EN ISO 8253-2:1998
(Main)Acoustics - Audiometric test methods - Part 2: Sound field audiometry with pure tone and narrow-band test signals (ISO 8253-2:1992)
Acoustics - Audiometric test methods - Part 2: Sound field audiometry with pure tone and narrow-band test signals (ISO 8253-2:1992)
Akustik - Audiometrische Prüfverfahren - Teil 2: Schallfeld-Audiometrie mit reinen Tönen und schmalbandigen Prüfsignalen (ISO 8253-2:1992)
Dieser Teil von ISO 8253 legt wesentliche Eigenschaften des Prüfsignals, Anforderungen an das freie, diffuse, und quasi-freie Schallfeld und Verfahren der Schalllfeld-Audiometrie mit reinen Tönen, frequenzmodulierten Tönen oder anderen schmalbandigen Prüfsignalen fest, die über einen oder mehrere Lautsprecher vorzugsweise zum Zweck der Bestimmung des Hörschwellenpegels im Frequenzbereich von 125 Hz bis 12500 Hz dargeboten werden.
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 8253-2:1992)
Akustika - Avdiometrijske preskusne metode - 2. del: Avdiometrija v zvočnem polju s čistimi toni in ozkopasovnimi preskusnimi signali (ISO 8253-2:1992)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 8253-2:1999
01-november-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 8253-2:1992)
Akustik - Audiometrische Prüfverfahren - Teil 2: Schallfeld-Audiometrie mit reinen Tönen
und schmalbandigen Prüfsignalen (ISO 8253-2:1992)
Acoustique - Méthodes d'essais audiométriques - Partie 2: Audiométrie en champ
acoustique avec des sons purs et des bruits a bande étroite comme signaux d'essai (ISO
8253-2:1992)
Ta slovenski standard je istoveten z: EN ISO 8253-2:1998
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 8253-2:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 8253-2:1999
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SIST EN ISO 8253-2:1999
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SIST EN ISO 8253-2:1999
INTERNATIONAL
STANDARD
First edition
1992-11-15
Acoustics - Audiometric test methods -
Part 2:
Sound field audiometry with pure tone and
narrow-band test Signals
Acoustique - AMthodes d’essais audiom&-Ques -
Partie 2: Audiomktt-ie en champ acoustique avec des sons purs et des
Bruifs 6 bande ktroite comme signaux d’essai
Reference number
ISO 8253-2: 1992(E)
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SIST EN ISO 8253-2:1999
ISO 8253~2:1992(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. Esch 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, govern-
mental 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 standavdization.
D.raft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Inter-
national Standard requires approval by at least 75 % of the member
bodies casting a vote.
International Standard ISO 8253-2 was prepared by Technical Committee
ISO/TC 43, Acoustics.
ISO 8253 consists of the following Parts, under the general title
- Audiometric test methods:
Acoustics
- Part 1: Basic pure fone air and bone condr.rc tion threshold audi-
ometry
- Part 2: Somd field audiometry with pure tone and tiar-row-band
test Signals
-- Part 3: Speech audiometry
Annexes A, 6 and C of this part of ISO 8253 are for information only.
0 ISO 1992
All rights reserved. No part of this publication may be reproduced or utilized in any ferm
or by any means, electt-onic or mechanical, including photocopying and microfilm, without
permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l Ct+1211 Geneve 20 * Switzerland
Printed in Switzerland
ii
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SIST EN ISO 8253-2:1999
ISO 825392:1992(E)
lntroduction
ISO 6189 and ISO 82534 cover procedures for the determination of
thresholds of hearing using pure tones presented to the subject by
means of earphone or bone Vibrator.
This patt of ISO 8253 covers procedurcs 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 proper-Ges of the
loudspeakers used, as well as by the acoustical characteristics of the
test room.
Sound field audiometry may be used for various purpases, for example
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.
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SIST EN ISO 8253-2:1999
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SIST EN ISO 8253-2:1999
INTERNATIONAL STANDARD ISO 8253=2:1992(E)
Acoustics 7 Audiometric test methods ‘-
Part 2:
Sound field audiometry with pure tone and narrow-band test
Signals
ISO, 226: 1987, Acoustics - Normal equ+loudness
1 Scope
level contours.
This part of ISO 8253 specifies relevant test Signal
ISO 266:1975, Acoustics -- Preferred frequencies for
characteristics, requirements for free, diffuse and
measurements.
quasi-free Sound fields, and procedures for Sound
,
field audiometry using pure tones, frequency modu-
ISO 8253-1:1989, Acoustics - Audiometric ’ fest
lated tones or other narrow-band test Signals pre-
methods - Part 1: Basic pure tone air and bone
sented by means of one or more loudspeakers,
conduction threihold audiometry.
prirnarily for the purpose of determining hearing
threshold levels in the frequency range from 125 Hz
IEC 225: 1966, Octave, half-octave and third-octave
to 12 500 Hz.
band filters intended for the analysis of Sounds and
vibra tions.
lt does not include specifications for the use of
hand-held loudspeakers.
IEC 581-7:1986, High fidelity audio equipment ‘and
Systems; Minimum performante requirements --
Speech as a test Signal is not covered.
Part 7: Loudspeakers.
The purpose of this part of ISO 8253 is to ensure that
tests of h’earing, using Sound field audiometry, give
IEC 645-1:1992, Audiometers - Part 1: Pure tone
as high a degree of accuracy and reproducibility as
audiometers.
possible.
IEC 651: 1979, Sound level meters.
Examples of graphical representations of the results
and a bibliography are given in annexes A and C.
3 Definitions
FOI the purposes of this part of ISO 8253, the follow-
2 Normative references
ing definitions apply.
The following Standards contain provisions which,
3.1 air canduction: The transmission of Sound
through reference in this text, constitute provisions
through the external and midd’le ear to the internal
of this part of ISO 8253. At the time of. publication,
ear.
the editions indicated were valid. All Standards are
subject to revision, and Parties to agreements based’
an this part of ISO 8253 are encouraged to investi- 3.2 otologically normal person: A pe.rson in a .
normal state of health who is free’ from all signs or ”
gate the possibility of applying the most recent edi-
symptoms of’ear disetise and from obstructing kax
tions of the Standards indicated below. Members of
in the ear canals, and who has no history of undue
IEC and ISO maintain registers of currentiy valid
exposure to noise.
International Standards.
1
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SIST EN ISO 8253-2:1999
ISO 8253-2:1992(E)
3.14 diffuse Sound field: A Sound field which in a
3.3 threshold of hearing: The level of a Sound at
given region has statistically uniform energy den-
which, under specified conditions, a person gives
sity, for which the directions of propagation at any
50 % of correct detection responses on a specified
Point are randomly distributed.
number of trials.
3.4 threshold Sound pressure level: For a given lis- 3.15 white noise: Noise whose power spectral
tener, a specified Signal and a specified manner of density is independent of frequency.
Signal presentation, the Sound pressure level at the
reference point in the specific Sound field, in the
3.16 noise bandwidth: The differente between the
absence of the listener, which in the presence of the
upper and lower band-edge frequencies of a noise
listener in the test Position would correspond with
band. At these frequencies the power spectral den-
the listener’s threshold of hearing.
sity of the noise is reduced to one-half of its average
within the noise band.
3.5 reference threshold Sound pressure level: For
a specific Signal and a specified manner of Signal
3.17 centre frequency of a noise band: The geo-
presentation, the median value of the threshold
metric mean of the band-edge frequencies which
Sound pressure levels of a sufficiently large number
define the noise bandwidth.
of otologically normal test persons, of both sexes,
aged between 18 years and 30 years inclusive, ex-
3.18 functional gain of a hearing aid: For a specified
pressing the threshold of hearing at the reference
test Signal, a specified type of Sound field, a speci-
Point in the specific Sound field.
fied manner of Signal presentation and for a par-
ticular listener, the differente in thresholds of
3.6 hearing Level: For a specified Signal and a
hearing of the listener with and without the hearing
specified manner of Signal presentation, the Sound
aid.
pressure level of this Signal at the reference Point in
the specific Sound field minus the appropriate refer-
ence threshold Sound pressure level.
4 Test Signal characteristics
3.7 hearing threshold level: For a specified ,Signal
This part of ISO 8253 covers test Signals that are ei-
and a specified Sound field, the threshold of hearing
ther pure tones, frequency-modulated (FM) tones or
expressed either as hearing level or as Sound
narrow bands of noise.
pressure level.
3.8 cayrier frequency of a frequency-modulated
4.1 Pure tones
tone: The average value of the periodically varying
tone frequency. The carrier frequency is designated
Pure tones shall be used only in a free Sound field
as the nominal test frequency.
which is in accordance with the specifications given
in 5.1.
3.9 frequency deviation: The maximum differente
between the instantaneous frequency of the
NOTE 1 In other types of Sound field, pure tones may
frequency-modulated tone and the carrier fre-
show large spatial variations in Sound pressure level due
quency.
to Starrding waves.
3.10 reference Point: The midpoint of a straight line
When test tones of fixed frequencies are used, they
connecting the listener’s ear canal openings when
shall be Chosen from the audiometric test fre-
positioned in the Iistening Position in the Sound field.
quencies given in IEC 645-1 or the frequencies given
in ISO 266.
3.11 reference axis: An axis perpendicular to the
radiating surface of the loudspeaker. For Single
The actual frequency shall be within + 2 % of the
radiator or horn loudspeakers, the axis Passes
nominal frequency. This corresponds to the specifi-
through the geometric centre of the diaphragm or
cation of a type 2 audiometer .complying, with the
the horn. For multi-unit loudspeakers, pthe Position
requirements of IEC 645-1.
of the axis is defined by the manufacturer.
4.2 FM tones
3.12 free Sound fiefd: A Sound field where the
boundaries of the room exert a negligible effect- on
FM tones are defined by the following character-
the Sound waves.
istics, which shall be reported:
quasi-free, Sound field:.A Sound field where the
3.13
a) carrier frequency;
boundaries of the room exert only a moderate effect
on the Sound waves, fulfilling the requirements
b) waveform of modulating Signal;
specified in 5.3.
2
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SIST EN ISO 8253-2:1999
ISO 8253~2:1992(E)
NOTE 4 It is usually sufficient to measure the harmonic
c) repetition rate of modulating Signal;
distortion at the maximum available output Sound press-
ure level.
d) frequency deviation.
The harmonic distortion of loudspeaktirs tan only
The carrier frequency shall ‘be Chosen from the
be tested in a free Sound field. Where only a quasi-
audiometric test frequencies as specified in
.free or a diffuse Sound field is available, harmonic
IEC 645-1 or the frequencies given in ISO 266.
distortion may be measured &lectrically across the
loudspeaker input terminal. The total harmonic dis-
The waveform of the modulating Signal shall be ei-
ther sinusoidal or triangular with symmetrical rising tortion shall be less than 1 % and th.e loudspeaker
and falling portions on a ,linear or on a logarithmic shall comply with the specifications given in
frequency scale. IEC 581-7:1986, clause 10.
The carrier frequency shall be within -- + 3 % of its lf pure tonesare not a,vaiIable as test Signals, the
nominal frequency. linearity of the equipment shall be tested by con-
necting an extemal pure-tone generator to replace
The repetition rate of the modulating Signal shall be
the original test .signal Source.
within the range from 4 Hz to 20 Hz with a tolerante
of & 10 % of its nominal value.
When narrow bands of noise are used as test
Signals, the output of the external pure-tone gener-
The frequency deviation shall be in the range from
ator shall be set to a level 9 dB above the root mean
+ 2,5 % to & 12,5 % with a tolerante of -+- IO % of
- -
Square (RMS) value delivered by the test Signal
its nominal value.
Source when in normal use.
If the modulating waveform is sinusoidal, its total
When FM tones are used as test Signals, the RMS
harmonic distortion shall not exceed 5 Y& If it is tri-
output Level of the external pure-tone generator
angular, its ramps shall not deviate from a linear
shall be equal to that delivered by the test Signal
form by more than 5 % of its amplitude. For the tri-
Source when in normal use.
angular waveform, the durations of the rising and
falling portions shall not differ by more than 10 %.
4.5 Signal gating
4.3 Narrow bands of noise
The Signal shall be presented either as Singular
Sound bursts of a duration in the range from 1 s to
The centre frequency and the bandwidth of a narrow
2 s or repeatedly gated on and off.‘The requirements
band of noise shall be the Same and have the Same
given in IEC 645-1 regarding rise and fall times,
tolerantes as the frequency response of filters
on/off-times and on/off ratio as weil as under- and
complying with IEC 225, or shall comply with the
overshoot shall be complied with when measured
specifications for narrow-band masking noise ac-
electrically at the loudspeaker terminals with pure
cording to IEC 645-1. The centre frequency and the
tones as test Signals.
bandwidth shall be reported.
NOTE 5 The reverberation characteristics of the test
NOTES
room may exert a significant influence on the decay of the
acoustic test Signal.
2 When bandwidths exceed one-third octave, reference
threshold Sound pressure Levels may differ from those
valid for bandwidths up to one-third octave.
4.6 Signal level control
3 Signal power outside the passband, which is mainiy
determined by the slopes and stop-band rejection
characteristics of the fitter, may influence the results of
4.6.1 Step size
Sound Geld audiometry, in particutar on hearing-impaired
test subjects.
The Signal level shall be variable in intervals of
5 dB or less.
4.4 Harmonie distortion
4.6.2 Accuracy
If pure tones are available as test sigrials, the lin-
The maximum accumul ated error in the d ifference
earity of the complete System shall be such that the
between any two Signal level set,tings over the total
total harmonic distortion dcies not exceed 5 :XJ at
Signal level range of the attivnuator shall not exceed
125 tiz and 3 % at 250 Hz, 500 Hz and 1 000 Hz
3 dß, as measured acoustically at the reference
when measured acoustically at the reference Point
Point. In addition, the specifications given in
in the test room. These conditions shall be met over
IEC 645-1 shall be complied with.
the whole dynamic range available.
3
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SIST EN ISO 8253-2:1999
ISO 8253=2:1992(E)
4.6.3 Dynamit range
The Signals for testing the Sound field shall be the
Same as those to be used for audiometry.
In the frequeccy range from 500 Hz to 6 000 Hz; the
test Signal hearing level at the reference Point shall
5.1 Free Sound field
cover at least the range 0 dB to 80 dB.
To establish that free Sound field conditions are ad-
NOTE 6 It is desirable that the same test Signal hea ring
equately met, the following requirements shall be
kVt?l range he covered outside this frequency range.
complied with.
a) The loudspeaker shall be arranged at the head-
4.7 Means and scales for calibration
height of a seated listener, the reference axis
being directed through the reference Point. The
The equipment shall provide means for adjusting the
distance between the reference Point and the
level of each test Sound separately. The scale shall
loudspeaker shall be at least 1 m.
be expressed in hearing level or Sound pressure
level. Measurements shall be made with a Sound
b) With the test subject and the subject’s. chair ab-
level meter conforming to type 1 of IEC 651.
sent, the Sound pressure level produced by the
loudspeaker at positions 0,15 m from the refer-
For pure tones and one-third-octave bands of noise
ence Point on the left-right and up-down axis
in a frontally incident field, and for one-third-octave
shall deviate by no more than + 1 dß from the
bands of noise in a diffuse Sound field, reference
Sound pressure level at the ref:rence Point for
threshold Sound pressure levels corresponding to
any of the test frequencies up to and including
the normal binaural threshold of hearing as speci-
4 000 Hz, and by no more than + 2 dB for any of
fied in ISO 226 shall be taken as reference threshold
the test Signals at frequenciesäbove 4 000 Hi.
Sound pressure levels. These data shall be used
The differente in Sound pressure levels between
also for FM tones complying with the requirements
the left-right positions shall ncjt exceed 3 dß at
of 4.2. For other combinations of test Signal and
any frequency above 4 000 Hz.
Sound field type, no standardized data exist.
NOTES c) With the test subject and the subject’s chair ab-
sent, the differente in Sound pressure levels
7 In practice, other angies of incidence are also used,
produced by the Ioudspeaker at points.on the
e.g. 45”. No standardized reference threshold Sound
reference axis 0,15 m in front of and 0,15 m be-
pressure levels presently exist. Howevkr, in annex B
hind the reference Point shall deviate from the
correction values for 45” and 90” angles of incidence are
theoretical value given by the inverse Sound
given.
pressure distance law by no more than + 1 dß
-
for any of the test Signals.
8 lt is recogniked that in applications where onty the
differentes in thresholds of hearing between two listening
conditions are to be determined (e.g. with/without heari
...
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