SIST EN IEC 60268-4:2019

SLOVENSKI STANDARD
01-maj-2019
1DGRPHãþD
SIST EN 60268-4:2014
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Sound system equipment - Part 4: Microphones (IEC 60268-4:2018)
Elektroakustische Geräte - Teil 4: Mikrofone (IEC 60268-4:2018)
Equipements pour systèmes électroacoustiques - Partie 4: Microphones (IEC 60268-
4:2018)
Ta slovenski standard je istoveten z: EN IEC 60268-4:2018
ICS:
33.160.50 Pribor Accessories
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60268-4

NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2018
ICS 33.160.50 Supersedes EN 60268-4:2014
English Version
Sound system equipment - Part 4: Microphones
(IEC 60268-4:2018)
Equipements pour systèmes électroacoustiques - Partie 4: Elektroakustische Geräte - Teil 4: Mikrofone
Microphones (IEC 60268-4:2018)
(IEC 60268-4:2018)
This European Standard was approved by CENELEC on 2018-10-17. 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 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 version 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, 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, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60268-4:2018 E

European foreword
The text of document 100/2992/CDV, future edition 6 of IEC 60268-4, prepared by IEC/TC 100 "Audio,
video and multimedia systems and equipment" was submitted to the IEC-CENELEC parallel vote and
approved by CENELEC as EN IEC 60268-4:2018.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2019-07-17
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2021-10-17
document have to be withdrawn
This document supersedes EN 60268-4:2014.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice
The text of the International Standard IEC 60268-4:2018 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
CISPR 22:2008 NOTE Harmonized as EN 55022:2010 (modified)
IEC 60065:2014 NOTE Harmonized as EN 60065:2014 (modified)
IEC 60958-4:2016 (series) NOTE Harmonized as EN 60958-4:2016 (series)
IEC 61000-3-2:2014 NOTE Harmonized as EN 61000-3-2:2014 (not modified)
IEC 61000-3-3:2013 NOTE Harmonized as EN 61000-3-3:2013 (not modified)
IEC 61606 (series) NOTE Harmonized as EN 61606 (series)
IEC 61672-1:2013 NOTE Harmonized as EN 61672-1:2013 (not modified)

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
NOTE 1  Where 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 Title EN/HD Year
CISPR 35 (mod) 2016 Electromagnetic compatibility of multimedia EN 55035 2017
equipment - Immunity requirements
IEC 60268-1 1985 Sound system equipment. Part 1: General HD 483.1 S2 1989
+ A1 1988  - -
+ A2 1988  - -
IEC 60268-2 1987 Sound system equipment. Part 2: Explanation HD 483.2 S2 1993
of general terms and calculation methods
+ A1 1991  - -
IEC 60268-3 2013 Sound system equipment - Part 3: Amplifiers EN 60268-3 2013
IEC 60268-5 2003 Sound system equipment - Part 5: EN 60268-5 2003
Loudspeakers
+ A1 2007  + A1 2009
IEC 60268-11 1987 Sound system equipment. Part 11: Application HD 483.11 S3 1993
of connectors for the interconnection of sound
system components
+ A1 1989  - -
+ A2 1991  - -
IEC 60268-12 1987 Sound system equipment. Part 12: Application EN 60268-12 1995
of connectors for broadcast and similar use
+ A1 1991  - -
+ A2 1994  + A2 1995
IEC 61000-4-2 2008 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-2 2009
2: Testing and measurement techniques -
Electrostatic discharge immunity test
IEC 61000-4-3 2006 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-3 2006
3 : Testing and measurement techniques -
Radiated, radio-frequency, electromagnetic
field immunity test
+ A1 2007  + A1 2008
+ A2 2010  + A2 2010
IEC 61000-4-4 2012 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-4 2012
4: Testing and measurement techniques -
Electrical fast transient/burst immunity test
IEC 61000-4-6 2013 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-6 2014
6: Testing and measurement techniques -
Immunity to conducted disturbances, induced
by radio-frequency fields
IEC 61000-4-8 2009 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-8 2010
8: Testing and measurement techniques -
Power frequency magnetic field immunity test
IEC 61000-4-16 2015 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-16 2016
16: Testing and measurement techniques -
Test for immunity to conducted, common
mode disturbances in the frequency range 0
Hz to 150 kHz
IEC 61000-4-17 1999 Electromagnetic compatibility (EMC) - Part 4- EN 61000-4-17 1999
17: Testing and measurement techniques -
Ripple on d.c. input power port immunity test
+ A1 2001  + A1 2004
+ A2 2008  + A2 2009
IEC 61260-1 2014 Electroacoustics - Octave-band and fractional- EN 61260-1 2014
octave-band filters - Part 1: Specifications
IEC 61938 2013 Multimedia systems - Guide to the - -
recommended characteristics of analogue
interfaces to achieve interoperability
ITU-T -  Artificial mouth - -
Recommendation
P.51
EN 55103-2 2009 Electromagnetic compatibility - Product family EN 55103-2 2009
standard for audio, video, audio-visual and
entertainment lighting control apparatus for
professional use - Part 2: Immunity
EN 300 422-2 2011 Electromagnetic compatibility and radio EN 300 422-2 2011
V1.3.1 spectrum matters (ERM) - Wireless V1.3.1
microphones in the 25 MHz to 3 GHz
frequency range - Part 2: Harmonized EN
covering the essential requirements of article
3.2 of the R&TTE Directive
IEC 60268-4 ®
Edition 6.0 2018-09
INTERNATIONAL
STANDARD
Sound system equipment –
Part 4: Microphones
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.50 ISBN 978-2-8322-5955-9

– 2 – IEC 60268-4:2018 © IEC 2018
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references. 8
3 Terms and definitions . 9
4 General conditions . 10
4.1 General . 10
4.2 Measurement conditions . 10
4.2.1 General . 10
4.2.2 Rated conditions . 11
5 Particular conditions . 12
5.1 Pre-conditioning . 12
5.2 Sound source . 12
5.3 Measurement of sound pressure . 12
5.4 Voltage measuring system . 12
5.5 Acoustical environment . 12
5.5.1 General . 12
5.5.2 Free-field conditions . 13
5.5.3 Diffuse field conditions . 14
5.5.4 Microphone coupled to a sound source by means of a small cavity
coupler . 15
5.6 Methods of measuring frequency response . 15
5.6.1 Point-by-point and continuous sweep frequency methods . 15
5.6.2 Calibration methods . 16
5.7 Overall accuracy . 16
5.8 Graphical presentation of results . 16
6 Type description (acoustical behaviour) . 17
6.1 Principle of the transducer . 17
6.2 Type of microphone . 17
6.3 Type of directional response characteristics . 17
6.4 Application . 17
7 Terminals and controls. 17
7.1 Marking . 17
7.2 Connectors and electrical interface values . 17
8 Reference point and axis . 18
8.1 Reference point . 18
8.2 Reference axis . 18
9 Rated power supply . 18
9.1 Characteristics to be specified . 18
9.2 Method of measurement . 18
10 Electrical impedance . 18
10.1 Internal impedance . 18
10.1.1 Characteristic to be specified . 18
10.1.2 Methods of measurement . 18
10.2 Rated impedance . 19
10.3 Rated minimum permitted load impedance . 19

IEC 60268-4:2018 © IEC 2018 – 3 –
11 Sensitivity . 19
11.1 General . 19
11.2 Sensitivities with respect to acoustical environment . 20
11.2.1 Free-field sensitivity . 20
11.2.2 Diffuse-field sensitivity . 21
11.2.3 Close-talking and near-field sensitivity . 21
11.2.4 Pressure sensitivity . 22
11.3 Rated sensitivity . 22
12 Response . 22
12.1 Frequency response . 22
12.1.1 Characteristic to be specified . 22
12.1.2 Method of measurement . 23
12.1.3 Graphical presentation of results . 23
12.2 Effective frequency range . 23
12.2.1 Characteristic to be specified . 23
12.2.2 Method of measurement . 23
13 Directional characteristics . 23
13.1 Directional pattern . 23
13.1.1 Characteristic to be specified . 23
13.1.2 Methods of measurement . 24
13.1.3 Graphical presentation of results . 25
13.2 Directivity index . 25
13.2.1 Characteristic to be specified . 25
13.2.2 Method of measurement . 25
14 Amplitude non-linearity . 25
14.1 General . 25
14.2 Total harmonic distortion . 25
14.2.1 Characteristic to be specified . 25
14.2.2 Method of measurement . 26
th
14.3 Harmonic distortion of the n order (n = 2, 3,.) . 26
14.3.1 Characteristic to be specified . 26
14.3.2 Method of measurement . 26
14.4 Difference frequency distortion of second order . 27
14.4.1 Characteristic to be specified . 27
14.4.2 Method of measurement . 27
15 Limiting characteristics . 28
15.1 Rated maximum permissible peak sound pressure . 28
15.2 Overload sound pressure . 28
15.2.1 Characteristic to be specified . 28
15.2.2 Method of measurement . 28
16 Balance . 28
16.1 Balance of the microphone output . 28
16.2 Balance under working conditions . 29
17 Equivalent sound pressure level due to inherent noise . 29
17.1 Characteristic to be specified . 29
17.2 Method of measurement . 29
18 Ambient conditions . 30
18.1 General . 30

– 4 – IEC 60268-4:2018 © IEC 2018
18.2 Pressure range . 30
18.3 Temperature range . 30
18.4 Relative humidity range . 30
19 External influences . 30
19.1 General . 30
19.1.1 Specification and methods of measurement . 30
19.1.2 Other external interferences . 31
19.2 Equivalent sound pressure due to mechanical vibration . 31
19.2.1 Characteristic to be specified . 31
19.2.2 Method of measurement . 31
19.3 Equivalent sound pressure due to wind . 31
19.3.1 Characteristic to be specified . 31
19.3.2 Method of measurement . 32
19.4 Transient equivalent sound pressure due to "pop" effect . 35
19.4.1 General . 35
19.4.2 Characteristic to be specified . 35
19.4.3 Method of measurement . 36
20 Electromagnetic compatibility (EMC) . 37
20.1 Regulatory requirements . 37
20.2 Requirements for preserving programme quality . 37
20.3 Performance criteria . 38
20.3.1 Criterion A . 38
20.3.2 Criterion B . 38
20.4 Testing for immunity to disturbances in the presence of acoustical noise . 39
20.5 Immunity to frequency-modulated radiated disturbances . 39
20.6 Immunity to magnetic fields . 39
20.7 Immunity to ripple on d.c. power supply . 39
20.8 Permanent magnetic field . 40
20.9 Evaluation and reporting of the test results . 40
21 Physical characteristics . 40
21.1 Dimensions . 40
21.2 Weight . 40
21.3 Cables and connectors . 40
22 Classification of the characteristics to be specified . 40
Annex A (normative) Additional characteristics . 43
A.1 Characteristic sensitivity for speech . 43
A.1.1 Characteristic to be specified . 43
A.1.2 Method of measurement . 43
A.2 Front-to-rear sensitivity index (0° – 180°) . 44
A.2.1 Characteristic to be specified . 44
A.2.2 Method of measurement . 44
A.3 Noise-cancelling index . 44
A.3.1 Characteristic to be specified . 44
A.3.2 Method of measurement . 44
A.4 Special characteristics for stereo microphones . 45
A.4.1 General . 45
A.4.2 Included angle of an XY (left-right) microphone . 45
A.4.3 Acceptance angle . 45

IEC 60268-4:2018 © IEC 2018 – 5 –
Annex B (informative) Sound insulation device . 46
Annex C (informative) Recommendations for professional digital microphones . 47
C.1 General . 47
C.2 Data sheets for digital microphones . 47
Annex D (informative) Recommended method for measuring noise levels according to
ITU-R BS.468-4 in the digital domain . 50
D.1 General . 50
D.2 Recommended method . 50
D.3 Matlab code . 51
Bibliography . 54

Figure 1 – Balance of the output . 28
Figure 2 – Balance under working conditions . 29
Figure 3 – Measurement set-up for wind influence . 32
Figure 4 – Wind generators, type 1 (Figure 4a) and type 2 (Figure 4b) . 34
Figure 5 – Electrical and mechanical setup for the measuring of the "pop" effect . 36
Figure B.1 – Sound insulation device . 46
Figure D.1 – ITU weighting filter for weighted and unweighted measurements . 50
Figure D.2 – Peak value rectifier scheme . 51

Table 1 – Reverberation time of the empty room . 15
Table 2 – Examples of EMC regulations and standards . 37
Table 3 – Basic EMC standards and their application to microphones . 38
Table 4 – Classification of characteristics . 41
Table A.1 – Speech power weighting factor at octave-band centre frequencies . 43
Table C.1 – Classification of the characteristics recommended to be specified . 47
Table C.2 – Additional digital characteristics to be specified . 49
Table D.1 – Time constants for the two PVRs . 51

– 6 – IEC 60268-4:2018 © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOUND SYSTEM EQUIPMENT –
Part 4: Microphones
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60268-4 has been prepared by IEC technical committee 100:
Audio, video and multimedia systems and equipment.
This sixth edition cancels and replaces the fifth edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Subclause 19.4 on "pop" measurement replaces Annex C;
b) new Annex D for noise measurements in the digital domain.
The text of this International Standard is based on the following documents:
CDV Report on voting
100/2992/CDV 100/3109/RVC
IEC 60268-4:2018 © IEC 2018 – 7 –

Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60268 series, under the general title Sound system equipment,
can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 8 – IEC 60268-4:2018 © IEC 2018
SOUND SYSTEM EQUIPMENT –
Part 4: Microphones
1 Scope
This part of IEC 60268 specifies methods of measurement for the electrical impedance,
sensitivity, directional response pattern, dynamic range and external influences of sound
system microphones, and also details the characteristics to be specified by the manufacturer.
It applies to sound system microphones for all applications for speech and music. It does not
apply to measurement microphones, but it does apply to each audio channel of microphones
having more than one channel, for example for stereo or similar use. It is also applicable to
flush-mounted microphones and to the analogue characteristics of microphones with digital
audio output.
For the purposes of this International Standard, a microphone includes all such devices as
transformers, pre-amplifiers, or other elements that form an integral part of the microphone,
up to the output terminals specified by the manufacturer.
The major characteristics of a microphone are considered in Clauses 6 to 21. Additional
characteristics are considered in Annex A and Annex C.
NOTE The characteristics specified in this document do not describe the subjective response of the microphone.
Further work is necessary to find new definitions and measurement procedures for a later introduction of objective
characteristics for at least some of the subjective descriptions used to describe microphone performance.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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.
CISPR 35:2016, Electromagnetic compatibility of multimedia equipment – Immunity
requirements
IEC 60268-1:1985, Sound system equipment – Part 1: General
IEC 60268-1:1985/AMD1:1988
IEC 60268-1:1985/AMD2:1988
IEC 60268-2:1987, Sound system equipment – Part 2: Explanation of general terms and
calculation methods
IEC 60268-2:1987/AMD1:1991
IEC 60268-3:2013, Sound system equipment – Part 3: Amplifiers
IEC 60268-5:2003, Sound system equipment – Part 5: Loudspeakers
IEC 60268-5:2003/AMD1:2007
IEC 60268-11:1987, Sound system equipment – Part 11: Application of connectors for the
interconnection of sound system components
IEC 60268-11:1987/AMD1:1989
IEC 60268-11:1987/AMD2:1991
IEC 60268-4:2018 © IEC 2018 – 9 –
IEC 60268-12:1987, Sound system equipment – Part 12: Application of connectors for
broadcast and similar use
IEC 60268-12:1987/AMD1:1991
IEC 60268-12:1987/AMD2:1994
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and
measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-3:2006/AMD1:2007
IEC 61000-4-3:2006/AMD2:2010
IEC 61000-4-4:2012, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test
IEC 61000-4-6:2013, Electromagnetic compatibility (EMC) – Part 4-6: Testing and
measurement techniques – Immunity to conducted disturbances, induced by radio-frequency
fields
IEC 61000-4-8:2009, Electromagnetic compatibility (EMC) – Part 4-8: Testing and
measurement techniques – Power frequency magnetic field immunity test
IEC 61000-4-16:2015, Electromagnetic compatibility (EMC) – Part 4-16: Testing and
measurement techniques – Test for immunity to conducted, common mode disturbances in
the frequency range 0 Hz to 150 kHz
IEC 61000-4-17:1999, Electromagnetic compatibility (EMC) – Part 4-17: Testing and
measurement techniques – Ripple on d.c. input power port immunity test
61000-4-17:1999/AMD1:2001
61000-4-17:1999/AMD2:2008
IEC 61260-1:2014, Electroacoustics – Octave-band and fractional-octave-band filters –
Part 1: Specifications
IEC 61938:2013, Multimedia systems – Guide to the recommended characteristics of
analogue interfaces to achieve interoperability
ITU-T Recommendation P.51:1996, Artificial mouth
EN 55103-2:2009, Electromagnetic compatibility – Product family standard for audio, video,
audio-visual and entertainment lighting control apparatus for professional use – Part 2:
Immunity
EN 300 422-2 V1.3.1:2011, Electromagnetic compatibility and radio spectrum matters (ERM)
– Wireless microphones in the 25 MHz to 3 GHz frequency range – Part 2: Harmonized EN
covering the essential requirements of article 3.2 of the R&TTE Directive
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60268-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/

– 10 – IEC 60268-4:2018 © IEC 2018
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
far-field microphone
microphone for use mainly at a distance of 1 m or more from the source of sound
Note 1 to entry: The term "far-field microphone" describes a microphone application (see 6.4) and not a type of
microphone. A specific microphone may have one or more applications, but the term is helpful in specifying the
method of measurement.
3.2
near-field microphone
microphone for use by an individual performer at a distance of approximately 30 cm
Note 1 to entry: The term "near-field microphone" describes a microphone application (see 6.4) and not a type of
microphone. A specific microphone may have one or more applications, but the term is helpful in specifying the
method of measurement.
3.3
close-talking microphone
microphone for use at a distance of approximately 25 mm from the source of sound
Note 1 to entry: The term "close-talking microphone" describes a microphone application (see 6.4) and not a type
of microphone. A specific microphone may have one or more applications, but the term is helpful in specifying the
method of measurement.
4 General conditions
4.1 General
Special reference is made to IEC 60268-1, concerning:
• units and system of measurement;
• frequencies of measurement;
• quantities to be specified and their accuracy (see also 5.7);
• marking (see also 7.1);
• ambient conditions;
• filters, networks and measuring instruments for noise specification and measurement;
• individual specifications and type specifications;
• graphical presentation of characteristics;
• scales for graphical presentation;
• personal safety and prevention of spread of fire;
• method of producing a uniform alternating magnetic field;
• search coils for measuring the magnetic field strength,
and to IEC 61938 concerning powering of microphones.
4.2 Measurement conditions
4.2.1 General
For convenience in specifying how microphones shall be set up for measurement, three sets
of conditions have been defined in this document, under the title of "rated conditions".
Microphones should be measured in conditions approximating those in which they are
intended to be used. Three sets of measurement conditions are specified in this document:
free-field, near-field and close-talking. The differences between these sets of conditions are in

IEC 60268-4:2018 © IEC 2018 – 11 –
the distance to the sound source and the sound pressure level of the measurement.
Measurements shall be reported using at least one of these sets of conditions. Additional data
may be included, provided that the measurement conditions are specified.
Three ratings are basic to the formulation of these concepts:
• rated power supply (see 9.1);
• rated impedance (see 10.2);
• rated sensitivity (see 11.3).
To obtain the correct conditions for measurement, the above-mentioned ratings shall be taken
from the specifications supplied by the manufacturer of the equipment.
The term "rated" applied to other characteristics relates to the specification or measurement
of the particular characteristic under rated conditions or under conditions unambiguously
connected to them. This applies, for example, to the following two characteristics:
• rated output voltage;
• rated equivalent sound pressure level due to inherent noise.
Methods of measurement are given in this document for electrical impedance, sensitivity,
directional pattern, dynamic range and external influences. Where alternative methods are
given, the chosen method shall be specified.
4.2.2 Rated conditions
The microphone is understood to be working under rated conditions when the following
conditions are fulfilled:
• the microphone is connected to the resistive load specified in 5.4, or as specified by the
manufacturer;
• if the microphone needs a power supply, this is the rated power supply;
• the microphone (except a close-talking or near-field microphone) is placed in a sound field
meeting the free-field conditions in 5.5.2, the waves having zero-degree incidence with
respect to the reference direction;
• far-field microphones shall be measured in free-field conditions;
• the undisturbed sound pressure (in the absence of the microphone) in the sound field at
the reference point of the microphone is sinusoidal and set at a level of 1 Pa (94 dB SPL);
• for close-talking microphones, the microphone is placed at a stated distance, no more
than 25 mm from the artificial mouth complying with ITU-T Recommendation P.51, and the
undisturbed sound pressure in the sound field at the reference point of microphone is
sinusoidal and set at a level of 3 Pa (104 dB SPL);
• for near-field microphones, the microphone is placed at 30 cm from the artificial mouth
complying with ITU-T Recommendation P.51, and the undisturbed sound pressure in the
sound field at the reference point of microphone is sinusoidal and set at a level of 1 Pa
(94 dB SPL);
• if a special microphone needs a different measurement level or procedure (e.g. Lavalier or
boundary layer microphones), it shall be stated in the technical data together with the
reason for this. Levels related to the normal reference level of 94 dB by multiples of 10 dB
are preferred;
• controls, if any, are set to the position recommended by the manufacturer;
• in the absence of a clear reason to the contrary, the measurement frequency
...