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1、BRITISH STANDARD BS EN ISO 389-7:1998 Acoustics Reference zero for the calibration of audiometric equipment Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions The European Standard EN ISO 389-7:1998 has the status of a British Standard ICS 13.140 Licensed
2、Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 389-7:1998 This British Standard, having been prepared under the direction of the Health and Environment Sector Board, was published under the authority of the Standards Board and comes into e
3、ffect on 15 April 1998 BSI 05-1999 ISBN 0 580 29805 1 National foreword This British Standard is the English language version of EN ISO 389-7:1998. It is identical with ISO 389-7:1996. The UK participation in its preparation was entrusted by Technical Committee EH/1, Acoustics, to Subcommittee EH/1/
4、1, Hearing, which has the responsibility to: 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 developments and
5、 promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications wi
6、th their corresponding European publications. The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index“, or by using the “Find” facili
7、ty of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligati
8、ons. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN ISO title page, page 2, the ISO title page, page ii, pages 1 to 10 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be i
9、ndicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 389-7:1998 BSI 05-1999i Contents Page National forewordInside front
10、 cover Foreword2 Forewordii Text of ISO 389-71 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPE
11、NNE EUROPISCHE NORM EN ISO 389-7 January 1998 ICS 13.140 Descriptors: See ISO document English version Acoustics Reference zero for the calibration of audiometric equipment Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions (ISO 389-7:1996) Acoustique Zro
12、de rfrence pour ltalonnage dquipements audiomtriques Partie 7: Niveau liminaire de rfrence dans des conditions dcoute en champ libre et en champ diffus (ISO 389-7:1996) Akustik Standard-Bezugspegel fr die Kalibrierung von audiometrischen Gerten Teil 7: Bezugshrschwellen unter Freifeld- und Diffusfel
13、dbedingungen (ISO 389-7:1996) This European Standard was approved by CEN on 30 November 1997. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-dat
14、e lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the
15、responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg
16、, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any
17、 means reserved worldwide for CEN national Members. Ref. No. EN ISO 389-7:1998 E Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 389-7:1998 BSI 05-1999 2 Foreword The text of the International Standard from Technical Committee ISO/TC
18、43 “Acoustics” of the International Organization for Standardization (ISO) has been taken over as an European Standard by Technical Committee CEN/TC 211 “Acoustics”, the secretariat of which is held by DS. This European Standard shall be given the status of a national standard, either by publication
19、 of an identical text or by endorsement, at the latest by July 1998, and conflicting national standards shall be withdrawn at the latest by July 1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this Europe
20、an Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard ISO 389-7:1996 has been approved
21、by CEN as a European Standard without any modification. NOTENormative references to International Standards are listed in Annex ZA (normative). Contents Page Foreword2 Introduction1 1Scope1 2Normative References2 3Definitions2 4Specification2 Annex A (informative) Notes on the derivation of the refe
22、rence thresholds of hearing5 Annex B (informative) Bibliography9 Annex ZA (normative) Normative references to international publications with their relevant European publications10 Figure 1 Reference thresholds of hearing for pure tones under binaural free-field listening conditions (frontal inciden
23、ce) and for one-third-octave bands of noise under binaural diffuse-field listening conditions4 Figure A.1 Experimental data used for the derivation of the reference thresholds of hearing under free-field listening conditions and the calculated curve giving best fit to these data5 Figure A.2 Experime
24、ntal data used for the derivation of %L as specified in Table 1 and the calculated curve giving best fit to these data8 Table 1 Reference thresholds of hearing for the listening conditions listed in clause 1 and differences between sound pressure levels in the two types of a sound field for threshol
25、d of hearing3 Table A.1 Investigations of reference thresholds of hearing under free-field listening conditions6 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006,
26、Uncontrolled Copy, (c) BSI EN ISO 389-7:1998 ii BSI 05-1999 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 commit
27、tees. 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 In
28、ternational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International 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 membe
29、r bodies casting a vote. International Standard ISO 389-7 was prepared by Technical Committee ISO/TC 43, Acoustics. This first edition of ISO 389-7 constitutes a partial revision of ISO 266:1987 with respect to the threshold of hearing for pure tones under free-field listening conditions Tf ISO 226:
30、1987, Table 1 (column 4) and Annex A (MAF-curve), the threshold of hearing for one-third-octave noise bands under diffuse-field listening conditions Tf ISO 226:1987, Table 4 (column 3), and the difference between these thresholds, %L ISO 226:1987, Table 4 (column 2). The equal-loudness level contour
31、s contained in ISO 226 are at present under revision within ISO/TC 43 and are not covered by this part of ISO 389. ISO 389 consists of the following pads, under the general title Acoustics Reference zero for the calibration of audiometric equipment: Part 1: Reference equivalent threshold sound press
32、ure levels for pure tones and supra-aural earphone; Part 2: Reference equivalent threshold sound pressure levels for pure tones and insert earphones; Part 3: Reference equivalent threshold force levels for pure tones and bone vibrators; Part 4: Reference levels for narrow-band masking noise; Part 5:
33、 Reference equivalent threshold sound pressure levels for pure tones in the frequency range 8 kHz to 16 kHz; Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions. Part 1 will be a re-issue of ISO 389:1991. Annex A and Annex B of this part of ISO 389 are for
34、information only. Descriptors: Acoustics, audiometry, audiometers, calibration, auditory threshold; reference data. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:55:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 389-7:1998 BSI 05-19991 Introduction Each part of ISO 389 specifies a
35、specific reference zero for the calibration of audiometric equipment. ISO 389:1991 (to be re-issued as ISO 389-1) and ISO 389-2 are applicable to audiometric equipment for the transmission of pure tones by means of supra-aural or insert earphones, respectively. Corresponding audiometric test methods
36、 are specified in ISO 8253-1. In some audiological applications it may, however, be desirable to deliver the test signals by means of loudspeakers, either in a free sound field or in a diffuse sound field. Corresponding audiometric test methods are specified in ISO 8253-2. This part of ISO 389 speci
37、fies the reference zero for the calibration of audiometric equipment used for sound field audiometry. In common with other subjective phenomena, the threshold of hearing varies in detail from person to person but, for a group of otologically normal persons within a restricted age range, values for t
38、he central tendency can be determined to characterize the group. This and other parts of ISO 389 specify threshold data applicable to otologically normal persons in the age range from 18 to 25 years. Compared with ISO 226, a more stringent age criterion has been applied in order to define a populati
39、on as homogeneous as practicable with respect to the relationship between the threshold of hearing and age. The data specified in this part of ISO 389 relate to a) pure tones heard under conditions of binaural listening in free progressive plane waves with the subject directly facing the source of s
40、ound (frontal incidence), and with the sound pressure level measured in the free progressive wave at the centre position of the listeners head with the listener absent; b) one-third-octave bands of (white or pink) noise heard under conditions of binaural listening in a diffuse sound field with the s
41、ound pressure level measured in the sound field at the centre position of the listeners head with the listener absent. For frequencies up to 8 kHz, each set of data may be equally applied to any other bands of (white or pink) noise for which the bandwidth is less than the critical bandwidth. The dat
42、a are based on an assessment of technical information provided by laboratories in different countries representing the most reliable data available at the time. For information, a note on the derivation of the reference values and the origin of the data is given in Annex A and a bibliography is give
43、n in Annex B. 1 Scope This part of ISO 389 specifies a reference threshold of hearing for the calibration of audiometric equipment used under the following conditions. a) The sound field in the absence of the listener consists of either a free progressive plane wave (free field) or a diffuse sound f
44、ield. In the case of a free progressive plane wave, the source of sound is directly in front of the listener (frontal incidence). NOTE 1Correction values for the threshold of hearing under free-field listening conditions and selected angles of sound incidence deviating from frontal incidence are giv
45、en in ISO 8253-2 for information. b) The sound signals are pure (sinusoidal) tones in the case of free-field conditions, and one-third-octave band of (white or pink) noise in the case of diffuse-field conditions. c) The sound pressure level is measured in the absence of the listener at the position
46、where the centre of the listeners head would be. d) Listening is binaural. e) The sound pressure levels corresponding to the reference threshold of hearing are determined by the median value of the thresholds of an adequately large group of listeners. f) The listeners are otologically normal persons
47、 in the age range from 18 to 25 years inclusive. NOTE 2The data given in this part of ISO 389 have been derived from listeners who have hearing threshold levels of 10 dB or less according to ISO 389:1991. This selection criterion is not identical with that used when data for ISO 389:1991 were derive
48、d. g) The threshold of hearing is determined by means of the bracketing or ascending method, as specified in ISO 8253-1. The data are given in numerical form for the preferred frequencies in the one-third-octave series from 20 Hz to 16 000 Hz inclusive, in accordance with ISO 266 and for intermediat
49、e audiometric frequencies. Figure 1 gives a graphical presentation. It should be emphasized that the threshold data differ from the audiometric zero specified in ISO 389:1991 and ISO 389-2, since the latter refer to monaural listening through earphones with sound pressure levels referred to specified couplers and ear simulators. Direct comparison between the data in ISO 389:1991 or ISO 389-2, respectively, and in this part of ISO 389 is therefore not appropriate. Licensed Copy: sheffieldun sheffieldun, na,
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