IEC 60268-7:2010

IEC 60268-7 ®
Edition 3.1 2020-09
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Sound system equipment –
Part 7: Headphones and earphones

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and definitions clause of
IEC publications issued between 2002 and 2015. Some
IEC Customer Service Centre - webstore.iec.ch/csc entries have been collected from earlier publications of IEC
If you wish to give us your feedback on this publication or TC 37, 77, 86 and CISPR.

need further assistance, please contact the Customer Service

Centre: sales@iec.ch.
IEC 60268-7 ®
Edition 3.1 2020-09
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Sound system equipment –
Part 7: Headphones and earphones

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.50 ISBN 978-2-8322-8891-7

IEC 60268-7 ®
Edition 3.1 2020-09
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Sound system equipment –
Part 7: Headphones and earphones

– 2 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION to Amendment 1 . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Classification, designation and coding . 11
5 Marking of terminals, controls and polarity . 15
6 User instructions . 15
7 Conditions for specifications and measurements . 16
7.1 Rated conditions . 16
7.2 Standard conditions for measurement . 17
7.3 Couplers and ear simulators . 17
7.4 Measurement conditions for simulated programme signal . 17
7.5 Loudness comparison conditions . 18
7.5.1 General . 18
7.5.2 Free-field comparison conditions . 18
7.5.3 Diffuse-field comparison conditions . 19
7.6 Ear canal sound pressure level measurement conditions . 19
8 Characteristics to be specified and their methods of measurement . 19
8.1 Power supply . 19
8.2 Electrical impedance . 19
8.2.1 Rated impedance . 19
8.2.2 Impedance/frequency characteristic . 20
8.2.3 Rated source impedance . 20
8.3 Input voltage . 20
8.3.1 Rated source e.m.f. . 20
8.3.2 Limiting values of input voltage . 20
8.3.3 Characteristic voltage . 21
8.3.4 Simulated programme signal characteristic voltage . 22
8.3.5 Simulated programme signal characteristic voltage corrected by
A-weighting characteristics and free-field response compensation . 22
8.3.6 Protective devices . 23
8.4 Input power . 23
8.5 Sound pressure (level) . 24
8.5.1 General . 24
8.5.2 Characteristics to be specified . 24
8.5.3 Method of measurement . 24
8.6 Frequency response . 25
8.6.1 General . 25
8.6.2 Coupler or ear simulator (including HATS) frequency response . 25
8.6.3 Free-field comparison frequency response . 26
8.6.4 Diffuse-field comparison frequency response . 27
8.6.5 Free-field and diffuse-field ear canal sound pressure level frequency
responses . 27
8.6.6 Rated frequency range . 29
8.6.7 Free-field compensated frequency response . 29

 IEC 2020
8.6.8 Diffuse-field compensated frequency response . 30
8.7 Amplitude non-linearity . 31
8.7.1 General . 31
8.7.2 Harmonic distortion . 31
8.7.3 Modulation distortion . 32
8.7.4 Difference-frequency distortion . 32
8.8 Rated climatic conditions . 33
8.9 External electric and/or magnetic field . 33
8.9.1 Characteristics to be specified . 33
8.9.2 Method of measurement . 33
8.10 Unwanted sound radiation . 34
8.10.1 Characteristic to be specified. 34
8.10.2 Method of measurement . 34
8.11 Sound attenuation . 34
8.11.1 Characteristic to be specified. 34
8.11.2 Method of measurement . 34
8.12 Crosstalk attenuation for multi-channel headphones . 34
8.12.1 Characteristic to be specified. 34
8.12.2 Method of measurement . 34
8.13 Application force . 34
8.13.1 Characteristic to be specified. 35
8.13.2 Method of measurement . 35
8.14 Physical characteristics, cables and connectors . 35
8.14.1 Characteristics to be specified . 35
9 Classification of characteristics . 36
Annex A (normative) Pinna simulators for measurements of headphones
and earphones . 37
Annex B (normative) Specification and conditions of use of a microphone for use inside
the ear canal . 46
Annex C (informative) Practical details of free-field comparison conditions . 47
Annex D (informative) Practical details of diffuse-field comparison conditions . 48
Annex E (informative) Practical details of the subjective comparison and ear canal
sound pressure level conditions . 49
Bibliography . 50

Figure 1 – Diagrammatic horizontal sections showing types of earphones and their
spatial relationships with the pinna and/or canal entrance . 13
Figure 2 – Diagrams showing the four possible construction: acoustically open or closed,
and closed- or open-back . 15
Figure 3 – Illustrated measurement diagram by simulated programme signal . 18
Figure 4 – Example of a setup for the measurement of free-field/ diffuse-field
compensated frequency response . 31
Figure A.1 – Shape of the recommended pinna simulator . 38
Figure A.2 – Coordinate for the recommended pinna simulator . 39
Figure A.3 – Cross-sectional shapes and dimensions of the recommended pinna
simulator, horizontal section . 42
Figure A.4 – Cross-sectional shapes and dimensions of the recommended pinna
simulator, vertical section . 45

– 4 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
Table 1 – Classification of characteristics . 36

 IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOUND SYSTEM EQUIPMENT –
Part 7: Headphones and earphones

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.
This consolidated version of the official IEC Standard and its amendment has been
prepared for user convenience.
IEC 60268-7 edition 3.1 contains the third edition (2010-01) [documents 100/1621/FDIS
and 100/1641/RVD] and its corrigendum (2012-11), and its amendment 1 (2020-09)
[documents 100/3316/CDV and 100/1641/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red
text. A separate Final version with all changes accepted is available in this publication.

– 6 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
International Standard IEC 60268-7 has been prepared by IEC technical committee TC 100:
Audio, video and multimedia systems and equipment.
This third edition constitutes a technical revision. This edition contains the following changes:
• clause/subclause renumbering in accordance with ISO/IEC Directives, Part 2;
• addition of a measurement system using HATS;
• addition of details on pinna simulators for high measurement reproducibility, see Annex A.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 60268 series, published under the general title Sound system
equipment, can be found on the IEC website.
The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

 IEC 2020
INTRODUCTION to Amendment 1
This Amendment 1 contains the following significant technical changes with respect to
• evaluation of free-field compensated frequency response has been added;
• evaluation of diffuse-field compensated frequency response has been added;
• the Bibliography has been updated;
• some normative references have been updated;
• the term "HATS" and its definition has been added.

– 8 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
SOUND SYSTEM EQUIPMENT –
Part 7: Headphones and earphones

1 Scope
This part of IEC 60268, is applicable to headphones, headsets, earphones and earsets,
intended to be used on, or in, the human ear. It also applies to equipment, such as pre-amplifiers,
passive networks and power supplies which form an integral part of the headphone system.
It does not deal with:
a) safety, for which reference should be made to IEC 60065 IEC 62368-1 or another
appropriate standard;
b) the characteristics of microphones of headsets, for which reference should be made to
IEC 60268-4;
c) earphones and other devices for hearing aids, for which reference should be made to
IEC 60118-0;
d) headphones for audiometry;
e) headphones and other devices which form part of an active ear-defender system, although
some of its provisions may be applicable.
This standard specifies the characteristics which should be included by the manufacturer in
specifications, and relevant methods of measurement. It includes a classification of the different
types of earphone, mainly characterized by the way in which the transducer is coupled
acoustically to the ear, and a classification code which may also be used for marking.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60038, IEC standard voltages
IEC 60050(801):1994, International Electrotechnical Vocabulary – Chapter 801: Acoustics and
electroacoustics
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60086-1, Primary batteries – Part 1: General
IEC Guide 106, Guide for specifying environmental conditions for equipment performance
rating
IEC 60263, Scales and sizes for plotting frequency characteristics and polar diagrams
IEC 60268-1, Sound system equipment – Part 1: General
IEC 60268-2, Sound system equipment – Part 2: Explanation of general terms and calculation
methods
 IEC 2020
IEC 60268-11, Sound system equipment – Part 11: Application of connectors for the
interconnection of sound system components
IEC 60268-12, Sound system equipment – Part 12: Application of connectors for broadcast
and similar use
IEC 60711, Occluded-ear simulator for the measurement of earphones coupled to the ear by
ear inserts
IEC TR 60959, Provisional head and torso simulator for acoustic measurements on air
conduction hearing aids
IEC TS 60318-7, Electroacoustics – Simulators of human head and ear – Part 7: Head and torso
simulator for the measurement of air-conduction hearing aids
IEC 61672-1, Electroacoustics – Sound level meters – Part 1: Specifications
ISO 3741, Acoustics – Determination of sound power levels of noise sources using sound
pressure – Precision methods for reverberation rooms
ISO 4869-1, Acoustics – Hearing protectors – Part 1: Subjective method for the measurement
of sound attenuation
ISO 4869-3, Acoustics – Hearing protectors – Part 3: Measurement of insertion loss of
ear-muff type protectors using an acoustic test fixture
ISO 7619-1, Rubber, vulcanized and thermoplastic – Determination of indentation hardness –
Part 1: Durometer method (Shore hardness)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply, see also
IEC 60050-801 (IEV).
NOTE Any device defined in 3.1 to 3.15 and their connector(s) for electrical input should be regarded as part of the
transducer.
3.1
earphone
electroacoustic transducer by which acoustic oscillations are obtained from electric signals and
intended to be closely coupled acoustically to the ear
[IEV 801-27-18]
3.2
headphone
assembly of one or two earphones on a headband or chinband, the use of which may be optional
(e.g. with intra-concha earphones)
3.3
headset
headphones equipped with a microphone
___________
This publication will be replaced by future IEC 60318-4 (to be published).
This publication is planned to be replaced by future IEC 60318-7 (under consideration).

– 10 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
3.4
earset
earphones equipped with a microphone
NOTE This definition is included because the term appears in the catalogue of IEC publications.
3.5
insert earphone
small earphone that is attached directly to a connecting element, for example an earmould,
inserted into the ear canal
[IEV 801-27-22, modified]
3.6
intra-concha earphone
small earphone that fits in the concha cavity, with its acoustic exit close to the entrance of the
ear canal
3.7
supra-aural earphone
earphone applied externally to the outer ear and intended to rest on the pinna
[IEV 801-27-23, modified]
3.8
supra-concha earphone
earphone intended to rest on the ridges of the concha cavity
3.9
circumaural earphone
earphone having a cavity large enough to cover the region of the head including the ear
[IEV 801-27-24]
3.10
ear shell
circumaural type of earphone hanging on the ear
3.11
stethoscopic headphone
insert headphone by which the earphone(s) is/are coupled to the ears by means of a pair of
rigid tubes, so that the assembly resembles a stethoscope
3.12
acoustically open earphone
earphone which intentionally provides an acoustic path between the external environment and
the ear canal
3.13
acoustically closed earphone
earphone which is intended to prevent acoustic coupling between the external environment
and the ear canal
3.14
closed-back earphone
earphone which does not emit significant sound radiation from the back of the transducer to
the external environment
 IEC 2020
3.15
open-back earphone
earphone which emits significant sound radiation from the back of the transducer to the external
environment
3.16
simulated programme signal
signal whose mean power spectral density closely resembles the average of the mean power
spectral densities of a wide range of programme material, in accordance with IEC 60268-1.
NOTE This signal is called as “wide band signal” in a few standards.
3.17
head and torso simulator
HATS
simulator of a median adult human head and part of the torso extending in total from the top of
the head to the waist and designed to simulate the sound pick-up characteristics and acoustic
diffraction
Note 1 to entry: The head simulator includes two pinna simulators, and at least one occluded-ear simulator.
[SOURCE: IEC TS 60318-7:2017, 3.1, modified – The preferred term "manikin" has been
omitted.]
4 Classification, designation and coding
The following designations and classification codes shall be used:
60268-7 - IEC - XXXX - NNRN - N
where
60268-7-IEC is the standard form of prefix.
• X (first letter) gives the principle of the transducer:
D - electrodynamic (moving coil);
E - electret (self-polarizing);
F - piezo-electric (polymer);
M - electromagnetic (moving armature or diaphragm);
P - piezo-electric (ceramic);
S - electrostatic (externally polarized).
• X (second letter) gives the type of earphone:
C - circumaural;
E - intra-concha;
H - earshell;
I - insert;
M - supra-concha;
S - supra-aural;
T - stethoscopic.
An illustration of the types, except “H”, is given in Figure 1.

– 12 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
• X (third letter) gives the intended nature of the acoustic coupling to the ear canal:
L - acoustically open (controlled leakage);
S - acoustically closed (minimum leakage).
• X (fourth letter) gives the intended nature of the radiation to the external environment:
C - closed-back (see 3.14);
O - open-back (see 3.15).
An illustration of the four possibilities defined in 3.12 to 3.15, and indicated by the third and
fourth classification letters, is given in Figure 2:
• NNRN (first number) gives the impedance in ohms in "mantissa and exponent" form. (For
example, 8 Ω as "08R0", 32 Ω as "32R0" and 600 Ω as "06R2");
• N (second number) gives the number of channels.
The code, compiled in accordance with the above rules, may be used for marking.

 IEC 2020
Type of earphone Acoustically closed earphone Acoustically open earphone Ear loudspeaker
(minimum leakage) (controlled leakage)
PROTECTOR PROTECTOR PROTECTOR
HOUSING HOUSING HOUSING
Dorsal Dorsal Dorsal
back back back
Circumaural
front front front
Rostral Rostral Rostral
EARPAD EARPAD
TRANSDUCER TRANSDUCER TRANSDUCER
EARPAD EARPAD
Dorsal Dorsal
back back
Supra-aural
front front
Rostral Rostral
TRANSDUCER TRANSDUCER
HOUSING HOUSING
PROTECTOR PROTECTOR
EARPAD EARPAD
Dorsal Dorsal
back back
Supra-concha
front front
Rostral Rostral
HOUSING HOUSING
TRANSDUCER TRANSDUCER
IEC  2481/09
NOTE The transducers shown in the schematics are not necessarily positioned in the centre of the housings or concentric to the ear canal.
Figure 1 – Diagrammatic horizontal sections showing types of earphones
and their spatial relationships with the pinna and/or canal entrance

– 14 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
Type of earphone Acoustically closed earphone Acoustically open earphone
(minimum leakage) (controlled leakage)
EARPAD EARPAD
Dorsal Dorsal
PROTECTOR
PROTECTOR
back back
Intra-concha
front front
HOUSING HOUSING
TRANSDUCER
TRANSDUCER
Rostral Rostral
EARPAD EARPAD
Dorsal Dorsal
PROTECTOR PROTECTOR
back back
Insert
front front
HOUSING HOUSING
Rostral Rostral
TRANSDUCER TRANSDUCER
Key
Cross hatching shows
Insert with sound tube
EARPIECE
acoustically closed
EARPIECE
between transducer
earpad to accomplish
and earpiece (for SOUNDTUBE
SOUNDTUBE
minimum leakage.
example, stethoscopic
type of earphone for
Spotted by small circle
hearing aid)
shows porous material
PROTECTOR
PROTECTOR earpad to accomplish
TRANSDUCER
TRANSDUCER controlled leakage.
HOUSING
HOUSING
IEC  2482/09
Figure 1 (continued)
 IEC 2020
Type of earphone Closed-back Open-back
(does not emit significant (emits significant sound
sound radiation from the radiation from the back of
back of the transducer to the transducer to the
the external environment) external environment)
PROTECTOR PROTECTOR
HOUSING HOUSING
Acoustically closed
Dorsal Dorsal
(intended to prevent
acoustic coupling
back back
between the external
environment and
front front
the ear canal)
Rostral Rostral
EARPAD
EARPAD
TRANSDUCER TRANSDUCER
HOUSING HOUSING
Dorsal Dorsal
Acoustically open
(intentionally provides
an acoustic path back back
between the external
front front
environment and
the ear canal)
Rostral Rostral
EARPAD EARPAD
TRANSDUCER TRANSDUCER
PROTECTOR PROTECTOR
IEC  2483/09
NOTE 1 Arrows show sound flow or sound leakage.
NOTE 2 The transducers shown in the schematics are not necessary positioned in the centre of the housings or
concentric to the ear canal.
Figure 2 – Diagrams showing the four possible construction:
acoustically open or closed, and closed- or open-back
5 Marking of terminals, controls and polarity
Requirements for marking terminals and controls are given in IEC 60268-1, and for polarity in
IEC 60268-2. In addition, headphones which are intended to be worn with a particular earphone
on each ear shall be marked to indicate the "left" and "right" earphones. If a colour marking is
used, the "right" earphone shall be indicated by a red marking. For the sake of visually-impaired
persons, it is recommended to indicate the left earphone by a projection of at least 1,5 mm
diameter and 0,3 to 0,5 mm height.
6 User instructions
The user instructions shall include information on:
• connector contact assignments (see IEC 60268-11);
• controls and switches (if any);
• microphone (if any);
– 16 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
• diagram of the interconnections of the earphones (if more than one);
• classification code (see Clause 4);
• description of the type of headphone.
Information shall also be provided on the safe use of the headphone, using wording similar to:
“To prevent possible hearing damage, do not listen at high volume levels for long periods, do
not use the headphones while driving or cycling, or in any situation where you should be able
to hear other sounds. As a guide to setting the volume level, check that you can still hear
your own voice, when speaking normally while listening with the headphones."
If the headphone is supplied with auxiliary equipment, information shall also be provided on:
• pre-amplifiers and/or passive networks;
• receivers (for cordless systems);
• power supplies;
• other parts, such as magnetic pick-up devices.
7 Conditions for specifications and measurements
7.1 Rated conditions
For an explanation of the meaning of "rated conditions" and "rated value of a characteristic",
reference shall be made to IEC 60268-2.
The rated conditions for a headphone are:
• rated impedance;
• rated source e.m.f. (or power, see 8.4);
• rated noise e.m.f. (or power, see 8.4);
• rated source impedance (see Note);
• rated frequency range;
• rated long-term maximum input voltage (or power);
• rated maximum permanent noise source e.m.f. (or power);
• rated power supply voltage (if any);
• rated climatic conditions (temperature, humidity, air pressure);
• rated damage limited source e.m.f.;
• rated application force.
These values are taken from the manufacturer's specification, and are not subject to
measurement; they constitute the basis for measuring the other characteristics.
For climatic conditions, reference is made to IEC 60268-1, and further information is given in
IEC 60068-1 and IEC Guide 106.
NOTE The performance of most types of headphones depends very little on the source impedance. However, in
order to allow headphones of widely different impedances to be reasonably well-matched, in terms of the sound
pressure level produced, to a single headphone output on other equipment, IEC 61938 at present specifies a source
impedance of 120 Ω, intermediate between the lowest and highest likely impedances of available headphones. It is
thus important for the manufacturer to specify the rated source impedance, particularly if, for some reason, it is not
120 Ω.
 IEC 2020
7.2 Standard conditions for measurement
A headphone is working under standard conditions for measurement when all of the following
conditions are fulfilled.
a) At least one earphone is applied to the appropriate coupler or ear simulator, with the rated
application force.
b) A sinusoidal voltage at the standard measuring frequency is applied, in series with the rated
source impedance. The voltage shall be such that a sound pressure level of 94 dB (reference
20 µPa) is generated in the coupler or ear simulator. Unless otherwise stated, the standard
measuring frequency shall be 500 Hz. The input signal shall be applied at the point where the
signal from an amplifier or other equipment is applied when the headphone is in use. This point
may be the input of a piece of auxiliary equipment, such as a preamplifier.
As an alternative, the manufacturer may specify this condition as being a signal voltage
which dissipates a power of 1 mW in a pure resistance equal to the rated impedance of the
earphone being measured.
NOTE Electrostatic, piezo-electric, electret condenser and cordless headphones are within the scope of this
standard. The signal may be sent to the headphone by infra-red, radio, light or magnetic induction (either directly
to the transducers or to a magnetic pick-up device and amplifier). These types of headphone are more easily dealt
with by specifying the sound pressure level to be generated (the input signal being applied to the transmitter unit),
rather than by specifying the power in the rated impedance.
c) Unless otherwise specified by the manufacturer, volume controls are set at minimum
attenuation. For headphones supplied with a preamplifier, and for cordless headphones, the
manufacturer shall specify a reference position of the gain control for use in measurements.
Other controls shall be set at the designated "normal" positions, or at stated positions,
preferably those giving the greatest range of frequency response. Balance controls shall be
set for equal voltages at the terminals of the channels. Crosstalk controls shall be set for
minimum crosstalk.
d) If the headphone requires a power supply, the rated supply voltage and frequency are
applied.
7.3 Couplers and ear simulators
The manufacturer should use the coupler or ear simulator which is specified in the international
standard for the measurement of the headphone or earphone, for which results are to be
published. The manufacturer shall state the type of the used coupler or ear simulator in the
results.
NOTE Examples of the international standards specifying the couplers and ear simulators are IEC 60318-1,
IEC 60318-2, IEC 60318-3, IEC 60318-5, IEC 60711, ITU-T Recommendation P.57, 4.3 and the ear part of HATS
(Head and torso simulator) in IEC 60959.
For the measurement using the ear part of HATS (Head and Torso Simulator), the manufacturer
should use the model specified in IEC 60959 or equivalent, see ITU Recommendation P.58.
Hardness of the rubber pinna used shall be stated in the results, see ISO 7619-1 (2004).
Information for the pinna simulator suitable for measurements of headphones is given in
Annex A.
If the coupler or ear simulator except specified in the international standards was used, the
manufacturer shall state its physical parameters, shape, dimension, volume of the cavity, etc., to
maintain repeatability of measurement.
7.4 Measurement conditions for simulated programme signal
The conditions specified in 7.2 are applied except that the simulated programme signal specified
in IEC 60268-1 shall be applied. The following filters can be used to process the output signal of
the ear simulator:
– 18 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
• a weighting filter specified in IEC 61672-1;
• free field compensating filter, that is the filter with inverse response of the free field response
of the manikin specified in IEC 60959.
Measurement diagram by the simulated program signal is illustrated in Figure 3.

Headphones or earphone to be measured
Pinna simulator
Ear canal extention
HATS (IEC 60959)
Analyzer
Free field compensating
Signal
filter, if necessary
generator
Power
amplifier
SPS
Simulated
program signal
(IEC 60268-1)
A weighting filter,
Ear simulator
if necessary
(IEC 60711)
IEC  2484/09
NOTE The output signal correction can be done numerically without use of any filtering devices. Power summation
of the 1/3-octave-analized data multiplied by filtering coefficients given by IEC 61672-1 and/or IEC 60969 gives the
corrected voltage.
Figure 3 – Illustrated measurement diagram by simulated programme signal
7.5 Loudness comparison conditions
7.5.1 General
The response of a headphone to a given electrical signal may be determined by subjective
comparison of the loudness of the sound from the headphone with that of a reference sound field
derived from the same electrical signal. Headphones provided with earphones for both ears shall
be operated with uncorrelated signals, having the same spectrum and amplitude, applied to both
earphones simultaneously.
7.5.2 Free-field comparison conditions
A headphone is working under free-field comparison conditions when both of the following
conditions are fulfilled:
a) the headphone is worn by a test person in accordance with the manufacturer's instructions or
in the usual way for that type. It is necessary to fit the headphone in accordance with the
manufacturer's instructions, so that the earphones are correctly positioned, and the
application force is close to the rated value;
b) the reference sound field simulates a progressive plane wave. The acoustic signal shall have
a specified bandwidth and sound pressure level at a stated reference point, in the absence of
the test person.
Practical details of free-field comparison conditions are given in Annex C.

 IEC 2020
7.5.3 Diffuse-field comparison conditions
A headphone is working under diffuse-field comparison conditions when both of the following
conditions are fulfilled:
a) the headphone is worn by a test person in accordance with the manufacturer's instructions or
in the usual way for that type. It is necessary to fit the headphone in accordance with the
manufacturer's instructions, so that the earphones are correctly positioned, and the
application force is close to the rated value;
b) the reference sound field simulates a diffuse sound field, as described in ISO 3741. The
acoustic signal shall have a specified bandwidth and sound pressure level at a stated
reference point, in the absence of the test person.
Practical details of diffuse-field comparison conditions are given in Annex D. The use of a
reverberant chamber for the generation of the diffuse field is suitable for ear canal probe
measurements, but less suitable for subjective loudness level comparison, because of the long
reverberation time.
7.6 Ear canal sound pressure level measurement conditions
A headphone is working under ear canal sound pressure level measurement conditions when
the conditions for free-field comparison (7.5.2) or diffuse-field comparison (7.5.3) are fulfilled, in
addition to the following condition. A very small microphone, in accordance with the
requirements in Annex B, is positioned inside the ear canal of the test person, with its sound
entrance at least 4 mm from the entrance of the canal. Practical details of these conditions are
given in Annex E.
8 Characteristics to be specified and their methods of measurement
8.1 Power supply
If the headphone requires a power supply, the manufacturer shall specify:
• the type of power supply (a.c. or d.c.);
• the rated supply voltage and frequency, or their ranges (see IEC 60038) and/or type of
battery (see IEC 60086-1). These are rated conditions (see 7.1);
• the maximum power drawn from the power supply.
Headphones, which require or tolerate a small direct current in addition to the signal, are not
regarded as requiring a power supply. However, details of the required or maximum permissible
direct current shall be given.
8.2 Electrical impedance
8.2.1 Rated impedance
NOTE This is a rated condition, see 7.1.
Characteristics to be specified:
a) the value of a pure resistance which is specified by the manufacturer for matching purposes;
b) the rated impedance shall be chosen so that the lowest value of the modulus of the actual
impedance within the rated frequency range is not less than 80 % of the rated value. If the
impedance at any frequency between 0 kHz and 20 kHz is less than this value, this should be
stated in the specification.
– 20 – IEC 60268-7:2010+AMD1:2020 CSV
 IEC 2020
8.2.2 Impedance/frequency characteristic
8.2.2.1 Characteristic to be specified
The characteristic to be specified is a representation of the modulus of the impedance as a
function of frequency.
8.2.2.2 Method of measurement
The method of measurement is detailed below.
a) The headphone is brought under standard conditions for measurement.
b) The signal is changed to a sinusoidal voltage or current of variable frequency, w
...

IEC 60268-7 ®
Edition 3.0 2010-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Sound system equipment –
Part 7: Headphones and earphones

Équipements pour systèmes électroacoustiques –
Partie 7: Casques et écouteurs

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC online collection - oc.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - IEC online collection - oc.iec.ch
webstore.iec.ch/advsearchform Découvrez notre puissant moteur de recherche et consultez
La recherche avancée permet de trouver des publications IEC gratuitement tous les aperçus des publications. Avec un
en utilisant différents critères (numéro de référence, texte, abonnement, vous aurez toujours accès à un contenu à jour
comité d’études, …). Elle donne aussi des informations sur adapté à vos besoins.
les projets et les publications remplacées ou retirées.

Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
Le premier dictionnaire d'électrotechnologie en ligne au
Restez informé sur les nouvelles publications IEC. Just
monde, avec plus de 22 000 articles terminologiques en
Published détaille les nouvelles publications parues.
anglais et en français, ainsi que les termes équivalents dans
Disponible en ligne et une fois par mois par email.
16 langues additionnelles. Egalement appelé Vocabulaire

Electrotechnique International (IEV) en ligne.
Service Clients - webstore.iec.ch/csc

Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
IEC 60268-7 ®
Edition 3.0 2010-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Sound system equipment –
Part 7: Headphones and earphones

Équipements pour systèmes électroacoustiques –

Partie 7: Casques et écouteurs

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.160.50 ISBN 978-2-8322-9436-9

– 2 – IEC 60268-7:2010  IEC 2010
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Classification, designation and coding . 9
5 Marking of terminals, controls and polarity . 13
6 User instructions . 13
7 Conditions for specifications and measurements . 14
7.1 Rated conditions . 14
7.2 Standard conditions for measurement . 15
7.3 Couplers and ear simulators . 15
7.4 Measurement conditions for simulated programme signal . 15
7.5 Loudness comparison conditions . 16
7.5.1 General . 16
7.5.2 Free-field comparison conditions . 16
7.5.3 Diffuse-field comparison conditions . 17
7.6 Ear canal sound pressure level measurement conditions . 17
8 Characteristics to be specified and their methods of measurement . 17
8.1 Power supply . 17
8.2 Electrical impedance . 17
8.2.1 Rated impedance . 17
8.2.2 Impedance/frequency characteristic . 18
8.2.3 Rated source impedance . 18
8.3 Input voltage . 18
8.3.1 Rated source e.m.f. . 18
8.3.2 Limiting values of input voltage . 18
8.3.3 Characteristic voltage . 19
8.3.4 Simulated programme signal characteristic voltage . 20
8.3.5 Simulated programme signal characteristic voltage corrected by
A-weighting characteristics and free-field response compensation . 20
8.3.6 Protective devices . 21
8.4 Input power . 21
8.5 Sound pressure (level) . 22
8.5.1 General . 22
8.5.2 Characteristics to be specified . 22
8.5.3 Method of measurement . 22
8.6 Frequency response . 23
8.6.1 General . 23
8.6.2 Coupler or ear simulator (including HATS) frequency response . 23
8.6.3 Free-field comparison frequency response . 24
8.6.4 Diffuse-field comparison frequency response . 25
8.6.5 Free-field and diffuse-field ear canal sound pressure level frequency
responses . 25
8.6.6 Rated frequency range . 27
8.7 Amplitude non-linearity . 27
8.7.1 General . 27
8.7.2 Harmonic distortion . 27

8.7.3 Modulation distortion . 28
8.7.4 Difference-frequency distortion . 28
8.8 Rated climatic conditions . 29
8.9 External electric and/or magnetic field . 29
8.9.1 Characteristics to be specified . 29
8.9.2 Method of measurement . 29
8.10 Unwanted sound radiation . 29
8.10.1 Characteristic to be specified. 29
8.10.2 Method of measurement . 30
8.11 Sound attenuation . 30
8.11.1 Characteristic to be specified. 30
8.11.2 Method of measurement . 30
8.12 Crosstalk attenuation for multi-channel headphones . 30
8.12.1 Characteristic to be specified. 30
8.12.2 Method of measurement . 30
8.13 Application force . 30
8.13.1 Characteristic to be specified. 30
8.13.2 Method of measurement . 30
8.14 Physical characteristics, cables and connectors . 31
8.14.1 Characteristics to be specified . 31
9 Classification of characteristics . 32
Annex A (normative) Pinna simulators for measurements of headphones and earphones . 33
Annex B (normative) Specification and conditions of use of a microphone for use inside
the ear canal . 42
Annex C (informative) Practical details of free-field comparison conditions . 43
Annex D (informative) Practical details of diffuse-field comparison conditions . 44
Annex E (informative) Practical details of the subjective comparison and ear canal
sound pressure level conditions . 45
Bibliography . 46

Figure 1 – Diagrammatic horizontal sections showing types of earphones and their

spatial relationships with the pinna and/or canal entrance . 11
Figure 2 – Diagrams showing the four possible construction: acoustically open or closed,
and closed- or open-back . 13
Figure 3 – Illustrated measurement diagram by simulated programme signal . 16
Figure A.1 – Shape of the recommended pinna simulator . 34
Figure A.2 – Coordinate for the recommended pinna simulator . 35
Figure A.3 – Cross-sectional shapes and dimensions of the recommended pinna
simulator, horizontal section . 38
Figure A.4 – Cross-sectional shapes and dimensions of the recommended pinna
simulator, vertical section . 41

Table 1 – Classification of characteristics . 32

– 4 – IEC 60268-7:2010  IEC 2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOUND SYSTEM EQUIPMENT –
Part 7: Headphones and earphones

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 60268-7 has been prepared by IEC technical committee TC 100:
Audio, video and multimedia systems and equipment.
This third edition cancels and replaces the second edition published in 1996, and constitutes a
technical revision. This edition contains the following changes:
• clause/subclause renumbering in accordance with ISO/IEC Directives, Part 2;
• addition of a measurement system using HATS;
• addition of details on pinna simulators for high measurement reproducibility, see Annex A.

The text of this standard is based on the following documents:
FDIS Report on voting
100/1621/FDIS 100/1641/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 60268 series, published under the general title Sound system
equipment, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of November 2012 have been included in this copy.

– 6 – IEC 60268-7:2010  IEC 2010
SOUND SYSTEM EQUIPMENT –
Part 7: Headphones and earphones

1 Scope
This part of IEC 60268 is applicable to headphones, headsets, earphones and earsets, intended
to be used on, or in, the human ear. It also applies to equipment, such as pre-amplifiers, passive
networks and power supplies which form an integral part of the headphone system.
It does not deal with:
a) safety, for which reference should be made to IEC 60065 or another appropriate standard;
b) the characteristics of microphones of headsets, for which reference should be made to
IEC 60268-4;
c) earphones and other devices for hearing aids, for which reference should be made to
IEC 60118-0;
d) headphones for audiometry;
e) headphones and other devices which form part of an active ear-defender system, although
some of its provisions may be applicable.
This standard specifies the characteristics which should be included by the manufacturer in
specifications, and relevant methods of measurement. It includes a classification of the different
types of earphone, mainly characterized by the way in which the transducer is coupled
acoustically to the ear, and a classification code which may also be used for marking.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60038, IEC standard voltages
IEC 60050(801):1994, International Electrotechnical Vocabulary – Chapter 801: Acoustics and
electroacoustics
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60086-1, Primary batteries – Part 1: General
IEC Guide 106, Guide for specifying environmental conditions for equipment performance
rating
IEC 60263, Scales and sizes for plotting frequency characteristics and polar diagrams
IEC 60268-1, Sound system equipment – Part 1: General
IEC 60268-2, Sound system equipment – Part 2: Explanation of general terms and calculation
methods
IEC 60268-11, Sound system equipment – Part 11: Application of connectors for the
interconnection of sound system components
IEC 60268-12, Sound system equipment – Part 12: Application of connectors for broadcast
and similar use
IEC 60711, Occluded-ear simulator for the measurement of earphones coupled to the ear by
ear inserts
IEC TR 60959, Provisional head and torso simulator for acoustic measurements on air
conduction hearing aids
IEC 61672-1, Electroacoustics – Sound level meters – Part 1: Specifications
ISO 3741, Acoustics – Determination of sound power levels of noise sources using sound
pressure – Precision methods for reverberation rooms
ISO 4869-1, Acoustics – Hearing protectors – Part 1: Subjective method for the measurement
of sound attenuation
ISO 4869-3, Acoustics – Hearing protectors – Part 3: Measurement of insertion loss of
ear-muff type protectors using an acoustic test fixture
ISO 7619-1, Rubber, vulcanized and thermoplastic – Determination of indentation hardness –
Part 1: Durometer method (Shore hardness)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply, see also
IEC 60050-801 (IEV).
NOTE Any device defined in 3.1 to 3.15 and their connector(s) for electrical input should be regarded as part of the
transducer.
3.1
earphone
electroacoustic transducer by which acoustic oscillations are obtained from electric signals and
intended to be closely coupled acoustically to the ear
[IEV 801-27-18]
3.2
headphone
assembly of one or two earphones on a headband or chinband, the use of which may be optional
(e.g. with intra-concha earphones)
3.3
headset
headphones equipped with a microphone
3.4
earset
earphones equipped with a microphone
___________
This publication will be replaced by future IEC 60318-4 (to be published).
This publication is planned to be replaced by future IEC 60318-7 (under consideration).

– 8 – IEC 60268-7:2010  IEC 2010
NOTE This definition is included because the term appears in the catalogue of IEC publications.
3.5
insert earphone
small earphone that is attached directly to a connecting element, for example an earmould,
inserted into the ear canal
[IEV 801-27-22, modified]
3.6
intra-concha earphone
small earphone that fits in the concha cavity, with its acoustic exit close to the entrance of the
ear canal
3.7
supra-aural earphone
earphone applied externally to the outer ear and intended to rest on the pinna
[IEV 801-27-23, modified]
3.8
supra-concha earphone
earphone intended to rest on the ridges of the concha cavity
3.9
circumaural earphone
earphone having a cavity large enough to cover the region of the head including the ear
[IEV 801-27-24]
3.10
ear shell
circumaural type of earphone hanging on the ear
3.11
stethoscopic headphone
insert headphone by which the earphone(s) is/are coupled to the ears by means of a pair of
rigid tubes, so that the assembly resembles a stethoscope
3.12
acoustically open earphone
earphone which intentionally provides an acoustic path between the external environment and
the ear canal
3.13
acoustically closed earphone
earphone which is intended to prevent acoustic coupling between the external environment
and the ear canal
3.14
closed-back earphone
earphone which does not emit significant sound radiation from the back of the transducer to
the external environment
3.15
open-back earphone
earphone which emits significant sound radiation from the back of the transducer to the external
environment
3.16
simulated programme signal
signal whose mean power spectral density closely resembles the average of the mean power
spectral densities of a wide range of programme material, in accordance with IEC 60268-1.
NOTE This signal is called as “wide band signal” in a few standards.
4 Classification, designation and coding
The following designations and classification codes shall be used:
60268-7 - IEC - XXXX - NNRN - N
where
60268-7-IEC is the standard form of prefix.
• X (first letter) gives the principle of the transducer:
D - electrodynamic (moving coil);
E - electret (self-polarizing);
F - piezo-electric (polymer);
M - electromagnetic (moving armature or diaphragm);
P - piezo-electric (ceramic);
S - electrostatic (externally polarized).
• X (second letter) gives the type of earphone:
C - circumaural;
E - intra-concha;
H - earshell;
I - insert;
M - supra-concha;
S - supra-aural;
T - stethoscopic.
An illustration of the types, except “H”, is given in Figure 1.
• X (third letter) gives the intended nature of the acoustic coupling to the ear canal:
L - acoustically open (controlled leakage);
S - acoustically closed (minimum leakage).
• X (fourth letter) gives the intended nature of the radiation to the external environment:
C - closed-back (see 3.14);
O - open-back (see 3.15).
– 10 – IEC 60268-7:2010  IEC 2010
An illustration of the four possibilities defined in 3.12 to 3.15, and indicated by the third and
fourth classification letters, is given in Figure 2:
• NNRN (first number) gives the impedance in ohms in "mantissa and exponent" form. (For
example, 8 Ω as "08R0", 32 Ω as "32R0" and 600 Ω as "06R2");
• N (second number) gives the number of channels.
The code, compiled in accordance with the above rules, may be used for marking.

Type of earphone Acoustically closed earphone Acoustically open earphone Ear loudspeaker
(minimum leakage) (controlled leakage)
PROTECTOR PROTECTOR PROTECTOR
HOUSING HOUSING HOUSING
Dorsal Dorsal Dorsal
back back back
Circumaural
front front front
Rostral Rostral Rostral
EARPAD EARPAD
TRANSDUCER TRANSDUCER TRANSDUCER
EARPAD EARPAD
Dorsal Dorsal
back back
Supra-aural
front front
Rostral Rostral
TRANSDUCER TRANSDUCER
HOUSING HOUSING
PROTECTOR PROTECTOR
EARPAD EARPAD
Dorsal Dorsal
back back
Supra-concha
front front
Rostral Rostral
HOUSING HOUSING
TRANSDUCER TRANSDUCER
IEC  2481/09
NOTE The transducers shown in the schematics are not necessarily positioned in the centre of the housings or concentric to the ear canal.
Figure 1 – Diagrammatic horizontal sections showing types of earphones
and their spatial relationships with the pinna and/or canal entrance

– 12 – IEC 60268-7:2010  IEC 2010

Type of earphone Acoustically closed earphone Acoustically open earphone
(minimum leakage) (controlled leakage)
EARPAD EARPAD
Dorsal Dorsal
PROTECTOR
PROTECTOR
back back
Intra-concha
front front
HOUSING HOUSING
TRANSDUCER
TRANSDUCER
Rostral Rostral
EARPAD EARPAD
Dorsal Dorsal
PROTECTOR PROTECTOR
back back
Insert
front front
HOUSING HOUSING
Rostral Rostral
TRANSDUCER TRANSDUCER
Key
Cross hatching shows
Insert with sound tube
EARPIECE
acoustically closed
EARPIECE
between transducer
earpad to accomplish
and earpiece (for SOUNDTUBE
SOUNDTUBE
minimum leakage.
example, stethoscopic
type of earphone for
Spotted by small circle
hearing aid)
shows porous material
PROTECTOR
PROTECTOR earpad to accomplish
TRANSDUCER
TRANSDUCER controlled leakage.
HOUSING
HOUSING
IEC  2482/09
Figure 1 (continued)
Type of earphone Closed-back Open-back
(does not emit significant (emits significant sound
sound radiation from the radiation from the back of
back of the transducer to the transducer to the
the external environment) external environment)
PROTECTOR PROTECTOR
HOUSING HOUSING
Acoustically closed
Dorsal Dorsal
(intended to prevent
acoustic coupling
back back
between the external
environment and
front front
the ear canal)
Rostral Rostral
EARPAD
EARPAD
TRANSDUCER TRANSDUCER
HOUSING HOUSING
Dorsal Dorsal
Acoustically open
(intentionally provides
an acoustic path back back
between the external
front front
environment and
the ear canal)
Rostral Rostral
EARPAD EARPAD
TRANSDUCER TRANSDUCER
PROTECTOR PROTECTOR
IEC  2483/09
NOTE 1 Arrows show sound flow or sound leakage.
NOTE 2 The transducers shown in the schematics are not necessary positioned in the centre of the housings or
concentric to the ear canal.
Figure 2 – Diagrams showing the four possible construction:
acoustically open or closed, and closed- or open-back
5 Marking of terminals, controls and polarity
Requirements for marking terminals and controls are given in IEC 60268-1, and for polarity in
IEC 60268-2. In addition, headphones which are intended to be worn with a particular earphone
on each ear shall be marked to indicate the "left" and "right" earphones. If a colour marking is
used, the "right" earphone shall be indicated by a red marking. For the sake of visually-impaired
persons, it is recommended to indicate the left earphone by a projection of at least 1,5 mm
diameter and 0,3 to 0,5 mm height.
6 User instructions
The user instructions shall include information on:
• connector contact assignments (see IEC 60268-11);
• controls and switches (if any);
• microphone (if any);
– 14 – IEC 60268-7:2010  IEC 2010
• diagram of the interconnections of the earphones (if more than one);
• classification code (see Clause 4);
• description of the type of headphone.
Information shall also be provided on the safe use of the headphone, using wording similar to:
“To prevent possible hearing damage, do not listen at high volume levels for long periods, do
not use the headphones while driving or cycling, or in any situation where you should be able
to hear other sounds. As a guide to setting the volume level, check that you can still hear
your own voice, when speaking normally while listening with the headphones."
If the headphone is supplied with auxiliary equipment, information shall also be provided on:
• pre-amplifiers and/or passive networks;
• receivers (for cordless systems);
• power supplies;
• other parts, such as magnetic pick-up devices.
7 Conditions for specifications and measurements
7.1 Rated conditions
For an explanation of the meaning of "rated conditions" and "rated value of a characteristic",
reference shall be made to IEC 60268-2.
The rated conditions for a headphone are:
• rated impedance;
• rated source e.m.f. (or power, see 8.4);
• rated noise e.m.f. (or power, see 8.4);
• rated source impedance (see Note);
• rated frequency range;
• rated long-term maximum input voltage (or power);
• rated maximum permanent noise source e.m.f. (or power);
• rated power supply voltage (if any);
• rated climatic conditions (temperature, humidity, air pressure);
• rated damage limited source e.m.f.;
• rated application force.
These values are taken from the manufacturer's specification, and are not subject to
measurement; they constitute the basis for measuring the other characteristics.
For climatic conditions, reference is made to IEC 60268-1, and further information is given in
IEC 60068-1 and IEC Guide 106.
NOTE The performance of most types of headphones depends very little on the source impedance. However, in
order to allow headphones of widely different impedances to be reasonably well-matched, in terms of the sound
pressure level produced, to a single headphone output on other equipment, IEC 61938 at present specifies a source
impedance of 120 Ω, intermediate between the lowest and highest likely impedances of available headphones. It is
thus important for the manufacturer to specify the rated source impedance, particularly if, for some reason, it is not
120 Ω.
7.2 Standard conditions for measurement
A headphone is working under standard conditions for measurement when all of the following
conditions are fulfilled.
a) At least one earphone is applied to the appropriate coupler or ear simulator, with the rated
application force.
b) A sinusoidal voltage at the standard measuring frequency is applied, in series with the rated
source impedance. The voltage shall be such that a sound pressure level of 94 dB (reference
20 µPa) is generated in the coupler or ear simulator. Unless otherwise stated, the standard
measuring frequency shall be 500 Hz. The input signal shall be applied at the point where the
signal from an amplifier or other equipment is applied when the headphone is in use. This point
may be the input of a piece of auxiliary equipment, such as a preamplifier.
As an alternative, the manufacturer may specify this condition as being a signal voltage
which dissipates a power of 1 mW in a pure resistance equal to the rated impedance of the
earphone being measured.
NOTE Electrostatic, piezo-electric, electret condenser and cordless headphones are within the scope of this
standard. The signal may be sent to the headphone by infra-red, radio, light or magnetic induction (either directly
to the transducers or to a magnetic pick-up device and amplifier). These types of headphone are more easily dealt
with by specifying the sound pressure level to be generated (the input signal being applied to the transmitter unit),
rather than by specifying the power in the rated impedance.
c) Unless otherwise specified by the manufacturer, volume controls are set at minimum
attenuation. For headphones supplied with a preamplifier, and for cordless headphones, the
manufacturer shall specify a reference position of the gain control for use in measurements.
Other controls shall be set at the designated "normal" positions, or at stated positions,
preferably those giving the greatest range of frequency response. Balance controls shall be
set for equal voltages at the terminals of the channels. Crosstalk controls shall be set for
minimum crosstalk.
d) If the headphone requires a power supply, the rated supply voltage and frequency are
applied.
7.3 Couplers and ear simulators
The manufacturer should use the coupler or ear simulator which is specified in the international
standard for the measurement of the headphone or earphone, for which results are to be
published. The manufacturer shall state the type of the used coupler or ear simulator in the
results.
NOTE Examples of the international standards specifying the couplers and ear simulators are IEC 60318-1,
IEC 60318-2, IEC 60318-3, IEC 60318-5, IEC 60711, ITU-T Recommendation P.57, 4.3 and the ear part of HATS
(Head and torso simulator) in IEC 60959.
For the measurement using the ear part of HATS (Head and Torso Simulator), the manufacturer
should use the model specified in IEC 60959 or equivalent, see ITU Recommendation P.58.
Hardness of the rubber pinna used shall be stated in the results, see ISO 7619-1 (2004).
Information for the pinna simulator suitable for measurements of headphones is given in
Annex A.
If the coupler or ear simulator except specified in the international standards was used, the
manufacturer shall state its physical parameters, shape, dimension, volume of the cavity, etc., to
maintain repeatability of measurement.
7.4 Measurement conditions for simulated programme signal
The conditions specified in 7.2 are applied except that the simulated programme signal specified
in IEC 60268-1 shall be applied. The following filters can be used to process the output signal of
the ear simulator:
– 16 – IEC 60268-7:2010  IEC 2010
• a weighting filter specified in IEC 61672-1;
• free field compensating filter, that is the filter with inverse response of the free field response
of the manikin specified in IEC 60959.
Measurement diagram by the simulated program signal is illustrated in Figure 3.

Headphones or earphone to be measured
Pinna simulator
Ear canal extention
HATS (IEC 60959)
Analyzer
Free field compensating
Signal
filter, if necessary
generator
Power
amplifier
SPS
Simulated
program signal
(IEC 60268-1)
A weighting filter,
Ear simulator
if necessary
(IEC 60711)
IEC  2484/09
NOTE The output signal correction can be done numerically without use of any filtering devices. Power summation
of the 1/3-octave-analized data multiplied by filtering coefficients given by IEC 61672-1 and/or IEC 60969 gives the
corrected voltage.
Figure 3 – Illustrated measurement diagram by simulated programme signal
7.5 Loudness comparison conditions
7.5.1 General
The response of a headphone to a given electrical signal may be determined by subjective
comparison of the loudness of the sound from the headphone with that of a reference sound field
derived from the same electrical signal. Headphones provided with earphones for both ears shall
be operated with uncorrelated signals, having the same spectrum and amplitude, applied to both
earphones simultaneously.
7.5.2 Free-field comparison conditions
A headphone is working under free-field comparison conditions when both of the following
conditions are fulfilled:
a) the headphone is worn by a test person in accordance with the manufacturer's instructions or
in the usual way for that type. It is necessary to fit the headphone in accordance with the
manufacturer's instructions, so that the earphones are correctly positioned, and the
application force is close to the rated value;
b) the reference sound field simulates a progressive plane wave. The acoustic signal shall have
a specified bandwidth and sound pressure level at a stated reference point, in the absence of
the test person.
Practical details of free-field comparison conditions are given in Annex C.

7.5.3 Diffuse-field comparison conditions
A headphone is working under diffuse-field comparison conditions when both of the following
conditions are fulfilled:
a) the headphone is worn by a test person in accordance with the manufacturer's instructions or
in the usual way for that type. It is necessary to fit the headphone in accordance with the
manufacturer's instructions, so that the earphones are correctly positioned, and the
application force is close to the rated value;
b) the reference sound field simulates a diffuse sound field, as described in ISO 3741. The
acoustic signal shall have a specified bandwidth and sound pressure level at a stated
reference point, in the absence of the test person.
Practical details of diffuse-field comparison conditions are given in Annex D. The use of a
reverberant chamber for the generation of the diffuse field is suitable for ear canal probe
measurements, but less suitable for subjective loudness level comparison, because of the long
reverberation time.
7.6 Ear canal sound pressure level measurement conditions
A headphone is working under ear canal sound pressure level measurement conditions when
the conditions for free-field comparison (7.5.2) or diffuse-field comparison (7.5.3) are fulfilled, in
addition to the following condition. A very small microphone, in accordance with the
requirements in Annex B, is positioned inside the ear canal of the test person, with its sound
entrance at least 4 mm from the entrance of the canal. Practical details of these conditions are
given in Annex E.
8 Characteristics to be specified and their methods of measurement
8.1 Power supply
If the headphone requires a power supply, the manufacturer shall specify:
• the type of power supply (a.c. or d.c.);
• the rated supply voltage and frequency, or their ranges (see IEC 60038) and/or type of
battery (see IEC 60086-1). These are rated conditions (see 7.1);
• the maximum power drawn from the power supply.
Headphones, which require or tolerate a small direct current in addition to the signal, are not
regarded as requiring a power supply. However, details of the required or maximum permissible
direct current shall be given.
8.2 Electrical impedance
8.2.1 Rated impedance
NOTE This is a rated condition, see 7.1.
Characteristics to be specified:
a) the value of a pure resistance which is specified by the manufacturer for matching purposes;
b) the rated impedance shall be chosen so that the lowest value of the modulus of the actual
impedance within the rated frequency range is not less than 80 % of the rated value. If the
impedance at any frequency between 0 kHz and 20 kHz is less than this value, this should be
stated in the specification.
– 18 – IEC 60268-7:2010  IEC 2010
8.2.2 Impedance/frequency characteristic
8.2.2.1 Characteristic to be specified
The characteristic to be specified is a representation of the modulus of the impedance as a
function of frequency.
8.2.2.2 Method of measurement
The method of measurement is detailed below.
a) The headphone is brought under standard conditions for measurement.
b) The signal is changed to a sinusoidal voltage or current of variable frequency, whose
amplitude is constant, and sufficiently small to ensure that the headphone operates in a
linear region.
c) The modulus of the impedance shall be measured, at least over the frequency range 20 Hz
to 20 kHz.
d) The results shall be presented graphically as a function of frequency. The value of signal
voltage or current shall be stated.
8.2.3 Rated source impedance
NOTE 1 This is a rated condition.
The characteristic
...