IEC 60268-21:2018

Sound system equipment - Part 21: Acoustical (output-based) measurements

IEC 60268-21:2018 specifies an acoustical measurement method that applies to electro-acoustical transducers and passive and active sound systems, such as loudspeakers, TV-sets, multi-media devices, personal portable audio devices, automotive sound systems and professional equipment. The device under test (DUT) can be comprised of electrical components performing analogue and digital signal processing prior to the passive actuators performing a transduction of the electrical input into an acoustical output signal. This document describes only physical measurements that assess the transfer behaviour of the DUT between an arbitrary analogue or digital input signal and the acoustical output at any point in the near and far field of the system. This includes operating the DUT in both the small and large signal domains. The influence of the acoustical boundary conditions of the target application (e.g. car interior) can also be considered in the physical evaluation of the sound system. This document does not assess the perception and cognitive evaluation of the reproduced sound and the impact of perceived sound quality.

Équipements pour systèmes électroacoustiques – Partie 21 : Mesures acoustiques (basées sur la sortie)

IEC 60268-21:2018 spécifie une méthode de mesure acoustique qui s’applique aux transducteurs électroacoustiques ainsi qu’aux systèmes électroacoustiques passifs et actifs tels que les haut-parleurs, les téléviseurs, les appareils multimédias, les appareils audio personnels portables, les systèmes électroacoustiques pour automobile et les équipements professionnels. L'appareil soumis à essai (DUT) peut être constitué de composants électriques qui effectuent un traitement analogique et numérique des signaux avant la transduction de l’entrée électrique en un signal de sortie acoustique par les excitateurs passifs. Le présent document décrit uniquement les mesures physiques qui évaluent le comportement de transfert du DUT entre un signal d’entrée analogique ou numérique arbitraire et la sortie acoustique en un point quelconque dans le champ proche et lointain du système. Cela inclut le fonctionnement du DUT dans les domaines à la fois des signaux faibles et des signaux forts. L’influence des conditions de limite acoustique de l’application visée (par exemple habitacle de véhicule) peut également être prise en considération dans l’évaluation physique du système électroacoustique. Le présent document n’évalue pas la perception et l’évaluation cognitive du son reproduit ni l’impact de la qualité perçue du son.

General Information

• Status: Published
• Publication Date: 06-Nov-2018
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.160.01 - Audio, video and audiovisual systems in general
• Technical Committee: TA 20 - Analogue and digital audio
• Drafting Committee: PT 60268-21 - TC 100/TA 20/PT 60268-21
• Current Stage: PPUB - Publication issued
• Start Date: 22-Oct-2018
• Completion Date: 07-Nov-2018

Standards Content (Sample)

IEC 60268-21 ®
Edition 1.0 2018-11
INTERNATIONAL
STANDARD
colour
inside
Sound system equipment –
Part 21: Acoustical (output-based) measurements

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
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International Standards for all electrical, electronic and related technologies.

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IEC 60268-21 ®
Edition 1.0 2018-11
INTERNATIONAL
STANDARD
colour
inside
Sound system equipment –
Part 21: Acoustical (output-based) measurements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.01 ISBN 978-2-8322-6176-7

– 2 – IEC 60268-21:2018  IEC 2018
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 11
3 Terms, definitions and abbreviated terms . 12
3.1 Terms and definitions . 12
3.2 Abbreviated terms . 12
4 Type description . 12
5 Physical characteristics . 12
5.1 Marking of terminals and controls . 12
5.2 Dimensions . 12
5.3 Mass . 12
5.4 Connectors and cable assemblies . 13
6 Design data . 13
7 Conditions . 13
7.1 Rated conditions . 13
7.2 Climatic conditions . 13
7.3 Normal measuring conditions . 13
8 Test signals . 14
8.1 General . 14
8.2 Sinusoidal chirp . 14
8.3 Steady-state single-tone signal . 15
8.4 Steady-state two-tone signal . 15
8.5 Sparse multi-tone complex . 15
8.6 Broadband noise signal . 16
8.7 Narrow-band noise signal . 16
8.8 Hann-burst signal . 16
8.9 Impulsive signal . 17
9 Acoustical environment . 17
9.1 General . 17
9.2 Free-field conditions . 17
9.3 Half-space, free-field conditions . 17
9.4 Simulated free-field conditions . 17
9.5 Half-space simulated free-field conditions . 17
9.6 Diffuse sound field conditions . 18
9.7 Target application conditions . 18
10 Positioning of the DUT . 18
10.1 Rated geometrical conditions . 18
10.1.1 General . 18
10.1.2 Reference plane and normal vector . 18
10.1.3 Reference point . 18
10.1.4 Reference axis . 19
10.1.5 Orientation vector . 19
10.1.6 Evaluation point . 19
10.1.7 Evaluation distance . 19

10.2 Measuring distance between DUT and microphone . 20
10.2.1 Far-field conditions . 20
10.2.2 Near-field conditions . 20
10.2.3 Diffuse field conditions . 20
10.2.4 Target application condition . 21
11 Measurement equipment and test results . 21
12 Accuracy of the acoustical measurement . 21
12.1 General . 21
12.2 Measurement uncertainty . 21
13 Mounting of the DUT . 22
13.1 Mounting and acoustic loading of drive units . 22
13.2 Mounting and acoustic loading of an electro-acoustic system . 22
14 Preconditioning . 23
15 Rated ambient conditions . 23
15.1 Temperature ranges . 23
15.1.1 Performance limited temperature range . 23
15.1.2 Damage limited temperature range . 23
15.2 Humidity ranges . 23
15.2.1 Relative humidity range . 23
15.2.2 Damage limited humidity range . 23
16 Rated frequency range . 23
17 Input signal . 23
17.1 Rated maximum input value . 23
17.1.1 Condition to be specified . 23
17.1.2 Direct measurement . 24
17.1.3 Indirect measurement based on SPL . 25
max
17.2 Maximum input level . 25
18 Sound-pressure output . 26
18.1 Rated maximum sound pressure . 26
18.1.1 Conditions to be specified . 26
18.1.2 Direct measurement . 26
18.1.3 Indirect measurement based on maximum input value . 27
18.2 Rated maximum sound-pressure level . 27
18.3 Short term maximum sound pressure level . 27
18.3.1 Conditions to be specified . 27
18.3.2 Method of measurement . 28
18.4 Long term maximum sound pressure level . 28
18.4.1 Conditions to be specified . 28
18.4.2 Method of measurement . 29
18.5 Sound pressure in a stated frequency band . 29
18.5.1 Condition to be specified . 29
18.5.2 Method of measurement . 29
18.6 Sound-pressure level in a stated frequency band . 30
18.7 Mean sound-pressure in a stated frequency range . 30
18.7.1 Condition to be specified . 30
18.7.2 Method of measurement . 30
18.8 Mean sound-pressure level in a stated frequency range . 30

– 4 – IEC 60268-21:2018  IEC 2018
19 Frequency response of the fundamental component .
...

IEC 60268-21 ®
Edition 1.0 2018-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Sound system equipment –
Part 21: Acoustical (output-based) measurements

Équipements pour systèmes électroacoustiques –
Partie 21: Mesures acoustiques (basées sur la sortie)

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 IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

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committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

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IEC publications issued since 2002. Some entries have been
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IEC 60268-21 ®
Edition 1.0 2018-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Sound system equipment –
Part 21: Acoustical (output-based) measurements

Équipements pour systèmes électroacoustiques –

Partie 21: Mesures acoustiques (basées sur la sortie)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.160.01 ISBN 978-2-8322-6657-1

– 2 – IEC 60268-21:2018  IEC 2018
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 11
3 Terms, definitions and abbreviated terms . 12
3.1 Terms and definitions . 12
3.2 Abbreviated terms . 12
4 Type description . 12
5 Physical characteristics . 12
5.1 Marking of terminals and controls . 12
5.2 Dimensions . 12
5.3 Mass . 12
5.4 Connectors and cable assemblies . 13
6 Design data . 13
7 Conditions . 13
7.1 Rated conditions . 13
7.2 Climatic conditions . 13
7.3 Normal measuring conditions . 13
8 Test signals . 14
8.1 General . 14
8.2 Sinusoidal chirp . 14
8.3 Steady-state single-tone signal . 15
8.4 Steady-state two-tone signal . 15
8.5 Sparse multi-tone complex . 15
8.6 Broadband noise signal . 16
8.7 Narrow-band noise signal . 16
8.8 Hann-burst signal . 16
8.9 Impulsive signal . 17
9 Acoustical environment . 17
9.1 General . 17
9.2 Free-field conditions . 17
9.3 Half-space, free-field conditions . 17
9.4 Simulated free-field conditions . 17
9.5 Half-space simulated free-field conditions . 17
9.6 Diffuse sound field conditions . 18
9.7 Target application conditions . 18
10 Positioning of the DUT . 18
10.1 Rated geometrical conditions . 18
10.1.1 General . 18
10.1.2 Reference plane and normal vector . 18
10.1.3 Reference point . 18
10.1.4 Reference axis . 19
10.1.5 Orientation vector . 19
10.1.6 Evaluation point . 19
10.1.7 Evaluation distance . 19

10.2 Measuring distance between DUT and microphone . 20
10.2.1 Far-field conditions . 20
10.2.2 Near-field conditions . 20
10.2.3 Diffuse field conditions . 20
10.2.4 Target application condition . 21
11 Measurement equipment and test results . 21
12 Accuracy of the acoustical measurement . 21
12.1 General . 21
12.2 Measurement uncertainty . 21
13 Mounting of the DUT . 22
13.1 Mounting and acoustic loading of drive units . 22
13.2 Mounting and acoustic loading of an electro-acoustic system . 22
14 Preconditioning . 23
15 Rated ambient conditions . 23
15.1 Temperature ranges . 23
15.1.1 Performance limited temperature range . 23
15.1.2 Damage limited temperature range . 23
15.2 Humidity ranges . 23
15.2.1 Relative humidity range . 23
15.2.2 Damage limited humidity range . 23
16 Rated frequency range . 23
17 Input signal . 23
17.1 Rated maximum input value . 23
17.1.1 Condition to be specified . 23
17.1.2 Direct measurement . 24
17.1.3 Indirect measurement based on SPL . 25
max
17.2 Maximum input level .
...