朗德科技声学测试2 Noise_measurements2-44.ppt

《朗德科技声学测试2 Noise_measurements2-44.ppt》由会员分享，可在线阅读，更多相关《朗德科技声学测试2 Noise_measurements2-44.ppt（44页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、噪声噪声 测量测量第二部分：噪声对人们的影响第二部分：噪声对人们的影响 柯柯 珂珂 1-Subjectivephenomenon.Sound/noise声音声音/噪声的主观现象噪声的主观现象Soundaffectdifferentpeopleindifferentways.Theperceptionofsoundissubjectivelyinterpreteddependingonthemoonofeachandthestateoftiredness.声音以各种方式影响着人们，声音的感知主观上依赖于人们自身的心理、生理状态，愉快、疲劳Enjoyablesound令人愉悦的声音Unwanted

2、sound让人反感的声音Communication/warn交谈/报警声Thereforeanindividualwillmakesubjectivejudgmentaboutvariousnoiseswhichimpingehim.因此，每个人都会对噪声作出自己的主观判断。Soundallowhumanbeingtomakequalityevaluationsanddiagnoses.人们可以对声音品质作出评价和诊断。Howcanweobtainobjectivemeasuresofthesesubjectiveeffects?那么如何对这些主观影响进行客观测量呢？Ratingoftheso

3、undsintermsofannoyingfeelings(loudness,sharpness,roughness,tonality.)meansofcomparingsoundsunderdifferentconditions.可以根据声音烦恼度不同(评价参数包括:响度、尖锐度、粗糙度、音调)或不同条件下各种声音间的对比,将其划分为不同等级。Measurementofthehearingdamage(audiometry)测量听力损害度(听力计)Allowtoreducenoisefromanyenvironment(airport,trainstation,factories.)减少各种

4、环境中的噪声(机场、火车站、工厂)2-Humanhearingsystem人类的听觉系统Humanhearrespondspredominantlytoairbornenoise=pressurechanges人耳对空气噪声的响应=气压变化Pressurevariationisanadequatenoisemeasurementquantitybecause:压力变化可用来充分度量噪声的原因是：Theauditorysystemrespondstopressurechanges听觉系统对声压的变化有响应Mechanicalstructuresrespondstopressure机械结构对压力有

5、响应Easiestacousticquantitytomeasure.Frompressure,soundintensityandpowercanbeevaluated.可用于测量最简单的声学量。通过测量声压，可以估计出声强度和声能量。3.Nonlinearityofthehearresponse人耳的非线性响应人耳的非线性响应Theauditorysystemsensitivityvarieswithfrequencies听觉系统的灵敏度会听觉系统的灵敏度会随着声音频率不同而发生变化。随着声音频率不同而发生变化。Speechrange:200Hz-6000Hz语音频率范围：200Hz-600

6、0HzSpeechintelligibilityrange:500Hz-4000Hz清晰语音频率范围：500Hz-4000HzLowfrequenciesneedmore“energy”orsoundpressureleveltobeheardthansoundwithin1kHz-5kHz.与频率在1kHz-5kHz之间的声音相比，低频声音往往需要具有更高的能量或者更高声压级时，才能被人们听见。TotakeintoaccountofthenonlinearityoftheearresponseatlowFrequencies,theA-weightingcurveisoftenused.通常

7、用A计权曲线来更好地说明人耳在低频段的非线性响应特性。AweightingcurveA计权曲线Frequency HzA weighting dBFrequency HzA weighting dB20-50.5800-0.825-44.71000031.5-39.412500.640-34.61600150-30.220001.263-26.225001.380-22.531501.2100-19.140001125-16.150000.5160-13.46300-0.1200-10.98000-1.1250-8.610000-2.5315-6.612500-4.3400-4.816000-

8、6.6500-3.220000-9.3630-1.9whereWA=weightingtobeapplied,dBf=frequency,HzButA-weightingcurvesimulatestheresponseonlyoftheearforlowlevelsound.TheA-weightingcurvefollowsapproximatelytheequalloudnesscurveof40phons.但A计权曲线只能模拟人耳对低声音的响应特性。下图所示，A计权曲线约对应于40宋等响度曲线。Eachcurvecorrespondstotheequalsensationofloudn

9、essperceptionfordifferentpuretonesfrequencies.每条曲线都是不同频率纯音的等响度曲线。ToneofdifferentfrequencybutsameSPLarenotperceivedequal.声压级相同但频率不同的纯音，其对应感知度并不相同。Atoneof10dB200Hzhasthesameloudnessperceptionthanatoneof0dB2kHz.10dB200Hz与0dB2kHz的声音拥有相同的响度感知度。Atlowlevelapurehighfrequencytonewilleasilymasklowfrequencypur

10、etone.在低声压级段，高频纯音可以轻易掩蔽低频纯音。LookingatthesecurvesthenoiseengineertaskwillneedtodecreasemoreSPLathighfrequenciesthanatlowfrequenciestogetthesamesubjectiveperceptionofloudness.从曲线中可看出，为了使高频和低频声音响度的主观感知度一致，噪声工程师需要更多地降低高频声音的声压级。Totakeintoaccountoftheearresponsefordifferentlevelofsoundseveralweightinghasb

11、eendeveloped:考虑到人耳对不同等级声音的响应，人们提出了几种不同计权方法：B-weightingcurveapproximatelyfollowsthe70phonsequalloudnesscurveB 计权曲线约对应于70宋等响度曲线C-weightingcurveapproximatelyequalloudnessfollowsthe100phonscurveC 计权曲线约对应于100宋等响度曲线whereWB=weightingtobeapplied,dBf=frequency,HzwhereWC=weightingtobeapplied,dBf=frequency,HzD

12、-weightingcurvefollowsaspecialcurvewhichemphasizesfrequenciesbetween1kHz-10kHz.Usedforaircraftapplications.D计权曲线对应于一条主频在1kHz-10kHz内的特殊曲线，主要应用于机场噪声。Perceptionofsoundpressurelevelvariation对声压级变化的感知度声压级变化的感知度:Change in sound levelHuman perceptionChange in powerincreaseChange in powerdecrease3 dBJustper

13、ceptible21/25 dBClearlynoticeable31/36 dBClearlynoticeableDoubleamplitude41/410 dBHalfortwiceasloud101/1020 dBMuchquieterorlouder10timesamplitude1001/100Resultsappliedforfrequencyaround1000Hz.以上结果适用于频率约1kHz的情况AthigherorlowerfrequenciesmuchlargerdifferenceofSPLneedtobeappliedtoperceivedthedifferencei

14、nloudness.当声音频率明显高于或低于1kHz时，相差相同的响度对应的声压级的变化更大。4.Speechintelligibility语音清晰度语音清晰度Speechintelligibility:accuracywithwhichanormallistenerwillunderstandaspokenwordorsentence.语音清晰度：正常人能听清一个单词或句子时的语音精度。Speechintelligibilitydependsuponthebackgroundnoiseinrelationtothelevelofofspokenwords.语音清晰度由背景噪声和语音声压级之比

15、决定。SpeechInterferenceLevelSILoftheinterferingbackgroundnoiseisgivenby:背景噪声对语音的干扰级定义为：Speechrange语音频率范围:200Hz-6000HzSpeechintelligibilityrange清晰语音频率范围:500Hz-4000kHzOfthebackgroundnoisePossiblewithNormalvoiceCommunicatingvoiceDifficult.impossibleAcceptablespeechcommunication可让人接受的语音交流=95%sentenceintel

16、ligibility95%的句子可以听清60%word-out-contextrecognition60%的单词可以辨识Speechintelligibilitydependsonthereverberationofthespace,sex,noisefluctuation.语音清晰度取决于空间混响、发声人性别、噪声起伏。Forsituationwherespeechortelephonecommunicationareimportantamaximumof70dB(A)background.在一些如演讲或电话交谈的重要场合，背景噪声不要超过70dB(A)。Expectedvoicelevel

17、=averagetalkerssubjectiveresponsetothebackgroundnoise期望语音等级是指谈话者对背景噪声的平均主观响应。5.Maskingeffect掩蔽效应掩蔽效应Maskingeffectisthephenomenonoftheonesoundinterferingwiththeperceptionofanothersound.掩蔽效应是一个声音掩盖住另一个声音，使其无法被感知的现象。Intensetonemaymasksoundofspeech高强度的纯音往往可能掩蔽住语音。Lowfrequencytonesaremoreeffectiveinmaski

18、ngsoundspeechthanhighertone.低频率的纯音比高频率的纯音更能掩蔽人们的语音。声音A被声音B掩蔽，如果A处于以B为中心的掩蔽范围内，掩蔽会更加明显，这个范围叫做临界带宽。每种频率的临界带宽都不一样，频率越高，临界带宽越宽。6.Psychologicaleffectofnoise噪声的心理效应噪声的心理效应Noiseasacauseofstress:噪声是心理压力的成因之一：Effectoffear,changeinpulserate,respirationrate,bloodpressure,acuityofvision噪声可以令人感到恐惧，改变人的脉搏、呼吸频率、血压

19、、视觉敏锐度。Effectonbehaviorandworkefficiency:对行为举止和工作效率的影响：Complextasksarelikelytobeimpairedinthepresenceofnoiseandsimpletasksimproved.做复杂工作时需要较低的环境噪声，而简单工作时的环境噪声可以适当增加。Ifthenoiselevelisfarexcessiveforaparticulartask,workersbecomeirritableaswellaslessefficient.过大量噪声往往使人变得急躁，同时也影响工作效率。7.NoiseratingNRandN

20、oiseCriteriaNCcurves噪声评价曲线噪声评价曲线NR和噪声标准曲线和噪声标准曲线NCForexampleNRcurvesareintendedtodeterminatetheacceptableindoornoiselevelforhearingpreservation,speechcommunicationandannoyance.例如：NR曲线被计划用于表征室内可接受的噪声等级，以便于听力保护、会话交谈、烦恼度评价。Thesecurvesmeanthatinnofrequencybandshalltheoctavebandsoundpressure(inthespecifi

21、edspace)exceedtheNRorNCvalue.这些曲线表明，在任何频带，倍频程带的声压(指定空间中)都不会超过NR或NC值。Theyintendforspecifyinganupperboundofacceptabilityforbackgroundnoise.这些曲线计划用于详细说明背景噪声的可接受上限。NCwasoriginallydevelopedinresponsetotheneedforspecificationofjustacceptableairconditioningnoise.NC曲线最初是用来控制可接受空调噪声的需要。Firstmeasurethesoundpr

22、essurelevelspectrum.ApplyitontheNRCurvesdiagramandevaluatetheNRofthenoiseunderinvestigation.首先测量出声压级谱，并将其应用在NR曲线图上，通过研究分析，估计出噪声的NR值。TheNRisdeterminedbythehighestweightingcurvewhichjustenvelopesthedata.NR值主要由超过最大频率值的加权曲线决定。ThemachineexhibitsaNRof80.这个机器显示的NR值是80。NoiseratingcurveApplicationNR25Concert

23、halls,broadcastingandrecordingstudios,churchesNR30Privatedwellings,hospitals,theatres,cinemas,conferenceroomsNR35Libraries,museums,courtrooms,schools,hospitalsoperatingtheatersandwards,flats,hotels,executiveofficesNR40Halls,corridors,cloakrooms,restaurants,nightclubs,offices,shopsNR45Departmentstore

24、s,supermarkets,canteens,generalofficesNR50Typingpools,officeswithbusinessmachinesNR60LightengineeringworksNR70Foundries,heavyengineeringworksTypeofRoom-SpaceTypeRecommendedNCLevelEquivalentSoundLevelNCCurvedBAApartments25-3535-45AssemblyHalls25-3035-40Churches30-3540-45Courtrooms30-4040-50Factories4

25、0-6550-75Hotels/Motels-Individualroomsorsuites25-3535-45-Meetingorbanquetrooms25-3535-45-ServiceandSupportAreas40-4545-50-Halls,corridors,lobbies35-4050-55Offices-Conferencerooms25-3035-40-Private30-3540-45-Open-planareas35-4045-50-Businessmachines/computers40-4550-55Hospitals and Clinics-Privateroo

26、ms25-3035-40-Operatingrooms25-3035-40-Wards30-3540-45-Laboratories35-4045-50-Corridors30-3540-45-Publicareas35-4045-50Schools-Lectureandclassrooms25-3035-40-Open-planclassrooms35-4045-50Moviemotionpicturetheaters30-3540-45Libraries35-4040-50Legitimatetheaters20-2530-65PrivateResidences25-3535-45Rest

27、aurants40-4550-55TVBroadcaststudies15-2525-35RecordingStudios15-2025-30Concertandrecitalhalls15-2025-30SportColiseums45-5555-65Recordingstudios15-2025-308.RoomCriteriaRCcurves室内标准室内标准RC曲线曲线TheNRandNCarenotdefinedforverylowfrequencies(rumblenoise)andtheyaretoopermissiveinthefrequencyrangeof2000Hzandh

28、igheroctavebands.NR和NC曲线低频噪声段没有定义，而只绘制了频率在2kHz或更高倍频程带时的值。CreationofRCcurves:RC曲线的产生：Toincludelowfrequencies包含低频成分Tospecifydesirablenoiselevelswithinnonindustrialinteriorspaces.定义非工业噪声领域中的室内期望噪声等级Tointroduceacoustic“perfume”了解声学”特性”Natureofthesoundundermeasures:所测噪声种类：Steadynoise:averageofthesoundlev

29、elpressure稳定噪声：平均声压级。Fluctuatingorcyclicnoise:equivalentcontinuousnoiselevelmustbeevaluated.起伏或周期噪声：必须评估等价连续噪声等级。Thesourceofnoiseischaracterizedbyitsfrequencycontentsandanycontrolofitmustbedoneaccordingly.频率成分是声源的特征，是一切控制手段的依据。频率成分是声源的特征，是一切控制手段的依据。Noisereductionperformancecannotbespecifiedindepende

30、ntlyofsourcefrequencies.抑制噪声性能的好坏，与声源的频率有关。20 HzAudible range20kHz20 Hz听听觉范范围80dB(A)causeslistenertoincurapartialdoseofnoise.噪声剂量：暴露在任何声压级大于80dB的噪声中，听者会招致部分剂量噪声影响。TinhourLindBTWAisthesoundlevelthatwouldproduceagivennoisedoseifanemployeewereexposedtothatsoundlevelcontinuouslyoveran8hourworkday.TWA是当工

31、人在8小时工作日内连续暴露在某个声压级时所产生的确定噪声剂量。Anoisedoseof50%(TWA=85dB(A)ispointatwhichemployeemustimplementcontinuinghearingconservationprogramwhichincludesexposuremonitoring,audiometrictesting,hearingprotection,employeetrainingandrecordkeeping.目前，我国政府部门要求从事TWA在85dB以上职业者需要听力保护，如：噪声监听、听力测试、听力保护等。9.7Noisedoseforimp

32、ulsenoiseandimpactnoise脉冲噪声和冲击噪声的噪声剂量脉冲噪声和冲击噪声的噪声剂量Thehumanearhasanexcellentrecuperationbetweendifferentimpulses.Increasingthenoiselevelby5dBwilldoublethenoisedose.Thenoisedosealsodependsonthenumberofimpulseduringan8hoursshift.声压级每增加5dB，噪声剂量增加1倍。噪声剂量同样依赖于8小时内的脉冲噪声数。Theequivalentnoisedosedependson:Du

33、rationofeachimpulseorimpactnoisetimethenumberofimpulsesorimpactnoisesCorrespondingpeakpressurelevel噪声剂量依赖于脉冲噪声和冲击噪声的持续时间和数量，与声压级峰值相关。10.Soundqualitymetrics音质计音质计Severalfunctionsexisttogiveaquantificationofthehumanperceptionofsoundanditssubjectivedescription.多个函数都可以对声音感知度作出定量评估和主观描述。10.1Loudness响度Lou

34、dness(inphonsorsones):describesthesensationofloudness(soundlevel)ofasound.响度(单位：方或宋)：描述人耳感觉到声音的强弱等级。Asalreadyseen:tonesofdifferentfrequencybutsameSPLarenotperceivedequalintermsofloudness.tocompareloudnessofasoundatoneof1kHzhasbeentakenasreference.频率不同，但声压级相同的纯音，其响度并不相同。通常以1kHz纯音的响度作为基准，以便于比较。60 phon

35、s means as loud as a 60dB,1000 Hz tone60phons等同于等同于1kHz，60dB单音的响度单音的响度TheuseofthephonasaunitofloudnessisanimprovementoverjustquotingthelevelindB,butitisstillnotameasurementwhichisdirectlyproportionaltoloudness.Thesonescalewascreatedtoprovidesuchalinearscaleofloudness.Itisusuallypresumedthatthestanda

36、rdrangefororchestralmusicisabout40to100phons.Ifthelowerendofthatrangeisarbitrarilyassignedaloudnessofonesone,then50phonswouldhavealoudnessof2sones,60phonswouldbe4sones,etc.与用分贝表示响度级相比，单位phon的使用是一大改进。但它与响度仍然没有直接的比例关系。所以又创建了单位sone，它与响度有直接的比例关系。通常认为标准管弦乐的响度范围约为40-100phons.如果上述响度范围的下限设为1sone，则50phons相当于

37、2sones，60phons相当于4sons，以此类推。DynamicLevelPhonsSonesfff10064.9032f8016.708p604.502ppp401Thesonescalehastheadvantagethatitisalinearfunctionofthehumansensation:2sonetoneisPerceivedtwiceasloudasa1sonetone.量级sone的优点在于，它是人感知度的线性函数：响度为2sone的单音，其感知度正好是1sone单音的两倍。Thelevelofa1kHztonehastoincreaseby10dBinordert

38、oenlargethesensationofloudnessby2.1kHz的单音，为使人耳响度感知度提高一倍，声压级需增大10dB。10.2Sharpness(acum)尖锐度尖锐度(acum)Sharpness(in acum)isdefinedastheratioofhighfrequencyleveltooveralllevel.Soundsthathavehigherenergyinhighfrequenciestendtobesharper.(cryofalittlegirl.)尖锐度定义为所有声音中高频成分所占的比率，能量集中在高频部分的声音听起来会比较尖锐。Sharpnessi

39、sparticularlysuitablefortheidlenoiseduetothehighfrequencycontent.Anexampleofthisphenomenonisaballbearingtypedriveofpoorquality.Minorimperfectionsinthesurfaceoftheballswillresultindiscretetonesatmultiplesoftherotationalspeed,commonlyreferredtoasbearingdefectfrequencies.尖锐度尤其适用于评价由高频成分引起的怠速噪声。低质量的球轴承驱

40、动装置所发出的噪声就是其中一例。轴承中球状铁珠的较小缺陷也会导致在多个转动速度时，发出离散的噪声，通常称为轴承缺陷频率。Thesharpnessisdeterminedfromnarrow-bandsoundpressurespectrum.Therefore,spectralcontentsandthecenterfrequencyofthenarrowbandsoundsareimportantforsharpnessanalysis.尖锐度由窄带声压谱决定。因此，在尖锐度分析中，窄带的谱结构和中心频率很重要。Thereferencesoundproducing1acumisanarrow

41、-bandofthecentrefrequencyof1kHz.参考声源产生的1acum声音是中心频率为1kHz的窄带声音。Sharpnessofasoundiscorrelatedwithannoyance.声音的尖锐度与烦恼度有关。Forabroadbandnoise:ifthelowercutofffrequenciescontentsincreasethenthesharpnessdecreases.iftheuppercutofffrequenciescontentsdecreasethenthesharpnessdecreases.对于宽带噪声：当宽带截止频率下限增大时，尖锐度降低

42、。当宽带截止频率的上限减小时，尖锐度升高。Problem:nostandardizationforsharpness:BismarkorAuresmethods.问题：尖锐度还未标准化：Bismark或Aures法Illustrationofasoundsignalwith(a)steadyamplitudeand(b)amplitudethatfluctuatesovertime.10.3Roughness(asper)/Fluctuationstrength(vacil)粗糙度粗糙度(asper)起伏强度起伏强度(vacil)Roughnessandfluctuationstrengthq

43、uantifythesubjectiveperceptionofamplitudeorfrequencymodulation.粗糙度和起伏强度可定量表示振幅或频率调制下的主观感知度。Amplitudefluctuationsdescribevariationsinthemaximumvalue(amplitude)ofsoundsignalsrelativetoareferencepointandaretheresultofwaveinterference.Theinterferenceprinciplestatesthatthecombinedamplitudeoftwoormorevibr

44、ations(waves)atanygiventimemaybelarger(constructiveinterference)orsmaller(destructiveinterference)thantheamplitudeoftheindividualvibrations(waves),dependingontheirphaserelationship.振幅起伏描述了声波振幅最大值与参考值之间的变化，其起因是声波的干涉。干涉法则表明，任意给定时刻，两个或多个振动(声波)相叠加后的振幅可能或大于(相长干涉)或小于(相消干涉)每个单一的振动(声波)的振幅，其大小取决各振动相位之间的关系。In

45、thecaseoftwoormorewaveswithdifferentfrequencies,theirperiodicallychangingphaserelationshipresultsinperiodicalterationsbetweenconstructiveanddestructiveinterference,givingrisetothephenomenonofamplitudefluctuations.当两个或多个不同频率声波相互叠加时，其周期性的相位变化会导致叠加后的声波周期性地交替产生相长或相消干涉，于是形成了振幅起伏的现象。Rateoffluctuationwilld

46、efinethetypeofmodulationencounter:起伏率定义了调制交会类型。Roughnessisthesubjectiveperceptionofrapid(15-300Hz)amplitudemodulationofsound.粗糙度描述了对声波快速(15-300Hz)振幅调制的主观感知度。Fluctuationstrengthquantifythesubjectiveperceptionofslow(20Hz)amplitudemodulationofsound(beating).起伏强度定量描述了对声波慢速(20Hz)振幅调制的主观感知度(如敲打)。Amplitude

47、fluctuationdegree:(=degreeofmodulation)theleveldifferencebetweenpeaksandvalleysinasignalsuchastheoneinFigure1b.Thedegreeofamplitudefluctuationdependsontherelativeamplitudesofthecomponentsinthesignalsspectrum.振幅起伏度：(调制度)表示波峰和波谷间的差分等级，如图1b。振幅起伏度由信号谱中各组成成分的相对振幅决定。Iftheinterferingtonesareofequalamplitud

48、esthenitwillresultthehighestfluctuationdegreeandthereforeinthehighestroughnessdegree.若相干音调具有相同的振幅，则结果的起伏度最大，同时导致粗糙度也最大。Frequencydeviationisthedifferencebetweenthetwofrequenciesofthesignalanditsmodulated.频率偏差表示信号中两个频率及调制度间的差别。Roughness粗糙度粗糙度Roughnessof1asper=1kHztoneof60dB100%modulatedinamplitudewith

49、amodulationfrequencyof70Hz.粗糙度1asper频率1kHz，声压级60dB纯音，经100%的振幅调制，调制频率为70H时，产生的粗糙度。Fluctuationstrength起伏强度起伏强度Fluctuationstrengthof1vacil=1kHztoneof60dB100%modulatedat4Hz.起伏强度1vacil频率1kHz，声压级60dB，经100%调制，调制频率为4Hz时，产生的起伏强度。10.4Prominenceratio显著率显著率Soundwithtonalcomponentsareveryannoying.Prominenceratio

50、andtonalityfindanddisplaytonalcomponentsofasignal.不同音调混在一起的声音是烦人的。显著率和调性有助于发现和显示一个信号的音调组成。ThemethodisdescribedinthestandardECMA-74“Measurementofairbornenoiseemittedbyinformationtechnologyandtelecommunicationequipment”.标准ECMA-74“信息技术和无线电通讯设备所发射噪声的测量方法”中介绍了具体的方法。Adiscretetonewhichoccurstogetherwithbro