1、BRITISH STANDARD BS ISO 226:2003 Acoustics Normal equal-loudness-level contours ICS 13.140 BS ISO 226:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 3 September 2003 BSI 3 September 2003 ISBN 0 580 42548 7 National foreword This British
2、 Standard reproduces verbatim ISO 226:2003 and implements it as the UK national standard. It supersedes BS 3383:1988 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee EH/1, Acoustics, to Subcommittee EH/1/1, Hearing, which has the responsibility to: A l
3、ist of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Corr
4、espondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not
5、 of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developmen
6、ts and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 18, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was la
7、st issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 226:2003(E)INTERNATIONAL STANDARD ISO 226 Second edition 2003-08-15 Acoustics Normal equal-loudness-level contours Acoustique Lignes isosoniques normales BSISO226:2003ii BSISO226:2003IS:622 O3002(E) iiiContent
8、s Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 1 4 Formula for derivation of normal equal-loudness-level contours . 2 4.1 Deriving sound pressure level from loudness level 2 4.2 Deriving loudness levels from sound pressure levels 3 Annex A (normative)
9、 Normal equal-loudness-level contours for pure tones under free-field listening conditions 5 Annex B (normative) Tables for normal equal-loudness-level contours for pure tones under free- field listening conditions 6 Annex C (informative) Notes on the derivation of the normal equal-loudness-level co
10、ntours 9 Bibliography . 17 BSISO226:2003IS:622 O3002(E) iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committ
11、ees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Int
12、ernational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International
13、Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the s
14、ubject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 226 was prepared by Technical Committee ISO/TC 43, Acoustics. This second edition cancels and replaces the first edition (ISO 226:1987), which has been technically revised. BSISO226:2003IS:6
15、22 O3002(E) vIntroduction Curves defining combinations of pure tones in terms of frequency and sound pressure level, which are perceived as equally loud, express a fundamental property of the human auditory system and are of basic importance in the field of psychoacoustics. Together with data on the
16、 threshold of hearing under free-field and diffuse-field listening conditions, such equal-loudness-level contours were specified in ISO 226:1987. NOTE 1 Equal-loudness levels can also be determined for bands of noise. However, only the equal-loudness-level contours for pure tones are specified in th
17、is International Standard because insufficient data for bands of noise are available. Nevertheless, this International Standard could be applicable to one-third-octave-bands of noise. During the technical revision of this International Standard, it was decided to separate threshold and supra- thresh
18、old data into two separate documents because the available equal-loudness-level data were not sufficient and hearing thresholds were needed. The threshold values were specified in ISO 389-7:1996, Acoustics Reference zero for the calibration of audiometric equipment Part 7: Reference threshold of hea
19、ring under free-field and diffuse-field listening conditions, as a part of the series of International Standards concerning reference zero values for the calibration of audiometric equipment. The equal-loudness-level contours are presented in this International Standard. They have been revised relat
20、ive to the data in ISO 226:1987. NOTE 2 ISO 389-7:1996 is presently under revision in order to align the threshold data with this edition of ISO 226. BSISO226:2003INTENRATIONAL TSANDADR IS:622 O3002(E)I SO 3002 All irhgts seredevr 1Acoustics Normal equal-loudness-level contours 1 Scope This Internat
21、ional Standard specifies combinations of sound pressure levels and frequencies of pure continuous tones which are perceived as equally loud by human listeners. The specifications are based on the following conditions: a) the sound field in the absence of the listener consists of a free progressive p
22、lane wave; b) the source of sound is directly in front of the listener; c) the sound signals are pure tones; d) the sound pressure level is measured at the position where the centre of the listeners head would be, but in the absence of the listener; e) listening is binaural; f) the listeners are oto
23、logically normal persons in the age range from 18 years to 25 years inclusive. The data are given in graphical form in Annex A and in numerical form in Annex B for the preferred frequencies in the one-third-octave series from 20 Hz to 12 500 Hz, inclusive, in accordance with ISO 266. 2 Normative ref
24、erences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 266, Acoustics Preferred frequencies
25、3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 otologically normal person person in a normal state of health who is free from all signs or symptoms of ear disease and from obstructing wax in the ear canals, and who has no history of undue ex
26、posure to noise, exposure to potentially ototoxic drugs or familial hearing loss 3.2 free sound field sound field where the boundaries of the room exert a negligible effect on the sound waves BSISO226:20031IS:622 O3002(E) 2 I SO 3002 All irhgts seredevr3.3 loudness level value in phons that has the
27、same numerical value as the sound pressure level in decibels of a reference sound, consisting of a frontally incident, sinusoidal plane progressive wave at a frequency of 1 000 Hz, which is judged as loud as the given sound 3.4 equal-loudness relationship curve or function expressing, for a pure ton
28、e of a given frequency, the relationship between its loudness level and its sound pressure level 3.5 equal-loudness-level contour curve in the sound pressure level/frequency plane connecting points whose coordinates represent pure tones judged to be equally loud 3.6 normal equal-loudness-level conto
29、ur equal-loudness-level contour that represents the average judgment of otologically normal persons within the age limits from 18 years to 25 years inclusive NOTE The method for deriving the normal equal-loudness-level contours is described in Annex C. 3.7 threshold of hearing level of a sound at wh
30、ich, under specified conditions, a person gives 50 % of correct detection responses on repeated trials 4 Formula for derivation of normal equal-loudness-level contours 4.1 Deriving sound pressure level from loudness level The sound pressure level L pof a pure tone of frequency f, which has a loudnes
31、s level L N , is given by: 10 lg dB 94 dB pfU f LAL = + (1) where N 9 10 0,025 3 4,47 10 (10 1 ,15) 0,4 10 f fU TL L f A + = + T fis the threshold of hearing; fis the exponent for loudness perception; L Uis a magnitude of the linear transfer function normalized at 1 000 Hz. These values are all give
32、n in Table 1. Equation (1) applies, at each frequency, for values from a lower limit of 20 phon to the following upper limits: 20 Hz to 4 000 Hz: 90 phon 5 000 Hz to 12 500 Hz: 80 phon BSISO226:20032IS:622 O3002(E) I SO 3002 All irhgts seredevr 3Equation (1) is only informative for loudness levels b
33、elow 20 phon because of the lack of experimental data between 20 phon and the hearing thresholds. The same holds for loudness levels above 90 phon up to 100 phon from 20 Hz to 1 000 Hz because data from only one institute are available at 100 phon. 4.2 Deriving loudness levels from sound pressure le
34、vels The loudness level L Nof a pure tone of frequency f, which has a sound pressure level L p , is given by: () N 40 lg phon 94 phon f LB = + (2) where 99 10 10 0,4 10 0,4 10 0,005 135 ff pU fU LL TL f B + = + and T f , fand L Uare the same as in 4.1. The same restrictions which apply to Equation (
35、1) also apply to Equation (2). Table 1 Parameters of Equation (1) used to calculate the normal equal-loudness-level contours Frequency, f Hz fL UdB T fdB 20 0,532 31,6 78,5 25 0,506 27,2 68,7 31,5 0,480 23,0 59,5 40 0,455 19,1 51,1 50 0,432 15,9 44,0 63 0,409 13,0 37,5 80 0,387 10,3 31,5 100 0,367 8
36、,1 26,5 125 0,349 6,2 22,1 160 0,330 4,5 17,9 200 0,315 3,1 14,4 250 0,301 2,0 11,4 315 0,288 1,1 8,6 400 0,276 0,4 6,2 500 0,267 0,0 4,4 630 0,259 0,3 3,0 800 0,253 0,5 2,2 1 000 0,250 0,0 2,4 BSISO226:20033IS:622 O3002(E) 4 I SO 3002 All irhgts seredevrTable 1 (continued) Frequency, f Hz fL UdB T
37、fdB 1 250 0,246 2,7 3,5 1 600 0,244 4,1 1,7 2 000 0,243 1,0 1,3 2 500 0,243 1,7 4,2 3 150 0,243 2,5 6,0 4 000 0,242 1,2 5,4 5 000 0,242 2,1 1,5 6 300 0,245 7,1 6,0 8 000 0,254 11,2 12,6 10 000 0,271 10,7 13,9 12 500 0,301 3,1 12,3 BSISO226:20034IS:622 O3002(E) I SO 3002 All irhgts seredevr 5Annex A
38、(normative) Normal equal-loudness-level contours for pure tones under free-field listening conditions NOTE 1 The hearing threshold under free-field listening condition, T f , is indicated by a dashed line. NOTE 2 The contour at 10 phon is drawn by dotted lines because of the lack of experimental dat
39、a between 20 phon and the hearing thresholds. Moreover, the 100-phon contour is also described by a dotted line because data from only one institute are available at this loudness level. Figure A.1 Normal equal-loudness-level contours for pure tones (binaural free-field listening, frontal incidence)
40、 BSISO226:20035IS:622 O3002(E) 6 I SO 3002 All irhgts seredevrAnnex B (normative) Tables for normal equal-loudness-level contours for pure tones under free-field listening conditions Table B.1 Sound pressure level corresponding to a given loudness level of pure tones ranging in frequency from 20 Hz
41、to 12 500 Hz Sound pressure level, dB Frequency, Hz Loudness level phon 20 25 31,5 40 50 63 80 100 125 160 10 (83,8) (75,8) (68,2) (61,1) (55,0) (49,0) (43,2) (38,1) (33,5) (28,8) 20 89,6 82,7 76,0 69,6 64,0 58,6 53,2 48,4 43,9 39,4 30 94,8 88,5 82,4 76,5 71,3 66,2 61,2 56,8 52,6 48,4 40 99,9 93,9 8
42、8,2 82,6 77,8 73,1 68,5 64,4 60,6 56,7 50 104,7 99,1 93,7 88,5 84,0 79,6 75,4 71,6 68,2 64,7 60 109,5 104,2 99,1 94,2 90,0 85,9 82,1 78,7 75,6 72,5 70 114,3 109,2 104,4 99,8 95,9 92,2 88,6 85,6 82,9 80,2 80 119,0 114,2 109,6 105,3 101,7 98,4 95,2 92,5 90,1 87,8 90 123,7 119,2 114,9 110,9 107,5 104,5
43、 101,7 99,3 97,3 95,4 100 (128,4) (124,2) (120,1) (116,4) (113,4) (110,6) (108,2) (106,2) (104,5) (103,0) Table B.1 (continued) Sound pressure level, dB Frequency, Hz Loudness level phon 200 250 315 400 500 630 800 1 000 1 250 1 600 10 (24,8) (21,3) (18,1) (15,1) (13,0) (11,2) (10,0) 10,0 (11,3) (10
44、,4) 20 35,5 32,0 28,7 25,7 23,4 21,5 20,1 20,0 21,5 21,4 30 44,8 41,5 38,4 35,5 33,4 31,5 30,1 30,0 31,6 32,0 40 53,4 50,4 47,6 45,0 43,1 41,3 40,1 40,0 41,8 42,5 50 61,7 59,0 56,5 54,3 52,6 51,1 50,0 50,0 52,0 52,9 60 69,9 67,5 65,4 63,5 62,1 60,8 59,9 60,0 62,2 63,2 70 77,9 75,9 74,2 72,6 71,5 70,
45、5 69,8 70,0 72,3 73,5 80 85,9 84,3 82,9 81,7 80,9 80,2 79,7 80,0 82,5 83,7 90 93,9 92,6 91,6 90,8 90,2 89,8 89,6 90,0 92,6 94,0 100 (101,8) (101,0) (100,3) (99,8) (99,6) (99,5) (99,4) 100,0 BSISO226:20036IS:622 O3002(E) I SO 3002 All irhgts seredevr 7Table B.1 (continued) Sound pressure level, dB Fr
46、equency, Hz Loudness level phon 2 000 2 500 3 150 4 000 5 000 6 300 8 000 10 000 12 500 10 (7,3) (4,5) (3,0) (3,8) (7,5) (14,3) (21,0) (23,4) (22,3) 20 18,2 15,4 14,3 15,1 18,6 25,0 31,5 34,4 33,0 30 28,8 26,0 25,0 26,0 29,4 35,5 41,7 44,6 42,5 40 39,2 36,5 35,6 36,6 40,0 45,8 51,8 54,3 51,5 50 49,6
47、 46,9 46,1 47,1 50,5 56,1 61,8 63,8 60,1 60 60,0 57,3 56,4 57,6 60,9 66,4 71,7 73,2 68,6 70 70,3 67,6 66,8 68,0 71,3 76,6 81,5 82,5 77,0 80 80,6 77,9 77,1 78,3 81,6 86,8 91,4 91,7 85,4 90 90,9 88,2 87,4 88,7 100 NOTE Values in brackets are for information only. Table B.2 Loudness levels correspondin
48、g to a given sound pressure level of pure tones ranging in frequency from 20 Hz to 12 500 Hz Loudness level, phon Frequency, Hz Sound pressure level dB 20 25 31,5 40 50 63 80 100 125 160 0 10 20 30 (4,3) (7,3) (11,1) 40 (7,5) (11,6) (16,0) 20,7 50 (6,0) (10,9) (16,5) 21,9 26,9 31,9 60 (8,9) (15,2) 21,8 28,4 34,2 39,3 44,1 70 (12,1) 20,6 28,2 35,5 42,2 47,8 52,5 56,8 80 (4,4) (15,9) 26,2 35,7 43,6 50,7 57,0 62,0 66,1 69,8 90 20,8 32,7 43,3 52,7 60,1 66,5 72,1 76
