Acoustics - Reference zero for the calibration of audiometric equipment - Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions (ISO 389-7:2019)

This document specifies a reference threshold of hearing for the calibration of audiometric equipment used under the following conditions.
a)    The sound field in the absence of the listener consists of either a free progressive plane wave (free field) or a diffuse sound field, as specified in ISO 8253‑2. In the case of a free field, the source of sound is directly in front of the listener (frontal incidence).
b)    The sound signals are pure (sinusoidal) tones in the case of free-field conditions and one-third-octave bands of (white or pink) noise in the case of diffuse-field conditions.
c)    The sound pressure level is measured in the absence of the listener at the position where the centre of the listener's head would be.
d)    Listening is binaural.
NOTE 1    Correction values for the threshold of hearing under free-field listening conditions and selected angles of sound incidence (45° and 90°) deviating from frontal incidence are given in ISO 8253-2 for information.
NOTE 2    Other conditions are given in Reference [1].
The data are given in numerical form for the preferred frequencies in the one-third-octave series from 20 Hz to 16 000 Hz inclusive in accordance with ISO 266 and, in addition, for some intermediate audiometric frequencies up to 18 000 Hz.
The threshold data differ from the audiometric zero specified in ISO 389‑1, ISO 389‑2, ISO 389‑5 and ISO 389‑8, since the latter refer to monaural listening through earphones with sound pressure levels referred to specified couplers and ear simulators. Direct comparison between the data in the parts of ISO 389 mentioned above and in this document is therefore not appropriate.

Akustik Standard-Bezugspegel für die Kalibrierung von audiometrischen Geräten - Teil 7: Bezugshörschwellen unter Freifeld- und Diffusbedingungen (ISO 389-7:2019)

Dieses Dokument legt eine Bezugshörschwelle zur Kalibrierung audiometrischer Geräte fest, die unter den folgenden Bedingungen benutzt werden:
a) Das Schallfeld besteht bei Abwesenheit des Hörers entweder aus einer sich frei ausbreitenden ebenen Welle (Freifeld) oder ist ein diffuses Schallfeld, wie in ISO 8253 2 festgelegt. Im Falle eines Freifeldes befindet die Schallquelle direkt vor dem Hörer (frontaler Schalleinfall).
b) Die Schallsignale sind reine (Sinus-)Töne im Falle der Freifeldbedingungen sowie terzbandbreites (weißes oder rosa) Rauschen im Falle der Diffusfeldbedingungen.
c) Der Schalldruckpegel wird in Abwesenheit des Hörers an der Position des Mittelpunktes des Kopfes des Hörers gemessen.
d) Das Hören erfolgt binaural.
ANMERKUNG 1 Korrektionswerte für die Freifeld-Hörschwelle bei ausgewählten, von frontalem Schalleinfall abweichenden Einfallswinkeln (45° und 90°) sind zur Information in ISO 8253-2 angegeben.
ANMERKUNG 2 Weitere Bedingungen sind in [1] angegeben.
Die Daten sind als Zahlenwerte für die Vorzugsfrequenzen in Terzen von 20 Hz bis 16 000 Hz nach ISO 266 und zusätzlich für einige audiometrische Zwischenfrequenzen bis 18 000 Hz angegeben.
Die Hörschwellendaten von den in ISO 389 1, ISO 389 2, ISO 389 5 und ISO 389 8 festgelegten audiometrischen Standard-Bezugspegeln abweichen, da die letzteren für monaurales Hören mit Kopfhörern gelten, wobei sich Schalldruckpegel auf festgelegte Kuppler und Ohrsimulatoren beziehen. Deshalb ist ein direkter Vergleich zwischen den Daten in den vorgenannten Teilen von ISO 389 und im vorliegenden Dokument nicht möglich.

Acoustique - Zéro de référence pour l'étalonnage d'équipements audiométriques - Partie 7: Niveau liminaire de référence dans des conditions d'écoute en champ libre et en champ diffus (ISO 389-7:2019)

Le présent document spécifie un seuil d'audition de référence pour l'étalonnage des équipements audiométriques utilisés dans les conditions suivantes:
a)    le champ acoustique en l'absence de l'auditeur consiste soit en une onde plane progressive libre (champ libre), soit en un champ acoustique diffus, tel qu'il est spécifié dans l'ISO 8253-2. Dans le cas d'un champ libre, la source sonore se trouve directement en face de l'auditeur (incidence frontale);
b)    les signaux sonores sont des sons purs (sinusoïdaux) dans le cas des conditions en champ libre et des bandes de tiers d'octave de bruit (blanc ou rose) dans le cas des conditions en champ diffus;
c)    le niveau de pression acoustique est mesuré, en l'absence de l'auditeur, à la position qu'aurait dû occuper le centre de sa tête;
d)    l'écoute est binaurale.
NOTE 1    Les valeurs de correction relatives au seuil d'audition dans des conditions d'écoute en champ libre et selon des angles d'incidence sélectionnés (45° et 90°) s'écartant de l'incidence frontale sont données dans l'ISO 8253-2 pour information.
NOTE 2    Les autres conditions sont données dans la Référence [1].
Les données sont présentées sous forme numérique pour les fréquences normales dans la série du tiers d'octave de 20 Hz à 16 000 Hz inclus, conformément à l'ISO 266 et, en plus, pour certaines fréquences audiométriques intermédiaires jusqu'à 18 000 Hz.
Les données concernant le seuil d'audition diffèrent du zéro audiométrique spécifié dans l'ISO 389-1, l'ISO 389-2, l'ISO 389-5 et l'ISO 389-8, étant donné que ces dernières concernent l'écoute monaurale par écouteurs, les niveaux de pression acoustique étant mesurés sur des coupleurs et des oreilles artificielles spécifiés. Une comparaison directe entre les données figurant dans les parties de l'ISO 389 mentionnées plus haut et les données du présent document n'est donc pas appropriée.

Akustika - Referenčna ničla za umerjanje avdiometrov - 7. del: Referenčni prag slišnosti v razmerah prostega in difuznega zvočnega polja (ISO 389-7:2019)

Standard EN-ISO 389-7 poleg standarda ISO 16092-1 določa tehnične varnostne zahteve in zaščitne ukrepe, ki jih morajo sprejeti osebe, ki se ukvarjajo s projektiranjem, proizvodnjo in dobavljanjem pnevmatskih stiskalnic, zasnovanih za obdelavo hladnih kovin ali materialov, ki so delno izdelani iz hladnih kovin. Ta dokument obravnava vse večje nevarnosti, povezane s pnevmatskimi stiskalnicami, kadar se uporabljajo v skladu s predvidenim namenom in pod pogoji pričakovane nepravilne uporabe, ki jih določa proizvajalec (glej točko 4). Upoštevane so vse faze življenjske dobe stroja, kot je opisano v točki 5.4. standarda ISO 12100:2010. Podatki so podani v številski obliki za prednostne frekvence v tretjinskih oktavnih pasovih od 20 Hz do vključno 16.000 Hz v skladu s standardom ISO 266 in, dodatno, za nekatere vmesne avdiometrične frekvence do 18.000 Hz. Podatki o pragu se razlikujejo od avdiometrične ničle, opredeljene v standardih ISO 389-1, ISO 389-2, ISO 389-5 in ISO 389-8, saj se slednji navezujejo na monavralno poslušanje prek slušalk z ravnmi zvočnega tlaka, ki se navezujejo na navedene spojnike in simulatorje ušesa. Neposredna primerjava podatkov v zgoraj omenjenih delih standarda ISO 389 in v tem dokumentu zato ni primerna.

General Information

Status
Published
Publication Date
26-Nov-2019
Technical Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
27-Nov-2019
Completion Date
27-Nov-2019

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SLOVENSKI STANDARD
SIST EN ISO 389-7:2020
01-februar-2020
Nadomešča:
SIST EN ISO 389-7:2006
SIST EN ISO 389-7:2006/A1:2016
Akustika - Referenčna ničla za umerjanje avdiometrov - 7. del: Referenčni prag
slišnosti v razmerah prostega in difuznega zvočnega polja (ISO 389-7:2019)

Acoustics - Reference zero for the calibration of audiometric equipment - Part 7:

Reference threshold of hearing under free-field and diffuse-field listening conditions (ISO

389-7:2019)

Acoustique - Zéro de référence pour l'étalonnage d'équipements audiométriques - Partie

7: Niveau liminaire de référence dans des conditions d'écoute en champ libre et en

champ diffus (ISO 389-7:2019)
Ta slovenski standard je istoveten z: EN ISO 389-7:2019
ICS:
13.140 Vpliv hrupa na ljudi Noise with respect to human
beings
17.140.01 Akustična merjenja in Acoustic measurements and
blaženje hrupa na splošno noise abatement in general
SIST EN ISO 389-7:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 389-7:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 389-7:2020
EN ISO 389-7
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2019
EUROPÄISCHE NORM
ICS 13.140 Supersedes EN ISO 389-7:2005
English Version
Acoustics - Reference zero for the calibration of
audiometric equipment - Part 7: Reference threshold of
hearing under free-field and diffuse-field listening
conditions (ISO 389-7:2019)
Acoustique - Zéro de référence pour l'étalonnage
d'équipements audiométriques - Partie 7: Niveau
liminaire de référence dans des conditions d'écoute en
champ libre et en champ diffus (ISO 389-7:2019)
This European Standard was approved by CEN on 20 October 2019.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, 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: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 389-7:2019 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 389-7:2020
EN ISO 389-7:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 389-7:2020
EN ISO 389-7:2019 (E)
European foreword

This document (EN ISO 389-7:2019) 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 May 2020, and conflicting national standards shall be

withdrawn at the latest by May 2020.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 389-7:2005.

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, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 389-7:2019 has been approved by CEN as EN ISO 389-7:2019 without any modification.

---------------------- Page: 5 ----------------------
SIST EN ISO 389-7:2020
---------------------- Page: 6 ----------------------
SIST EN ISO 389-7:2020
INTERNATIONAL ISO
STANDARD 389-7
Third edition
2019-10
Acoustics — Reference zero for
the calibration of audiometric
equipment —
Part 7:
Reference threshold of hearing under
free-field and diffuse-field listening
conditions
Acoustique — Zéro de référence pour l'étalonnage d'équipements
audiométriques —
Partie 7: Niveau liminaire de référence dans des conditions d'écoute
en champ libre et en champ diffus
Reference number
ISO 389-7:2019(E)
ISO 2019
---------------------- Page: 7 ----------------------
SIST EN ISO 389-7:2020
ISO 389-7:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 389-7:2020
ISO 389-7:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Specification .............................................................................................................................................................................................................. 2

Annex A (informative) Notes on the derivation of the reference thresholds of hearing ................................5

Bibliography .............................................................................................................................................................................................................................10

© ISO 2019 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 389-7:2020
ISO 389-7:2019(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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 43, Acoustics.

This third edition cancels and replaces the second edition (ISO 389-7:2005), which has been technically

revised to incorporate the Amendment ISO 389-7:2005/Amd.1:2016. The main changes compared to

the previous edition are as follows:

— the reference thresholds of hearing at 20 Hz under the conditions of free-field and diffuse-field

listening and the reference threshold of hearing at 18 000 Hz under the condition of free-field

listening were recalculated using additional experimental data;
— the Bibliography was updated.
A list of all parts in the ISO 389 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2019 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 389-7:2020
ISO 389-7:2019(E)
Introduction

In some audiological applications, the test signals are delivered by means of loudspeakers, either in a

free sound field or in a diffuse sound field. This document specifies the reference zero for the calibration

of audiometric equipment used for sound field audiometry. Corresponding audiometric test methods

are specified in ISO 8253-1 and ISO 8253-2.

In common with other subjective phenomena, the threshold of hearing varies in detail from person

to person but, for a group of otologically normal persons within a restricted age range, values for

the central tendency can be determined to characterize the group. This document and other parts of

ISO 389 specify threshold data applicable to otologically normal persons in the age range from 18 years

to 25 years.
The data specified in this document relate to

a) pure tones heard under conditions of binaural listening in free progressive plane waves with

the subject directly facing the source of sound (frontal incidence), and with the sound pressure

level measured in the free progressive wave at the centre position of the listener’s head with the

listener absent;

b) one-third-octave bands of (white or pink) noise heard under conditions of binaural listening in a

diffuse sound field with the sound pressure level measured in the sound field at the centre position

of the listener’s head with the listener absent.

For frequencies up to 8 kHz, each set of data may be equally applied to any other bands of (white or

pink) noise for which the bandwidth is less than the critical bandwidth.

The data are based on an assessment of technical information provided by laboratories in different

countries representing the most reliable data available at the time. For information, a note on the

derivation of the reference values and the origin of the data is given in Annex A.

© ISO 2019 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 389-7:2020
---------------------- Page: 12 ----------------------
SIST EN ISO 389-7:2020
INTERNATIONAL STANDARD ISO 389-7:2019(E)
Acoustics — Reference zero for the calibration of
audiometric equipment —
Part 7:
Reference threshold of hearing under free-field and
diffuse-field listening conditions
1 Scope

This document specifies a reference threshold of hearing for the calibration of audiometric equipment

used under the following conditions.

a) The sound field in the absence of the listener consists of either a free progressive plane wave (free

field) or a diffuse sound field, as specified in ISO 8253-2. In the case of a free field, the source of

sound is directly in front of the listener (frontal incidence).

b) The sound signals are pure (sinusoidal) tones in the case of free-field conditions and one-third-

octave bands of (white or pink) noise in the case of diffuse-field conditions.

c) The sound pressure level is measured in the absence of the listener at the position where the centre

of the listener’s head would be.
d) Listening is binaural.

NOTE 1 Correction values for the threshold of hearing under free-field listening conditions and selected

angles of sound incidence (45° and 90°) deviating from frontal incidence are given in ISO 8253-2 for information.

NOTE 2 Other conditions are given in Reference [1].

The data are given in numerical form for the preferred frequencies in the one-third-octave series

from 20 Hz to 16 000 Hz inclusive in accordance with ISO 266 and, in addition, for some intermediate

audiometric frequencies up to 18 000 Hz.

The threshold data differ from the audiometric zero specified in ISO 389-1, ISO 389-2, ISO 389-5 and

ISO 389-8, since the latter refer to monaural listening through earphones with sound pressure levels

referred to specified couplers and ear simulators. Direct comparison between the data in the parts of

ISO 389 mentioned above and in this document is therefore not appropriate.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
© ISO 2019 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 389-7:2020
ISO 389-7:2019(E)
3.1
threshold of hearing

level of a sound at which, under specified conditions, a person gives 50 % of correct detection responses

on repeated trials

Note 1 to entry: The results of threshold determination depend to a certain degree on the test procedure used.

The data presented in the ISO 389 series are all based on the use of the threshold test procedures defined in

ISO 8253-1. When a test procedure with other characteristics is used, differences of up to several decibels on

average may be expected.
3.2
otologically normal person

person in a normal state of health who is free from all signs or symptoms of ear disease and from

obstructing wax in th
...

SLOVENSKI STANDARD
kSIST prEN ISO 389-7:2019
01-september-2019
Akustika - Referenčna ničla za umerjanje avdiometrov - 7. del: Referenčni prag
slišnosti v razmerah prostega in difuznega zvočnega polja (ISO/FDIS 389-7:2019)

Acoustics - Reference zero for the calibration of audiometric equipment - Part 7:

Reference threshold of hearing under free-field and diffuse-field listening conditions

(ISO/FDIS 389-7:2019)
Ta slovenski standard je istoveten z: prEN ISO 389-7
ICS:
13.140 Vpliv hrupa na ljudi Noise with respect to human
beings
17.140.01 Akustična merjenja in Acoustic measurements and
blaženje hrupa na splošno noise abatement in general
kSIST prEN ISO 389-7:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
kSIST prEN ISO 389-7:2019
---------------------- Page: 2 ----------------------
kSIST prEN ISO 389-7:2019
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 389-7
ISO/TC 43
Acoustics — Reference zero for
Secretariat: DIN
the calibration of audiometric
Voting begins on:
2019-06-27 equipment —
Voting terminates on:
Part 7:
2019-09-19
Reference threshold of hearing under
free-field and diffuse-field listening
conditions
Acoustique — Zéro de référence pour l'étalonnage d'équipements
audiométriques —
Partie 7: Niveau liminaire de référence dans des conditions d'écoute
en champ libre et en champ diffus
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 389-7:2019(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2019
---------------------- Page: 3 ----------------------
kSIST prEN ISO 389-7:2019
ISO/FDIS 389-7:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
kSIST prEN ISO 389-7:2019
ISO/FDIS 389-7:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Specification .............................................................................................................................................................................................................. 2

Annex A (informative) Notes on the derivation of the reference thresholds of hearing ................................5

Bibliography .............................................................................................................................................................................................................................10

© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
kSIST prEN ISO 389-7:2019
ISO/FDIS 389-7:2019(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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 43, Acoustics.

This third edition cancels and replaces the second edition (ISO 389-7:2005), which has been technically

revised to incorporate the Amendment ISO 389-7:2005/Amd.1:2016. The main changes compared to

the previous edition are as follows:

— the reference thresholds of hearing at 20 Hz under the conditions of free-field and diffuse-field

listening and the reference threshold of hearing at 18 000 Hz under the condition of free-field

listening were recalculated using a larger number of experimental data;
— the Bibliography was updated.
A list of all parts in the ISO 389 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members. html.
iv © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
kSIST prEN ISO 389-7:2019
ISO/FDIS 389-7:2019(E)
Introduction

In some audiological applications, the test signals are delivered by means of loudspeakers, either in a

free sound field or in a diffuse sound field. This document specifies the reference zero for the calibration

of audiometric equipment used for sound field audiometry. Corresponding audiometric test methods

are specified in ISO 8253-1 and ISO 8253-2.

In common with other subjective phenomena, the threshold of hearing varies in detail from person

to person but, for a group of otologically normal persons within a restricted age range, values for

the central tendency can be determined to characterize the group. This document and other parts of

ISO 389 specify threshold data applicable to otologically normal persons in the age range from 18 years

to 25 years.
The data specified in this document relate to

a) pure tones heard under conditions of binaural listening in free progressive plane waves with

the subject directly facing the source of sound (frontal incidence), and with the sound pressure

level measured in the free progressive wave at the centre position of the listener’s head with the

listener absent;

b) one third-octave bands of (white or pink) noise heard under conditions of binaural listening in a

diffuse sound field with the sound pressure level measured in the sound field at the centre position

of the listener’s head with the listener absent.

For frequencies up to 8 kHz, each set of data may be equally applied to any other bands of (white or

pink) noise for which the bandwidth is less than the critical bandwidth.

The data are based on an assessment of technical information provided by laboratories in different

countries representing the most reliable data available at the time. For information, a note on the

derivation of the reference values and the origin of the data is given in Annex A.

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kSIST prEN ISO 389-7:2019
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kSIST prEN ISO 389-7:2019
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 389-7:2019(E)
Acoustics — Reference zero for the calibration of
audiometric equipment —
Part 7:
Reference threshold of hearing under free-field and
diffuse-field listening conditions
1 Scope

This document specifies a reference threshold of hearing for the calibration of audiometric equipment

used under the following conditions.

a) The sound field in the absence of the listener consists of either a free progressive plane wave (free

field) or a diffuse sound field, as specified in ISO 8253-2. In the case of a free field, the source of

sound is directly in front of the listener (frontal incidence).

b) The sound signals are pure (sinusoidal) tones in the case of free field conditions and one third

octave bands of (white or pink) noise in the case of diffuse field conditions.

c) The sound pressure level is measured in the absence of the listener at the position where the centre

of the listener’s head would be.
d) Listening is binaural.

NOTE 1 Correction values for the threshold of hearing under free-field listening conditions and selected

angles of sound incidence (45° and 90°) deviating from frontal incidence are given in ISO 8253-2 for information.

NOTE 2 Other conditions are given in Reference [1].

The data are given in numerical form for the preferred frequencies in the one-third-octave series

from 20 Hz to 16 000 Hz inclusive in accordance with ISO 266 and, in addition, for some intermediate

audiometric frequencies up to 18 000 Hz.

The threshold data differ from the audiometric zero specified in ISO 389-1, ISO 389-2, ISO 389-5 and

ISO 389-8, since the latter refer to monaural listening through earphones with sound pressure levels

referred to specified couplers and ear simulators. Direct comparison between the data in the parts of

ISO 389 mentioned above and in this document is therefore not appropriate.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:/ /www .iso. org/obp
— IEC Electropedia: available at http: //www .electropedia. org/
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kSIST prEN ISO 389-7:2019
ISO/FDIS 389-7:2019(E)
3.1
threshold of hearing

level of a sound at which, under specified conditions, a person gives 50 % of correct detection responses

on repeated trials

Note 1 to entry: The results of threshold determination depend to a certain degree on the test procedure used.

The data presented in the ISO 389 series are all based on the use of the threshold test procedures defined in

ISO 8253-1. When a test procedure with other characteristics is used, differences of up to several decibels on

average may be expected.
3.2
otologically normal person

person in a normal state of health who is free from all signs or symptoms of ear disease and from

obstructing wax in the ear canals, and who has no history of undue exposure to noise, exposure to

potentially ototoxic substances, or familial hearing loss
3.3
reference threshold of hearing

at a specified frequency, sound pressure level of a pure tone or a one third-octave band of noise

corresponding to the median value of the binaural thresholds of hearing of otologically normal persons

(3.2) within the age limits from 18 years to 25 years inclusive
3.4
free sound field

sound field where the boundaries of the room exert a negligible effect on the sound waves

3.5
diffuse sound field

sound field consisting of sound waves arriving at a given location more or less simultaneously from all

directions with equal probability and level
4 Specification

The reference thresholds of hearing for the listening conditions specified in Clause 1 are given in

Table 1. This table also gives the differences between sound pressure levels of one third-octave bands

of noise in a diffuse sound field and the sound pressure levels of pure tones in a frontally incident free

progressive wave for equal thresholds of hearing. A graphical illustration of the reference thresholds of

hearing is given in Figure 1.

Table 1 — Reference thresholds of hearing for the listening conditions specified in Clause 1 and

differences between sound pressure levels in the two types of sound field
Frequency Reference threshold of hearing under the condition of Difference
free-field listening
diffuse-field listening
(frontal incidence)
T (ref. 20 μPa) T´ (ref. 20 μPa) ΔL = T − T´
f f f f
Hz dB dB dB
20 78,1 78,1 0
25 68,7 68,7 0
31,5 59,5 59,5 0
40 51,1 51,1 0
50 44,0 44,0 0
63 37,5 37,5 0
80 31,5 31,5 0
100 26,5 26,5 0
At 16 000 Hz, experimental data for ΔL was reported from one laboratory only.
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