EN ISO 389-3:2016

SLOVENSKI STANDARD
01-junij-2016
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SIST EN ISO 389-3:1999
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Acoustics - Reference zero for the calibration of audiometric equipment - Part 3:
Reference equivalent threshold vibratory force levels for pure tones and bone vibrators
(ISO 389-3:2016)
Akustik - Standard-Bezugspegel für die Kalibrierung audiometrischer Geräte - Teil 3:
Äquivalente Bezugs-Schwellenkraftpegel für reine Töne und Knochenleitungshörer (ISO
389-3:2016)
Acoustique - Zéro de référence pour l'étalonnage d'équipements audiométriques - Partie
3: Niveaux de référence équivalents de force vibratoire liminaire pour les vibrateurs à
sons purs et les ossivibrateurs (ISO 389-3:2016)
Ta slovenski standard je istoveten z: EN ISO 389-3:2016
ICS:
13.140 Vpliv hrupa na ljudi Noise with respect to human
beings
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 389-3
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2016
EUROPÄISCHE NORM
ICS 13.140 Supersedes EN ISO 389-3:1998
English Version
Acoustics - Reference zero for the calibration of
audiometric equipment - Part 3: Reference equivalent
threshold vibratory force levels for pure tones and bone
vibrators (ISO 389-3:2016)
Acoustique - Zéro de référence pour l'étalonnage Akustik - Standard-Bezugspegel für die Kalibrierung
d'équipements audiométriques - Partie 3: Niveaux de audiometrischer Geräte - Teil 3: Äquivalente Bezugs-
référence équivalents de force vibratoire liminaire Schwellenkraftpegel für reine Töne und
pour les vibrateurs à sons purs et les ossivibrateurs Knochenleitungshörer (ISO 389-3:2016)
(ISO 389-3:2016)
This European Standard was approved by CEN on 2 January 2016.

CEN 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 CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 389-3:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 389-3:2016) has been prepared by Technical Committee ISO/TC 43 "Acoustics"
in collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by
DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2016, and conflicting national standards shall
be withdrawn at the latest by August 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 389-3:1998.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 389-3:2016 has been approved by CEN as EN ISO 389-3:2016 without any modification.
INTERNATIONAL ISO
STANDARD 389-3
Second edition
2016-02-01
Acoustics — Reference zero for
the calibration of audiometric
equipment —
Part 3:
Reference equivalent threshold
vibratory force levels for pure tones
and bone vibrators
Acoustique — Zéro de référence pour l’étalonnage d’équipements
audiométriques —
Partie 3: Niveaux de référence équivalents de force vibratoire
liminaire pour les vibrateurs à sons purs et les ossivibrateurs
Reference number
ISO 389-3:2016(E)
©
ISO 2016
ISO 389-3:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 389-3:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Reference equivalent threshold vibratory force levels (RETVFL) . 3
5 Test conditions and requirements . 4
5.1 General . 4
5.2 Bone vibrator . . 4
5.3 Fitting of the bone vibrator . 4
5.4 Mechanical coupler . 5
5.5 Test signal . 5
5.6 Masking noise . 5
5.7 Masking transducer . 5
5.8 Fitting of masking transducer . 5
5.9 Baseline masking level . 6
Annex A (informative) Note on the derivation of RETVFL values . 7
Annex B (informative) Guidance on the application of the reference zero to the calibration
of bone-conduction audiometers . 8
Annex C (informative) Differences in reference equivalent threshold vibratory force levels
between forehead and mastoid location of vibrator .10
Annex D (informative) Bone-conduction threshold of hearing for frequencies below 250 Hz .12
Bibliography .13
ISO 389-3:2016(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 43, Acoustics.
This second edition cancels and replaces the first edition (ISO 389-3:1994), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 389-3:1994/Cor 1:1995.
ISO 389 consists of the following parts, under the general title Acoustics — Reference zero for the
calibration of audiometric equipment:
— Part 1: Reference equivalent threshold sound pressure levels for pure tones and supra-aural earphones
— Part 2: Reference equivalent threshold sound pressure levels for pure tones and insert earphones
— Part 3: Reference equivalent threshold vibratory force levels for pure tones and bone vibrators
— Part 4: Reference levels for narrow-band masking noise
— Part 5: Reference equivalent threshold sound pressure levels for pure tones in the frequency range
8 kHz to 16 kHz
— Part 6: Reference threshold of hearing for test signals of short duration
— Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions
— Part 8: Reference equivalent threshold sound pressure levels for pure tones and circumaural earphones
— Part 9: Preferred test conditions for the determination of reference hearing threshold levels
iv © ISO 2016 – All rights reserved

ISO 389-3:2016(E)
Introduction
Each part of ISO 389 specifies a specific reference zero for the calibration of audiometric equipment.
ISO 389-1, ISO 389-2 and ISO 389-8 are applicable to audiometric equipment for the transmission of
pure tones by air conduction.
For clinical diagnostic and other audiometric purposes, it is often necessary to compare the measured
hearing threshold levels of a person for sound transmitted to the inner ear by the air-conduction and
bone-conduction pathways, respectively. Bone-conducted sound is provided for this purpose by an
electromechanical vibrator applied to the mastoid prominence or to the forehead of the person under test.
The reference zero for the calibration of audiometric equipment for air conduction is defined in
ISO 389-1, ISO 389-2 and ISO 389-8 in terms of reference equivalent threshold sound pressure levels
(RETSPL), i.e. threshold sound pressure levels produced in an ear simulator or acoustic coupler of
specified characteristics by supra-aural, circumaural or insert earphones of various patterns, when
excited electrically at a level corresponding to the threshold of hearing of young otologically normal
persons. Similarly, this part of ISO 389 provides a reference zero for bone-conduction audiometry in
terms of reference equivalent threshold vibratory force levels (RETVFL), i.e. the vibratory force levels
produced by a bone vibrator on a specified mechanical coupler when the vibrator is excited electrically
at a level corresponding to the threshold of hearing of young otologically normal persons. In some
countries, the preferred location is the mastoid prominence; in other countries, the forehead location
is used in addition to the mastoid prominence. Different RETVFL values are valid for each of the two
positions (see Annex C).
For bone-conduction measurements, it is necessary to specify the static force of application of the
vibrator to the test subject and to the mechanical coupler, as well as certain geometrical features of the
vibrator tip. In addition, it is usually necessary to apply masking noise to the ear not under test, since
excitation of the cranial bones by the vibrator may be heard by that ear instead of (or in addition to) the
ear intended for the test. An appropriate specification of the masking noise is, therefore, required as an
adjunct to the reference equivalent threshold vibratory force levels, and such a specification is given
in this part of ISO 389. Due to the so-called “occlusion effect” whereby the wearing of the transducer
needed to provide the (air-conducted) masking noise causes a lowering of the bone-conduction
threshold of hearing of the ear receiving the masking signal, it is necessary for the level of masking
noise to be raised to cancel out the occlusion effect and provide adequate masking of the ear not under
test. The specification of masking noise given in this part of ISO 389 is based on the procedures used in
the experimental investigations from which the reference zero of this part of ISO 389 is derived.
Use of this reference zero to calibrate audiometers will ensure that measured bone-conduction hearing
threshold levels of persons with unimpaired hearing or with hearing losses of purely sensorineural
type (i.e. having unimpaired outer and middle ear function) will be compatible with the air-conduction
hearing threshold levels of the same persons when using the reference zero of ISO 389-1, ISO 389-2 or
ISO 389-8, respectively. Although exact equivalence of air-conduction and bone-conduction thresholds
for any individual in these classes cannot be expected, due to biological variability of sound transmission
through the external and middle ear and through the cranial bones, this part of ISO 389 will ensure
that systematic deviations averaged over groups of such persons are reduced to a practical minimum.
This part of ISO 389 is based on an assessment of technical data provided by laboratories in three
countries using methods of threshold testing which, in the respects described, were essentially uniform.
Examination of the data showed that the experimental results were consistent. It has, therefore, been
possible to standardize a reference zero by means of RETVFL values which are to be used for all bone
vibrators used in audiometry having similar characteristics to those used by the laboratories. The
systematic uncertainties introduced by this deliberate simplification will be small in comparison to the
usual step size of hearing level controls in clinical audiometers (5 dB).
INTERNATIONAL STANDARD ISO 389-3:2016(E)
Acoustics — Reference zero for the calibration of
audiometric equipment —
Part 3:
Reference equivalent threshold vibratory force levels for
pure tones and bone vibrators
1 Scope
This part of ISO 389 specifies the following data applicable to the calibration of bone vibrators for pure-
tone bone-conduction audiometry:
a) reference equivalent threshold vibratory force levels (RETVFL), corresponding to the threshold of
hearing of young otologically normal persons by bone-conduction audiometry;
b) essential characteristics of the bone vibrator and the method of coupling to the test subject, and to
the mechanical coupler;
c) essential characteristics of the masking noise and the baseline masking noise level applied to the
ear not under test.
Guidance on the practical application of this part of ISO 389 in the calibration of audiometers is
given in Annex B.
RETVFL is the vibratory force level transmitted to a mechanical coupler of specified characteristics by a
vibrator when applied to the mechanical coupler under stated conditions of test and when energized at the
voltage level corresponding to the normal threshold of hearing for location on the mastoid prominence.
NOTE 1 Values for the differences in reference equivalent threshold vibratory force levels between location on
the forehead and mastoid are included for information in Annex C.
NOTE 2 Recommended procedures for carrying out bone-conduction audiometry are specified in ISO 8253-1.
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.
ISO 389-1, Acoustics — Reference zero for the calibration of audiometric equipment — Part 1: Reference
equivalent threshold sound pressure levels for pure tones and supra-aural earphones
ISO 389-2, Acoustics — Reference zero for the calibration of audiometric equipment — Part 2: Reference
equivalent threshold sound pressure levels for pure tones and insert earphones
ISO 389-4, Acoustics — Reference zero for the calibration of audiometric equipment — Part 4: Reference
levels for narrow-band masking noise
IEC 60318-6, Electroacoustics — Simulators of human head and ear — Part 6: Mechanical coupler for the
measurement of bone vibrators
ISO 389-3:2016(E)
3 Terms and definitions
For the purposes of this document, the definitions given in ISO 389-1 and ISO 389-2, and the following
terms and definitions apply.
3.1
bone conduction
transmission of sound to the inner ear primarily by means of mechanical vibration of the cranial bones
3.2
bone vibrator
electromechanical transducer intended to produce the sensation of hearing by vibrating the cranial bones
3.3
vibratory force level
ten times the logarithm to base ten of the ratio of the mean square vibratory force by the square of the
reference force, 1 μN
Note 1 to entry: The vibratory force level is expressed in decibels (dB).
3.4
mechanical coupler
device for calibrating bone vibrators, designed to present a specified mechanical impedance to a bone
vibrator applied with a specified static force, an
...