EN IEC 60268-16:2020
(Main)Sound system equipment - Part 16: Objective rating of speech intelligibility by speech transmission index
Sound system equipment - Part 16: Objective rating of speech intelligibility by speech transmission index
IEC 60268-16:2020 defines the STI model, test signals, measurement and prediction methods. The objective of this document is to provide a comprehensive manual for all types of users of the STI model in the fields of audio, communications and acoustics. This document does not provide STI criteria for certification of transmission channels (e.g. criteria for a voice-alarm system), but some typical application values are provided in Annex G. Every measurement method has limitations, and the reader is referred to clauses relating to limitations such as speech privacy, echo and systems using digital voice compression (vocoders). This document does not cover the case of fluctuating noise on the STI, although some general comments on dealing with this complex issue are provided in 7.13 and 8.9.3. IEC 60268-16:2020 cancels and replaces the fourth edition published in 2011. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the spectrum of the male speech test signal has been changed, with significant reductions in the 125 Hz and 250 Hz bands being implemented; b) some corrections to formulae have been made; c) additional information has been included on prediction and measurement procedures; d) spectrum and weighting factors for female speech have been removed; e) verification information for STI measurement devices added; f) the relationships between STI and number of other speech intelligibility measures have been updated in Annex E; g) greater information is given in Annex M about adjustments to the measured STI results to simulate effects of alternative ambient noise and speech levels.
Elektroakustische Geräte - Teil 16: Objektive Bewertung der Sprachverständlichkeit durch den Sprachübertragungsindex
Équipements pour systèmes électroacoustiques - Partie 16: Évaluation objective de l'intelligibilité de la parole au moyen de l'indice de transmission de la parole
L'IEC 60268-16:2020 définit le modèle, les signaux d'essai, la mesure et les méthodes de prévision STI. L'objectif du présent document est de mettre un manuel complet à la disposition de tous les types d'utilisateurs du modèle STI dans les domaines de l'audio, des communications et de l'acoustique. Le présent document ne donne pas de critères STI destinés à la certification des canaux de transmission (par exemple, critères pour un système d'alarme vocale), mais certaines valeurs d'application courante sont fournies dans l'Annexe G. Chaque méthode de mesure présente ses limites, et le lecteur est prié de se référer aux articles correspondants, par exemple concernant la confidentialité des conversations, l'écho et les systèmes qui utilisent la compression vocale numérique (vocodeurs). Le présent document ne couvre pas les cas du bruit fluctuant sur le STI, bien que certains commentaires généraux qui traitent de cette question complexe soient fournis en 7.13 et 8.9.3. L'IEC 60268-16:2020 annule et remplace la quatrième édition parue en 2011. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) le spectre du signal d'essai de la parole masculine a été modifié pour appliquer des réductions significatives au niveau des bandes de 125 Hz et 250 Hz; b) certaines formules ont été corrigées; c) des informations supplémentaires relatives aux modes opératoires de prédiction et de mesure ont été incluses; d) le spectre et les facteurs de pondération pour la parole féminine ont été supprimés; e) des informations de vérification pour les dispositifs de mesure STI ont été ajoutées; f) les relations entre le STI et plusieurs autres mesures de l'intelligibilité de la parole ont été mises à jour en Annexe E; g) des informations supplémentaires sont données en Annexe M concernant les ajustements des résultats STI mesurés afin de simuler les effets d'autres niveaux de bruit ambiant et de parole.
Oprema za zvokovne sisteme - 16. del: Objektivno ocenjevanje govorne razumljivosti z uporabo indeksa prenosa govora (IEC 60268-16:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2021
Nadomešča:
SIST EN 60268-16:2011
Oprema za zvokovne sisteme - 16. del: Objektivno ocenjevanje govorne
razumljivosti z uporabo indeksa prenosa govora (IEC 60268-16:2020)
Sound system equipment - Part 16: Objective rating of speech intelligibility by speech
transmission index (IEC 60268-16:2020)
Elektroakustische Geräte - Teil 16: Objektive Bewertung der Sprachverständlichkeit
durch den Sprachübertragungsindex (IEC 60268-16:2020)
Equipements pour systèmes électroacoustiques - Partie 16: Evaluation objective de
l'intelligibilité de la parole au moyen de l'indice de transmission de la parole (IEC 60268-
16:2020)
Ta slovenski standard je istoveten z: EN IEC 60268-16:2020
ICS:
33.160.30 Avdio sistemi Audio systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 60268-16
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2020
ICS 33.160.01 Supersedes EN 60268-16:2011 and all of its
amendments and corrigenda (if any)
English Version
Sound system equipment - Part 16: Objective rating of speech
intelligibility by speech transmission index
(IEC 60268-16:2020)
Équipements pour systèmes électroacoustiques - Partie 16: Elektroakustische Geräte - Teil 16: Objektive Bewertung der
Évaluation objective de l'intelligibilité de la parole au moyen Sprachverständlichkeit durch den Sprachübertragungsindex
de l'indice de transmission de la parole (IEC 60268-16:2020)
(IEC 60268-16:2020)
This European Standard was approved by CENELEC on 2020-10-30. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60268-16:2020 E
European foreword
The text of document 100/3202/CDV, future edition 5 of IEC 60268-16, prepared by IEC/TC 100
"Audio, video and multimedia systems and equipment" was submitted to the IEC-CENELEC parallel
vote and approved by CENELEC as EN IEC 60268-16:2020.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2021-07-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2023-10-30
document have to be withdrawn
This document supersedes EN 60268-16:2011 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 60268-16:2020 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60318-1:2009 NOTE Harmonized as EN 60318-1:2009 (not modified)
IEC 61672-1 NOTE Harmonized as EN 61672-1
IEC 60118-4 NOTE Harmonized as EN 60118-4
ISO 9921:2003 NOTE Harmonized as EN ISO 9921:2003 (not modified)
ISO/TR 22411:2008 NOTE Harmonized as CEN ISO/TR 22411:2011 (not modified)
ISO 3382-1:2009 NOTE Harmonized as EN ISO 3382-1:2009 (not modified)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 61260-1 2014 Electroacoustics - Octave-band and fractional- EN 61260-1 2014
octave-band filters - Part 1: Specifications
IEC 60268-16 ®
Edition 5.0 2020-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Sound system equipment –
Part 16: Objective rating of speech intelligibility by speech transmission index
Équipements pour systèmes électroacoustiques –
Partie 16: Evaluation objective de l'intelligibilité de la parole au moyen
de l'indice de transmission de la parole
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.160.01 ISBN 978-2-8322-8862-7
– 2 – IEC 60268-16:2020 © IEC 2020
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 12
4 Description of the STI model. 18
4.1 Overview. 18
4.2 Applicability of the STI model . 19
4.3 Theoretical details . 19
4.3.1 Envelope function and envelope spectrum . 19
4.3.2 Reduction of modulation . 20
4.3.3 Role of the octave-band noise carriers . 20
4.3.4 Theoretical overview . 20
4.4 Measurement of STI . 22
4.4.1 Direct and indirect methods . 22
4.4.2 Full STI . 23
4.4.3 STIPA . 23
4.4.4 Choice of method . 23
5 Direct method of measuring STI – User guidance . 25
5.1 Overview. 25
5.2 STIPA . 26
5.3 Application . 26
5.4 Limitations . 26
6 Indirect method of measuring STI (impulse response) – User guidance . 27
6.1 Overview. 27
6.2 Application . 27
6.3 Limitations (non-linear distortion) . 28
7 Limitations of the STI model . 29
7.1 General . 29
7.2 Frequency shifts . 30
7.3 Centre clipping . 30
7.4 Dropouts . 30
7.5 Jitter . 30
7.6 Digital voice compression systems . 30
7.7 Overestimation of STI under low background noise conditions . 31
7.8 Frequency response . 31
7.9 Echoes . 32
7.10 Fast amplitude compression and expansion . 34
7.11 Non-linear distortion. 35
7.12 Hearing impaired listeners . 35
7.13 Impulsive and fluctuating noise . 35
7.14 Conclusion . 35
8 Measurement procedures, post-processing of data and applications . 36
8.1 General . 36
8.2 Acoustical input . 36
IEC 60268-16:2020 © IEC 2020 – 3 –
8.3 Acoustical output . 38
8.4 Electrical input . 38
8.5 Electrical output . 38
8.6 Examples of input/output combinations . 38
8.6.1 Acoustical input – Acoustical output . 38
8.6.2 Electrical input – Electrical output (e.g. assessment of wired and
wireless) communication systems) . 38
8.6.3 Acoustical input – Electrical output (e.g. assessment of microphones) . 38
8.6.4 Electrical input – Acoustical output (e.g. assessment of PA systems) . 39
8.7 Spatial averaging of STI measurements . 39
8.8 Post-processing of measured MTF data . 40
8.9 Issues concerning noise . 40
8.9.1 General . 40
8.9.2 Measurement of background noise . 41
8.9.3 Fluctuating noise . 41
8.10 Analysis and interpretation of the results. 41
8.11 Binaural STI measurements . 42
9 Use of the STI as a design prediction tool . 42
9.1 Overview. 42
9.2 Statistical predictions .
...
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