Bob Smith Principal Scientist Acoustic Systems PhysioControl Agenda Overview of an Acoustic Measurement System System Calibration Microphones Measurement System Comparis ons Dedicated Hardware vs Computer ID: 1031101
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1. Acoustic MeasurementSystems 101Bob SmithPrincipal Scientist, Acoustic Systems Physio-Control
2. AgendaOverview of an Acoustic Measurement SystemSystem CalibrationMicrophonesMeasurement System ComparisonsDedicated Hardware vs. Computer + SWAudio InterfacesExample real world useDemonstrations
3. Input Overview
4. Output Overview
5. 1 Channel System
6. 2 Channel System
7. 3 Channel System
8. System CalibrationMicrophone mV/PaGain staging between mic and digital domainDigital domain 0dBFS representationHow many mV / Pa at microphone = ?? dBFS in digital domainMic calibrator (level only) Bruel & Kjaer 4231 Type 1 NIST traceable ~ $2K Landtek ND9 – not traceable ~ $120
9. System CalibrationIf the mv/Pa is known for a measurement mic the following can be used in place of a mic calibrator to get close to calibrated SPL levels:Signal generator (even an iPod will work)AC voltmeter with a mV scaleSet the sig gen for 1 KHz (or use 1 KHz wavefile)Connect sig gen to voltmeter and adjust output such that the voltmeter reads the same mV as the mic mV/PaNow connect the sig gen output between Pins 2 & 3 of the audio I/O mic preamp input (P48 off!) and adjust the preamp gain for the dBFS representation desired
10. Gain Staging: -0.05 dBFS no clipping
11. Gain Staging: 0 dBFS clipping
12. Gain Staging: -2 dBFS inter-stage clipping
13. System Cal: 94 dBSPL = -16 dBFS
14. Measurement MicrophonesBruel & Kjaer, ACO Pacific, Microtech Gefell, DPAJosephson, Earthworks, LinearXBeyerdynamic MM1, Audix TM1Dayton EMM-6, Nady CM-100, The B wordDIY Panasonic wm61a
15. Measurement MicrophonesFrequency Response AccuracyOff axis performance (how omni is omni?)Self NoiseDynamic RangeMaximum SPL
16. DPA 4006 Polar Response
17. dB AmV/PamV/PaHz - HzdBdB$ mfgmodeltypeself noisesensitivitymeasuredfreq resptol +/-max SPLpricenotesACO+Josephson7046+C617ext126770.92-20K2.01452,000 AudixTM-1pre286.5 20-25K2130300 BeyerdynamicMM-1pre281514.950-16K1.5128200 dbxM2preNS76.4620-20KNSNS100 BehringerECM-8000preNSNS10 ~ 1415-20K2.5NS50unbalNadyCM-100preNS109.1820-20KNS12050unbalDaytonEMM-6pre24 ?10 8.9918-20KNS12750unbalEarthworksM-30pre278 9-27K1.0150650 EarthworksM-50pre2230 3-50K1.01421,300 DPA4003pre1540 10-20K2.01351,925 DPA4006pre1510 10-20K2.01241,925 SennheiserMKH-20ext1025 12-20K2.01351,200 SchoepsCMC6+MK2ext1115 20-20K0.51301,800 JosephsonC550Hpre26109.8520-20K2.0135400 Josephson606+KA11Next1515 20-20K2.01401,280 NA
18. Microphone CalibrationReciprocity – primary standard method IEC 61094-2, edition 2Free Field Comparison IEC 61094-5, edition 1Pistonphone typically 250 Hz, 114 or 124 dBSPLElectronic Sound Calibrator typically 1000 Hz, 94, 104, 114 or 124 dBSPL
19. Reference Mic 1
20. Reference Mic 2
21. Free Field Comparison Calibration
22. Measurement Mics Compared
23. Measurement Mics Compared
24. ACO 7046-28439
25. Josephson C550H-5938
26. Beyerdynamic MM1-2267
27. Dayton EMM6-2372
28. Nady CM-100
29. dbx M2
30. The B company ECM8000 3 mics
31. Measurement SystemsBruel & Kjaer, NT Instruments, Meyer SIM, Audio Precision, Rohde & SchwarzCLIO, LinearX, DRA MLSSAEASERA, Smaart, PraxisOmnimic, TrueRTA, ETF5Room EQ Wizard, Speaker Workshop
32. Dedicated HW vs. Computer + SWPurpose Specific Imbedded OS instead of Win7, Lion or LinixSystem crashes, BSOD occurrence minimizedDedicated controls for rapid feature accessMinimal or no system integrationSystem calibrationCan be more $$$
33. Rohde & Schwarz UPV
34. Audio Precision SYS-2722
35. Measurement SystemsBruel & Kjaer, NT Instruments, Meyer SIM, Audio Precision, Rohde & SchwarzPurpose built imbedded OS / hybrid with host OSTurnkeyHigh AccuracyCalibratedComprehensive$5K to $50K
36. Measurement SystemsCLIO, LinearX, DRA MLSSAHybrid embedded OS / computer host OSMinor integrationHigh AccuracyCalibratedComprehensive$2K to $10K
37. Measurement SystemsEASERA, Smaart, PraxisHost OSModerate integrationAccuracy depends on quality of audio interfaceCan be calibratedEASERA comprehensive, Smaart more focused$800 to $1K except EASERA$800 to $5K EASERA depending on configuration
38. Measurement SystemsOmnimic, TrueRTA, ETF5Host OSMore complex integration except OmnimicAccuracy depends on quality of audio interfaceCan be calibratedOmnimic is a unique systemUseful feature setsFree to $300
39. Measurement SystemsRoom EQ Wizard, Speaker WorkshopHost OSDIY integrationAccuracy depends on quality of audio interfaceCan be calibratedUseful feature setsFree
40. Audio InterfacesComputer InterfaceFirewire 400 & 800USB 1.1, 2, 3Computer internal busOS drivers
41. Audio Interfaces - ExamplesRME Fireface UC $1300MOTU UltraLite-mk3 $550 (FW + USB)M-Audio Fast Track Pro $200Lexicon I-Onix U22 $250 Focusrite Scarlett 2i2 $150Mackie Onyx Blackjack $150Tascam US-100 $100
42. RME Fireface UC (USB)
43. M-Audio Fast Track Pro
44. 1 Channel System Example
45. 2 Channel System Example
46. Useful Integration Toolsdpc latency checkerdeferred procedure calls timedMicrosoft rattv3time spent in ISR, deferred procedure calls and timer dpcCentrance ASIO latency checker
47. Real World MeasurementsSpeaker frequency responseMeasurement system comparisonMicrophone comparisonAcoustic door performance
48.
49. Genelec 8030a – ACO 7046 mic
50. Genelec 8030a – ACO 7046 mic
51. Genelec 8030a – Dayton EMM6 mic
52. Genelec 8030a – 7046 - EMM6 mics
53. Acoustic Door Gasket Sound Leak
54. Acoustic Door Gasket Seal Improved
55. DemonstrationsMeyer SIMSmaartLive v7Speaker measurement – nominalSpeaker measurement – contaminatedDelay measurementOmnimic – time permittingRoom EQ Wizard – time permitting
56. Links to Mfgs mentionedMeasurement Microphones:http://www.bksv.com/Products/TransducersConditioning/AcousticTransducers/Microphones.aspxhttp://www.acopacific.com/micdetal.htmlhttp://www.acopacific.com/chart.htmlhttp://www.microtechgefell.de/index.php/en/measuring-equipment/sound--noisehttp://www.dpamicrophones.com/en/products.aspx?c=Catalog&category=234http://www.josephson.com/pdf/srs5.pdfhttp://www.earthworksaudio.com/our-microphones/m-series/http://www.linearx.com/products/microphones/m51/M51_1.htmhttp://north-america.beyerdynamic.com/shop/ct/conference-technology/product-line/microphones/special-microphones/mm-1.htmlhttp://www.audixusa.com/docs/products/TM1.shtmlhttp://www.daytonaudio.com/index.php/emm-6-electret-measurement-microphone.htmlhttp://www.nady.com/cm100.htmlhttp://www.behringer.com/EN/Products/ECM8000.aspx
57. Links to Mfgs mentionedDIY wm61a measurement mic:http://www.johncon.com/john/wm61a/http://www.linkwitzlab.com/sys_test.htmhttp://www.speakerbuilder.net/web_files/Articles/diymic/diymicmain.htm Microphone Calibration Service:http://www.scantekinc.com/ Microphone Field Calibrators (SPL level):http://www.bksv.com/products/telecomaudiosolutions/electroacousticsaccessories/soundcalibratortype4231.aspxhttp://01640c0.netsolhost.com/fieldcali.htmhttp://www.acopacific.com/splcali.htmlhttp://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l2736&_nkw=nd9+calibratorAudio Interfaces:http://www.rme-audio.de/en_products_fireface_uc.phphttp://www.motu.com/products/motuaudio/ultralite-mk3http://www.m-audio.com/products/en_us/FastTrackPro.htmlhttp://www.focusrite.com/products/audio_interfaces/scarlett_2i2/http://www.mackie.com/products/onyxblackjack/http://tascam.com/product/us-100/
58. Links to Mfgs mentionedAcoustic Measurement Systems:http://www.bksv.com/http://www.nti-audio.com/http://www.meyersound.com/http://ap.com/http://www.rohde-schwarz.us/en/products/test_and_measurement/audio/audio_products/http://www.audiomatica.com/clio10/home1.htmhttp://www.linearx.com/http://www.mlssa.com/http://www.renkus-heinz.com/easera/index.htmlhttp://www.rationalacoustics.com/http://www.libinst.com/http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-790http://www.trueaudio.com/http://www.etfacoustic.com/http://www.hometheatershack.com/roomeq/http://www.audua.com/http://www.purebits.com/http://www.sigview.com/
59. Links to Useful Integration ToolsUseful Integration Tools:http://www.thesycon.de/deu/latency_check.shtmlhttp://msdn.microsoft.com/en-us/windows/hardware/gg487354http://msdn.microsoft.com/en-us/windows/hardware/gg487334http://centrance.com/downloads/ltu/