SIST EN ISO 8253-2:2010
(Main)Acoustics - Audiometric test methods - Part 2: Sound field audiometry with pure-tone and narrow-band test signals (ISO 8253-2:2009)
Acoustics - Audiometric test methods - Part 2: Sound field audiometry with pure-tone and narrow-band test signals (ISO 8253-2:2009)
This part of ISO 8253 specifies relevant test signal characteristics, requirements for free, diffuse, and quasi-free sound fields, and procedures for sound field audiometry using pure tones, frequency-modulated tones or other narrow-band test signals presented by means of one or more loudspeakers. The primary purpose is the determination of hearing threshold levels in the frequency range 125 Hz to 8 000 Hz, but this range can be extended to 20 Hz to 16 000 Hz. This part of ISO 8253 does not include specifications for the use of hand-held loudspeakers. Speech as a test signal is not covered. The purpose of this part of ISO 8253 is to ensure that tests of hearing, using sound field audiometry, give as high a degree of accuracy and reproducibility as possible. Examples of graphical representations of the results are given in Annex A.
Akustik - Audiometrische Prüfverfahren - Teil 2: Schallfeld-Audiometrie mit reinen Tönen und schmalbandigen Prüfsignalen (ISO 8253-2:2009)
Dieser Teil von ISO 8253 legt wesentliche Eigenschaften des Prüfsignals, Anforderungen an das freie, dif-fuse, und quasi-freie Schallfeld und Verfahren der Schallfeld-Audiometrie mit reinen Tönen, frequenzmodu-lierten Tönen oder anderen schmalbandigen Prüfsignalen fest, die über einen oder mehrere Lautsprecher dargeboten werden. Der hauptsächliche Verwendungszweck ist die Bestimmung von Hörschwellenpegeln im Frequenzbereich von 125 Hz bis 8 000 Hz. Dieser Bereich kann aber auf 20 Hz bis 16 000 Hz erweitert wer-den.
Dieser Teil von ISO 8253 enthält keine Festlegungen zur Verwendung von handgehaltenen Lautsprechern. Sprache als Prüfsignal wird hier nicht behandelt.
Der Zweck dieses Teils von ISO 8253 ist es, sicherzustellen, dass Hörprüfungen mittels Schallfeld-Audio-metrie höchstmögliche Genauigkeit und Reproduzierbarkeit ergeben.
Beispiele für die grafische Darstellung der Ergebnisse und Literaturhinweise werden in Anhang A angegeben.
Acoustique - Méthodes d'essais audiométriques - Partie 2: Audiométrie en champ acoustique avec des sons purs et des bruits à bande étroite comme signaux d'essai (ISO 8253-2:2009)
L'ISO 8253-2:2009 spécifie les caractéristiques utiles des signaux d'essai, les exigences relatives aux champs acoustiques libre, diffus et quasi libre, ainsi que les modes opératoires s'appliquant à l'audiométrie en champ acoustique réalisée à l'aide de sons purs, de sons modulés en fréquence ou d'autres signaux d'essai de bande étroite émis par un ou plusieurs haut-parleurs. L'objectif principal est la détermination des niveaux liminaires d'audition dans la gamme de fréquences comprises entre 125 Hz et 8 000 Hz, celle-ci pouvant être étendue entre 20 Hz et 16 000 Hz.
L'ISO 8253-2:2009 ne comporte pas de spécifications relatives à l'utilisation de haut-parleurs portatifs. Elle ne couvre pas les essais vocaux.
L'objectif de l'ISO 8253-2:2009 est de garantir un degré de précision et de reproductibilité des essais d'audition effectués par audiométrie en champ acoustique aussi élevé que possible.
Des exemples de représentations graphiques des résultats d'essai y sont donnés.
Akustika - Avdiometrijske preskusne metode - 2. del: Avdiometrija v zvočnem polju s čistimi toni in ozkopasovnimi preskusnimi signali (ISO 8253-2:2009)
Ta del ISO 8253 določa ustrezne lastnosti preskusnega signala, zahteve za prosto, difuzno in navidezno prosto zvočno polje ter postopke za avdiometrijo zvočnega polja z uporabo čistih tonov, frekvenčno moduliranih tonov ali drugih ozkopasovnih preskusnih signalov, ki jih proizvaja eden ali več zvočnikov. Glavni namen je ugotavljanje ravni slušnega praga v frekvenčnem območju med 125 Hz in 8.000 Hz, vendar se lahko razširi na območje med 20 Hz in 16.000 Hz. Ta del ISO 8253 ne vključuje specifikacij za uporabo ročnih zvočnikov. Govor kot preskusni signal ni vključen. Namen tega dela ISO 8253 je zagotoviti, da so preskusi sluha z uporabo avdiometrije z zvočnim poljem čim bolj natančni in ponovljivi. Primeri grafičnih prikazov rezultatov so podani v Dodatku A.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 8253-2:2010
01-april-2010
1DGRPHãþD
SIST EN ISO 8253-2:1999
$NXVWLND$YGLRPHWULMVNHSUHVNXVQHPHWRGHGHO $YGLRPHWULMDY]YRþQHP
SROMXVþLVWLPLWRQLLQR]NRSDVRYQLPLSUHVNXVQLPLVLJQDOL ,62
Acoustics - Audiometric test methods - Part 2: Sound field audiometry with pure-tone and
narrow-band test signals (ISO 8253-2:2009)
Akustik - Audiometrische Prüfverfahren - Teil 2: Schallfeld-Audiometrie mit reinen Tönen
und schmalbandigen Prüfsignalen (ISO 8253-2:2009)
Acoustique - Méthodes d'essais audiométriques - Partie 2: Audiométrie en champ
acoustique avec des sons purs et des bruits à bande étroite comme signaux d'essai (ISO
8253-2:2009)
Ta slovenski standard je istoveten z: EN ISO 8253-2:2009
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 8253-2:2010 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 8253-2:2010
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SIST EN ISO 8253-2:2010
EUROPEAN STANDARD
EN ISO 8253-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2009
ICS 13.140 Supersedes EN ISO 8253-2:1998
English Version
Acoustics - Audiometric test methods - Part 2: Sound field
audiometry with pure-tone and narrow-band test signals (ISO
8253-2:2009)
Acoustique - Méthodes d'essais audiométriques - Partie 2: Akustik - Audiometrische Prüfverfahren - Teil 2: Schallfeld-
Audiométrie en champ acoustique avec des sons purs et Audiometrie mit reinen Tönen und schmalbandigen
des bruits à bande étroite comme signaux d'essai (ISO Prüfsignalen (ISO 8253-2:2009)
8253-2:2009)
This European Standard was approved by CEN on 26 October 2009.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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 and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8253-2:2009: E
worldwide for CEN national Members.
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SIST EN ISO 8253-2:2010
EN ISO 8253-2:2009 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 8253-2:2010
EN ISO 8253-2:2009 (E)
Foreword
This document (EN ISO 8253-2:2009) has been prepared by Technical Committee ISO/TC 43 "Acoustics" in
collaboration with the 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 June 2010, and conflicting national standards shall be withdrawn at
the latest by June 2010.
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 8253-2:1998.
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, 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 and the United Kingdom.
Endorsement notice
The text of ISO 8253-2:2009 has been approved by CEN as a EN ISO 8253-2:2009 without any modification.
3
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SIST EN ISO 8253-2:2010
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SIST EN ISO 8253-2:2010
INTERNATIONAL ISO
STANDARD 8253-2
Second edition
2009-12-15
Acoustics — Audiometric test methods —
Part 2:
Sound field audiometry with pure-tone
and narrow-band test signals
Acoustique — Méthodes d'essais audiométriques —
Partie 2: Audiométrie en champ acoustique avec des sons purs et des
bruits à bande étroite comme signaux d'essai
Reference number
ISO 8253-2:2009(E)
©
ISO 2009
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
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Published in Switzerland
ii © ISO 2009 – All rights reserved
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Test signal characteristics .3
4.1 General .3
4.2 Pure tones .3
4.3 FM tones.4
4.4 Narrow bands of noise.4
4.5 Harmonic distortion .4
4.6 Signal gating .5
4.7 Signal level control.5
4.8 Means and scales for calibration.5
5 Sound field characteristics.6
5.1 General .6
5.2 Free sound field.6
5.3 Diffuse sound field .6
5.4 Quasi-free sound field.7
6 Ambient noise levels in the test room.7
7 Preparation and instruction of test subject.7
8 Determination of hearing threshold level .8
8.1 General .8
8.2 Monaural testing.8
8.3 Binaural testing .8
9 Testing with a hearing aid .8
10 Screening audiometry.8
11 Reporting of data.10
11.1 General .10
11.2 Equipment calibrated by hearing level.10
11.3 Equipment calibrated by sound pressure level .10
12 Maintenance and calibration of equipment .10
12.1 General .10
12.2 Intervals between tests.10
12.3 Stage A: routine examination and listening tests.11
12.4 Stage B: periodic electroacoustic tests.11
12.5 Stage C: basic calibration tests .12
Annex A (informative) Graphical display of results.13
Annex B (informative) Correction values for 45° and 90° angles of incidence.15
Bibliography.16
© ISO 2009 – All rights reserved iii
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(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 8253-2 was prepared by Technical Committee ISO/TC 43, Acoustics.
This second edition cancels and replaces the first edition (ISO 8253-2:1992), of which it constitutes a minor
revision.
ISO 8253 consists of the following parts, under the general title Acoustics — Audiometric test methods:
⎯ Part 1: Basic 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
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
Introduction
ISO 8253-1 covers procedures for the determination of thresholds of hearing using pure tones presented to
the subject by means of earphone or bone vibrator.
This part of ISO 8253 covers procedures for the determination of thresholds of hearing in a sound field. In
general, sound field testing implies binaural Iistening to a test signal, presented by means of one or more
loudspeakers in a test room. The test signal may be a pure tone, a frequency-modulated tone or a narrow
band of noise. The acoustical characteristics of the sound field are determined by the choice of test signal, by
the number and acoustical properties of the loudspeakers used, as well as by the acoustical characteristics of
the test room.
Sound field audiometry may be used for various purposes, e.g. the evaluation of hearing acuity in young
children and the determination of the functional gain of a hearing aid when worn by a particular listener.
© ISO 2009 – All rights reserved v
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SIST EN ISO 8253-2:2010
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SIST EN ISO 8253-2:2010
INTERNATIONAL STANDARD ISO 8253-2:2009(E)
Acoustics — Audiometric test methods —
Part 2:
Sound field audiometry with pure-tone and narrow-band test
signals
1 Scope
This part of ISO 8253 specifies relevant test signal characteristics, requirements for free, diffuse, and
quasi-free sound fields, and procedures for sound field audiometry using pure tones, frequency-modulated
tones or other narrow-band test signals presented by means of one or more loudspeakers. The primary
purpose is the determination of hearing threshold levels in the frequency range 125 Hz to 8 000 Hz, but this
range can be extended to 20 Hz to 16 000 Hz.
This part of ISO 8253 does not include specifications for the use of hand-held loudspeakers. Speech as a test
signal is not covered.
The purpose of this part of ISO 8253 is to ensure that tests of hearing, using sound field audiometry, give as
high a degree of accuracy and reproducibility as possible.
Examples of graphical representations of the results are given in Annex A.
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 226, Acoustics — Normal equal-loudness-level contours
ISO 266, Acoustics — Preferred frequencies
ISO 389-7, Acoustics — Reference zero for the calibration of audiometric equipment — Part 7: Reference
threshold of hearing under free-field and diffuse-field listening conditions
1)
ISO 8253-1:— , Acoustics — Audiometric test methods — Part 1: Basic pure-tone air and bone conduction
threshold audiometry
IEC 60581-7:1986, High fidelity audio equipment and systems — Minimum performance requirements —
Part 7: Loudspeakers
IEC 60645-1, Electroacoustics — Audiometric equipment — Part 1: Pure-tone audiometers
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
1) To be published. (Revision of ISO 8253-1:1989)
© ISO 2009 – All rights reserved 1
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
air conduction
transmission of signal through the external and middle ear to the inner ear
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 canal, and who has no history of undue exposure to noise, exposure to potentially ototoxic
drugs, or of familial hearing loss
3.3
reference point
midpoint of a straight line connecting the ear canal openings of the listener when positioned in the Iistening
position in the sound field
3.4
reference axis
axis perpendicular to the radiating surface of the loudspeaker
NOTE 1 For single radiator or horn loudspeakers, the axis passes through the geometric centre of the diaphragm or
the horn.
NOTE 2 For multi-unit loudspeakers, the position of the axis is defined by the manufacturer.
3.5
threshold of hearing
level of a sound at which, under specified conditions, a person gives 50 % of correct detection responses on
repeated trials
3.6
threshold sound pressure level
for a given listener, a specified signal and a specified manner of signal presentation, sound pressure level at
the reference point (3.3) in the specific sound field, in the absence of the listener, which in the presence of
the listener in the test position would correspond to the threshold of hearing (3.5) of the listener
3.7
reference threshold sound pressure level
for a specific signal and a specified manner of signal presentation, median value of the threshold sound
pressure levels (3.6) of a sufficiently large number under test of otologically normal persons (3.2), of both
genders, aged between 18 years and 25 years inclusive, expressing the threshold of hearing (3.5) at the
reference point (3.3) in the specific sound field
3.8
hearing level
for a specified signal and a specified manner of signal presentation, sound pressure level of this signal at the
reference point (3.3) in the specific sound field minus the appropriate reference threshold sound pressure
level (3.7)
3.9
hearing threshold level
for a specified signal and a specified sound field, threshold of hearing (3.5) expressed either as hearing
level (3.8) or as sound pressure level
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
3.10
carrier frequency of a frequency-modulated tone
average value of the periodically varying tone frequency
NOTE The carrier frequency is designated as the nominal test frequency.
3.11
frequency deviation
maximum difference between the instantaneous frequency of the frequency-modulated tone and the carrier
frequency
3.12
free sound field
sound field where the boundaries of the room exert a negligible effect on the sound waves
3.13
quasi-free sound field
sound field where the boundaries of the room exert only a moderate effect on the sound waves
NOTE The requirements for a quasi-free sound field are specified in 5.4.
3.14
diffuse sound field
sound field which in a given region has statistically uniform energy density, for which the directions of
propagation at any point are randomly distributed
3.15
white noise
noise whose power spectral density is independent of frequency
3.16
noise bandwidth
difference between the upper and lower band-edge frequencies of a noise band
NOTE At these frequencies the power spectral density of the noise is reduced to one-half of its average within the
noise band.
3.17
centre frequency of a noise band
geometric mean of the band-edge frequencies which define the noise bandwidth (3.16)
3.18
functional gain of a hearing aid
for a specified test signal, a specified type of sound field, a specified manner of signal presentation, and for a
particular listener, difference in thresholds of hearing of the listener with and without the hearing aid
4 Test signal characteristics
4.1 General
This part of ISO 8253 covers test signals that are either pure tones, frequency-modulated (FM) tones or
narrow bands of noise.
4.2 Pure tones
Pure tones shall be used only in a free sound field which is in accordance with the specifications given in 5.2.
NOTE In other types of sound field, pure tones may show large spatial variations in sound pressure level due to
standing waves.
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
When test tones of fixed frequencies are used, they shall be chosen from the audiometric test frequencies
given in IEC 60645-1 or the frequencies given in ISO 266.
The actual frequency shall be within ± 1,5 % of the nominal frequency. This corresponds to the specification of
an audiometer complying with the requirements of IEC 60645-1, type 1 and type 2.
4.3 FM tones
FM tones are defined by the following characteristics, which shall be reported:
a) carrier frequency;
b) waveform of modulating signal;
c) repetition rate of modulating signal;
d) frequency deviation.
The carrier frequency shall be chosen from the audiometric test frequencies as specified in IEC 60645-1 or
the frequencies given in ISO 266.
The waveform of the modulating signal shall be either sinusoidal or triangular. The triangular waveform shall
have symmetrical rising and falling portions on a linear or on a logarithmic frequency scale.
The carrier frequency shall be within ± 3 % of its nominal frequency.
The repetition rate of the modulating signal shall be within the range 4 Hz to 20 Hz with a tolerance of ± 10 %
of its nominal value.
The frequency deviation shall be in the range ± 2,5 % to ± 12,5 % with a tolerance of ± 10 % of its nominal
value.
If the modulating waveform is sinusoidal, its total harmonic distortion shall not exceed 5 %. If it is triangular, its
ramps shall not deviate from a linear form by more than 5 % of its amplitude. For the triangular waveform, the
durations of the rising and falling portions shall not differ by more than 10 %.
4.4 Narrow bands of noise
The centre frequency and the bandwidth of a narrow band of noise shall comply with the specifications for
narrow-band masking noise according to IEC 60645-1. The centre frequency and the bandwidth shall be
reported.
NOTE 1 When bandwidths exceed one-third octave, reference threshold sound pressure levels may differ from those
valid for bandwidths up to one-third octave.
NOTE 2 Signal power outside the passband, which is mainly determined by the slopes and stop-band rejection
characteristics of the filter, may influence the results of sound field audiometry, in particular on hearing-impaired test
subjects.
4.5 Harmonic distortion
If pure tones are available as test signals, the linearity of the complete system shall be such that the total
harmonic distortion does not exceed 5 % at 125 Hz and 3 % at 250 Hz, 500 Hz and 1 000 Hz when measured
acoustically at the reference point in the test room. These conditions shall be met over the whole dynamic
range available.
NOTE It is usually sufficient to measure the harmonic distortion at the maximum available output sound pressure
level.
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
The harmonic distortion of loudspeakers can only be tested in a free sound field. Where only a quasi-free or a
diffuse sound field is available, harmonic distortion may be measured electrically across the loudspeaker input
terminal. The total harmonic distortion shall be less than 1 % and the loudspeaker shall comply with the
specifications given in IEC 60581-7:1986, Clause 10.
lf pure tones are not avaiIable as test signals, the linearity of the equipment shall be tested by connecting an
external pure-tone generator to replace the original test signal source.
When FM tones are used as test signals, the r.m.s. output level of the external pure-tone generator shall be
equal to that delivered by the test signal source when in normal use.
When narrow bands of noise are used as test signals, the output of the external pure-tone generator shall be
set to a level 9 dB above the root mean square (r.m.s.) value delivered by the test signal source when in
normal use.
4.6 Signal gating
The signal shall be either presented as singular sound bursts of a duration in the range 1 s to 2 s or
repeatedly gated on and off. The requirements given in IEC 60645-1 regarding rise and fall times, on/off-times
and on/off ratio as well as under- and overshoot shall be complied with when measured electrically at the
loudspeaker terminals with pure tones as test signals.
NOTE The reverberation characteristics of the test room may exert a significant influence on the decay of the
acoustic test signal.
4.7 Signal level control
4.7.1 Step size
The signal level shall be variable in intervals of 5 dB or less.
4.7.2 Accuracy
The maximum accumulated error in the difference between any two signal level settings over the total signal
level range of the attenuator shall not exceed 3 dB, as measured acoustically at the reference point. In
addition, the specifications given in IEC 60645-1 shall be complied with.
4.7.3 Dynamic range
In the frequency range 500 Hz to 6 000 Hz, the test signal hearing level at the reference point shall cover at
least the range 0 dB to 80 dB.
NOTE It is desirable that the same test signal hearing level range be covered outside this frequency range.
4.8 Means and scales for calibration
The equipment shall provide means for adjusting the level of each test sound separately. The scale shall be
expressed in hearing level or sound pressure level. Measurements shall be made with a sound level meter
conforming to IEC 61672-1, type 1.
For pure tones and one-third-octave bands of noise in a frontally incident field, and for one-third-octave bands
of noise in a diffuse sound field, reference threshold sound pressure levels corresponding to the normal
binaural threshold of hearing as specified in ISO 226 shall be taken as reference threshold sound pressure
levels. These data shall be used also for FM tones complying with the requirements of 4.3. For other
combinations of test signal and sound field type, no standardized data exist.
NOTE 1 In practice, other angles of incidence are also used, e.g. 45°. No standardized reference threshold sound
pressure levels presently exist. However, in Annex B, correction values for 45° and 90° angles of incidence are given.
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SIST EN ISO 8253-2:2010
ISO 8253-2:2009(E)
NOTE 2 lt is recognized that, in applications where only the differences in thresholds of hearing between two listening
conditions are to be determined (e.g. with/without hearing aid), relative values of the test sound pressure level can suffice.
5 Sound field characteristics
5.1 General
The environment in which sound field audiometry is undertaken can vary considerably. Three types are
specified that allow a suitable sound field to be established in most situations in practice. Two wel
...
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