EN 60118-0:2015

SLOVENSKI STANDARD
01-december-2015
1DGRPHãþD
SIST EN 60118-0:2002
SIST EN 60118-0:2002/A1:2002
SIST EN 60118-1:2002 + A1:2002
SIST EN 60118-2:2004
SIST EN 60118-2:2004/A2:2006
SIST EN 60118-6:2002
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Electroacoustics - Hearing aids - Measurement of the performance characteristics of
hearing aids
/
Electroacoustique Appareils de correction auditive Mesure des caractéristiques de
performance des corrections auditives
Ta slovenski standard je istoveten z: EN 60118-0:2015
ICS:
11.180.15 3ULSRPRþNL]DJOXKHRVHEHLQ Aids for deaf and hearing
RVHEH]RNYDURVOXKD impaired people
17.140.50 Elektroakustika Electroacoustics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 60118-0
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2015
ICS 17.140.50 Supersedes EN 60118-0:1993, EN 60118-1:1995, EN
60118-2:1995, EN 60118-6:1999
English Version
Electroacoustics - Hearing aids - Part 0: Measurement of the
performance characteristics of hearing aids
(IEC 60118-0:2015)
Electroacoustique - Appareils de correction auditive - Partie Akustik - Hörgeräte - Teil 0: Messung der
0: Mesure des caractéristiques fonctionnelles des appareils Leistungsmerkmale von Hörgeräten
de correction auditive (IEC 60118-0:2015)
(IEC 60118-0:2015)
This European Standard was approved by CENELEC on 2015-07-14. 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, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60118-0:2015 E
European foreword
The text of document 29/867A/FDIS, future edition 3 of IEC 60118-0, prepared by IEC TC 29,
Electroacoustics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
The following dates are fixed:
(dop) 2016-04-14
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2018-07-14
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60118-0:1993, EN 60118-1:1995, EN 60118-2:1995, EN 60118-6:1999.

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 60118-0:2015 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated :
IEC 60068 (series) NOTE Harmonized as EN 60068 (series).
IEC 60118-7:2005 NOTE Harmonized as EN 60118-7:2005.
IEC 60118-8:2005 NOTE Harmonized as EN 60118-8:2005.
IEC 60118-12 NOTE Harmonized as EN 60118-12.
IEC 60118-15 NOTE Harmonized as EN 60118-15.
IEC 60318-1 NOTE Harmonized as EN 60318-1.
IEC 60118-15 NOTE Harmonized as EN 60118-15.
IEC 60318-4:2010 NOTE Harmonized as EN 60318-4:2010.

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year

IEC 60318-5 -  Electroacoustics - Simulators of human EN 60318-5 -
head and ear -- Part 5: 2 cm³ coupler for the
measurement of hearing aids and
earphones coupled to the ear by means of
ear inserts
ISO 3 -  Preferred numbers; Series of preferred - -
numbers
IEC 60118-0 ®
Edition 3.0 2015-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electroacoustics – Hearing aids –

Part 0: Measurement of the performance characteristics of hearing aids

Électroacoustique – Appareils de correction auditive –

Partie 0: Mesure des caractéristiques fonctionnelles des appareils de correction

auditive
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50 ISBN 978-2-8322-2692-6

– 2 – IEC 60118-0:2015 © IEC 2015
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 8
4 General conditions . 12
4.1 Acoustic test method . 12
4.2 Acoustic coupler . 13
4.3 Measurement frequency range . 13
4.4 Reporting of data . 13
5 Test enclosure and test equipment . 13
5.1 General . 13
5.2 Unwanted stimuli in the test enclosure . 13
5.3 Sound source . 13
5.4 Measurement system for the measurement of the sound pressure level and
harmonic distortion produced by a hearing aid . 14
5.5 Direct-current measuring system . 14
5.6 Magnetic field source for ETLS and MASL measurements . 15
6 Test conditions . 15
6.1 General . 15
6.2 Control of the sound field . 16
6.3 Measurement configuration for directional hearing aids . 17
6.4 Normal operating conditions for a hearing aid . 18
6.4.1 General . 18
6.4.2 Battery or supply voltage . 18
6.4.3 Settings of controls . 19
6.4.4 Ambient conditions . 19
6.4.5 Sound outlet system . 19
6.4.6 Accessories . 20
7 Test procedures . 20
7.1 Frequency response curves . 20
7.2 OSPL90 frequency response curve . 20
7.3 Full-on gain response curve . 21
7.4 Basic frequency response curve . 21
7.4.1 Test procedure . 21
7.4.2 Frequency range . 22
7.4.3 Reference test gain (RTG) . 23
7.5 Total harmonic distortion . 23
7.6 Equivalent input noise . 23
7.7 Battery current . 23
7.8 Measurements for hearing aids having induction pick-up coil . 24
7.8.1 General . 24
7.8.2 Equivalent test loop sensitivity (ETLS) . 24
7.8.3 Maximum HFA magneto-acoustical sensitivity level (HFA MASL) of
induction pick-up coil . 24
8 Characteristics of electrical input circuits for hearing aids . 24
8.1 Electrical characteristics . 24
8.1.1 General . 24

IEC 60118-0:2015 © IEC 2015 – 3 –
8.1.2 Input impedance . 25
8.1.3 Input sensitivity . 25
8.2 Mechanical characteristics and electrical function of connector system for
electrical input. 25
9 Additional optional test procedures . 25
9.1 General . 25
9.2 Effects of tone control and gain control . 25
9.2.1 Basic frequency response: effect of tone control . 25
9.2.2 Frequency response: effect of gain control position . 25
9.2.3 Characteristics of the gain control . 26
9.3 Intermodulation distortion . 26
9.4 Effects of variation of battery or supply voltage and internal resistance . 26
9.4.1 Full-on gain . 26
9.4.2 OSPL90 . 27
9.4.3 Total harmonic distortion . 27
9.4.4 Total intermodulation distortion . 27
9.5 Equivalent input noise in one-third-octave bands . 27
9.6 Additional measurements for hearing aids having induction pick-up coil . 30
9.6.1 General . 30
9.6.2 Basic frequency response . 30
9.6.3 Frequency response with full-on gain control setting . 30
9.6.4 Effect of gain control position on frequency response . 30
9.6.5 Harmonic distortion . 31
9.7 Additional measurements for hearing aids having induction pick-up coil for
use with a telephone . 31
9.7.1 General . 31
9.7.2 SPLITS response curve . 32
9.7.3 HFA-SPLITS . 32
9.7.4 Relative simulated equivalent telephone sensitivity (RSETS). 32
9.8 Additional measurements applying to AGC hearing aids . 33
9.8.1 General . 33
9.8.2 Steady-state input-output characteristics . 33
9.8.3 Dynamic AGC characteristics (attack and release time) . 34
9.9 Additional optional measurements with ear simulator, according to
IEC 60318-4 . 34
9.9.1 General . 34
9.9.2 Output sound pressure level frequency response curve for an input
sound pressure level of 90 dB . 34
9.9.3 Full-on gain response curve . 34
9.9.4 Basic frequency response curve . 34
9.9.5 Presentation of data . 34
10 Maximum permitted expanded uncertainty of measurements . 34
Bibliography . 36

Figure 1 – Example of test arrangement for behind-the-ear hearing aid . 16
Figure 2 – Example of test arrangement for in-the-ear hearing aid . 17
Figure 3 – Example of test arrangement for directional hearing aid . 18
Figure 4 – Example of OSPL90 curve and basic frequency response curve . 21

– 4 – IEC 60118-0:2015 © IEC 2015
Figure 5 – Example of determination of frequency range from basic frequency
response curve . 22
Figure 6 – Example of hearing aid acoustic gain . 28
Figure 7 – Example of hearing aid output noise and test equipment noise . 29
Figure 8 – Hearing aid equivalent input noise and ambient noise . 29
Figure 9 – Telephone magnetic field simulator (TMFS) . 31
Figure 10 – Example of hearing aids on TMFS for SPLITS test . 32
Figure 11 – Example of a steady-state input-output characteristic . 33

Table 1 – Resistors and open circuit voltages for zinc-air battery simulators . 19
Table 2 – Distortion test frequencies and input sound pressure levels . 23
Table 3 – Values of U for basic measurements . 35
max
IEC 60118-0:2015 © IEC 2015 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS –
HEARING AIDS –
Part 0: Measurement of the performance
characteristics of hearing aids

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 60118-0 has been prepared by IEC technical committee 29:
Electroacoustics.
This third edition cancels and replaces the second edition published in 1983 and its
Amendment 1:1994 as well as IEC 60118-1:1995, Amendment 1:1998, IEC 60118-2:1983,
Amendment 1:1993, Amendment 2:1997 and IEC 60118-6:1999. This edition constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the use of an acoustic coupler according to IEC 60318-5;
b) the addition of measurements for automatic gain control circuits, for induction pick-up coil
inputs and for electrical inputs.

– 6 – IEC 60118-0:2015 © IEC 2015
The text of this standard is based on the following documents:
FDIS Report on voting
29/867A/FDIS 29/874/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 in the IEC 60118 series, published under the general title Electroacoustics –
Hearing aids, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website 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.
IEC 60118-0:2015 © IEC 2015 – 7 –
ELECTROACOUSTICS –
HEARING AIDS –
Part 0: Measurement of the performance
characteristics of hearing aids

1 Scope
This part of IEC 60118 gives recommendations for the measurement of the performance
characteristics of air conduction hearing aids based on a free field technique and measured
with an acoustic coupler.
This part of IEC 60118 is applicable to the measurement and evaluation of the
electroacoustical characteristics of hearing aids, for example for type testing and
manufacturer data sheets.
The test results obtained by the methods specified in this part of IEC 60118 will express the
performance under conditions of the test and may deviate substantially from the performance
of the hearing aid under actual conditions of use.
This part of IEC 60118 uses an acoustic coupler according to IEC 60318-5 which is only
intended for loading a hearing aid with a specified acoustic impedance and is not intended to
model the sound pressure in a person’s ear. The use of this acoustic coupler will yield
different results from those obtained using the occluded ear simulator of IEC 60318-4 as used
in former editions of IEC 60118-0.
For the measurement of the performance characteristics of hearing aids for simulated in situ
working conditions, IEC 60118-8 can be used. For measurement of hearing aids under typical
user settings and using a speech-like signal, IEC 60118-15 can be used.
For the measurement of the performance characteristics of hearing aids for production, supply
and delivery quality-assurance purposes, IEC 60118-7 can be used. The frequency range has
been extended to 8 kHz in this part of IEC 60118 as opposed to 5 kHz in IEC 60118-7.
Though the number of measurements covered by this part of IEC 60118 is limited, it is not
intended that all measurements described herein are mandatory.
In cases of custom-made in-the-ear instruments, the data supplied by the manufacturer
applies only to the particular hearing aid being tested.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60318-5, Electroacoustics – Simulators of human head and ear – Part 5: 2 cm coupler
for the measurement of hearing aids and earphones coupled to the ear by means of ear
inserts
ISO 3, Preferred numbers -- Series of preferred numbers

– 8 – IEC 60118-0:2015 © IEC 2015
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
hearing aid
wearable instrument intended to aid a person with impaired hearing
Note 1 to entry: A hearing aid usually consists of a microphone, amplifier, signal processor and earphone,
powered by a low-voltage battery and possibly also containing an induction pick-up coil. It is fitted using
audiometric and prescriptive methods.
Note 2 to entry: Hearing aids can be placed on the body (BW), behind the ear (BTE), in the ear (ITE) or in the
canal (ITC).
3.2
SPL
sound pressure level
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to
the square of a reference value, p , expressed in decibels, where the reference value, p , is
0 0
20 µPa
Note 1 to entry: This note applies to the French language only.
[SOURCE: ISO/TR 25417:2007, 2.2]
3.3
acoustic coupler
device for measuring the acoustic output of sound sources where the sound pressure is
measured by a calibrated microphone coupled to the source by a cavity of predetermined
shape and volume which does not necessarily approximate the acoustical impedance of the
normal human ear
3.4
ear simulator
device for measuring the acoustic output of sound sources where the sound pressure is
measured by a calibrated microphone coupled to the source so that the overall acoustic
impedance of the device approximates that of the normal human ear at a given location and in
a given frequency band
[SOURCE: IEC 60318-4:2010, 3.4]
3.5
input sound pressure level
sound pressure level at the hearing aid reference point
3.6
frequency response
sound pressure level measured in the acoustic coupler expressed as a function of frequency
under specified test conditions
3.7
basic frequency response curve
frequency response curve obtained at RTS with an input sound pressure level of 60 dB
3.8
input-output characteristic
for a single frequency, a plot of the sound pressure level measured in the acoustic coupler on
the ordinate, against the sound pressure level applied to the hearing aid on the abscissa, with
equal decibel scale divisions on each axis

IEC 60118-0:2015 © IEC 2015 – 9 –
3.9
vertical reference
line through or on a hearing aid which is vertical when the aid is positioned as worn on a head
and torso simulator (as per Figure C.1 in IEC 60118-8:2005) or, in the case of custom-made
hearing aids, as worn by a seated individual
3.10
reference point
point on the hearing aid chosen for the purpose of defining its position
3.11
test point
position in the test enclosure to which the measurements of the sound pressure level refer or
at which the strength of the magnetic field is determined and at which the hearing aid
reference point is located for test purposes
3.12
test space
space which contains the test point where the hearing aid is placed for testing
3.13
HFA
high-frequency average
average of gain or SPL in decibels at 1 000 Hz, 1 600 Hz and 2 500 Hz
Note 1 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.2]
3.14
acoustic gain
at each test frequency, the difference in decibels obtained by subtracting the input SPL from
the SPL developed by the output from the hearing aid in the acoustic coupler
[SOURCE: IEC 60118-7:2005, 3.5, modified — "to the hearing aid microphone" has been
deleted]
3.15
gain control
manually or electronically operated control for the adjustment of overall gain
[SOURCE: IEC 60118-7:2005, 3.6]
3.16
OSPL90
output SPL for 90 dB input SPL
SPL developed in the acoustic coupler with an input SPL of 90 dB with the gain control of the
hearing aid full-on
Note 1 to entry: It is recognized that the maximum output level may occur with more, or occasionally with less,
input SPL than 90 dB. However, the differences are usually small over the frequency range of interest and the
single input SPL of 90 dB makes automatic recording of the OSPL90 curve very convenient.
Note 2 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.7]

– 10 – IEC 60118-0:2015 © IEC 2015
3.17
HFA-OSPL90
high-frequency average OSPL90
high-frequency average of the OSPL90
Note 1 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.8, modified — "SPL levels" has been deleted from the
definition.]
3.18
HFA-FOG
high-frequency average full-on gain
HFA gain for an input SPL of 50 dB when the gain control of the hearing aid is at its full-on
position
Note 1 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.9]
3.19
RTS
reference test setting of the gain control
for an input SPL of 60 dB, the setting of the gain control required to produce an HFA-gain
within ± 1,5 dB of the HFA-OSPL90 minus 77 dB, or, if the full-on HFA gain for an input SPL
of 60 dB is less than the HFA-OSPL90 minus 77 dB, the full-on setting of the gain control
Note 1 to entry: For most hearing aids, the use of an input SPL of 60 dB and a 17 dB difference from the OSPL90
helps to ensure that, for an overall speech level of 65 dB SPL, peaks do not exceed the OSPL90.
Note 2 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.10]
3.20
RTG
reference test gain
HFA gain for an input SPL of 60 dB with the gain control at RTS
Note 1 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.11]
3.21
AGC
automatic gain control
means (other than peak clipping) by which the gain is automatically controlled as a function of
the level of the signal being amplified
Note 1 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.13]
3.22
AGC hearing aid
hearing aid incorporating automatic gain control (AGC)
[SOURCE: IEC 60118-7:2005, 3.14]

IEC 60118-0:2015 © IEC 2015 – 11 –
3.23
compression
type of AGC in which an incremental change in input sound pressure level produces a smaller
incremental change of output sound pressure level
3.24
expansion
type of AGC in which an incremental change in input sound pressure level produces a larger
incremental change of output sound pressure level
3.25
directional hearing aid
hearing aid for which the gain is dependent on the direction of sound incidence when
measured under free-field conditions
[SOURCE: IEC 60118-7:2005, 3.15]
3.26
non-directional hearing aid
hearing aid for which the gain is independent of the direction of sound incidence when
measured under free-field conditions
[SOURCE: IEC 60118-7:2005, 3.16]
3.27
supply voltage
voltage at the battery terminals of the hearing aid with the hearing aid switched on
3.28
magneto-acoustical sensitivity
at a specified frequency and under essentially linear input/output conditions, the quotient of
the sound pressure in pascals (Pa) produced by the hearing aid in the acoustic coupler and
the magnetic field strength in milliamperes per metre (mA/m) at the test point
3.29
MASL
magneto-acoustical sensitivity level
twenty times the logarithm to the base 10 of the ratio of the magneto-acoustical sensitivity to
the reference sensitivity 20 Pa/(1 mA/m)
Note 1 to entry: MASL is expressed in decibels.
Note 2 to entry: This note applies to the French language only.
3.30
maximum magneto-acoustical sensitivity level
maximum obtainable MASL, allowing all possible settings of the hearing aid controls
3.31
SPLIV
SPL in a vertical magnetic field
SPL developed in the acoustic coupler with the gain control at RTS when the input is
−30 dB re 1 A/m (= 31,6 mA/m) sinusoidal alternating magnetic field parallel to the vertical
reference with T-programme selected
Note 1 to entry: This note applies to the French language only.

– 12 – IEC 60118-0:2015 © IEC 2015
3.32
HFA-SPLIV
high frequency average SPL in a vertical magnetic field
high-frequency average of the SPLIV levels
Note 1 to entry: This note applies to the French language only.
3.33
ETLS
equivalent test loop sensitivity
difference in decibels obtained by subtracting the RTG + 60 dB from the HFA-SPLIV
Note 1 to entry: This note applies to the French language only.
[SOURCE: IEC 60118-7:2005, 3.19, modified — In the definition, "HFA-SPLI" has been
replaced by "HFA-SPLIV".]
3.34
SPLITS
SPL for an inductive telephone simulator
SPL developed in the coupler by a hearing aid with the gain control in the RTS when the input
is the magnetic field generated by a telephone magnetic field simulator
Note 1 to entry: This note applies to the French language only.
3.35
HFA-SPLITS
high frequency average (HFA) SPL for an inductive telephone simulator
high-frequency average of the SPLITS values
Note 1 to entry: This note applies to the French language only.
3.36
RSETS
relative simulated equivalent telephone sensitivity
difference in decibels obtained by subtracting the RTG + 60 dB SPL from the HFA-SPLITS
Note 1 to entry: This note applies to the French language only.
3.37
TMFS
telephone magnetic field simulator
device for producing a magnetic field of consistent level and geometric shape when driven by
a current of I = 6/N mA, where N is the number of coil turns
Note 1 to entry: This note applies to the French language only.
4 General conditions
4.1 Acoustic test method
The preferred acoustic test procedure is based on a method of measurement in which the
sound pressure level at the hearing aid reference point is kept constant to simulate free field
conditions. This is accomplished in a test enclosure or acoustic test box by the use of a
pressure-calibrated control microphone, on the assumption that the sound field is
homogeneous around the reference point of the hearing aid.
This method is designated "constant entrance sound pressure method" or shortened
"pressure method" throughout this part of IEC 60118.

IEC 60118-0:2015 © IEC 2015 – 13 –
As an alternative to the pressure method, storage of a test enclosure frequency response
correction curve may be used. This method is designated “substitution method”.
For testing directional hearing aids, manufacturer and purchaser should use acoustic test
boxes of the same make and type to secure identical measurement conditions.
NOTE 1 The test results can differ substantially from those obtained under real free-field conditions, especially for
body-worn types of hearing aids having the sound entry located on the surface of the outer housing where the
housing may have physical dimensions comparable to the wavelength of the incident sound.
For measuring the variation of acoustical parameters of hearing aids as a function of the
direction of sound incidence, plane progressive wave conditions (i.e. not having standing
wave conditions) are required.
NOTE 2 Small acoustic test boxes in which progressive wave conditions are not present cannot therefore be used
for this purpose.
NOTE 3 The results from testing directional hearing aids may not represent the true directional characteristics of
the hearing aid.
4.2 Acoustic coupler
Measurements of the hearing aid performance characteristics are made using a 2 cm
acoustic coupler in accordance with IEC 60318-5.
NOTE The basic specifications of IEC 60318-5 are limited to the frequency range 125 Hz to 8 000 Hz.
For any type of air conduction hearing aids, sound leakage from the coupling tube shall be
low enough not to affect the test result. One way of accomplishing this is to use a rigid tube.
The dimensions of the tubing shall be maintained in accordance with IEC 60318-5.
4.3 Measurement frequency range
All measurements shall be made for a stated frequency range (also named bandwidth) of
200 Hz to 8 000 Hz.
4.4 Reporting of data
All data reported shall be clearly labelled: "According to IEC 60118-0:2015".
5 Test enclosure and test equipment
5.1 General
The conditions specified in 5.2 to 5.6 apply. Measurements shall be made at the ISO R40
preferred frequencies (1/40 decade or 1/12 octave) as specified in ISO 3 unless otherwise
stated.
5.2 Unwanted stimuli in the test enclosure
Unwanted stimuli in the test enclosure, such as ambient noise, mechanical vibrations and
electrical or magnetic stray fields shall be sufficiently low so as not to affect the test results by
more than 0,5 dB. This can be verified if the output level of the hearing aid falls by at least
10 dB in each frequency analysis band, when the signal source is switched off.
5.3 Sound source
5.3.1 The sound source (pure-tone) shall be capable of producing at the test point the
requisite sound pressure levels between 50 dB and 90 dB, with a minimum step size of 5 dB.

– 14 – IEC 60118-0:2015 © IEC 2015
The level of the sound source shall be within ± 1,5 dB of the indicated value over the
frequency range from 200 Hz to 3 000 Hz, and within ± 2,5 dB of the indicated value over the
range from 3 000 Hz to 8 000 Hz.
If the calibration of the sound source depends on ambient conditions, corrections for such
dependence shall be made when necessary.
5.3.2 The frequency of the sound source shall be within ± 2 % of the indicated value. The
frequency interval between data points in frequency response curves shall not exceed one-
twelfth octave or 100 Hz, whichever is greater.
5.3.3 For frequency response and full-on gain measurements, the total harmonic distortion
of the sound source shall not exceed 1 % for a sound pressure level up to and including 70 dB
and 2 % for a sound pressure level greater than 70 dB and up to and including 90 dB.
For harmonic distortion measurements, the total harmonic distortion of the sound source at
the frequencies of the THD measurement shall not exceed 0,5 % up to and including a sound
pressure level of 70 dB and 1 % for a sound pressure level greater than 70 dB and up to and
including 90 dB.
5.4 Measurement system for the measurement of the sound pressure level and
harmonic distortion produced by a hearing aid
The equipment for the measurement of the sound pressure level produced by the hearing aid
shall fulfil the following requirements.
a) The sound pressure level measurement system shall be accurate within ± 0,5 dB at the
frequency of calibration.
b) The indication of sound pressure level relative to the indication at the frequency of
calibration shall be measured with an expanded uncertainty of no more than ± 1 dB in the
range from 200 Hz to 5 000 Hz and within ± 2 dB in the range from 5 000 Hz to 8 000 Hz.
If, under certain conditions, it is necessary to use a selective measuring system in order to
ensure that the response of the hearing aid to the signal can be differentiated from
inherent noise in the hearing aid, the use of the selective system shall be stated in the test
report.
c) The total harmonic distortion in the measuring equipment shall be less than 1 % for sound
pressure levels up to 130 dB and less than 2 % for levels above, up to and including
145 dB.
5.5 Direct-current measuring system
The direct-current measuring system shall have the following characteristics:
a) a tolerance of ± 5 % at the value of current measured;
b) direct-current voltage drop across current-measuring device ≤ 50 mV;
c) an impedance not exceeding 1 Ω over the frequency range 200 Hz to 8 000 Hz.
One method of realizing item c) above is to bypass the current meter with an 8 000 µF
capacitor. The capacitor should not shunt the battery or the power supply.

IEC 60118-0:2015 © IEC 2015 – 15 –
5.6 Magnetic field source for ETLS and MASL measurements
5.6.1 For the measurement of the equivalent test loop sensitivity (ETLS) and the magneto-
acoustical sensitivity level (MASL), the magnetic field strength produced by the magnetic loop
is computed from the geometry of the loop.
5.6.2 As the material and the construction of the power source may influence the results,
the actual type of source should be stated.
NOTE 1 For example, the magnetic field strength in the centre of a square loop with a side of "a" metres and
carrying a current of "i" amperes is given by:
2 2 i
H = A/m
π a
In the centre of a circular loop with a diameter of "d" in metres, carrying a current of "i" amperes, the magnetic field
strength is given by:
i
H = A/m
d
NOTE 2 One way to secure essentially constant current conditions is to drive the magnetic field source from a
device having a constant electromotive force and an internal impedance at least 100 times greater than the
magnetic field source input impedance in the frequency range 200 Hz to 8 000 Hz, which, in the case of a low
impedance generator, can be accomplished by a resistor connected in series with the output of the generator.
5.6.3 The test space shall be remote from any field-disturbing iron or other ferromagnetic
material or other material in which eddy currents can be induced that could give rise to a field
disturbance.
5.6.4 The magnetic field source shall be provided with a calibration expressing the
relationship between the magnetic fie
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