1、Standards Secretariat Acoustical Society of America 335 East 45th Street New York, New York 1 O01 7 ANSI S1.4-1983 (Revision of S1 .el 971 ) (ASA 47-1 983) (Includes Amendment SI .4a-1985) SI .4 and SI .4a Reaffirmed by ANSI on 10 July 2001 SI .4 and SI .4a Reaffirmed by ANSI on 21 March 2006 AMERIC
2、AN NATIONAL STANDARD Specification for Sound Level Meters ABSTRACT This standard is a revision of the American National Standard Specification for Sound Level Meters, S1.4-1971. It conforms as closely as possible to the IEC Stan- dard for Sound Level Meters, Publication 65 1, First Edition issued in
3、 1979. This revi- sion represents a significant improvement over ANSI S1.4-1971, particularly in its specifications relating to measurement of transient sound signals. It also permits the use of digital techniques and displays. The principal changes from ANSI Sl.4-1971 are: inclusion of an optional
4、impulse exponential-time averaging characteristic, inclu- sion of an optional peak characteristics, more rigorous definition of the dynamic characteristics for the Fast and Slow exponential-time-averaging, increase in the crest factor requirement to ten for type 1 instruments, specification of a typ
5、e O laboratory instrument with generally smaller tolerance limits than those previously specified for type 1, and deletion of the type 3 survey instrument. Published by the American Institute of Physics for the Acoustical Society of America I Copyright Acoustical Society of America Provided by IHS u
6、nder license with ASA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMERICAN NATIONAL STANDARDS ON ACOUSTICS The Acoustical Society of America is the Secretariat for American National Standards Committees S1 on Acoustics, S2 on Mechanical Shock and Vibration, S3
7、on Bioacoustics, and S12 Noise. Standards developed by these committees, which have wide representation from the technical community (manufacturers, consumers, and general-interest representatives), are published by the Acoustical Society of America as American National Standards after approval by t
8、heir respective standards committees. These standards are developed as a public service to provide standards useful to the public, industry, and consumers, and to Federal, State, and local governments. This standard was approved by the American National Standards Institute as ANSI S1.4-1983 on 17 Fe
9、bruary 1983. An American National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The existence of an American National Standard does not i
10、n any respect preclude anyone, whether he has approved the standard or not, from manufacturing, mar- keting, purchasing, or using products, processes, or procedures not conforming to the standard. American National Standards are subject to periodic review and users are cautioned to obtain the latest
11、 editions. Caufjoon Notjce An American National Standard may be revised or withdrawn at any time The procedures of the American National Standards Institute require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of publication Copyright 0 1
12、983 by the Acoustical Society of America. No portion of this publication may be quoted or reproduced in any form without permission of the Acoustical Society of America. second printing, 1992 Il Copyright Acoustical Society of America Provided by IHS under license with ASA Not for ResaleNo reproduct
13、ion or networking permitted without license from IHS-,-,-FOREWORD This Foreword is for information only and is not a part of American National Standard Specification for Sound Level Meters, 51.4-1 983, a revision of S1.4-1971 (ASA Catalog No. 47-1983). This standard comprises a part of a group of de
14、finitions, standards, and specifications for use in acoustical work. It has been developed under the American National Standards Institute by the Standards Committee Method of Procedure under the Secretariat of the Acoustical Society of America. American National Standards Committee S1, under whose
15、jurisdiction this standard was developed, has the following scope: Standards, specifications, methods of measurement and test, and terminology in the fields of physical acoustics, architectural acous- tics, electroacoustics, sonics and ultrasonics, and underwater sound, but excluding those aspects w
16、hich pertain to biological safety, tolerance, and comfort. This standard is a revision of the American National Standard Specifications for Sound Level Meters, S1.4- 1971. It conforms as closely as possible to the IEC Standard for Sound Level Meters, Publication 651, First Edition, issued in 1979. T
17、he principal deviations from publication 65 1 are: requirement for random-incidence calibration, as has been the United States custom, rather than the free-field method, requirement that the crest factor capability for type 1 instruments be the same, regardless of the inclusion of an impulse exponen
18、tial-time- averaging characteristic, deletion of the type 3 survey instrument. At the time this standard was submitted to Standards Committee S1 for final approval, the membership was as follows: D. R. Flynn, Chirman A. H. Marsh, Vice-chairman A. Brenig, Secrerary Acoustical Society of America o G.
19、C. Maling, Ir., A. H. Marsh Air-Conditioning and Refrigeration Institute o A. C. Potter, R.J. Evans (Alt) American Industrial Hygiene Association o C. D. Bohl American Iron and two exponential-time-averaging characteristics, slow and fast. Also it defines a socalled impulse-re- sponse characteristic
20、 which is optional for any type. The standard permits special features in a sound level meter, such as peak-measuring capabilities, wide ranges for the display of sound level on an analog indi- cator, digital displays, recording displays, and auto- matic range changing. Because sound level meters ma
21、y be needed for spe- cial purposes that do not require the complexity of any of the three basic types, provision is made for a special purpose sound level meter, type S. The type S meter may be qualified to the performance of any of the basic types (O, 1, and 2), but is not required to have all thre
22、e frequency-weighting networks, or more than one expo- nential-time-averaging characteristic. 1.4 Limitations If a sound level meter that conforms with the re- quirements of this standard is modified, it shall be demonstrated that the modified sound level meter also conforms with this standard provi
23、ding the measure- ments are to be reported as sound levels and said to be measured by an instrument that complies with the re- quirements of this standard. 2 DEFINITIONS 2.1 sound pressure level: In decibels, 20 times the loga- rithm to the base ten of the ratio of the sound pressure, in a stated fr
24、equency band, to the reference sound pressure. The sound pressure is understood to be a time-period, root-mean-square sound pressure, unless another time-averaging process is indicated. For sound in air, the reference sound pressure is 20 micropascals (20 pPa). Abbreviation: SPL; quantity symbol: L,
25、 . 2.2 exponentid-timeaverage sound pressure level: In decibels, ten times the logarithm to the base ten of the ratio of an exponential-time-average squared frequen- cy-weighted sound pressure to the square of the refer- ence sound pressure. Quantity symbol, L,; unit, deci- bel; unit symbol, dB. NOT
26、ES: (1) in symbols, exponential-time-average sound level at any time I is where r is the exponential time constant in seconds, p(5) is the in- stantaneous time-varying sound pressure with stated frequency weighting, 4 is a dummy variable of integration, and p, is the refer- ence sound pressure. Runn
27、ing integration of squared frequency- weighted sound pressure with exponential time weighting occurs from some time in the past (as noted by the - 00 at the start of the integration period) to the present at the time r. Division by the expo- nential time constant T yields a running time average. (2)
28、 Exponential time constants standardized in acoutics are 35, 125. and loo0 ms: the resulting exponential-time-average sound pressure levels are identified respectively by Impulse, Fast, and Slow. 2.3 sound level: Sound pressure level in decibels mea- sured by use of the A, B, or C frequency weightin
29、g and fast (F), slow (S), or impulse (I), exponential-time-aver- aging, or peak (pK) time-relatedcharacteristic, as specified in this standard. The frequency weighting and exponential-time-averaging constant shall be specified, otherwise the standarized fast (125 millisec- Copyright Acoustical Socie
30、ty of America Provided by IHS under license with ASA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI S1.4-1983 3 onds) exponential-time-averaging and A-frequency weighting are understood. The reference sound pres- sure is 20 micropascals. Abbreviation for fast
31、 A- weighted sound level, FAL; quantity symbol: L AF. Abbreviations and symbols for other weightings have the same stucture, but with the substitution of letters appropriate to the actual frequency and time averag- ing, e.g., SAL and L AS, FCL and L CF. 2.4 maximum sound level: Greatest sound level
32、in deci- bels for a specific exponential-time-averaging constant during a given time period. Abbreviation for maxi- mum fast A-weighted sound level: MXFAL; quantity symbol: L AF mar. 2.5 peak sound level: In decibels, 20 times the loga- rithm to the base ten of the ratio of the greatest instan- tane
33、ous sound pressure during a given time period to the reference pressure of 20 micropascals. Abbrevia- tion for peak A-weighted sound level: PkAL; quantity 2.6 slow sound level: Sound level in decibels measured by the use of the standarized slow (lo00 ms) exponen- tial-time-averaging. Abbreviation fo
34、r slow A-weighted sound level: SAL; quantity symbol: LAS. 2.7 impulse sound level: Sound level in decibels mea- sured by the use of the standard impulse (35 ms) expo- nential-time-averaging for increasing portions of the, signal and 1500-ms time constant for decreasing por-. tions of the signal. Abb
35、reviation for impulse A-weight-. ed sound level: IAL; quantity symbol: L A,. 2.8 time constant: Time required for a quantity that varies exponentially with time, but less any constant component, to change by the factor l/e(i/ e = 0.36787 .). Quantity symbol: r. 2.9 crest factor: Ratio of the peak so
36、und pressure in a stated frequency band to the square root of the one- second exponential-time-average squared sound pres- sure in the same frequency band. Measured during a specified time interval and with the instantaneous val- ues of sound pressure being measured with respect to the arithmetic me
37、an value during the time interval. 2.10 indicator range: The range in decibels of sound levels that can be indicated on the display or other out- put device. 2.11 primary indicator range: A specified part of the indicator range in decibels for which the measure- ments of sound level are within parti
38、cularly close to- lerances. 2.12 calibration frequency: A frequency in hertz speci- fied by the manufacturer in the nominal range from 200 to loo0 hertz and used for calibration of the abso- lute sensitivity level of a sound level meter. A nominal calibration frequency of lo00 hertz is preferred. 2.
39、13 calibration sound pressure level: A sound pres- symbol: L Apk. sure level in decibels specified by the manufacturer to be used for calibrating the absolute sensitivity level of a sound level meter. 2.14 calibration range: A sound level measuring range in decibels specified by the manufacturer for
40、 calibra- tion which includes the calibration sound pressure lev- el. 2.15 calibration angle of incidence: Angle of incidence from axis of symmetry that for plane waves in a free field, provides a frequency response most closely ap- proximating that for random incidence. 2.16 relative response level
41、: Amount, in decibels, by which the frequency-weighted sound level exceeds the sound pressure level. Relative response level of a sound level meter is usually negative. 3 GENERAL CHARACTERISTICS 3.1 General A sound level meter can be generally described as a combination of a microphone, an amplifier
42、 with a standardized frequency weighting, a standardized ex- ponential-time-averaging device, a logarithm taker, and a means to display the results in decibels. In Secs. 4, 5, and 6 specifications are given for those compon- ents of a sound level meter along with tolerance limits for the three types
43、 of sound level meters. Additional items necessary to meet any of the requirements (such as extension rods or cables or a special correction grid or cap on the microphone to approximate random-in- cidence response) are regarded as integral parts of a sound level meter. 3.2 Accuracy For sounds incide
44、nt on the microphone with ran- dom incidence and after any warmup period less than 10 minutes specified by the manufacturer, a sound lev- el meter shall be able to measure the sound level of a sinusoidal signal at the calibration frequency, for each frequency weighting provided, within an accuracy o
45、f - + 0.4, E = (i + 0.5 + 0.5 + 0.5 + 0.5* + 1.0 + 1.52)”2, E = 2.3 dB (100 to 1250 Hz). The same type of calculation may be used to esti- mate the total allowable errors for other types of sound level meters and for various assumptions on the char- acteristics of the sound field and minimization of
46、 en- vironmental and warmup errors. For the same as- sumptions as used in the preceding example, a type 1 instrument has an expected allowable total error of - + 1.6 dB. or 1.4 dB, if it is assumed the factors 2, 3, 4, and 5 are zero after correction. In this case for steady broadband noise with a c
47、rest factor less than three and a diffuse field, a type 1 instrument should have an expected total allowable error of 1.5 dB and a type 2 instrument, an error of 2.3 dB factors 1, 6 (pri- mary), 7, and lo. These expected values of total al- lowable errors apply to an instrument of a given type selec
48、ted at random. They may be reduced for a specific instrument through careful calibration and adjust- ment. APPENDIX 6: APPROXIMATION OF THE LEVEL RANDOM-INCIDENCE RELATIVE RESPONSE Thn Appendix 15 not a part of American Naiional Standard Specifi- cation for Sound Level Meter SI 4-1983, hui 15 includ
49、ed for infor- mation purposri only This Appendix reviews the concept of the random incidence calibration required in 4.1 and suggests a method for determination of the random-incidence rel- ative response level. See Sec. 8 of American National Standards S1.10-1966 (R1976j.l The square of the random incidence sensitivity, Sd(f), is the space average mean of the squares of the sensitivities for all directions, given by whereS,f?, the extend of the area is defined by the elements A# and d and
