Acoustics - Determination of sound immission from sound sources placed close to the ear - Part 2: Technique using a manikin (ISO 11904-2:2021)

This document specifies basic framework measurement methods for sound immission from sound
sources placed close to the ear. These measurements are carried out with a manikin, equipped
with ear simulators including microphones. The measured values are subsequently converted into
corresponding free-field or diffuse-field levels. The results are given as free-field related or diffusefield
related equivalent continuous A-weighted sound pressure levels. The technique is denoted the
manikin technique.
This document is applicable to exposure to sound from sources close to the ear, for example during
equipment tests or at the workplace to sound from earphones or hearing protectors with audio
communication facilities.
This document is applicable in the frequency range from 20 Hz to 10 kHz. For frequencies above 10 kHz,
ISO 11904-1 can be used.

Akustik - Bestimmung der Schallimmission von ohrnahen Schallquellen - Teil 2: Verfahren unter Verwendung eines Kopf- und Rumpfsimulators (ISO 11904-2:2021)

Dieses Dokument legt Rahmenmessverfahren für die Messung von Schallimmissionen durch ohrnahe Schallquellen fest. Diese Messungen werden unter Verwendung einer Messpuppe durchgeführt, die mit Ohrsimulatoren und Mikrofonen ausgestattet ist. Die Messwerte werden im Anschluss in entsprechende Freifeld- oder Diffusfeldpegel umgerechnet. Die Ergebnisse werden als freifeld- oder diffusfeldbezogene A bewertete äquivalente Dauerschalldruckpegel angegeben. Das Verfahren wird als Messpuppen- oder Manikin Verfahren bezeichnet.
Dieses Dokument ist anwendbar auf die Exposition durch ohrnahe Schallquellen, wie etwa Ohrhörer oder Gehörschützer mit Sprachübertragungssystemen, beispielsweise bei Geräteprüfungen oder am Arbeitsplatz.
Dieses Dokument ist anwendbar für den Frequenzbereich von 20 Hz bis 10 kHz. Für Frequenzen oberhalb von 10 kHz kann ISO 11904 1 verwendet werden.

Acoustique - Détermination de l'exposition sonore due à des sources placées à proximité de l'oreille - Partie 2: Technique utilisant un mannequin (ISO 11904-2:2021)

Akustika - Ugotavljanje imisije zvoka iz zvočnih virov v neposredni bližini ušesa - 2. del: Uporaba lutke (ISO 11904-2:2021)

General Information

Status
Published
Public Enquiry End Date
19-Jan-2021
Publication Date
24-May-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
30-Mar-2021
Due Date
04-Jun-2021
Completion Date
25-May-2021

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SLOVENSKI STANDARD
SIST EN ISO 11904-2:2021
01-julij-2021
Nadomešča:
SIST EN ISO 11904-2:2005

Akustika - Ugotavljanje imisije zvoka iz zvočnih virov v neposredni bližini ušesa -

2. del: Uporaba lutke (ISO 11904-2:2021)

Acoustics - Determination of sound immission from sound sources placed close to the

ear - Part 2: Technique using a manikin (ISO 11904-2:2021)
Akustik - Bestimmung der Schallimmission von ohrnahen Schallquellen - Teil 2:
Verfahren unter Verwendung eines Kopf- und Rumpfsimulators (ISO 11904-2:2021)

Acoustique - Détermination de l'exposition sonore due à des sources placées à proximité

de l'oreille - Partie 2: Technique utilisant un mannequin (ISO 11904-2:2021)
Ta slovenski standard je istoveten z: EN ISO 11904-2:2021
ICS:
17.140.01 Akustična merjenja in Acoustic measurements and
blaženje hrupa na splošno noise abatement in general
33.160.50 Pribor Accessories
SIST EN ISO 11904-2:2021 en,fr,de

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

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SIST EN ISO 11904-2:2021
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SIST EN ISO 11904-2:2021
EN ISO 11904-2
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2021
EUROPÄISCHE NORM
ICS 13.140 Supersedes EN ISO 11904-2:2004
English Version
Acoustics - Determination of sound immission from sound
sources placed close to the ear - Part 2: Technique using a
manikin (ISO 11904-2:2021)

Acoustique - Détermination de l'exposition sonore due Akustik - Bestimmung der Schallimmission von

à des sources placées à proximité de l'oreille - Partie 2: ohrnahen Schallquellen - Teil 2: Verfahren unter

Technique utilisant un mannequin (ISO 11904-2:2021) Verwendung eines Kopf- und Rumpfsimulators (ISO

11904-2:2021)
This European Standard was approved by CEN on 9 March 2021.

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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11904-2:2021 E

worldwide for CEN national Members.
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SIST EN ISO 11904-2:2021
EN ISO 11904-2:2021 (E)
Contents Page

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

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SIST EN ISO 11904-2:2021
EN ISO 11904-2:2021 (E)
European foreword

This document (EN ISO 11904-2:2021) 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 September 2021, and conflicting national standards

shall be withdrawn at the latest by September 2021.

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 11904-2:2004.

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 11904-2:2021 has been approved by CEN as EN ISO 11904-2:2021 without any

modification.
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SIST EN ISO 11904-2:2021
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SIST EN ISO 11904-2:2021
INTERNATIONAL ISO
STANDARD 11904-2
Second edition
2021-03
Acoustics — Determination of sound
immission from sound sources placed
close to the ear —
Part 2:
Technique using a manikin
Acoustique — Détermination de l'exposition sonore due à des sources
placées à proximité de l'oreille —
Partie 2: Technique utilisant un mannequin
Reference number
ISO 11904-2:2021(E)
ISO 2021
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
Contents Page

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

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

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

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

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

4 Measurement principle ................................................................................................................................................................................. 2

5 Instrumentation .................................................................................................................................................................................................... 3

5.1 Manikin (head and torso simulator) .................................................................................................................................... 3

5.2 Check of calibration ............................................................................................................................................................................ 3

5.3 Filters .............................................................................................................................................................................................................. 3

6 Determination of free-field or diffuse-field related equivalent continuous

A-weighted sound pressure level ........................................................................................................................................................ 3

6.1 Measurement of manikin sound pressure level ......................................................................................................... 3

6.2 Conversion to free-field or diffuse-field related sound pressure level ................................................... 4

6.3 A-weighting and summation ....................................................................................................................................................... 6

7 Test report ................................................................................................................................................................................................................... 6

Annex A (informative) Examples of sources of measurement uncertainty ..................................................................7

Annex B (informative) Example of an uncertainty analysis ......................................................................................................14

Bibliography .............................................................................................................................................................................................................................16

© ISO 2021 – All rights reserved iii
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(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 in collaboration with

the European Committee for Standardization (CEN) Technical Committee CEN/TC 211, Acoustics, in

accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 11904-2:2004), of which it constitutes a

minor revision. The changes compared to the previous edition are editorial.
A list of all parts in the ISO 11904 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 2021 – All rights reserved
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
Introduction

ISO 11904 is a series of standards which specify methods for the determination of sound immissions

from sources located close to the ear in which situations the sound pressure level measured at the

position of the exposed person (but with the person absent) does not adequately represent the sound

exposure.

In order to make it possible to assess the exposure by means of well-established criteria, the exposure

of the ear is measured and subsequently converted into a corresponding free-field or diffuse-field level.

The result is given as a free-field related or diffuse-field related equivalent continuous A-weighted

sound pressure level, L or L when ISO 11904-1 is used, or L or L when
FF,H,Aeq DF,H,Aeq FF,M,Aeq DF,M,Aeq
ISO 11904-2 is used.

ISO 11904-1 describes measurements carried out using miniature or probe microphones inserted in the

ears of human subjects (microphones in real ear, MIRE technique). ISO 11904-2 describes measurements

carried out using a manikin equipped with ear simulators including microphones (manikin technique).

ISO 11904 may, for instance, be applied to equipment tests and the determination of noise exposure

at the workplace where, in the case of exposure from sources close to the ears, the sound pressure

level measured at the position of the exposed person (but with the person absent) does not adequately

represent the sound exposure. Examples of applications are head- and earphones used to reproduce

music or speech, whether at the workplace or during leisure, nail guns used close to the head, and

combined exposure from a close-to-ear sound source and an external sound field.

When specific types of equipment are to be tested (e.g. portable cassette players or hearing protectors

provided with radio receivers), test signals suitable for this particular type of equipment have to be

used. Neither such test signals nor the operating conditions of the equipment are included in ISO 11904

but might be specified in other standards.

When workplace situations are measured, the various noise sources contributing to the immission

should be identified. Operating conditions for machinery and equipment used might be specified in

other standards.

Both parts of ISO 11904 strive for the same result: a mean value for a population of the free-field or

the diffuse-field related level. ISO 11904-1 does this by specifying the mean of measurements on a

number of human subjects; ISO 11904-2 does this by using a manikin, which aims at reproducing the

acoustical effects on an average human adult. However, the two methods yield different measurement

uncertainties which can influence the choice of method. Only the method described in ISO 11904-1

gives results which indicate the variance in a human population. Information on the uncertainties is

given in Annexes A and B.

When using the MIRE technique for measurement of sound from earphones of insert and stethoscopic

types, practical problems can occur with the positioning of microphones in the ear canal. When using

the manikin technique, the headphone or earphone is coupled to the pinna simulator and ear canal

extension as closely as possible to the way it is coupled to the human ear. In cases where headphones,

earphones, or other objects touch the pinna, a possible deviation in stiffness or shape of the artificial

pinna from human pinnae has a significant impact on the result and can even make the results invalid.

An overview of the differences between the two parts of ISO 11904 is given in Table 0.1.

© ISO 2021 – All rights reserved v
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
Table 0.1 — Overview of differences between MIRE and manikin techniques
Parameter ISO 11904-1 ISO 11904-2
Type of method Microphone in real ear technique Manikin technique

Limitation of the With earphones of insert and stethoscopic type, Proper coupling may not always be obtained

method practical problems can occur with positioning if the artificial pinna deviates from human

of microphones in the ear canal. pinnae in stiffness or shape.
In some cases the exposed person cannot be
replaced by a manikin, e.g., if the person has
to operate equipment.
Main issues affecting Number of subjects Similarity of manikin to humans
accuracy
When tabulated values are used for ΔL Calibration of manikin
FF,H
or ΔL :
DF,H
— calibration of ear canal microphone
— accuracy in positioning of microphones
in the ear canal
When individual values are used for ΔL
FF,H
or ΔL :
DF,H
— quality of reference sound field
— stability of sensitivity and frequency
response as well as position of ear canal
microphone
Frequency range 20 Hz to 16 kHz 20 Hz to 10 kHz
vi © ISO 2021 – All rights reserved
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SIST EN ISO 11904-2:2021
INTERNATIONAL STANDARD ISO 11904-2:2021(E)
Acoustics — Determination of sound immission from
sound sources placed close to the ear —
Part 2:
Technique using a manikin
1 Scope

This document specifies basic framework measurement methods for sound immission from sound

sources placed close to the ear. These measurements are carried out with a manikin, equipped

with ear simulators including microphones. The measured values are subsequently converted into

corresponding free-field or diffuse-field levels. The results are given as free-field related or diffuse-

field related equivalent continuous A-weighted sound pressure levels. The technique is denoted the

manikin technique.

This document is applicable to exposure to sound from sources close to the ear, for example during

equipment tests or at the workplace to sound from earphones or hearing protectors with audio

communication facilities.

This document is applicable in the frequency range from 20 Hz to 10 kHz. For frequencies above 10 kHz,

ISO 11904-1 can be used.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
ITU-T P.58:2013, Head and torso simulator for telephonometry
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/
3.1
manikin sound pressure level
M,exp,f

equivalent continuous sound pressure level in one-third-octave frequency bands with nominal

midband frequency f, measured with the microphone of an ear simulator integrated in a manikin when

the manikin is exposed to the sound under test
© ISO 2021 – All rights reserved 1
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
3.2
free-field frequency response for use with manikins
FF,M,f

average human free-field frequency response for use with manikins, corrected for the difference

between the sound transmission inside the average human ear canal and the corresponding

transmission of the manikin ear simulator

Note 1 to entry: For applicability with manikins, the eardrum reference is replaced by the output of the manikin

ear simulator in tabulated values of ΔL .
FF,M,f

Note 2 to entry: The free-field frequency response for use with manikins is identical to the amplitude of the head-

related transfer function (HRTF) for frontal sound incidence.

Note 3 to entry: The human free-field frequency response is defined in ISO 11904-1.

3.3
diffuse-field frequency response for use with manikins
DF,M,f

average human diffuse-field frequency response for use with manikins, corrected for the difference

between the sound transmission inside the average human ear canal and the corresponding

transmission of the manikin ear simulator

Note 1 to entry: For applicability with manikins, the eardrum reference is replaced by the output of the manikin

ear simulator in tabulated values of ΔL .
DF,M,f

Note 2 to entry: The human diffuse-field frequency response is defined in ISO 11904-1.

3.4
free-field related sound pressure level determined with a manikin
FF,M
free-field sound pressure level determined with the method using a manikin

Note 1 to entry: The definition may be applied to specific frequencies or frequency bands, weighted or unweighted

levels, specific time weightings, etc., for instance “free-field related equivalent continuous A-weighted sound

pressure level" (free-field related L , also denoted L ).
M,Aeq FF,M,Aeq

Note 2 to entry: The method is aimed at the mean free-field related sound pressure level that would be obtained

with a large human population.

Note 3 to entry: The free-field related sound pressure level for a human subject is defined in ISO 11904-1.

3.5
diffuse-field related sound pressure level determined with a manikin
DF,M
diffuse-field sound pressure level determined with the method using a manikin

Note 1 to entry: The definition may be applied to specific frequencies or frequency bands, weighted or unweighted

levels, specific time weightings, etc., for instance “diffuse-field related equivalent continuous A-weighted sound

pressure level" (diffuse-field related L , also denoted L ).
M,Aeq DF,M,Aeq

Note 2 to entry: The method is aimed at the mean diffuse-field related sound pressure level that would be

obtained with a large human population.

Note 3 to entry: The diffuse-field related sound pressure level for a human subject is defined in ISO 11904-1.

4 Measurement principle

A manikin (head and torso simulator) is exposed to the sound source(s) in question and, for each of

the ear simulators integrated in the manikin, the sound pressure level is measured in one-third-octave

frequency bands, L .
M,exp,f
2 © ISO 2021 – All rights reserved
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)

Each of the one-third-octave-band levels is adjusted with the free-field or diffuse-field frequency

response for the manikin, ΔL or ΔL , in order to obtain the corresponding free-field related or

FF,M,f DF,M,f

diffuse-field related one-third-octave-band sound pressure levels. These one-third-octave-band levels

are adjusted using A-weighting constants, and subsequently combined to obtain the free-field related

or diffuse-field related equivalent continuous A-weighted sound pressure level, L or L .

FF,M,Aeq DF,M,Aeq

The measurements may be carried out for one or both ears, as appropriate. The free-field or diffuse-

field frequency response for use with manikins is taken from Table 1.
5 Instrumentation
5.1 Manikin (head and torso simulator)

The manikin used shall satisfy the requirements of ITU-T P.58:2013, 5.3 (first paragraph), 6.1 and 7.1,

for the ear simulator and the acoustic characteristics of the manikin respectively.

The manikin used should be checked regularly for compliance with the requirements of ITU-T P.58:2013,

5.3 (first paragraph), 6.1 and 7.1.

In cases where sound sources touch the pinna (such as earphones or hearing protectors with

communication facilities), they shall be coupled to the pinna simulator and ear canal extension in a way

that represents as closely as possible the way they are coupled to the human ear.

NOTE In cases where head- or earphones or other objects touch the pinna, the deviation in stiffness or shape

of the artificial pinna from human pinnae has a significant impact on the result and may even make the results

invalid.
5.2 Check of calibration

The calibration of the microphones and the measuring equipment shall be checked as follows.

For checking the calibration of the measurement system together with the occluded ear simulator, an

acoustic calibrator (class 1 according to IEC 60942) shall be coupled to the occluded ear simulator. The

sound pressure level shall, in this case, be measured without any frequency weighting.

NOTE Calibration of the manikin is usually performed using an adapter for the acoustic calibrator. The

presence of the adapter changes the effective output level of the calibrator. Check the manikin user manual for

the corrected acoustic calibrator output level with the adapter.

The frequency response of the measuring system without the occluded ear simulator may be measured

using suitable electrical input signals.
5.3 Filters

Signals shall be analysed with one-third-octave-band filters complying with the requirements for

class 1 of IEC 61260.
6 Determination of free-field or diffuse-field related equivalent continuous
A-weighted sound pressure level
6.1 Measurement of manikin sound pressure level

With the manikin exposed to the sound under test, the equivalent continuous sound pressure levels

for each one-third-octave frequency band should be measured with each ear simulator. The frequency

range shall cover all frequencies of significance for the test purposes, and a signal-to-noise ratio of at

least 10 dB shall be guaranteed in each one-third-octave frequency band. If only one ear simulator is

used, this shall be stated.
© ISO 2021 – All rights reserved 3
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)

The measurement period shall be chosen to give a proper representation of the exposure. For the one-

third-octave frequency band with centre frequency f, the measurement period t shall be as follows:

− for f ≤2000Hz :
5000
− and for f >2000Hz :
t≥25,s

NOTE 1 The specifications given refer to random noise; the period for other test signals can be different,

provided the measurement uncertainty is not increased.

The level in each one-third-octave frequency band shall be corrected for the pressure frequency

response of the microphone of the ear simulator.

NOTE 2 The pressure frequency response of the microphone can be obtained from the manufacturer's

calibration data.

The result, the manikin one-third-octave-band sound pressure level during exposure to the sound

under test, is denoted L .
M,exp,f

If only sounds from sources coupled directly to the ears are to be taken into account, only the head of

the manikin (without torso) is required for the measurements.
6.2 Conversion to free-field or diffuse-field related sound pressure level

To obtain the free-field or diffuse-field related one-third-octave band sound pressure level, L or

FF,M,f

L , the free-field or diffuse-field frequency response for use with manikin, ΔL or ΔL , shall

DF,M,f FF,M,f DF,M,f
be subtracted from the manikin sound pressure level, L :
M,exp,f
LL=−ΔL (1)
FF,,MMff,,expFFM,,f
LL=−ΔL (2)
DF,,MMff,,expDFM,,f
ΔL or ΔL shall be taken from Table 1.
FF,M,f DF,M,f
4 © ISO 2021 – All rights reserved
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
Table 1 — Free-field and diffuse-field frequency response for use with manikins
One-third-octave band Free-field Diffuse-field
centre frequency response frequency response
frequency
ΔL ΔL
FF,M,f DF,M,f
Hz dB dB
≤100 0 0
125 0,4 0,3
160 0,8 0,6
200 1,2 0,9
250 1,5 1,2
315 1,5 1,4
400 1,7 1,8
500 2,1 2,3
630 2,5 3,2
800 2,2 4,0
1 000 1,7 4,6
1 250 3,8 6,0
1 600 8,4 8,1
2 000 12,9 11,4
2 500 15,6 15,0
3 150 15,6 14,2
4 000 14,2 11,9
5 000 10,6 9,8
6 300 4,0 8,5
8 000 2,0 11,0
10 000 −0,3 7,1
NOTE 1 Data have been taken from Reference [11].

NOTE 2 The mean human blocked-entrance data from Reference [12] have been transferred to

the “manikin eardrum” using the blocked entrance to the “manikin eardrum” transfer function

for ear simulators according to IEC 60318-4 (see Reference [11]). Systematic deviations are found

for exposure to sound sources placed close to the ear measured with manikins, compared to MIRE

measurements using human subjects. For compensation, the frequency responses listed in this

table differ from frequency responses of manikins specified in ITU-T P.58 or IEC 60318-7.

© ISO 2021 – All rights reserved 5
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SIST EN ISO 11904-2:2021
ISO 11904-2:2021(E)
6.3 A-weighting and summation

The free-field or diffuse-field related equivalent continuous A-weighted sound pressure level, L

FF,M,Aeq

or L , shall be calculated using A-weighting constants A specified in IEC 61672-1, and the

DF,M,Aeq f
following formulae:
 
 ()LA + /10 
FF,M ,ff
L = 10 lg 10 dB (3)
 
FF,M,Aeq ∑
 
 
 
 ()LA + /10
DF,M ,ff
L = 10 lg 10 dB (4)
 
DF,M,Aeq
 
 
7 Test report
...

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