1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationElectroacoustics Measurement microphonesPart 8: Methods for free-field calibration of working standard microphones by comparisonBS EN 61094-8:2012Copyright European Committee for
2、 Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-National forewordThis British Standard is the UK implementation of EN 61094-8:2012. It is identical to IEC 61094-8:2012.The UK participation
3、in its preparation was entrusted to Technical Committee EPL/29, Electroacoustics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its co
4、rrect application. The British Standards Institution 2012.Published by BSI Standards Limited 2012 ISBN 978 0 580 77250 4 ICS 17.140.50Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and S
5、trategy Committee on 31 January 2013.Amendments issued since publicationDate Text affectedBRITISH STANDARDBS EN 61094-8:2012Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without licens
6、e from IHS-,-,-EUROPEAN STANDARD EN 61094-8 NORME EUROPENNE EUROPISCHE NORM November 2012 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Bru
7、ssels 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61094-8:2012 E ICS 17.140.50 English version Electroacoustics - Measurement microphones - Part 8: Methods for free-field calibration of working standard microphones by com
8、parison (IEC 61094-8:2012) Electroacoustique - Microphones de mesure - Partie 8: Mthodes pour ltalonnage en champ libre par comparaison des microphones talons de travail (CEI 61094-8:2012) Elektroakustik - Messmikrofone - Teil 8: Verfahren zur Ermittlung des Freifeld-bertragungskoeffizienten von Geb
9、rauchs-Normalmikrofonen nach der Vergleichsmethode (IEC 61094-8:2012) This European Standard was approved by CENELEC on 2012-10-24. 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
10、standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained 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 vers
11、ion in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria,
12、 Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
13、 Turkey and the United Kingdom. BS EN 61094-8:2012Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN 61094-8:2012 - 2 - Foreword The text of document 29/752/
14、CDV, future edition 1 of IEC 61094-8, prepared by IEC/TC 29 “IEC TC 29, Electroacoustics“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61094-8:2012. The following dates are fixed: latest date by which the document has to be implemented at national level by publication
15、 of an identical national standard or by endorsement (dop) 2013-07-24 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2015-10-24 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
16、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 61094-8:2012 was approved by CENELEC as a European Standard without any modification. BS EN 61094-8:2012Copyright European Committee for Elect
17、rotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- 3 - EN 61094-8:2012 Annex ZA (normative) Normative references to international publications with their corresponding European publications The fol
18、lowing 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 amendments) applies. NOTE When an i
19、nternational publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 61094-1 - Measurement microphones - Part 1: Specifications for laboratory standard microphones EN 61094-1 - IEC 61094-2 - Electroacoustics - Measu
20、rement microphones - Part 2: Primary method for the pressure calibration of laboratory standard microphones by the reciprocity technique EN 61094-2 - IEC 61094-3 - Measurement microphones - Part 3: Primary method for free-field calibration of laboratory standard microphones by the reciprocity techni
21、que EN 61094-3 - IEC 61094-4 - Measurement microphones - Part 4: Specifications for working standard microphones EN 61094-4 - IEC 61094-5 - Measurement microphones - Part 5: Methods for pressure calibration of working standard microphones by comparison EN 61094-5 - IEC 61094-6 - Measurement micropho
22、nes - Part 6: Electrostatic actuators for determination of frequency response EN 61094-6 - IEC/TS 61094-7 - Measurement microphones - Part 7: Values for the difference between free-field and pressure sensitivity levels of laboratory standard microphones - - ISO/IEC Guide 98-3 - Uncertainty of measur
23、ement - Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) - - ISO 26101 - Acoustics - Test methods for the qualification of free-field environments - - BS EN 61094-8:2012Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELE
24、CNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- 2 61094-8 IEC:2012 CONTENTS 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 7 4 Reference environmental conditions . 8 5 Principles of free-field calibration by comparison 8 5.1 General principle .
25、8 5.2 General principles using sequential excitation . 8 5.3 General principles using simultaneous excitation . 8 6 General requirements . 9 6.1 The test space . 9 6.2 Methods of establishing the free-field 9 6.2.1 General . 9 6.2.2 Using a test space with sound absorbing surfaces . 9 6.2.3 Time sel
26、ective methods for obtaining the free-field sensitivity 10 6.3 The sound source 10 6.4 Reference microphone 11 6.5 Monitor microphone . 12 6.6 Test signals . 12 6.7 Configuration for the reference microphone and microphone under test 13 7 Factors influencing the free-field sensitivity 13 7.1 General
27、 . 13 7.2 Polarizing voltage 13 7.3 Acoustic centre of the microphone . 13 7.4 Angle of incidence and alignment with the sound source . 14 7.5 Mounting configuration 14 7.6 Dependence on environmental conditions 14 8 Calibration uncertainty components 14 8.1 General . 14 8.2 Sensitivity of the refer
28、ence microphone . 15 8.3 Measurement of the microphone output . 15 8.4 Differences between the sound pressure applied to the reference microphone and to the microphone under test . 15 8.5 Influence of indirect sound 15 8.6 Influence of signal processing . 16 8.7 Influence of microphone characteristi
29、cs and measurement system performance 16 8.7.1 Microphone capacitance 16 8.7.2 Measurement system non-linearity 16 8.7.3 Validation of calibration system . 16 8.8 Uncertainty on free-field sensitivity level 16 Annex A (informative) Basic substitution calibration in a free-field chamber . 18 Annex B
30、(informative) Time selective techniques . 22 Bibliography 30 BS EN 61094-8:2012Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-61094-8 IEC:2012 3 Figure A.1
31、Illustration of source and receiver setup in a free-field room, where the monitor microphone has been integrated into the loudspeaker 18 Figure A.2 Practical implementation in a hemi-anechoic room with a source flush-mounted in the floor 19 Figure A.3 Examples of loudspeaker sources . 21 Figure B.1
32、Illustration of set-up for measurement with time selective techniques 23 Table 1 Calibration options for the reference microphone and associated typical measurement uncertainty 12 Table 2 Typical uncertainty components 17 BS EN 61094-8:2012Copyright European Committee for Electrotechnical Standardiz
33、ation Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- 6 61094-8 IEC:2012 MEASUREMENT MICROPHONES Part 8: Methods for determining the free-field sensitivity of working standard microphones by comparison 1 Scope This part of
34、 the IEC 61094 series is applicable to working standard microphones meeting the requirements of IEC 61094-4. It describes methods of determining the free-field sensitivity by comparison with a laboratory standard microphone or working standard microphone (where applicable) that has been calibrated a
35、ccording to either: IEC 61094-3, IEC 61094-2 or IEC 61094-5, and where factors given in IEC/TS 61094-7 have been applied, IEC 61094-6, this part of IEC 61094. Methods performed in an acoustical environment that is a good approximation to an ideal free-field (e.g. a high quality free-field chamber),
36、and methods that use post processing of results to minimise the effect of imperfections in the acoustical environment, to simulate free-field conditions, are both covered by this part of IEC 61094. Comparison methods based on the principles described in IEC 61094-3 are also possible but beyond the s
37、cope of this part of IEC 61094. NOTE 1 This part of IEC 61094 is also applicable to laboratory standard microphones meeting the requirements of IEC 61094-1, noting that these microphones also meet the electroacoustic specifications for working standard microphones. NOTE 2 This part of IEC 61094 is a
38、lso applicable to combinations of microphone and preamplifier where the determined sensitivity is referred to the unloaded output voltage of the preamplifier. NOTE 3 Other devices, for example, sound level meters can be calibrated using the principles of this part of IEC 61094, but are not within th
39、e scope of this standard. 2 Normative references 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 doc
40、ument (including any amendments) applies. IEC 61094-1, Measurement microphones Part 1: Specifications for laboratory standard microphones IEC 61094-2, Electroacoustics Measurement microphones Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity techni
41、que IEC 61094-3, Measurement microphones Part 3: Primary method for free-field calibration of laboratory standard microphones by the reciprocity technique IEC 61094-4, Measurement microphones Part 4: Specifications for working standard microphones BS EN 61094-8:2012Copyright European Committee for E
42、lectrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-61094-8 IEC:2012 7 IEC 61094-5, Measurement microphones Part 5: Methods for pressure calibration of working standard microphones by comparison
43、IEC 61094-6, Measurement microphones Part 6: Electrostatic actuators for determination of frequency response IEC/TS 61094-7, Measurement microphones Part 7: Values for the difference between free-field and pressure sensitivity levels of laboratory standard microphones ISO/IEC Guide 98-3, Uncertainty
44、 of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) ISO 26101, Acoustics Test methods for the qualification of free-field environments 3 Terms and definitions For the purpose of this document, the terms and definitions given in IEC 61094-1 and IEC 61094-3, as wel
45、l as the following apply. 3.1 reference microphone laboratory standard microphone or working standard microphone where the free-field sensitivity has been previously determined 3.2 microphone under test device under test working standard microphone to be calibrated by comparison with a reference mic
46、rophone Note 1 to entry: Other devices, for example, sound level meters, can be calibrated using the principles of this part of IEC 61094, but are not within the scope of this standard. 3.3 monitor microphone microphone used to detect changes in sound pressure in the test environment 3.4 microphone
47、reference point point specified on the microphone or close to it, to describe the position of the microphone Note 1 to entry: The microphone reference point may be at the centre of the diaphragm of the microphone. 3.5 reference direction inward direction toward the microphone reference point and spe
48、cified for determining the acoustical response and directional response Note 1 to entry: The reference direction may be specified with respect to an axis of symmetry. 3.6 angle of incidence angle between the reference direction and a line between the acoustic centre of a sound source and the microphone reference point Note 1 to entry: Angle of incidence is expressed in degrees. BS EN 61094-8:2012Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without
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