EN 60318-3-2015 en Electroacoustics - Simulators of human head and ear - Part 3 Acoustic coupler for the calibration of supra-aural earphones used in audiometry.pdf

1、BSI Standards PublicationElectroacoustics Simulators of human head and earPart 3: Acoustic coupler for the calibration of supra-aural earphones used in audiometryBS EN 60318-3:2015National forewordThis British Standard is the UK implementation of EN 60318-3:2015. It is identical to IEC 60318-3:2014.

2、 It supersedes BS EN 60318-3:1998 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee EPL/29, Electroacoustics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all

3、the necessary provisions ofa contract. Users are responsible for its correct application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 79115 4ICS 13.140; 17.140.50Compliance with a British Standard cannot confer immunity fromlegal obligations.This Brit

4、ish Standard was published under the authority of theStandards Policy and Strategy Committee on 28 February 2015.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN 60318-3:2015EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60318-3 February 2015 ICS 17.140.50

5、Supersedes EN 60318-3:1998 English Version Electroacoustics - Simulators of human head and ear - Part 3: Acoustic coupler for the calibration of supra-aural earphones used in audiometry (IEC 60318-3:2014) lectroacoustique - Simulateurs de tte et doreille humaines - Partie 3: Coupleur acoustique pour

6、 ltalonnage des couteurs supra-auraux utiliss en audiomtrie (IEC 60318-3:2014) Akustik - Simulatoren des menschlichen Kopfes und Ohres - Teil 3: Akustischer Kuppler zur Kalibrierung von supra-auralen Audiometrie-Kopfhrern (IEC 60318-3:2014) This European Standard was approved by CENELEC on 2015-01-1

7、5. CENELEC 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-date lists and bibliographical references concerning such national standards may be obtain

8、ed on application to the CEN-CENELEC Management Centre or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to

9、the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,

10、Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotec

11、hnique Europisches Komitee fr Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members. Ref. No. EN 60318-3:2015 E BS EN 60318-3:2015EN 60318-3:2015 - 2 - For

12、eword The text of document 29/796/CDV, future edition 2 of IEC 60318-3, prepared by IEC TC 29, Electroacoustics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60318-3:2015. The following dates are fixed: latest date by which the document has to be implemented at na

13、tional level by publication of an identical national standard or by endorsement (dop) 2015-10-15 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2018-01-15 This document supersedes EN 60318-3:1998. Attention is drawn to the possibility that some o

14、f the elements of this document may be the subject of patent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 60318-3:2014 was approved by CENELEC as a European Standard without any m

15、odification. In the official version, for Bibliography, the following note has to be added for the standard indicated : IEC 61094-4 NOTE Harmonised as EN 61094-4. BS EN 60318-3:2015- 3 - EN 60318-3:2015 Annex ZA (normative) Normative references to international publications with their corresponding

16、European publications The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendm

17、ents) applies. NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu. Publication Year T

18、itle EN/HD Year IEC 61094-1 - Measurement microphones - Part 1: Specifications for laboratory standard microphones EN 61094-1 - ISO/IEC Guide 98-3 - Uncertainty of measurement - Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) - - BS EN 60318-3:2015 2 IEC 60318-3:2014 IEC 201

19、4 CONTENTS 1 Scope 5 2 Normative references 5 3 Terms and definitions 5 4 Construction 5 4.1 General . 5 4.2 Cavity dimensions . 6 4.3 Static pressure equalization 8 4.4 Calibrated pressure type microphone 8 5 Coupling of earphone to acoustic coupler 9 6 Calibration . 9 6.1 Reference environmental c

20、onditions . 9 6.2 Method of calibration 10 7 Maximum permitted uncertainty of measurements . 10 Bibliography 12 Figure 1 Dimensions of acoustic coupler 7 Figure 2 Coupling of earphone to coupler. 9 Table 1 Height of the coupler as a function of the acoustic volume of the microphone 8 Table 2 Values

21、of maximum permitted uncertainties Umaxfor a level of confidence of approximately 95 % 11 BS EN 60318-3:2015IEC 60318-3:2014 IEC 2014 5 ELECTROACOUSTICS SIMULATORS OF HUMAN HEAD AND EAR Part 3: Acoustic coupler for the calibration of supra-aural earphones used in audiometry 1 Scope This part of IEC

22、60318 specifies an acoustic coupler for the measurement of supra-aural audiometric earphones in the frequency range from 125 Hz to 8 000 Hz. The sound pressure developed by an earphone is not, in general, the same in the coupler as in a persons ear. However, the acoustic coupler can be used as an ob

23、jective and reproducible means of measuring the output of supra-aural earphones. It can be used for specifying reference equivalent threshold sound pressure levels (RETSPL) for the calibration of audiometers. 2 Normative references The following documents, in whole or in part, are normatively refere

24、nced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 61094-1, Measurement microphones Part 1: Specifications for laboratory

25、standard microphones ISO/IEC Guide 98-3, Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) 3 Terms and definitions For the purpose of this document, the following definition applies: 3.1 acoustic coupler device for measuring the acoustic output of so

26、und sources where the sound pressure is measured by a calibrated microphone coupled to the source by a cavity of predetermined shape and volume which does not necessarily approximate the acoustical impedance of the normal human ear 4 Construction 4.1 General The coupler consists essentially of a cyl

27、indrical cavity whose acoustic transfer impedance is determined by the volume of air in the cavity and its dimensions (see 4.2). A microphone with a diaphragm having high acoustic impedance is located in the base of the cylindrical cavity. The coupler shall be made of a material that has no negative

28、 influences on its performance. For example it should be acoustically hard and dimensionally stable. The general construction BS EN 60318-3:2015 6 IEC 60318-3:2014 IEC 2014 of the coupler and mounting of the microphone shall aim to reduce the response to vibration of any earphone or to sound outside

29、 the cavity. In the following, the specified tolerance shall be reduced by an amount equal to the actual expanded measurement uncertainty of the test laboratory before deciding if a device conforms to this specification. 4.2 Cavity dimensions The critical dimensions (see Figure 1) of the coupler are

30、 those that determine the shape and volume of the cavity terminated by the microphone, the static pressure equalization mechanism, the upper edge (lip) and the 45 angle. The effective acoustic volume of the coupler shall be 5 780 mm3 130 mm3. The diameter d1shall be 23,825 mm 0,080 mm. Diameter d2sh

31、all be 18,55 mm 0,16 mm. The height l2shall be 1,950 mm 0,065 mm. The angle defining the slope of the external part of the coupler shall be 45 5,5. The height h of the coupler shall be calculated according to the following formula: 212eq141dVVV= h(1) where V1is the effective acoustic volume; Veqis t

32、he equivalent acoustic volume of the microphone; V2is the volume of the front cavity of the microphone, given by 222241ldV = (2) It is recommended that a value of h be selected from Table 1, according to the value of the equivalent acoustic volume of the microphone. NOTE 1 It is recognized that cert

33、ain combinations of coupler cavity and microphone could cause problems if the tolerance of the coupler diameter is exploited towards the smallest allowed diameter and at the same time, the tolerance of the microphone diameter is exploited towards the largest allowed diameter. Practical experience ho

34、wever, has proven that those problems are very unlikely to occur. BS EN 60318-3:2015IEC 60318-3:2014 IEC 2014 7 Dimension Specification mm A 73 B 57,2 C 25,27 d123,825 d218,55 l21,95 h See 4.2, Equation.(1), Table 1 H 7,5 Angle In degrees Y 25 45 25 The dimensions printed in bold are the critical di

35、mensions that determine the shape and volume of the cavity terminated by the microphone, the capillary leak, the upper edge (lip) and the 45 angle, see 4.2 Key 1 hole for thermometer 2 microphone 3 ground shield 4 contact pin 5 venting mechanism, see 4.3. Figure 1 Dimensions of acoustic coupler IEC

36、BS EN 60318-3:2015 8 IEC 60318-3:2014 IEC 2014 Table 1 Height of the coupler as a function of the acoustic volume of the microphone Equivalent acoustic volume of the microphone mm3Height of the coupler mm 0 Veq 50 11,72 0,15 50 Veq 100 11,62 0,15 100 Veq 150 11,50 0,15 150 Veq 200 11,39 0,15 NOTE 2

37、If the coupler described in this standard is constructed with a fixed value of h + l2= 13,41 mm regardless of the equivalent volume of the microphone, then the coupler will be identical with the NBS 9A coupler, see 11. The nominal effective acoustic volume of the type 9A coupler is: V1= Veq+ 5 640 m

38、m34.3 Static pressure equalization Any change in the static pressure within the cavity caused by assembly of the earphone to the coupler and microphone shall decay toward the static ambient pressure with a time constant of less than 1,5 s. If this necessitates the introduction of a controlled leak i

39、n the coupler, it shall have the following characteristics. a) It shall not alter the cavity volume by more than 20 mm3; b) It shall attenuate external sound reaching the cavity, with the entrance of the cavity blocked, by at least 16 dB at 100 Hz, increasing by 6 dB per octave for increasing freque

40、ncy. NOTE Equalization can be realized, for example, by a capillary tube with a diameter of 0,6 mm 0,05 mm containing a wire with a diameter of 0,4 mm 0,05 mm. 4.4 Calibrated pressure type microphone The overall pressure sensitivity level of the microphone and associated measuring system (e.g. pream

41、plifier) over the specified frequency range shall be known with a maximum measurement uncertainty not exceeding 0,2 dB for a level of confidence of 95 %. The internal shape of the base of the coupler shall correspond to that of the laboratory standard (LS) configuration specified in IEC 61094-1. NOT

42、E A WS1P microphone conforming to IEC 61094-4 2, without protective grid but with a coupler ring that converts the microphone to an LS1P configuration can be used. WS2P microphones conforming to IEC 61094-4 2 can also be used, provided that the LS1 configuration and the stipulated volume are preserv

43、ed, for example by using an adaptor. The microphone used shall have a high acoustic impedance, the equivalent acoustic volume being less than 200 mm3at frequencies between 125 Hz and 8 000 Hz. The manufacturer of the microphone shall state the equivalent acoustic volume. If it is necessary to use a

44、microphone for which the diameter of the free part of the diaphragm is less than the diameter of the coupler cavity, the axes of the microphone and the cylindrical cavity shall coincide The microphone to be used shall be stated by the manufacturer. There shall be an effective seal between the couple

45、r and the microphone. However, any obstruction in the static pressure equalization device of the microphone shall be avoided. _ 1Numbers in square brackets refer to the Bibliography. BS EN 60318-3:2015IEC 60318-3:2014 IEC 2014 9 5 Coupling of earphone to acoustic coupler The earphone to be calibrate

46、d shall be applied to the acoustic coupler without acoustic leakage with a force 4,5 N 0,5 N, not including the weight of the earphone itself (see Figure 2). If, for a specific earphone, a different coupling force is specified this shall be stated. The earphone shall not rest on the sloping side of

47、the acoustic coupler, but only on the upper edge (or lip, see Figure 2). In the case of earphones with a hard earcap, a thin film of sealing material or thin soft rubber ring should be used on the lip in order to produce an effective seal between the earphone and the upper edge of the coupler. NOTE

48、With some earphones, a special adapter can be used for coupling the earphone to the coupler, e.g. see 3. Key 1 coupling force between 4 N and 5 N 2 earphone 3 lip 4 coupler 5 microphone Figure 2 Coupling of earphone to coupler 6 Calibration 6.1 Reference environmental conditions The reference enviro

49、nmental conditions are the following: IEC BS EN 60318-3:2015 10 IEC 60318-3:2014 IEC 2014 static pressure: 101,325 kPa temperature: 23 C relative humidity: 50 % 6.2 Method of calibration The manufacturer shall provide in an instruction manual a method of calibration for the complete acoustic coupler including the microphone, and for determining stability. The quantity to be measured and the calibration method may vary