Acoustics - Audiometric test methods - Part 3: Speech audiometry (ISO 8253-3:2012)

ISO 8253-3:2012 specifies basic methods for speech recognition tests for audiological applications.
In order to ensure minimum requirements of precision and comparability between different test procedures including speech recognition tests in different languages, ISO 8253-3:2012 specifies requirements for the composition, validation and evaluation of speech test materials, and the realization of speech recognition tests. ISO 8253-3:2012 does not specify the contents of the speech material because of the variety of languages.
Furthermore, ISO 8253-3:2012 also specifies the determination of reference values and fulfilment requirements for the realization and manner of presentation.
ISO 8253-3:2012 specifies procedures and requirements for speech audiometry with the recorded test material being presented by air conduction through an earphone, or from a loudspeaker for sound field audiometry. Methods for using noise either for masking the non-test ear or as a competing sound are described.
Some test subjects, for example children, can require amended test procedures not specified in ISO 8253-3:2012.
Specialized tests such as those used for evaluating directional hearing and dichotic hearing are outside the scope of ISO 8253-3:2012.

Akustik - Audiometrische Prüfverfahren - Teil 3: Sprachaudiometrie (ISO 8253-3:2012)

Dieser Teil von ISO 8253 beschreibt grundlegende Verfahren für in der Audiologie angewandte Sprachverständlichkeitstests.
Im Hinblick auf die Vielzahl der Sprachen legt ISO 8253-3 nicht die Inhalte der einzelnen Sprachmaterialien
fest. Um sicherzustellen, dass Mindestanforderungen hinsichtlich der Genauigkeit und der Vergleichbarkeit
zwischen verschiedenen Testverfahren - einschließlich Sprachverständlichkeitstests in verschiedenen Sprachen
- eingehalten werden, beschreibt diese Norm Anforderungen an die Zusammensetzung, Validierung
und Auswertung von Sprachtestmaterialien und an die Realisierung von Sprachverständlichkeitstests.
Weiterhin beschreibt diese Norm, wie Bezugswerte zu bestimmen sind und welche Anforderungen an die
Realisierung und die Art der Darbietung erfüllt werden müssen.
Dieser Teil von ISO 8253 legt Verfahren und Anforderungen für die Sprachaudiometrie mit aufgezeichnetem
Sprachtestmaterial fest, das über Luftleitung durch einen Kopfhörer, über Knochenleitung durch einen Knochenleitungshörer
oder über einen Lautsprecher für die Schallfeldaudiometrie angeboten wird. Die Verfahren
für den Einsatz von Rauschen, entweder zur Verdeckung am nichtgeprüften Ohr oder als Zusatzschall, werden
beschrieben. Alle Prüfverfahren beruhen auf der Verwendung offener Prüfmaterialien.
Einige Probanden, z. B. Kinder, können geänderte Prüfabläufe erfordern, die nicht in diesem Teil von
ISO 8253 festgelegt sind.
Dieser Teil von ISO 8253 legt keine speziellen Prüfverfahren fest, wie sie für die Bestimmung des Richtungshörens
und des dichotischen Hörens verwendet werden.

Acoustique - Méthodes d'essais audiométriques - Partie 3: Audiométrie vocale (ISO 8253-3:2012)

Akustika - Avdiometrijske preskusne metode - 3. del: Govorna avdiometrija (ISO 8253-3:2012)

Ta del standarda ISO 8253 določa osnovne preskusne metode za prepoznavanje govora za avdiološke naprave. Za zagotovitev minimalnih zahtev glede natančnosti in primerljivosti med različnimi preskusnimi postopki, vključno s preskusi prepoznavanja govora v različnih jezikih, ta del standarda ISO 8253 določa zahteve za sestavo, validacijo in vrednotenje gradiva za preskus govora ter izvedbo preskusov prepoznavanja govora. Ta del standarda ISO 8253 zaradi različnih jezikov ne določa vsebine govornega gradiva. Ta del standarda ISO 8253 določa tudi referenčne vrednosti ter izpolnjevanje zahtev za izvedbo in obliko predstavitve. Ta del standarda ISO 8253 določa postopke in zahteve za govorno avdiometrijo, pri čemer je posneto preskusno gradivo predstavljeno s prevajanjem po zraku prek slušalk ali zvočnika pri avdiometriji zvočnega polja. Opisane so metode za uporabo hrupa kot sredstva za zakrivanje ušesa, ki ne sodeluje pri preskusu, ali kot konkurenčnega zvoka. Pri nekateri preskuševalcih, na primer otrocih, so mogoče potrebni prilagojeni preskusni postopki, ki niso določeni v tem delu standarda ISO 8253. Specializirani preskusi, kot so preskusi, ki se uporabljajo za vrednotenje usmerjenega sluha in razdeljenega sluha, niso zajeti v tem delu standarda ISO 8253.

General Information

Status
Withdrawn
Publication Date
29-Feb-2012
Technical Committee
Current Stage
9960 - Withdrawal effective - Withdrawal
Completion Date
09-Feb-2022

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SLOVENSKI STANDARD
SIST EN ISO 8253-3:2012
01-september-2012
1DGRPHãþD
SIST EN ISO 8253-3:1999
Akustika - Avdiometrijske preskusne metode - 3. del: Govorna avdiometrija (ISO
8253-3:2012)

Acoustics - Audiometric test methods - Part 3: Speech audiometry (ISO 8253-3:2012)

Akustik - Audiometrische Prüfverfahren - Teil 3: Sprachaudiometrie (ISO 8253-3:2012)

Acoustique - Méthodes d'essais audiométriques - Partie 3: Audiométrie vocale (ISO

8253-3:2012)
Ta slovenski standard je istoveten z: EN ISO 8253-3:2012
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
SIST EN ISO 8253-3:2012 en

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

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SIST EN ISO 8253-3:2012
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SIST EN ISO 8253-3:2012
EUROPEAN STANDARD
EN ISO 8253-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2012
ICS 13.140 Supersedes EN ISO 8253-3:1998
English Version
Acoustics - Audiometric test methods - Part 3: Speech
audiometry (ISO 8253-3:2012)

Acoustique - Méthodes d'essais audiométriques - Partie 3: Akustik - Audiometrische Prüfverfahren - Teil 3:

Audiométrie vocale (ISO 8253-3:2012) Sprachaudiometrie (ISO 8253-3:2012)
This European Standard was approved by CEN on 29 February 2012.

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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8253-3:2012: E

worldwide for CEN national Members.
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SIST EN ISO 8253-3:2012
EN ISO 8253-3:2012 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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SIST EN ISO 8253-3:2012
EN ISO 8253-3:2012 (E)
Foreword

This document (EN ISO 8253-3:2012) 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 DS.

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 September 2012, and conflicting national standards shall be

withdrawn at the latest by September 2012.

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 8253-3:1998.

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, 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 8253-3:2012 has been approved by CEN as a EN ISO 8253-3:2012 without any modification.

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SIST EN ISO 8253-3:2012
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SIST EN ISO 8253-3:2012
INTERNATIONAL ISO
STANDARD 8253-3
Second edition
2012-03-01
Acoustics — Audiometric test methods —
Part 3:
Speech audiometry
Acoustique — Méthodes d’essais audiométriques —
Partie 3: Audiométrie vocale
Reference number
ISO 8253-3:2012(E)
ISO 2012
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

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 ISO at the address below or ISO’s

member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
Contents Page

Foreword ............................................................................................................................................................................. v

Introduction .......................................................................................................................................................................vi

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

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

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

4 Requirements for recording of speech material ......................................................................................... 5

4.1 General requirements ......................................................................................................................................... 5

4.2 Reference recording ........................................................................................................................................... 5

4.3 Recording environment ..................................................................................................................................... 6

4.4 Frequency response of recording equipment ............................................................................................. 6

4.5 Interval between successive test items ........................................................................................................ 6

4.6 Levels ..................................................................................................................................................................... 6

4.7 Signal-to-noise ratio ........................................................................................................................................... 6

4.8 Phonemic balance across test lists ............................................................................................................... 6

4.9 Perceptual balance across test lists .............................................................................................................. 7

5 Validation of speech material recordings ..................................................................................................... 7

5.1 General ................................................................................................................................................................... 7

5.2 Determination of reference speech recognition curve ............................................................................. 7

5.3 Determination of perceptual equivalence of test lists ............................................................................... 8

5.4 Determination of repeatability of results (average test-retest reliability) ............................................ 8

5.5 Documentation ..................................................................................................................................................... 9

6 Requirements for speech audiometry ........................................................................................................... 9

7 Ambient sound pressure levels in test room for speech audiometry ................................................... 9

8 Sound field speech audiometry ....................................................................................................................... 9

9 Preparation and instruction of test subject ...............................................................................................10

9.1 General .................................................................................................................................................................10

9.2 Preparation of test subject .............................................................................................................................10

9.3 Instruction of test subject ...............................................................................................................................10

10 Subject’s response mode ................................................................................................................................10

11 Determination of speech detection threshold level ................................................................................. 11

12 Determination of speech recognition threshold level ............................................................................. 11

12.1 General ................................................................................................................................................................. 11

12.2 Descending procedure using 5 dB steps ...................................................................................................12

12.3 Alternative descending procedure ...............................................................................................................12

12.4 Adaptive procedure using fixed step sizes ................................................................................................13

12.5 Other adaptive procedure ...............................................................................................................................14

13 Determination of speech recognition scores ............................................................................................14

14 Contralateral masking ......................................................................................................................................14

15 Speech audiometry with competing sound ...............................................................................................15

15.1 Type of competing sound ................................................................................................................................15

15.2 Presentation of competing sound ................................................................................................................15

15.3 Speech and competing sound levels ...........................................................................................................15

15.4 Test procedure ...................................................................................................................................................15

16 Format of speech audiogram .........................................................................................................................17

17 Measurement uncertainty ...............................................................................................................................17

18 Maintenance and calibration of equipment ................................................................................................18

18.1 General .................................................................................................................................................................18

© ISO 2012 – All rights reserved iii
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)

18.2 Intervals between tests ....................................................................................................................................18

18.3 Stage A: Routine checking and listening tests .........................................................................................18

18.4 Stage B: Periodic electroacoustic tests ......................................................................................................19

18.5 Stage C: Basic calibration tests ....................................................................................................................19

Annex A (informative) Example of speech materials ..............................................................................................20

Annex B (informative) Examples of competing sound conditions ......................................................................21

Annex C (informative) Typical results .........................................................................................................................22

Annex D (informative) Optimization of perceptual balance of test lists ............................................................24

Annex E (informative) Measurement uncertainty .....................................................................................................25

Bibliography .....................................................................................................................................................................30

iv © ISO 2012 – All rights reserved
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 8253-3 was prepared by Technical Committee ISO/TC 43, Acoustics.

This second edition cancels and replaces the first edition (ISO 8253-3:1996), which has been technically revised.

ISO 8253 consists of the following parts, under the general title Acoustics — Audiometric test methods:

— Part 1: Pure-tone air and bone conduction threshold audiometry
— Part 2: Sound field audiometry with pure-tone and narrow-band test signals
— Part 3: Speech audiometry
© ISO 2012 – All rights reserved v
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
Introduction

Speech audiometry is used for the assessment of hearing in connection with diagnostic evaluation and

audiological rehabilitation.

The results of speech audiometry depend on the speech material and test method used. This part of ISO 8253

sets conditions for speech materials in order to assure minimum requirements of precision and comparability

between different tests using different speech materials including materials in different languages. It also

specifies procedures to be used when testing speech recognition.
vi © ISO 2012 – All rights reserved
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SIST EN ISO 8253-3:2012
INTERNATIONAL STANDARD ISO 8253-3:2012(E)
Acoustics — Audiometric test methods —
Part 3:
Speech audiometry
1 Scope

This part of ISO 8253 specifies basic methods for speech recognition tests for audiological applications.

In order to ensure minimum requirements of precision and comparability between different test procedures

including speech recognition tests in different languages, this part of ISO 8253 specifies requirements for the

composition, validation and evaluation of speech test materials, and the realization of speech recognition tests.

This part of ISO 8253 does not specify the contents of the speech material because of the variety of languages.

Furthermore, this part of ISO 8253 also specifies the determination of reference values and fulfilment

requirements for the realization and manner of presentation.

This part of ISO 8253 specifies procedures and requirements for speech audiometry with the recorded

test material being presented by air conduction through an earphone, or from a loudspeaker for sound field

audiometry. Methods for using noise either for masking the non-test ear or as a competing sound are described.

Some test subjects, for example children, can require amended test procedures not specified in this part of ISO 8253.

Specialized tests such as those used for evaluating directional hearing and dichotic hearing are outside the

scope of this part of ISO 8253.
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.
ISO 266, Acoustics — Preferred frequencies

ISO 8253-1, Acoustics — Audiometric test methods — Part 1: Pure-tone air and bone conduction audiometry

ISO 8253-2, Acoustics — Audiometric test methods — Part 2: Sound field audiometry with pure-tone and

narrow-band test signals

ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in

measurement (GUM:1995)

IEC 60645-1, Electroacoustics — Audiological equipment — Part 1: Pure-tone audiometers

IEC 60645-2:1993, Audiometers — Part 2: Equipment for speech audiometry
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 8253-1 and ISO 8253-2 and the

following apply.
© ISO 2012 – All rights reserved 1
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
3.1
speech signal
acoustic signal which carries information in a given language

NOTE A speech signal may be a voice signal or an acoustic signal simulating a voice signal.

3.2
test item

particular monosyllabic or polysyllabic word or logatom, or sentence, or time-limited segment of connected

speech, used in accordance with defined rules of presentation and scoring in a speech audiometric procedure

NOTE Scoring may be based on a complete test item or parts thereof being correctly recognized.

3.3
speech material
entire set of test items which is used for speech recognition tests
NOTE Usually the speech material is subdivided into several test lists.
3.4
open-set test material

set of test items in which the number of alternative responses to each test item is unlimited

3.5
closed-set test material

set of test items in which the number of alternative responses to each test item is limited

3.6
phoneme
smallest recognizable unit of speech in a given natural language
3.7
phoneme class

subdivision of phonemes that show characteristic similarities in vocal production mode as well as in acoustical

signal properties
3.8
syllable

segment of speech which consists of a vowel with or without one or more accompanying consonants immediately

preceding or following
3.9
spondee
two-syllable word with equal stress on each syllable
3.10
logatom
syllabic unit that has no verbal meaning to the listener
NOTE A logatom is sometimes called a “nonsense syllable”.
3.11
test list
number of selected test items, presented and scored as a single unit
3.12
set of test items
selected number of test items from a test list
2 © ISO 2012 – All rights reserved
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
3.13
phonemically balanced test list

test list which contains approximately the same proportions of the various phonemes as are present in typical

speech communication within a given language
3.14
perceptually balanced test list

test list which yield equivalent speech recognition score with minimized variance at a specified speech level

under equivalent conditions (specified manner of presentation and specified group of listeners)

NOTE Usually the specified group of listeners consists of otologically normal persons with an age from 18 years to

25 years inclusive. For special tests, different groups (e.g. otologically normal children within a specified age range) may

be used as well.
3.15
carrier phrase

sentence or phrase in which a test item is embedded such that the correct recognition of the test item is not

dependent upon the context or meaning of the sentence or phrase
3.16
reference recording of speech material
master recording

well-defined recording that represents the speech material and that is used for validation and application of the

speech material
3.17
speech level

equivalent continuous sound pressure level of the speech material as measured in an appropriate coupler, ear

simulator or in a sound field, with frequency weighting C according to IEC 61672-1

NOTE For speech test lists based on single test items separated by silent intervals, the integration does not include

these intervals. For test lists based on single test items with a carrier phrase, the integration includes the test items only. In

a digital recording, the silent intervals can be removed by editing. Numerical correction may also be made by determination

of the total duration of the test items and the total duration of the silent intervals.

3.18
equivalent continuous sound pressure level
p,eqT

ten times the logarithm to the base 10 of the ratio of the time average of the square of the sound pressure, p,

during a stated time interval of duration, T (starting at t and ending at t ), to the square of a reference value,

1 2
p , expressed in decibels
 2 
 
pt()dt
T 
 1 
L =10 lg dB
pT,eq
 
 
 
 
 
where the reference value, p , is 20 µPa

NOTE Because of practical limitations of the measuring instruments, p is always understood to denote the square

of a frequency-weighted and frequency-band-limited sound pressure. If a specific frequency weighting as specified in

IEC 61672-1 and/or specific frequency bands are applied, this should be indicated by appropriate subscripts; e.g. L

p,A,10 s
denotes the A-weighted time-averaged sound pressure level over 10 s.
[3]
[ISO/TR 25417 , 2.3]
3.19
speech detection threshold level

for a given test subject, for specified speech material and a specified manner of signal presentation, the speech

level at which it is detected (not necessarily understood) in 50 % of the trials
© ISO 2012 – All rights reserved 3
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
3.20
speech recognition score

for a given test subject, for specified speech material, a specified manner of signal presentation and at a

specified speech level, the percentage of correctly recognized test items or scorable items if the scoring

method is not based on whole test items
3.21
maximum speech recognition score

for a given test subject, for specified speech material and a specified manner of signal presentation, the

maximum speech recognition score obtained regardless of speech level
3.22
speech recognition threshold level

for a given test subject, for specified speech material and a specified manner of signal presentation, the lowest

speech level or speech-to-noise ratio at which the speech recognition score is equal to 50 %

NOTE Speech recognition threshold has been called “speech reception threshold”.
3.23
reference speech recognition threshold level

for specified speech material and a specified manner of signal presentation, the median value of the speech

recognition threshold levels of a sufficiently large number of otologically normal persons, of both sexes, between

18 years and 25 years inclusive for whom the test material is appropriate
3.24
optimum speech level

for a given test subject, for specified speech material and a specified manner of signal presentation, the speech

level or range of speech levels at which maximum speech recognition score is obtained

3.25
half-optimum speech level

for a given test subject, for specified speech material and a specified manner of signal presentation, the speech

level at which half of the maximum speech recognition score is obtained
3.26
speech recognition curve

for a given test subject, for specified speech material and a specified manner of signal presentation, a curve

that describes the speech recognition score as a function of speech level
3.27
reference speech recognition curve

for specified speech material and a specified manner of presentation, a curve that describes the median speech

recognition score as a function of speech level for a sufficiently large number of otologically normal persons of

both sexes, aged between 18 years and 25 years inclusive and for whom the test material is appropriate

3.28
hearing level for speech

for specified speech material and a specified manner of signal presentation, the speech level minus the

appropriate reference speech recognition threshold level
3.29
competing sound
additional sound that is presented during speech recognition tests
3.30
competing sound pressure level

equivalent continuous sound pressure level of a competing sound as measured in an appropriate coupler, ear

simulator or in a sound field, with frequency weighting C according to IEC 61672-1

4 © ISO 2012 – All rights reserved
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SIST EN ISO 8253-3:2012
ISO 8253-3:2012(E)
3.31
speech-to-noise level difference
speech-to-noise ratio
SNR
difference between the speech level and the competing sound level
3.32
effective masking level for speech

level of a specified masking sound which is numerically equal to that hearing level for speech to which the

speech recognition threshold level for a specified speech signal would be raised by the presence of that

masking sound
3.33
most comfortable level for speech

for a given test subject and a specified manner of presentation, the speech level at which the loudness of the

speech signal is judged by the test subject to be the most comfortable
3.34
connected speech
running speech

continuous speech with natural intonation, consisting of consecutive sentences with logical connections

4 Requirements for recording of speech material
4.1 General requirements
Each copy of the recording shall contain the following signals:
a) the speech material;

b) a signal for the calibration of the equipment for speech audiometry, of a duration not less than 60 s; the

calibration signal shall be a weighted random noise, e.g. as specified in IEC 60645-2:1993, 13.1, a band

of noise centred at 1 kHz and having a bandwidth of one-third octave, or a frequency-modulated tone at

1 kHz having a bandwidth of at least one-third octave — the modulating signal shall be either sinusoidal or

triangular with a repetition rate in the range from 4 Hz to 20 Hz;

c) signals for testing the frequency response of the equipment to be used for speech audiometry including

the playback equipment and the recording — such signals shall have a duration of not less than 15 s and

consist of one-third-octave bands of white noise centred at the preferred one-third-octave frequencies in

accordance with ISO 266 in the frequency range 125 Hz to 8 000 Hz.

NOTE For speech material based on other time and/or frequency weightings than C-weighted equivalent sound

pressure level, correction factors can be determined describing the difference related to C-weighted equivalent sound

pressure level for speech level, calibration signal level and competing noise level.

4.2 Reference recording

A suitable speaker, either male or female, should have a normal and clear articulation without pronounced

dialect. The speaker should be instructed to maintain
...

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