噪聲測量之噪聲對人影響

1、噪聲測量之噪聲對人影響 噪聲噪聲 測量測量 第二部分：噪聲對人們的影響第二部分：噪聲對人們的影響 噪聲測量之噪聲對人影響 1-Subjective phenomenon. Sound/noise聲音聲音/ /噪聲的主觀現象噪聲的主觀現象 Sound affect different people in different ways. The perception of sound is subjectively interpreted depending on the moon of each and the state of tiredness.聲音以各種方式影響著人們，聲音的感知主觀上依賴

2、于人們自身的心理、 生理狀態(tài)，愉快、疲勞 Enjoyable sound令人愉悅的聲音 Unwanted sound讓人反感的聲音 Communication/warn交談/報警聲 噪聲測量之噪聲對人影響 Therefore an individual will make subjective judgment about various noises which impinge him. 因此，每個人都會對噪聲作出自己的主觀判斷。 Sound allow human being to make quality evaluations and diagnoses. 人們可以對聲音品質作出評價和

3、診斷。 How can we obtain objective measures of these subjective effects? 那么如何對這些主觀影響進行客觀測量呢？ Rating of the sounds in terms of annoying feelings (loudness, sharpness, roughness, tonality.) means of comparing sounds under different conditions.可以根據聲音煩 惱度不同(評價參數包括: 響度、尖銳度、粗糙度、音調)或不同條件下各種聲 音間的對比, 將其劃分為不同等級。

4、 Measurement of the hearing damage (audiometry)測量聽力損害度(聽力計) Allow to reduce noise from any environment (airport, train station, factories.) 減少各種環(huán)境中的噪聲(機場、火車站、工廠) 噪聲測量之噪聲對人影響 2-Human hearing system人類的聽覺系統 Human hear responds predominantly to airborne noise = pressure changes 人耳對空氣噪聲的響應 =氣壓變化 噪聲測量之噪聲對

5、人影響 Pressure variation is an adequate noise measurement quantity because : 壓力變化可用來充分度量噪聲的原因是： The auditory system responds to pressure changes 聽覺系統對聲壓的變化有響應 Mechanical structures responds to pressure 機械結構對壓力有響應 Easiest acoustic quantity to measure. From pressure, sound intensity and power can be eva

6、luated. 可用于測量最簡單的聲學量。通過測量聲壓，可以估計出聲強度和聲能量。 噪聲測量之噪聲對人影響 3. Non linearity of the hear response人耳的非線性響應人耳的非線性響應 The auditory system sensitivity varies with frequencies 聽覺系統的靈敏度會隨著聲音頻率不同而發(fā)生變化。聽覺系統的靈敏度會隨著聲音頻率不同而發(fā)生變化。 Speech range: 200Hz-6000Hz 語音頻率范圍：200Hz-6000Hz Speech intelligibility range: 500Hz-4000Hz

7、 清晰語音頻率范圍：500Hz-4000Hz 噪聲測量之噪聲對人影響 Low frequencies need more “energy” or sound pressure level to be heard than sound within 1kHz-5kHz. 與頻率在1kHz-5kHz之間的聲音相比，低 頻聲音往往需要具有更高的能量或者更高 聲壓級時，才能被人們聽見。 To take into account of the non linearity of the ear response at low Frequencies, the A-weighting curve is of

8、ten used. 通常用A計權曲線來更好地說明人耳在低 頻段的非線性響應特性。 噪聲測量之噪聲對人影響 A weighting curve A計權曲線 FrequencFrequenc y Hzy Hz A A weighting weighting dBdB FrequencFrequenc y Hzy Hz A A weighting weighting dBdB 20-50.5800-0.8 25-44.710000 31.5-39.412500.6 40-34.616001 50-30.220001.2 63-26.225001.3 80-22.531501.2 100-19.140

9、001 125-16.150000.5 160-13.46300-0.1 200-10.98000-1.1 250-8.610000-2.5 315-6.612500-4.3 400-4.816000-6.6 500-3.220000-9.3 630-1.9 where WWA = weighting to be applied, dB f f = frequency, Hz 噪聲測量之噪聲對人影響 But A-weighting curve simulates the response only of the ear for low level sound. The A-weighting

10、curve follows approximately the equal loudness curve of 40phons. 但A計權曲線只能模擬人耳對低聲音的響應特性。下圖所示，A計權曲線約對應于40宋等響度曲線。 Each curve corresponds to the equal sensation of loudness perception for different pure tones frequencies.每條曲線都是不同頻率純音的等響度曲線。 Tone of different frequency but same SPL are not perceived equa

11、l. 聲壓級相同但頻率不同的純音，其對應感知度并不相同。 A tone of 10 dB 200Hz has the same loudness perception than a tone of 0 dB2kHz. 10dB 200Hz與0dB 2kHz的聲音擁有相同的響度感知度。 At low level a pure high frequency tone will easily mask low frequency pure tone. 在低聲壓級段，高頻純音可以輕易掩蔽低頻純音。 噪聲測量之噪聲對人影響 Looking at these curves the noise engine

12、er task will need to decrease more SPL at high frequencies than at low frequencies to get the same subjective perception of loudness. 從曲線中可看出，為了使高頻和 低頻聲音響度的主觀感知度一 致，噪聲工程師需要更多地降低 高頻聲音的聲壓級。 噪聲測量之噪聲對人影響 To take into account of the ear response for different level of sound several weighting has been dev

13、eloped:考慮到人耳對不同等級聲音的響應，人們提出了幾種不同計權方法： B-weighting curve approximately follows the 70 phons equal loudness curve B計權曲線約對應于70宋等響度曲線 C-weighting curve approximately equal loudness follows the 100 phons curve C計權曲線約對應于100宋等響度曲線 where WWB = weighting to be applied, dB f f = frequency, Hz where WWC = weig

14、hting to be applied, dB f f = frequency, Hz D-weighting curve follows a special curve which emphasizes frequencies between 1kHz-10kHz. Used for air craft applications. D計權曲線對應于一條主頻在1kHz-10kHz內的特殊曲線， 主要應用于機場噪聲。 噪聲測量之噪聲對人影響 Perception of sound pressure level variation 對聲壓級變化的感知度聲壓級變化的感知度: : Change in

15、Change in sound levelsound level Human perceptionHuman perceptionChange in powerChange in power increaseincrease Change in powerChange in power decreasedecrease 3 dB3 dBJust perceptible21/2 5 dB5 dBClearly noticeable31/3 6 dB6 dBClearly noticeable Double amplitude 41/4 10 dB10 dBHalf or twice as lou

16、d101/10 20 dB20 dBMuch quieter or louder 10 times amplitude 1001/100 Results applied for frequency around 1000Hz.以上結果適用于頻率約1kHz的情況 At higher or lower frequencies much larger difference of SPL need to be applied to perceived the difference in loudness. 當聲音頻率明顯高于或低于1kHz時，相差相同的響度對應的聲壓級的變化更大。 噪聲測量之噪聲對人影

17、響 4. Speech intelligibility 語音清晰度語音清晰度 Speech intelligibility : accuracy with which a normal listener will understand a spoken word or sentence. 語音清晰度：正常人能聽清一個單詞或句子時的語音精度。 Speech intelligibility depends upon the background noise in relation to the level of of spoken words. 語音清晰度由背景噪聲和語音聲壓級之比決定。 Spee

18、ch Interference Level SIL of the interfering background noise is given by: 背景噪聲對語音的干擾級定義為： Speech range語音頻率范圍: 200Hz-6000Hz Speech intelligibility range清晰語音頻率范圍: 500Hz-4000kHz 3 20001000500bandoctaveHzatSPLbandoctaveHzatSPLbandoctaveHzatSPL SIL 噪聲測量之噪聲對人影響 Of the background noise Possible with Norma

19、l voice Communicating voice Difficult.impossible Acceptable speech communication 可讓人接受的語音交流 = 95% sentence intelligibility 95%的句子可以聽清 60% word-out-context recognition 60%的單詞可以辨識 Speech intelligibility depends on the reverberation of the space, sex, noise fluctuation. 語音清晰度取決于空間混響、發(fā)聲人性別、噪聲起伏。 For sit

20、uation where speech or telephone communication are important a maximum of 70dB(A) background. 在一些如演講或電話交談的重要場合， 背景噪聲不要超過70dB(A)。 Expected voice level = average talkers subjective response to the background noise 期望語音等級是指談話者對背景噪聲的平均主 觀響應。 噪聲測量之噪聲對人影響 5. Masking effect 掩蔽效應掩蔽效應 Masking effect is the p

21、henomenon of the one sound interfering with the perception of another sound. 掩蔽效應是一個聲音掩蓋住另一個聲音，使其無法被感知的現象。 Intense tone may mask sound of speech高強度的純音往往可能掩蔽住語音。 Low frequency tones are more effective in masking sound speech than higher tone. 低頻率的純音比高頻率的純音更能掩蔽人們的語音。 聲音A被聲音B掩蔽，如果A處于以B為中心的掩蔽范圍內，掩蔽會更加明

22、顯，這個范圍叫做臨界帶寬。每種頻率的臨界帶寬都不一樣，頻率越高， 臨界帶寬越寬。 噪聲測量之噪聲對人影響 6. Psychological effect of noise噪聲的心理效應噪聲的心理效應 Noise as a cause of stress :噪聲是心理壓力的成因之一： Effect of fear, change in pulse rate, respiration rate, blood pressure, acuity of vision 噪聲可以令人感到恐懼，改變人的脈搏、呼吸頻率、血壓、視覺敏銳度。 Effect on behavior and work efficien

23、cy:對行為舉止和工作效率的影響： Complex tasks are likely to be impaired in the presence of noise and simple tasks improved. 做復雜工作時需要較低的環(huán)境噪聲，而簡單工作時的環(huán)境噪聲可以適當增加。 If the noise level is far excessive for a particular task, workers become irritable as well as less efficient. 過大量噪聲往往使人變得急躁，同時也影響工作效率。 噪聲測量之噪聲對人影響 7. Nois

24、e rating NR and Noise Criteria NC curves 噪聲評價曲線噪聲評價曲線NRNR和噪聲標準曲線和噪聲標準曲線NCNC For example NR curves are intended to determinate the acceptable indoor noise level for hearing preservation, speech communication and annoyance. 例如：NR曲線被計劃用于表征室內可接受的噪聲等級，以便于聽力保護、會話交談、煩 惱度評價。 These curves mean that in no fre

25、quency band shall the octave band sound pressure (in the specified space) exceed the NR or NC value. 這些曲線表明，在任何頻帶，倍頻程帶的聲壓(指定空間中)都不會超過NR或NC值。 They intend for specifying an upper bound of acceptability for background noise. 這些曲線計劃用于詳細說明背景噪聲的可接受上限。 NC was originally developed in response to the need fo

26、r specification of just acceptable air conditioning noise. NC曲線最初是用來控制可接受空調噪聲的需要。 噪聲測量之噪聲對人影響 First measure the sound pressure level spectrum. Apply it on the NR Curves diagram and evaluate the NR of the noise under investigation. 首先測量出聲壓級譜，并將其應用在NR曲線圖上，通 過研究分析，估計出噪聲的NR值。 The NR is determined by the

27、 highest weighting curve which just envelopes the data. NR值主要由超過最大頻率值的加權曲線決定。 The machine exhibits a NR of 80. 這個機器顯示的NR值是80。 噪聲測量之噪聲對人影響 Noise rating curve Application NR 25 Concert halls, broadcasting and recording studios, churches NR 30 Private dwellings, hospitals, theatres, cinemas, conference

28、 rooms NR 35 Libraries, museums, court rooms, schools, hospitals operating theaters and wards, flats, hotels, executive offices NR 40 Halls, corridors, cloakrooms, restaurants, night clubs, offices, shops NR 45 Department stores, supermarkets, canteens, general offices NR 50Typing pools, offices wit

29、h business machines NR 60Light engineering works NR 70Foundries, heavy engineering works Type of Room - Space Type Recommended NC Level Equivalent Sound Level NC CurvedBA Apartments25-3535-45 Assembly Halls25-3035-40 Churches30-3540-45 Courtrooms30-4040-50 Factories40-6550-75 Hotels/MotelsHotels/Mot

30、els - Individual rooms or suites25-3535-45 - Meeting or banquet rooms25-3535-45 - Service and Support Areas40-4545-50 - Halls, corridors, lobbies35-4050-55 OfficesOffices - Conference rooms25-3035-40 - Private30-3540-45 - Open-plan areas35-4045-50 - Business machines/computers40-4550-55 Hospitals an

31、d ClinicsHospitals and Clinics - Private rooms25-3035-40 - Operating rooms25-3035-40 - Wards30-3540-45 - Laboratories35-4045-50 - Corridors30-3540-45 噪聲測量之噪聲對人影響 噪聲測量之噪聲對人影響 8. Room Criteria RC curves室內標準室內標準RCRC曲線曲線 The NR and NC are not defined for very low frequencies (rumble noise) and they are

32、too permissive in the frequency range of 2000 Hz and higher octave bands. NR和NC曲線低頻噪聲段沒有定義，而只繪制了頻率在2kHz或更高倍頻程帶時的值。 Creation of RC curves :RC曲線的產生： To include low frequencies包含低頻成分 To specify desirable noise levels within non industrial interior spaces.定義非工業(yè)噪聲領域 中的室內期望噪聲等級 To introduce acoustic “perf

33、ume” 了解聲學”特性” 噪聲測量之噪聲對人影響 噪聲測量之噪聲對人影響 Nature of the sound under measures :所測噪聲種類： Steady noise : average of the sound level pressure 穩(wěn)定噪聲：平均聲壓級。 Fluctuating or cyclic noise : equivalent continuous noise level must be evaluated. 起伏或周期噪聲：必須評估等價連續(xù)噪聲等級。 噪聲測量之噪聲對人影響 The source of noise is characterized b

34、y its frequency contents and any control of it must be done accordingly.頻率成分是聲源的特征，是一切控制手段的依據。頻率成分是聲源的特征，是一切控制手段的依據。 Noise reduction performance can not be specified independently of source frequencies. 不研究聲源的頻率特性，減振降噪工作就無從談起。 20 HzAudible range20kHz20 HzAudible range20kHz 20 Hz20 Hz聽覺范圍聽覺范圍20kHz80d

35、B(A) causes listener to incur a partial dose of noise. 噪聲劑量：暴露在任何聲壓級大于80dB的噪聲中，聽者會招致部分劑量噪聲影 響。 T in hour L in dB 5 90 2 8 L T 噪聲測量之噪聲對人影響 TWA is the sound level that would produce a given noise dose if an employee were exposed to that sound level continuously over an 8 hour work day. TWA是當工人在8小時工作日內

36、連續(xù)暴露在某個聲壓級時所產生的確定噪 聲劑量。 A noise dose of 50% (TWA=85dB(A) is point at which employee must implement continuing hearing conservation program which includes exposure monitoring, audiometric testing, hearing protection, employee training and record keeping. 目前，我國政府部門要求從事TWA在85dB以上職業(yè)者需要聽力保護，如： 噪聲監(jiān)聽、聽力測試、

37、聽力保護等。 噪聲測量之噪聲對人影響 9.7 Noise dose for impulse noise and impact noise 脈沖噪聲和沖擊噪聲的噪聲劑量脈沖噪聲和沖擊噪聲的噪聲劑量 The human ear has an excellent recuperation between different impulses. Increasing the noise level by 5dB will double the noise dose. The noise dose also depends on the number of impulse during an 8 hou

38、rs shift. 聲壓級每增加5dB，噪聲劑量增加1倍。噪聲劑量同樣依賴于8小時內的脈沖噪聲數。 The equivalent noise dose depends on: Duration of each impulse or impact noise time the number of impulses or impact noises Corresponding peak pressure level 噪聲劑量依賴于脈沖噪聲和沖擊噪聲的持續(xù)時間和數量，與聲壓級峰值相關。 噪聲測量之噪聲對人影響 10. Sound quality metrics 聲音品質 Several functi

39、ons exist to give a quantification of the human perception of sound and its subjective description. 多個函數都可以對聲音感知度作出定量評估和主觀描述。 10.1 Loudness響度 Loudness (in phons or sones): describes the sensation of loudness (sound level) of a sound. 響度(單位：方或宋)：描述人耳感覺到聲音的強弱等級。 As already seen : tones of different fr

40、equency but same SPL are not perceived equal in terms of loudness. to compare loudness of a sound a tone of 1kHz has been taken as reference. 頻率不同，但聲壓級相同的純音，其響度并不相同。 通常以1kHz純音的響度作為基準，以便于比較。 60 phons means as loud as a 60dB, 1000 Hz tone60 phons means as loud as a 60dB, 1000 Hz tone 60phons60phons等同于

41、等同于1kHz1kHz，60dB60dB單音的響度單音的響度 噪聲測量之噪聲對人影響 The use of the phon as a unit of loudness is an improvement over just quoting the level in dB, but it is still not a measurement which is directly proportional to loudness. The sone scale was created to provide such a linear scale of loudness. It is usually

42、 presumed that the standard range for orchestral music is about 40 to 100 phons. If the lower end of that range is arbitrarily assigned a loudness of one sone, then 50 phons would have a loudness of 2 sones, 60 phons would be 4 sones, etc. 與用分貝表示響度級相比，單位phon的使用是一大改進。但它與響度仍然沒有直接的比例關系。所以又 創(chuàng)建了單位sone，它與

43、響度有直接的比例關系。通常認為標準管弦樂的響度范圍約為40-100phons.如果 上述響度范圍的下限設為1sone，則50phons相當于2sones，60phons相當于4sons，以此類推。 Dynamic LevelPhonsSones fff 10064 . 90 32 f 8016 . 708 p 604 . 502 ppp 40 1 The sone scale has the advantage that it is a linear function of the human sensation: 2 sone tone is Perceived twice as loud

44、as a 1sone tone. 量級sone的優(yōu)點在于，它是人感知度的線性函數：響度為 2sone的單音，其感知度正好是1sone單音的兩倍。 The level of a 1kHz tone has to increase by 10dB in order to enlarge the sensation of loudness by 2. 1kHz的單音，為使人耳響度感知度提高一倍，聲壓級需增 大10dB。 噪聲測量之噪聲對人影響 10.2 Sharpness (acum) 尖銳度尖銳度(acum)(acum) Sharpness (in acum) is defined as the

45、ratio of high frequency level to overall level. Sounds that have higher energy in high frequencies tend to be sharper. (cry of a little girl.) 尖銳度定義為所有聲音中高頻成分所占的比率，能量集中在高頻部分的聲音聽起來會比較尖銳。 Sharpness is particularly suitable for the idle noise due to the high frequency content. An example of this phenom

46、enon is a ball bearing type drive of poor quality. Minor imperfections in the surface of the balls will result in discrete tones at multiples of the rotational speed, commonly referred to as bearing defect frequencies. 尖銳度尤其適用于評價由高頻成分引起的怠速噪聲。低質量的球軸承驅動裝置所發(fā)出的噪聲就 是其中一例。軸承中球狀鐵珠的較小缺陷也會導致在多個轉動速度時，發(fā)出離散的噪聲，

47、通常 稱為軸承缺陷頻率。 The sharpness is determined from narrow-band sound pressure spectrum. Therefore, spectral contents and the center frequency of the narrow band sounds are important for sharpness analysis. 尖銳度由窄帶聲壓譜決定。因此，在尖銳度分析中，窄帶的譜結構和中心頻率很重要。 噪聲測量之噪聲對人影響 The reference sound producing 1 acum is a narrow

48、-band of the centre frequency of 1 kHz. 參考聲源產生的1acum聲音是中心頻率為1kHz的窄帶聲音。 Sharpness of a sound is correlated with annoyance. 聲音的尖銳度與煩惱度有關。 For a broad band noise: if the lower cutoff frequencies contents increase then the sharpness decreases. if the upper cutoff frequencies contents decrease then the s

49、harpness decreases. 對于寬帶噪聲：當寬帶截止頻率下限增大時，尖銳度降低。當寬帶截止頻率的上限 減小時，尖銳度升高。 Problem : no standardization for sharpness : Bismark or Aures methods. 問題：尖銳度還未標準化： Bismark 或 Aures法 噪聲測量之噪聲對人影響 Illustration of a sound signal with (a) steady amplitude and (b) amplitude that fluctuates over time. 10.3 Roughness (a

50、sper)/ Fluctuation strength (vacil) 粗糙度粗糙度(asper)(asper)起伏強度起伏強度(vacil)(vacil) Roughness and fluctuation strength quantify the subjective perception of amplitude or frequency modulation. 粗糙度和起伏強度可定量表示振幅或頻率調制下的主觀感知度。 Amplitude fluctuations describe variations in the maximum value (amplitude) of sound

51、 signals relative to a reference point and are the result of wave interference. The interference principle states that the combined amplitude of two or more vibrations (waves) at any given time may be larger (constructive interference) or smaller (destructive interference) than the amplitude of the

52、individual vibrations (waves), depending on their phase relationship. 振幅起伏描述了聲波振幅最大值與參考值之間的變化，其起因是聲波的干涉。干涉法則表明，任意給定時刻，兩個 或多個振動(聲波)相疊加后的振幅可能或大于(相長干涉)或小于(相消干涉)每個單一的振動(聲波)的振幅，其大小取決 各振動相位之間的關系。 In the case of two or more waves with different frequencies, their periodically changing phase relationship re

53、sults in periodic alterations between constructive and destructive interference, giving rise to the phenomenon of amplitude fluctuations. 當兩個或多個不同頻率聲波相互疊加時，其周期性的相位變化會導致疊加后的聲波周期性地交替產生相長或相消干 涉，于是形成了振幅起伏的現象。 噪聲測量之噪聲對人影響 Rate of fluctuation will define the type of modulation encounter : 起伏率定義了調制交會類型。 Ro

54、ughness is the subjective perception of rapid (15-300 Hz) amplitude modulation of sound. 粗糙度描述了對聲波快速(15-300 Hz)振幅調制的主觀感知度。 Fluctuation strength quantify the subjective perception of slow (20 Hz) amplitude modulation of sound (beating). 起伏強度定量描述了對聲波慢速(20 Hz)振幅調制的主觀感知度(如敲打)。 Amplitude fluctuation degr

55、ee: (=degree of modulation) the level difference between peaks and valleys in a signal such as the one in Figure 1b. The degree of amplitude fluctuation depends on the relative amplitudes of the components in the signals spectrum. 振幅起伏度：(調制度)表示波峰和波谷間的差分等級，如圖1b。振幅起伏度由信號譜中各組成 成分的相對振幅決定。 If the interfe

56、ring tones are of equal amplitudes then it will result the highest fluctuation degree and therefore in the highest roughness degree. 若相干音調具有相同的振幅，則結果的起伏度最大，同時導致粗糙度也最大。 Frequency deviation is the difference between the two frequencies of the signal and its modulated. 頻率偏差表示信號中兩個頻率及調制度間的差別。 噪聲測量之噪聲對人影

57、響 Roughness 粗糙度粗糙度 Roughness of 1 asper = 1 kHz tone of 60dB 100% modulated in amplitude with a modulation frequency of 70Hz. 粗糙度1asper頻率1kHz，聲壓級60dB純音，經100%的振幅調制，調制頻率為 70H時，產生的粗糙度。 Fluctuation strength 起伏強度起伏強度 Fluctuation strength of 1 vacil = 1kHz tone of 60dB 100% modulated at 4Hz. 起伏強度1vacil頻率1

58、kHz，聲壓級60dB，經100%調制，調制頻率為4Hz時， 產生的起伏強度。 噪聲測量之噪聲對人影響 10.4 Prominence ratio 顯著率顯著率 Sound with tonal components are very annoying. Prominence ratio and tonality find and display tonal components of a signal. 不同音調混在一起的聲音是煩人的。顯著率和調性有助于發(fā)現和顯示一個信號的音調組成。 The method is described in the standard ECMA-74 “Measu

59、rement of airborne noise emitted by information technology and telecommunication equipment”. 標準ECMA-74“信息技術和無線電通訊設備所發(fā)射噪聲的測量方法”中介紹了具體的方法。 A discrete tone which occurs together with broadband noise is partially masked by that part of the noise contained in a relatively narrow frequency band, called the critical band, that is centered at the frequency of the tone. Noise at frequencies outside the critical band does not contribute significantly to the masking effect. The width of a critical