icon as shown in FIGURE 11 1 Control Panel Control Panel Data Calibrate Explorer Setup Manager Voice Recorder System Properties FIGURE 11 1 Control Panel Press the key to open the Data Explorer Page Press the Close Softkey to exit from this page LxT Technical Reference Manual Data Explorer 11 1 Data Explorer Scrolling Modes 11 2 Data Explorer There is one Data Explorer Page It shows a directory of all the stored data files There is a scroll bar to indicate the relative position in the list of data files Up to nine data files will be displayed at one time so there may be more data files in the directory than are displayed in the first view All files may be viewed by scrolling through the list 9 0 00 00 7 Data Explorer LD LxT_Data 000 Highlighted Data File sone Mato 19 22 20 0 02 17 29kB LD LxT_Data 001 LD 1 Data 002 LD LxT_Data 003 LD LxT_Data 004 LD LxT_Data 005 LD LxT_Data 006 LD LxT_Data 007 LD LxT_Data 008 Toggles Between page Close mMenu Scrolling Modes FIGURE 11 2 Data Explorer There are two scrolling modes item default mode pressing the up or down arrow key moves the highlight to the previous or next respectively data file in
292. t tede AE A D 17 Fixed average eee eon Oe D 19 GI OSSARY sid ese P D 16 tote de RE rrt OA On aT D 20 Inf D 19 Intensity cervo ere OE D 21 Moving average 18 der EE D 18 Sound pressure level SPL Ep eh GRA ak eA AI ETE D 19 Unweighted peak D 20 Weighted e EE ER eee ee ee D 21 Sound EXpoSUre eere rores eoe 5 13 Sound Level Threshold Lt o e e CER E TERN ERREUR D 21 Sound E evel Profile rrr D AOT NEWER RECHNER 5 2 Sound Levels E 5 8 de e e 5 8 b DAR e EE NER dE EU 5 8 1 12 Index LxT Technical Reference Manual sound Power Level ire eR RE OE ERES Sound Pressure Level see Sound Sound Speed eee a REESE OE RETE RE Speaker Outputs t atte deti t aer CORE De Specifications Directional Characteristics etiem Frequency Response wi dee deer Orr eet RETE e E ERES PEORES qud Noise Levels citet tte Doge totes REI EE Stability Indicator ee e Start Up Period esset wee nee D We pU D Oe D n e qd Stop eee Ete ERE ERN CE NEE RR EI StopiStote Key oou eee dad iie en E eR Store Icon eode e Rr Displays s meni
293. t uses the motion of a thin diaphragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal For high sensitivity this device has a voltage applied across the diaphragm from an internal source Electret A microphone that uses the motion of a thin diaphragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal The voltage across the diaphragm is caused by the charge embedded in the electret material so no internal source is needed Microphone Uses The frequency response of microphones can be adjusted to be used in specific applications Among those used are Frontal incidence Free Field The microphone has been adjusted to have an essentially flat frequency response when in a space relatively free of reflections and when pointed at the source of the sound Random incidence The microphone has been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions Pressure The microphone has not been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions LxT Technical Reference Manual LxT Technical Reference Manual What a microphone measures 4 microphone detects more than just sound The motion of a microphone diaphragm is in response to a force acting on it The force can be caused by a number of sources only one
294. ta The LxT can measure many additional sound parameters simultaneously with these basic sound measurements as described in subsequent chapters LxT Technical Reference Manual Basic Measurement Setup 4 1 Measurement Properties Screen Accessing the Measurement Properties Screen Settings In Use Message If the LxT is not already connected to a computer running Blaze or SLM Utility G3 software ignore this section The parameters defining a measurement are set from the Measurement Properties Screen This screen can only be accessed from the Data Views Press the Center Softkey labeled Menu press the C key to highlight Settings and press the key The Measurement Properties Screen will now be displayed with the page selected that is most appropriate for the data display from which it was activated If the Blaze or SLM Utility G3 software is already connected to the LxT when an attempt is made to access the Measurement Properties Screen the display shown in FIGURE 4 1 Settings In Use By SLM Utility G3 Message will appear LxT_Data Live Overall SessionLog CED Settings in use by PC Continue FIGURE 4 1 Settings In Use By SLM Utility G3 Message This warns the user that accessing the Measurement Properties Screen will cause setup changes which had been made using the SLM Utility G3 during this session to be lost To continue and access the Measurement Properties Screen highlight Yes and press the key To ca
295. ta format and units are configured here Displays set displays to appear or be hidden Softkey Selection of Setup Pages Control Time History Triggers Markers Day Night FIGURE 2 11 System Property Pages The Right and Left Softkeys are used to scroll between System Property Pages Lock For a detailed description of the Lock permits the LxT to be configured such that certain keys Lock feature see Chapter 13 Lock locked so their functionality cannot be utilized Unlock the LxT on page 13 1 Calibrate For a detailed description of the Calibrate is used to verify and adjust the calibration of the calibration procedure see Chapter LxT prior to a measurement 15 Calibration on page 15 1 Voice Recorder For a detailed description of the method to allow voice annotation of the data is described voice recording feature see Chapter in Chapter 8 Voice Recording on page 8 1 8 Voice Recording on page 8 1 2 18 Tools Screen LxT Technical Reference Manual About For a detailed description of the About Pages see Chapter 14 About on page 14 1 LxT Technical Reference Manual The About Pages provide the user with information specific to this instrument such as serial number options etc These are single section pages There are four About Pages About shows information such as serial number and firmware revision
296. table Microphone Damage Level Overload Level Preamplifier Sound Pressure Level dB Electrical Input Sound Pressure Level dB Electrical Input Facility Vpeak Facility Vpeak 377 01 177 60 170 26 PRMLxTI 377B02 153 60 140 14 PRMLxTI C 12 LxTI LxT Technical Reference Manual j Battery Power Voltage Range The battery power supply voltage range for which the LxT1 conform to this standard 6 4 Volts maximum The LxT will shut down if the battery is below 4 0 Volts when used with alkaline batteries Therefore from 4 0 to 6 4 Volts is the usable range of battery voltage The instrument will shut off to ensure that no data is taken that would not meet the requirements of the IEC61672 1 standard k Display Device The display device will display all levels over the entire linear operating range Typical Stabilization Time The typical time interval needed to stabilize after changes in environmental conditions For a temperature change of 5 C then 30 minutes are required For a static pressure change of 5 kPa then 15 seconds are required For a humidity change of 30 non condensing then 30 minutes are required Field Strength gt 10 V m The Larson Davis model LxT1 was not measured for field strengths greater than 10 V m n Radio Frequency Emission The mode of operation of the LxT1 that produces the greatest radio frequency emission levels was with the LxT1 set to run and with an EXCO10
297. tailed description of the Run Mode is presented in Chapter 6 Run Control on page 6 1 LxT Technical Reference Manual The LxT can calculate six different Ln values based on user defined values of n which can be in the range 00 01 to 99 99 Using the keys select the desired Ln percentage to change Press the key Use the C 0 keys to adjust the value to the desired Ln percentile Press the key to accept this new value Use the same procedure to modify other values as needed Control Run Mode Manual Stop Y O Enable Measurement History FIGURE 4 12 Control Page The Control Page is used to set the Run Mode for the measurement to be performed There are six modes of measurement duration available In this chapter we will address only the first three Manual Stop The measurement is initiated manually by pressing the CZP Run Pause key and it is paused upon pressing the Run Pause key a second time Timed Stop The measurement is initiated manually by pressing the Run Pause key and will be stopped automatically after a user defined time period Dosimeter 1 and 2 Pages 4 13 Run Until Level Stable The measurement is initiated manually by pressing the Run Pause key The measurement will stop when the measured level has remained within a user defined range and the measurement has run for a user defined time period Left click the down arrow
298. tained in the previous paragraph to get the actual level of the CAL200 or 1 150 375 02 microphone s sensitivity varies with static pressure If the instrument is calibrated in one environment and moved to another then the sensitivity will change after stabilization depending on the change of temperature and pressure The coefficient of static pressure is 0 036 dB kPa If the system is calibrated at 85 kPa for instance then it will be 0 57 dB less sensitive at sea level The sensitivity of the 375A02 and LxT vary slightly with temperature also The coefficient of temperature is 0 01 dB C If the system is calibrated at 18 C then it will be 0 05 dB less sensitive at 23 C The Larson Davis 3 Wind Screen has less than 0 05dB effect on the system response at kHz For proper calibration the calibration procedure and the correction values apply over the ranges presented in Table 15 15 2 Instrument Class Parameter Range Class 1 LxT1 with 377B02 Static Pressure 65 kPa to 108 kPa 9 4 psi to 15 7 psi microphone Temperature 10 C to 50 C 14 F to 122 F Relative Humidity 25 to 90 without condensation from 10 to 39 C 14 F to 102 F Class 2 Lx T2 with 375A02 Static Pressure 65 kPa to 108 kPa 9 4 psi to 15 7 psi microphone Temperature 0 C to 40 C 14 F to 104 F Relative Humidity 25 to 90 without condensation from 1
299. the battery drain LxT Technical Reference Manual OBA Range Setting In the Low range the full scale level is reduced by 30 dB on the display The default display ranges will be as follows Normal Range 20 to 140 dB Low Range 10 to 110 dB However the graph scaling range can be modified by the user as described in Adjust Graph Scale on page 5 19 OBA Bandwidth Setting The user can select to utilize a single 1 1 Octave analysis module a single 1 3 Octave analysis module or both simultaneously Select Off to have no real time analysis module active OBA Frequency Weighting The user can select that the 1 1 and or 1 3 Octave frequency analysis modules process data from the A C or Z weighting filters When the Lx T OB3 firmware is enabled the user can select to perform 1 1 Octave analysis 1 3 Octave analysis both 1 1 and 1 3 Octave analysis simultaneously or None Setup Pages 4 7 OBA Time Averaging Setup Pages OBA Max Spectrum Setting There are two methods available which can be used to define the maximum spectrum At Lmax using this method the maximum values for each frequency band are those which were being measured at the instant the overall sound pressure level reached its maximum value during the measurement period Bin Max using this method the level measured for each frequency band is the maximum measured during the measurement period Since the maximum levels for the different frequency
300. tions A 41 Preamplifier Model PRMLxT1 Serial Number 0163 Larson Davis Certificate of Electrical Conformance Frequency response of this model PRMLxT1 preamplifier was tested at a level of 13 858 Vrms with 18pF microphone capacitance and driving a short cable Output level at 1KHz is 0 9442 Vrms 0 499 dBV uncertainty 0 045 dB Output is 3 511 V DC uncertainty 0 001 Results are displayed relative to the level at 1KHz 0 5 50 100 200 501 1000 1995 5012 10000 19953 50000 100000 Frequency Hz Measured dB Uncert dB Tolerance dB Freq Hz Measured dB Uncert dB Tolerance dB 01 02 05 06 07 08 08 08 09 09 09 09 10 10 10 10 10 10 10 10 10 10 Ooooooooooooooooooooo 126000 Noise floor data 1kHz 1 3 Octave 0 16 uV 15 7 dBuV uncertainty 0 47 dB Flat 20Hz 20kHz 1 7 uV 4 4 dBuV uncertainty 0 47 dB Awt 1 0 uV 0 3 dBuV uncertainty 0 46 dB Uncertainties are given as expanded uncertainty at 95 confidence level k 2 Technician Ron Harris Test Date 30SEP2005 FIGURE A 19 Certificate of Conformance PRMLxT1 A 42 Technical Specifications LxT Technical Reference Manual Model PRMLxT1L The Larson Davis PRMLxTIL is an electret microphone preamplifier for use with Larson Davis LxT So
301. to listen to live and recorded sounds It may be used for other purposes but may not function as expected as a source for additional analysis equipment The output is amplified for listening purposes and therefore is limited in its maximum output to be less than the instrument s maximum input level For connection to external analysis equipment use the adapter ADP015 and cable EXC006 to extract the signal directly from the preamplifier output When using the PRMLXxT series preamplifiers there will be a DC bias on the output of the BNC connector of the ADP015 of approximately 3 4 Volts AC Output Voltage Range 2 3 Vpeak maximum output 0 5 mV to 1 6 Vrms sine wave 70 dB dynamic range AC Output Gain relative to instrument input AC Output Frequency Weighting Signal is unweighted with frequency limitations imposed by 39 2 dB hardware design see below AC Output Frequency Response 20 Hz to 23 6 kHz 3 dB 10 21 Hz to 23 6 kHz 3 dB 600 Q 95 Hz to 23 6 kHz 3 dB Ry 16 Q AC Output Recommended Loads AC Output Impedance Low impedance headset speaker driver with 100 uF coupling Headset with 16 or greater speaker impedance Resistive loads greater than 600 Q for maximum frequency response range capacitor Z 1 5 1592 f where Z 1s output impedance in Ohms and f is frequency in Hz Instrument readings are not affected by AC output loading although a short circuit
302. tor AC DC Output and Headset FIGURE 17 3 LxT Bottom Panel DO NOT use the hardware power switch to turn the LxT ON or OFF This will cause data to be lost The purpose of this switch is to disconnect the batteries for storage 1 to 2 weeks It is recommended that the batteries be removed from the instrument if it will not be used for a month or longer the batteries may self discharge and leak damaging the instrument See Hardware Power Switch page 2 7 for additional information on the use of the hardware power switch LxT Technical Reference Manual Hardware Power Switch When set to O completely powers down the LxT for storage However the real time clock will maintain its value for six minutes long enough to complete a battery change Set to for instrument operation USB Interface USB 2 0 peripheral full speed port used for communication with a PC control of the LxT from the PC and downloading of data from the LxT to the PC The PSA029 external power supply may be connected here The maximum USB cable length is 5 m and the cable is part number CBL138 Refer to SLM Utility G3 manual for system requirements AC DC Output and Headset Jack used to output analog AC and DC signals or to connect to a headset for the recording and playback of voice records See Jack Function on page 15 10 Components 17 5 Batteries See Chapter 2 Page on page 2 6 17 6 Power Control Batteri
303. tteries and terminals Inserting Batteries 3 5 FIGURE 3 7 Insert Batteries After the batteries are installed insert the two tabs on the bottom edge of the battery door into the mating slots in the case Close the battery door allowing the clip to snap in place on the case Install the screw that was removed at the beginning of the procedure Hardware Power Switch DO NOT use the hardware power switch to turn the LxT OFF This may cause data to be lost Press the C6 then the Off soft key to turn the LxT off The Hardware Power Switch on the bottom of the LxT as shown in FIGURE 1 4 LxT Bottom View on page 1 13 and FIGURE 17 3 LxT Bottom Panel on page 17 5 disconnects the batteries from the LxT hardware including the real time clock This prevents battery drain when the LxT is not in use for an extended period of time gt 2 weeks If the Hardware Power Switch is in the O position the batteries are disconnected After installing batteries be sure to move the switch to the position This applies power to all of the LxT hardware The Hardware Power Switch should not be used to turn the LxT ON and OFF If the Hardware Power Switch is used to turn the LxT off data may be lost 3 6 Hardware Power Switch LxT Technical Reference Manual Using USB Power The LxT cannot be operated under USB power if the internal batteries are discharged flat for reasons described in this section LxT Technica
304. tual value of a specific item such as sound power for which the sound level is calculated First the sound power value is divided with the reference used and then the ten based logarithm is applied This value is then multiplied by 10 to create the decibel value see equation D 1 below For every 10 decibels a unit called Bel is created The decibel stands for deci for one tenth and bel for Bel compare decimeter The relationship between Bel and decibel is thus 1 Bel 10 decibels It is not possible to directly add or subtract decibel values since addition of logarithmic values correspond to multiplication of the original quantity Glossary D 5 Power form squared units Level form Ration of Value to Reference Exponental Fomor IOE ponni Ratio 1 10 0 10 10 10 100 10 20 200 107 23 1 000 10 30 10 000 10 40 100 000 10 50 1000 000 10 60 Glossary Each time the sound pressure level increases by 6 dB the corresponding sound pressure value is doubled and thus multiplied by 2 Each time the sound power level increases by 3 dB the sound power value is multiplied by 2 Thus it is important to notice that a doubling of the sound power is equal to 3 dB and a doubling of the sound pressure is equal to 6 dB since a doubling of the sound pressure will result in a quadruple increase of the sound power The advantage with using dB is simply that they remain the same even if
305. uces little or no Noise Dose accumulation and may be disregarded It is used for hearing damage risk assessment Standard ANSI 51 25 Glossary D 21 Time Weighted Average Sound It is the level of a constant sound over the Criterion Level TWA Ltwatc Duration that would expose a person to the same Noise Dose as the actual unsteady sound over the same period If the Exchange Rate is 3 dB then the TWA is equal to the Leg T _ Kogyo 10 at T where and is the Exchange Rate Factor It is used for hearing damage risk assessment Standard ANSI 812 19 Time Weighting The response speed of the detector in a sound level meter There are several speeds used Slow The time constant is 1 second 1000 ms This is the slowest and is commonly used in environmental noise measurements Fast The time constant is 1 8 second 125 ms This is a less commonly used weighting but will detect changes in sound level more rapidly Impulse The time constant is 35ms for the rise and 1 5 seconds 1500 ms for the decay The reason for the double constant is to allow the very short signal to be captured and displayed Vibration The oscillatory movement of mechanical system generally taken to be solid It is used as a broad descriptor of oscillations Wavelength 1 The distance between peaks of a propagating wave with a well defined frequency It is related to the frequency through the follo
306. ument circuitry Calibration Stability The LxT should maintain a stable value of sensitivity over long periods of time Significant changes in sensitivity or a pattern of small but regular sensitivity changes are indicative of problems with the measurement system calling for laboratory calibration and possibly service To assist the user in identifying these situations the LxT provides two notifications Calibration History Data and date time of the most recent ten calibrations LxT Technical Reference Manual Calibration 15 1 Large Change Notification During calibration an automatic comparison is made between the sensitivity determined by the calibration and a published value of sensitivity An on screen window will appear to warn the user when the difference between these two values exceed 1 5 dB Control Panel Calibrate 15 2 To activate the Calibration function press the A TOOLS key and highlight the Calibrate icon as shown below U 10 45 7 gt Calibrate Explorer petup Manager Voice Recorder System Properties FIGURE 15 1 Control Panel Press the key to open the Calibrate Pages The four Calibration Pages are shown in FIGURE 15 2 Control Panel Calibrate LxT Technical Reference Manual 0 00 00 0 Calibrate Tool Calibrate Calibrate Calibrator ranee nope Save Description LD CAL150 114 00dB 1kHz LD CAL150 114 00dB 1kHz LD CAL200 94 00dB 1kHz OLD CAL
307. und Level Meters It requires very little supply current and will drive 200 feet of cable The pream plifier operates over wide temperature and humidity ranges It is for use with 50 mV Pa sensitivity microphones up to 118 dBSPL Specifications Note that all electroacoustic values are at 23 C 50 RH 7 5 Volt supply 3 m 10 cable and equivalent microphone of 18pF unless otherwise stated Frequency response with respect to the response at 1 kHz with 1 1 Volts rms input and 18 pF equivalent microphone 4 Hz to 10 Hz 0 1 0 5 dB 10 Hz to 40 kHz 0 1 0 18 dB Lower 3 dB limit 1 5 Hz Attenuation 1 2 dB typical Input Impedance 10 G Ohm 3 pF Output Impedance 50 Ohm Maximum Output 2 8 Vpp 121 dB peak for microphones with 50 mV Pa sensitivity Maximum Output Current 10 mA peak Distortion Harmonics lt 67 dBc with 0 7 Volt rms output at 1 kHz LxT Technical Reference Manual Technical Specifications A 43 Output Slew Rate 2 V uS typical Electronic Noise with 18pF equivalent microphone 1 8 uV typical A weighted 2 5 uV max 3 2 uV typical Flat 20 Hz to 20 kHz 5 max Power Supply Voltage 6 to 15 Volts DC Output Level 1 2 power supply voltage Power Supply Current 1 3 mA typical Temperature Sensitivity lt 0 05 dB from 10 to 50 C 14 to 122 F operating range to 60 C 140 F Humidity Sensitivity lt 0 05 dB from 0 to 90 RH non condensing at 40 C 104
308. urement as described in Modifying Ln Values During a Mea surement on page 4 8 it should be noted that the Ln data presented for each record will correspond to the val ues selected at the beginning of the record 11 Events Row 3 Column 1 12 Overloads Row 3 Column 2 13 C A and Impulsivity Row 3 Column 3 TABLE 10 1Examples of Displays on Measurement Page LxT Technical Reference Manual Display of Measurement History Data 10 7 F5 0 10 43 7 5 0 10 43 7 NS 010437 5 WO 010437 5 010437 si T_Data LxT_Data LxT_Data LxT_Data LxT_Data Measurement C Measurement Tin Measurement Measurement C Measurement mA 53 7 dB 71 5 dB 12 96 3 dB 1 96 3 dB 2007 Apr 16 15 44 47 LaSmax 65 2 dB 2007 Apr 16 15 44 32 Lasmin 33 4 dB 2007 Apr 16 15 44 58 LASeq LASE Las gt 85 0 dB LASmax 65 2 dB LASeq LASmin 33 4 dB LASmax 65 2 dB Run Time 0 01 00 0 LASmin 33 4 dB 53 7 dB A LASmax 53 7 dB 1 00kHz 51 9 dB 60 7 dB 31 7 dB 65 2 dB 2007 Apr 16 15 44 08 2007 16 15 44 08 0104317 010437 2 010437 5 010437 5 010437 LxT_Data LxT_Data LxT_Data LxT_Data LxT_Data Measurement Tint d Current Measurement maad Measurement Tint Measurement i gt I Current Measurement mA bound Exposure Level LASE 71 5 dB bou
309. value of time and press the key to conclude the process The interval time sync feature ensures that all measurement records except the first will begin at a time equal to a multiple of the measurement time selected For example if the measurement time is five minutes and the measurement begins at 08 14 00 h m s format the first measurement will be cut short such that the subsequent measurements will begin at 08 15 08 20 08 25 etc The interval time sync function is intended to be used with the following measurement time values 1 5 10 15 20 or 30 minutes 1 hour When the interval time sync function is used each hour is divided into a number of equal time segments based on the number of time intervals contained within one hour For example when the time interval is five minutes there will be twelve segments within any one hour period beginning at xx 00 00 05 00 xx 10 00 etc The instrument will begin the first measurement when the Run Pause key is pressed Regardless of the start time LxT Technical Reference Manual Other Measurement Times when the clock of each instrument reaches the time corresponding to the beginning of the next segment the measurement in progress will be stopped and stored and a new measurement will be started When values of measurement other than those listed above are used the clock time at which the first measurement is cut short is based solely on the units of t
310. various descriptors attached to this level depending on how the actual sound pressure is processed in the meter Instantaneous The time varying reading on a meter face on in a meter output due to changes in the sound pressure The reading will depend on the time weighting applied The fundamental relationship between the two is logarithmic LS 201010 1 20 0 Prms po10 Glossary D 19 where is the reference sound pressure of 20 uPa The square of the sound pressure is a power like quantity that can be expressed in the original form of the level definition Sound Pressure Level can be converted to sound pressure as follows If the sound pressure is 1 Pascal then the sound pressure level is i 2010 201og 9 50000 20 4 699 94 048 20 10 209109410 Glossary Calibrators often use a level of 94 dB so they generate a sound pressure of Pascal If the sound pressure level 76 3 dB then the sound pressure is 763 20 _ 20 e 1935 6 20107218 20 0 0065 0 13 Energy Average Leg The value of a steady sound measured over a fixed time period that has the same sound energy as the actual time varying sound over the same period This descriptor is widely used It is a fixed average See Sound Pressure Impulse The value of an impulsive sound The reading will depend on the time weighting applied Unweighted Peak The peak value of a sound with a meter that has flat freque
311. vely selecting a different record to be displayed In FIGURE 9 6 the value of the first of the time history parameters in this case Leq is displayed for the cursor position We can also see that the and keys programmed to change record numbers To display the value of this parameter for other record numbers use the and keys move the cursor and select a different record number Displaying Other Single Value Metrics As explained in section Parameters Logged on page 9 1 the user can select to log up to sixteen different parameters or metrics as a function of time setup as described in section Select Time History Parameters on page 9 5 The default value is the first parameter selected during the setup procedure 9 8 Time History Display LxT Technical Reference Manual Selected Paramete Display LApeak Time History Leq x where x is the time 85 0 dB history interval Selected Metric To use the keys to change metrics rather than change records press the key such that the lower portion of the display resembles FIGURE 9 8 When repeatedly pressing the 0 key the logged metric values will be displayed in the same sequence as they appeared in the list when selected as described in Select Time History Parameters on page 9 5 By pressing the 0 keys the value displayed be shifted to represent a metric one later or earlier respectively
312. vening period begins at Dosimeter 1 and 2 Pages 4 19 0700 1900 2200 2400 1 L 10 10 1 10 L 5 10 L 10 10 CNEL 1026 5 0000 0700 1900 2200 22 00 instead of 23 00 Thus by making this change in the Settings the measured value will represent CNEL Exiting Measurement Property Screens To exit the Measurement Properties Screen press the Center Softkey labeled Close If any setup parameters have been changed the Apply Changes message box will be displayed as shown in FIGURE 4 20 Apply Changes Settings General sm OBA Dosimet Fe Nh le bim m Apply Changes res No FIGURE 4 20 Apply Changes At this point the parameter changes made from the Measurement Properties Screen have not yet been implemented in the instrument Use the c keys to select either Yes or No and press the er key to implement the changes or cancel the changes respectively This will return the Data Display Screen to the display 4 20 Exiting Measurement Property Screens LxT Technical Reference Manual Basic Data Display In the previous chapter the setup procedure for a basic sound level measurement was described This chapter describes how this data would be displayed during or following a measurement sequence The LxT can measure many additional sound parameters simultaneously with these basic sound measurements as described in subsequent chapters Data Labels
313. we use sound pressure or sound power Compare this to the use of voltage and power units in electrical engineering units being related by P V In table 2 an illustration is made of values calculated on sound pressure non squared units The original definition of decibel was intended for power like quantities such as sound power If we consider sound pressure levels instead usually denoted P in acoustics the equation will be the same since the two in the squared units will move from within the bracket and become a 20 log instead of a 0 Jog and thus compensate for using linear or quadratic units Please note that it is not allowed to use 20 log for squared units since that expression assumes that we use linear units like sound pressure in acoustics or voltage in electrical engineering This is illustrated in equation D 1 below LxT Technical Reference Manual 2 dB 10104 25 20Log gt Po 20pPa Po Po Table 2 illustrates how a a tenfold increase of the sound pressure will result in an increase in 20 dB steps while sound power increases in 10 dB steps See the linear form Table 2 and compare with equation D 1 In conclusion dB values are always the same independent of using sound power or sound pressure as the base unit A 6 dB increase implies four times the sound power or two times the sound pressure Linear form non squared units Level form Exponential Form of 20 Exponent
314. when there is a large signal output may draw excessive power such that the instrument could power off AC Output Phase and Delay 180 relative to input 128 ps digital delay DC Output Frequency Weighting DC Output Time Weighting Follows the SLM Frequency Weighting A C or Z Follows the SLM Detector F S or I LxT Technical Reference Manual Table 9 AC DC Output Technical Specifications 9 DC Output Voltage Range 0 to 3 Volt 0 to 300 dB V0 SPL 100 SPL 100 0 Sensitivity 0 01 V dB with resolution of 0 001 V DC Output Impedance 36500 DC Output Recommended Loads gt 1 MQ for less than 0 4 error A 10 MO DC Voltmeter represents negligible error 0 036 The output resistance can be accounted for in the interface design For example if a chart recorder has an input load of 10 kQ the gain can be set to 1 365 to correct for the loading Table A 9 AC DC Output Min Max Integration Time Minimum and maximum integration time for measurement of time average levels and sound exposure levels Time Average Levels and Sound Exposure Levels s Minimum 0 1 Maximum Unlimited daily autostore enabled Maximum gt 23 days daily autostore disabled errors less than 0 5 dB Dosimeter Metrics TWA Dose s Minimum 0 1 Maximum Unlimited Table A 10 Min Max Integration Time A 10 Technical Specifications LxT Technical
315. wing equation qu D 22 Glossary LxT Technical Reference Manual Wavenumber LxT Technical Reference Manual where c is the sound speed and fis the frequency in Hz It has the dimensions of length A number that is related to the wavelength of sound and is used to compare the size of objects relative to the wavelength or the time delay in sound propagation It is related to wavelength through the following equation 2n _ 2nf where A is the wavelength is the sound speed is the frequency in Hz and o is the radian frequency It has the dimensions of inverse length Glossary D 23 D 24 Glossary LxT Technical Reference Manual APPENDIX Integrated Level Calculations Basic Integrated Level Calculations Equivalent Continuous Sound Level The Larson Davis SoundTrack LxT calculates equivalent continuous sound levels based on equations from IEC standard 61672 1 Section 3 9 which defines Leg as follows Note that LxT displays the equiv Equivalent continuous A weighted sound pressure level alent continuous A weighted sound also average A weighted sound pressure level is defined as pressure level as L Aeg follows Lat 201g P f where L AeqT 15 the equivalent continuous A weighted sound pressure level re 20 Pa determined over a time interval T amp is a dummy variable of time integration over the averaging time interval ending at the time of
316. y weighting Reference Normal range range Exchange 3 4 5 or 6 dB rates Sample rate 51 200 Hz Peak rise time 28 uS Table A 3 Sound Level Meter Specifications Technical Specifications Performance Specifications LxT1 LxT1L LxT2 LxT2L Direct In Measurement 39 to 140 dB 27 to 118 dB 37 to 139 dB 31 to 126 dB 13 to 117 dBuV Range 39 to 140 dB 29 to 118 dB 37 to 139 dB 35 to 126 dB 10 to 117 dBuV 7 44 to 140 dB 34 to 118 dB 42 to 139 dB 42 to 126 dB 16 to 117 dBuV Noise Floor A 29 dB 17 dB 27 dB 21dB 2 8 dBuV 29 19 27 dB 254 1 3 dBuV Z 34 dB 24 dB 32 dB 32dB 5 6 dBuV Linearity A 2104dB gt 102 dB gt 103 dB gt 102 dB gt 106 dBuv Range 36 to 140 dB 16 to 118 dB 36 to 139 dB 24 to 126 dB 11 to 117 dBuV gt 105 gt 100 gt 104 gt 100 gt 107 dBuv 35 to 140 dB 18 to 118 dB 35 to 139 dB 26 to 126 dB 10 to 117 dBuV Z gt 103 dB gt 93 dB gt 100 dB gt 93 dB gt 103 dBuv 37 to 140 dB 25 to 118 dB 39 to 139 dB 33 to 126 dB 14 to 117 dBuV Peak Range A 72 143 dB 50 121 dB 68 139 dB 58 129 dB 72 143 dBuV 72 143 dB 51 121 dB 68 139 58 129 dB 73 143 dBuV 7 77 143 dB 55 121 dB 73 139 dB 63 129 dB 77 143 dBuV SPL Max 140 dB 118 dB 139 dB 126 dB 117 dBuv Level Peak Max 143 dB 121 dB 139 dB 129 dB 43 dBuV Level
317. y power only 2007 Apr 16 13 33 16 Run Timer 0 00 09 4 Battery h 0 1 USB Powered 5 0 Memory 99 Free 50920kB of 51061kB 1 Data Files Started 2007 Apr 16 13 28 33 FIGURE 5 7 Live Page Section 6 In Section 5 the status view indicates the current date and time the run time for the measurement battery voltage calculated run time and memory usage The Memory section indicates the amount of memory available as a percentage and in number of kBytes The number of stored data files is also indicated Overall Page In this section we only address those sections of the Overall Page associated with basic sound level measurements Other pages associated with data provided by optional firmware may also appear Although the 1 1 and 1 3 octave spectra require optional firmware LxT OB3 we do include the display of this data in this chapter 5 6 Overall Page The Overall Page may have as many as fifteen sections To scroll between sections use the C 7 or keys Use the Right and Left Softkeys to scroll between pages LxT Technical Reference Manual Overall Leq with Profile Leq using Frequency Weighting and Detector from Setup Laseq 52 3 Sound Level for Currectly Las 39 5 dB Selected Weighting and Detector Started 2007 Apr 18 16 40 19 FIGURE 5 8 Overall Page Section 1 Overall Enforcement Sound Level Leq using Frequency 0 0 01 50 2 Weighting and Detector from Setup
318. ys On The default is 10 sec This field sets the intensity of the backlight Options for backlight mode are Off Dim and Bright The default is Off The Backlight mode can also be set by pressing the key as described in the section ON OFF Key on page 2 6 LxT Technical Reference Manual Display Contrast Note that the Display Contrast can also be set from the display by pressing the key as described in the section ON OFF Key on page 2 6 This is the preferred method of adjusting contrast because the changes are made immediately With the method described here the change is not applied until the System Properties display is closed Battery Type To avoid damage to batteries always set the correct battery type This parameter is used to adjust the contrast of the display to accommodate varying viewing angles temperature and lighting condition Adjustment ranges from 9 to 9 The default is 0 Select the type of battery installed in the LxT This information is used for the calculation of battery life Available battery types are Alkaline NiMH and e2 lithium The default is Alkaline Preferences LxT Technical Reference Manual The Preferences Page is used to select general instrument formatting QD 00 02 17 6 System Properties BIET Preferences Mic Corr Auto Store Jack Function Reset Prompting O Takt Maximal Data USB Host Port FIGURE 12 6 Preferences Page Us
319. z 6 3 7 9 10 0 12 6 15 8 20 0 25 1 31 6 39 8 50 1 63 1 79 4 100 0 125 9 158 5 199 5 251 2 316 2 398 1 501 2 631 0 794 3 1000 0 1258 9 1584 9 1995 3 2511 9 3162 3 3981 1 5011 9 6309 6 7943 3 10000 0 12589 3 15848 9 19952 6 Awt Cwt Zwt LxT2 amp PRMLxT2 Noise dB SPL 13 6 12 9 10 6 11 7 11 1 10 4 10 0 375A02 Noise dB SPL 17 2 16 2 15 2 14 2 13 2 12 2 11 2 10 2 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 2 0 8 1 8 2 8 3 8 4 8 5 5 64 7 0 7 5 8 0 8 4 8 8 9 2 9 5 9 6 9 4 8 8 8 5 19 5 21 3 26 3 LxT2 PRMLxT2 and 375A02 Noise dB SPL 13 6 12 9 10 6 11 7 11 1 10 4 Table A 21 Noise LxT2 PRMLxT2 with 375A02 LxT Technical Reference Manual Technical Specifications A 35 LxT2 PRMLxT2L with 375A02 375A02 PRMLxT2L and LxT2 Noise LxT2 amp PRMLxT2L 375A02 LxT2 PRMLxT2L and 375A02 Frequency Noise Noise Noise Hz dB SPL dB SPL dB SPL 6 3 13 9 17 2 13 9 7 9 11 9 16 2 11 9 10 0 10 8 15 2 10 8 12 6 10 7 14 2 10 7 15 8 10 5 13 2 20 0 9 7 12 2 25 1 8 9 11 2 31 6 7 9 10 2 39 8 7 8 9 2 50 1 6 0 8 2 63 1 5 6 7 2 79 4 4 2 6 2 100 0 5 2 125 9 4 4 2 158 5 3 2 199 5 2 2 251 2 1 2 316 2 0 2 398 1 0 8 501 2 631 0 794 3 1000 0 1258 9 1584 9 1995 3 2511 9 3162 3 3981 1 5011 9 6309 6 7943 3 10000 0 12589 3 15848 9 19952 6 Cwt Zwt Table A 22 Noise LxT2 PRMLxT2L with 37
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