1、BRITISH STANDARD BS EN 61094-4:1996 IEC 1094-4: 1995 Specification for Measurement microphones Part 4: Specifications for working standard microphones The European Standard EN 61094-4:1995 has the status of a British Standard ICS 17.140.50;33.160.50BS EN61094-4:1996 This British Standard, having bee
2、n prepared under the directionof the Electrotechnical Sector Board,was published undertheauthority of the StandardsBoard and comes into effect on 15 July 1996 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference EPL/29 Draft for comment 94/202601 DC ISBN
3、0 580 25909 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EPL/29, Electroacoustics, upon which the following bodies were represented: British Association of Otolaryngologists British Hearing Aid Industry Association B
4、ritish Medical Association British Society of Audiology British Telecommunications plc Confederation of British Industry Department of Health Department of Trade and Industry (National Physical Laboratory) Health and Safety Executive Institute of Acoustics Institute of Sound and Vibration Research I
5、nstitution of Electrical Engineers Medical Research Council Ministry of Defence Royal Aeronautical Society Royal National Institute for Deaf people Society of Environmental Engineers University of Exeter Amendments issued since publication Amd. No. Date CommentsBS EN61094-4:1996 BSI 09-1999 i Conten
6、ts Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 61094-4 3 List of references Inside back coverBS EN61094-4:1996 ii BSI 09-1999 National foreword This British Standard has been prepared by Technical Committee EPL/29 and is the English language version ofEN
7、61094-4:1995, Measurement microphones Part 4: Specifications for working standard microphones, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical withIEC1094-4, first edition 1995. A British Standard does not purport to include all the necessary provi
8、sions 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 obligations. Cross-references Publication referred to Corresponding British Standard HD 556 S1:1991 (IEC 942:1988) BS 7189:1
9、989 Specification for sound calibrators BS EN 61094 Specification for measurement microphones EN 61094-1:1994 (IEC 1094-1:1992) Part 1:1995 Specifications for laboratory standard microphones EN 61094-2:1993 (IEC 1094-2:1992) Part 2:1994 Primary method for pressure calibration of laboratory standard
10、microphones by the reciprocity technique EN 61094-3:1995 (IEC 1094-3:1995) Part 3:1996 Primary method for free-field calibration of laboratory standard microphones by the reciprocity technique Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title
11、page, pages 2 to 12, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61094-4 December 1995
12、 ICS 17.140.50; 33.160.50 Descriptors: Electroacoustics, measuring instruments, microphones, definitions, classifications, standard measures, characteristics, specifications English version Measurement microphones Part 4: Specifications for working standard microphones (IEC 1094-4:1995) Microphones
13、de mesure Partie 4: Spcifications des microphones talons de travail (CEI 1094-4:1995) Memikrofone Teil 4: Anforderungen an Gebrauchs-Normalmikrofone (IEC 1094-4:1995) This European Standard was approved by CENELEC on 1995-11-28. CENELEC members are bound to comply with the CEN/CENELEC Internal Regul
14、ations 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 obtained on application to the Central Secretariat or to any CENELEC member. Thi
15、s 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 the Central Secretariat has the same status as the official versions. CENELEC member
16、s are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Euro
17、pen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1995 Copyright reserved to CENELEC members Ref. No. EN 61094-4:1995 EEN61094-4:1995 BSI 09-1999 2 Foreword The text of document 29/295/DIS, future edition1o
18、fIEC1094-4, prepared byIECTC 29, Electroacoustics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC asEN61094-4 on 1995-11-28. The following dates were fixed: Annexes designated “normative” are part of the body of the standard. Annexes designated “informative” are given for
19、 information only. In this standard,Annex ZA is normative andAnnex A is informative.Annex ZA has been added by CENELEC. Contents Page Foreword 2 1 Scope and object 3 2 Normative references 3 3 Definitions 3 3.1 Working standards microphone 3 3.2 Principal axis of a microphone 3 3.3 Reference plane o
20、f a microphone 3 3.4 Effective front volume of a microphone 3 3.5 Correction grid 3 4 Reference environmental conditions 4 5 Classification of working standard microphones 4 5.1 General 4 5.2 Type designation 4 6 Characteristics of working standard microphones 4 6.1 Sensitivity 4 6.2 Effective front
21、 volume 4 6.3 Upper limit of the dynamic range of a microphone 4 6.4 Linearity range of the microphone sensitivity level 4 6.5 Static pressure dependence of microphone sensitivity 5 6.6 Temperature dependence of microphone sensitivity 5 6.7 Humidity dependence of microphone sensitivity 5 6.8 Stabili
22、ty of microphone sensitivity 5 6.9 Pressure equalizing leakage 5 7 Specifications 5 7.1 Mechanical dimensions 5 7.2 Electroacoustical specifications 6 7.3 Identification markings 7 Annex A (informative) Provisional ground-shield reference configuration for type WS3 microphones 10 Annex ZA (normative
23、) Normative references tointernational publications with their correspondingEuropean publications 11 Figure 1 Mechanical configuration of microphones 6 Figure 2 Tolerance curves for frequency responseon a logarithmic frequency scale, where f 0 , f 1and f 2are specified in Table 2 7 Figure A.1 Mechan
24、ical attachment to microphone, showing the provisional ground-shield reference configuration for type WS3 microphones 10 Table 1 Nominal mechanical dimensions andtolerance limits for working standard microphones in Figure 1 6 Table 2 Electrocoustical specifications for workingstandard microphones 8
25、Table 3 Tolerance values for the frequency response (in details) 9 latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1996-09-01 latest date by which the national standards conflicting with the EN have to be wi
26、thdrawn (dow) 1996-09-01EN61094-4:1995 BSI 09-1999 3 1 Scope and object This part ofIEC1094 is applicable to working standard microphones. It specifies mechanical dimensions and certain electroacoustical characteristics for working standard microphones used in measuring systems for the determination
27、 of sound pressure to enable these microphones to be used as transfer standards in the calibration of acoustic measurement instruments. It establishes a system for classifying working standard microphones into a number of types according to their dimensions and properties in order to facilitate the
28、specification of measurement systems, the calibration of measuring systems and microphones by sound calibrators, and the interchangeability of microphones in given measuring and calibration systems. It does not specify the transduction principle by which working standard microphones operate. 2 Norma
29、tive references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part ofIEC1094. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on
30、 this part ofIEC1094 are encouraged to investigate the possibility of applying the most recent editions of the normative documents listed below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 942:1988, Sound calibrators. IEC 1094-1:1992, Measurement microph
31、ones Part 1: Specifications for laboratory standard microphones. IEC 1094-2:1992, Measurement microphones Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique. IEC/DIS 1094-3:199x, Measurement microphones Part 3: Primary method for free-fiel
32、d calibration of laboratory standard microphones by the reciprocity technique 1) . (revision of IEC 486) ANSI B1.1:1982, Unified inch screw threads 2) . ISO: 1993, Guide to the expression of uncertainty in measurement. 3 Definitions For the purpose of this part ofIEC1094, the following definitions a
33、pply in addition to the definitions given inIEC1094-1. 3.1 working standard microphone microphone capable of being calibrated by at least one of the following: a) a method specified inIEC1094-2 or IEC1094-3; b) by comparison with a calibrated laboratory standard microphone; c) by a sound calibrator
34、as specified inIEC942. a working standard microphone meets certain requirements on mechanical dimensions and electroacoustical characteristics, especially with respect to stability in time and dependence on environmental conditions 3.2 principal axis of a microphone line through the centre of and pe
35、rpendicular to the diaphragm of the microphone 3.3 reference plane of a microphone plane perpendicular to the principal axis immediately in front of the protection grid of the microphone 3.4 effective front volume of a microphone at reference conditions, the volume of air that has the same acoustic
36、compliance as the cavity bounded by the reference plane, the diaphragm and the outer cylindrical surface of the microphone at the reference plane, including the equivalent volume of the microphone configuration. The effective front volume is generally a function of frequency 3.5 correction grid spec
37、ially shaped grid, substituted for the normal protection grid of a microphone, for the purpose of changing the directivity response of the microphone, thereby changing the acoustical classification of the microphone 1) At present at the stage of draft International Standard (29/294/DIS). 2) Referenc
38、e is given to ANSI B1.1 in the absence of an equivalent International Standard.EN61094-4:1995 4 BSI 09-1999 4 Reference environmental conditions The reference environmental conditions are: NOTEThe reference temperature is chosen to be23,0 C because practical considerations require that most calibrat
39、ions be carried out at, or near, this temperature. 5 Classification of working standard microphones 5.1 General The sound pressure in a given sound field will generally depend on position and should ideally be measured at a point with a transducer of infinitesimally small dimensions and infinitely h
40、igh acoustic impedance. However, the finite dimensions and acoustic impedance of a real microphone, and the mounting of this microphone cause practical measurements of sound pressure to depart from this ideal. The effect of diffraction is accounted for by defining different sensitivities of a microp
41、hone each referring to idealized sound fields, for example pressure, free-field, and diffuse-field sensitivities. A microphone is usually so constructed that one of the above sensitivities is essentially independent of frequency in the widest possible frequency range. 5.2 Type designation Working st
42、andard microphones are described by a mnemonic system consisting of the letters WS (for Working Standard) followed by a number representing the mechanical configuration and a third letter representing the electroacoustical characteristic. The third letter may be P, F or D representing, respectively,
43、 microphones having a pressure, free-field or diffuse field sensitivity, which is approximately independent of frequency in the widest possible frequency range. The designation WS2P thus refers to a working standard microphone of mechanical configuration2having a nearly constant pressure sensitivity
44、 as a function of frequency. The type designation does not always prevent the use of these microphones under other conditions, such as pressure, free-field or diffuse field conditions after proper calibration. 6 Characteristics of working standard microphones 6.1 Sensitivity The sensitivity of the m
45、icrophone is the open-circuit sensitivity as defined inIEC1094-1. If the insert voltage technique is used to determine this sensitivity for type WS1 and WS2 microphones, the appropriate ground-shield reference configuration given inIEC1094-1 shall apply. For type WS3 the provisional ground-shield re
46、ference configuration given inAnnex A is recommended. NOTEIf the microphone is equipped with a protection grid, this will influence the free-field and diffuse field sensitivities. The manufacturer should state whether the sensitivity has been specified with or without grid. By definition, the pressu
47、re sensitivity of a microphone does not depend on the presence or absence of a protection grid. However, the sound pressure that is measured in a small cavity with a microphone is influenced by the microphone grid. 6.2 Effective front volume The effective front volume of the microphone is an importa
48、nt quantity when the microphone is calibrated with a sound calibrator see 4.2 item d) ofIEC942 and when used in small couplers such as ear simulators. The effective front volume shall be specified as a function of frequency in the frequency range from160Hz to1000Hz inclusive. NOTEMethods for determi
49、ning the effective front volume are given in clause E.2 of Annex E ofIEC1094-2 6.3 Upper limit of the dynamic range of a microphone The upper limit of the dynamic range shall be stated in terms of the sound pressure level which, throughout the frequency range from160Hz to1000Hz, results in a total harmonic distortion of3%. NOTEAt present no generally accepted measuring method exist for determining this upper limit at frequencies above1000Hz. 6.4 Linearity range of the microphone sensitivity level The sensitivity level of the microphone at refe
