SIST-TS CEN ISO/TS 9241-126:2022

Ergonomics of human-system interaction - Part 126: Guidance on the presentation of auditory information (ISO/TS 9241-126:2019)

This document provides guidance for the auditory presentation of information controlled by software, irrespective of the device. It includes specific properties such as the syntactic or semantic aspects of information, e.g. coding techniques, and gives provisions for the organization of information taking account of human perception and memory capabilities.
This document does not address the hardware issues of the transmission and the production of auditory information.
NOTE 1  Volume is dependent on hardware and thus cannot always be absolutely controlled by software. Environmental conditions can also affect the ability for sounds to be perceived, which can be beyond the ability of the software to take into account.
This document does not apply to auditory alarms, warnings or other safety-related uses of auditory information.
NOTE 2  Safety-related uses of auditory presentation of information are covered in various domain specific standards, such as ISO 7731:2003 which deals with auditory danger signals for public and work areas, and IEC 60601-1-8:2006 which provides very specific requirements for auditory alarms for medical devices.
While this document applies to the presentation of all non-safety-related information, it does not include application domain specific guidance (e.g., audio instructions for consumer products).
This document can be utilized throughout the design process (e.g. as specification and guidance for designers during design or as a basis for heuristic evaluation). Its provisions for the presentation of information depend on the auditory design approach, the task, the user, the environment and the single or multiple technologies that can be used for presenting the information. Consequently, this document cannot be applied without knowledge of the context of use. It is not intended to be used as a prescriptive set of rules to be applied in its entirety but rather assumes that the designer has proper information available concerning task and user requirements and understands the use of available technology.
This document does not address visual or tactile/haptic presentation of information or modality shifting for the presentation of auditory information in other modalities.
NOTE 3  ISO 9241-112 provides high-level ergonomic guidance that applies to all modalities.

Ergonomie der Mensch-System-Interaktion - Teil 126: Empfehlungen zur auditiven Informationsdarstellung (ISO/TS 9241 126:2019)

Dieses Dokument enthält Leitlinien für die auditive Darstellung von Informationen, die über eine Software (ungeachtet des Geräts) gesteuert wird. Es enthält bestimmte Eigenschaften wie syntaktische oder semantische Aspekte von Informationen, z. B. Codierungsmethoden, sowie Bestimmungen für die Organisation von Informationen unter Berücksichtigung menschlicher Wahrnehmung und Gedächtnis-leistungen.
Dieses Dokument beschäftigt sich nicht mit hardwaretechnischen Fragen im Zusammenhang mit der Übertragung und Erzeugung auditiver Informationen.
ANMERKUNG 1   Die Lautstärke ist hardwareabhängig und kann daher nicht immer vollständig über Software gesteuert werden. Auch Umgebungsbedingungen können sich auf die Fähigkeit zur Wahrnehmung von Klängen auswirken, was die Software gegebenenfalls nicht berücksichtigen kann.
Dieses Dokument gilt nicht für akustische Alarmsignale, Warnsignale oder die sonstige sicherheitstechnische Verwendung auditiver Informationen.
ANMERKUNG 2   Die sicherheitstechnische Verwendung auditiver Informationsdarstellung wird in verschiedenen bereichsspezifischen Normen behandelt, darunter ISO 7731:2003, die sich mit akustischen Gefahrensignalen für öffentliche Bereiche und Arbeitsstätten beschäftigt, und IEC 60601 1 8:2006, die sehr spezifische Anforderungen für akustische Alarmsignale von medizinischen elektrischen Geräten bereitstellt.
Dieses Dokument gilt zwar für die Darstellung aller Informationen, die nicht sicherheitstechnischer Natur sind, enthält jedoch keine Anwendungsbereich-spezifischen Leitlinien (z. B. Audioanweisungen für Konsum¬güter).
Dieses Dokument kann während des Entwicklungsprozesses herangezogen werden (z. B. als Spezifikation und Leitfaden für Entwickler während der Entwicklungsphase oder als Basis für eine heuristische Bewertung). Die Bestimmungen für die Darstellung von Informationen in diesem Dokument hängen von dem Ansatz der auditiven Gestaltung, der Aufgabe, dem Benutzer, der Umgebung und der Technologie bzw. den Technologien ab, die zur Darstellung dieser Informationen verwendet werden können. Folglich kann dieses Dokument nicht ohne Kenntnis des Nutzungskontextes angewendet werden. Es ist nicht als vorschreibendes Regelwerk gedacht, das in seiner Gänze anzuwenden ist, sondern geht vielmehr davon aus, dass der Entwickler über angemessene Informationen hinsichtlich der Aufgaben- und Benutzeranforderungen verfügt und die Anwendung der verfügbaren Technologie versteht.
Dieses Dokument behandelt keine visuelle oder taktile/haptische Darstellung von Informationen oder Modalitätsänderungen für die Darstellung auditiver Informationen in anderen Modalitäten.
ANMERKUNG 3   ISO 9241 112 enthält übergeordnete ergonomiebezogene Empfehlungen, die auf alle Modalitäten anwendbar sind.

Ergonomie de l'interaction homme-système - Partie 126: Recommandations relatives à la présentation d'informations auditives (ISO/TS 9241-126:2019)

Le présent document fournit des recommandations pour la présentation auditive d'informations sous le contrôle d'un logiciel, indépendamment du support. Il inclut des propriétés spécifiques telles que les aspects syntaxiques ou sémantiques des informations, par exemple les techniques de codage, et fournit des dispositions relatives à l'organisation des informations en tenant compte des capacités humaines de perception et de mémorisation.
Le présent document ne traite pas des problèmes matériels de la transmission ni de la production des informations auditives.
NOTE 1    Le volume est dépendant du matériel et ne peut donc pas toujours être sous le contrôle total du logiciel. Les conditions environnementales peuvent également affecter la perceptibilité des sons, ce que le logiciel n'est pas forcément en mesure de prendre en compte.
Le présent document ne s'applique pas aux alarmes et avertissements auditifs ou autres utilisations d'informations auditives liées à la sécurité.
NOTE 2    Les utilisations d'informations auditives à des fins de sécurité sont couvertes par différentes normes de domaine spécifiques, telles que l'ISO 7731:2003 qui traite des signaux de danger auditifs pour les lieux publics et les lieux de travail, et l'IEC 60601-1-8:2006 qui établit des exigences très précises pour les alarmes auditives des dispositifs médicaux.
Si le présent document s'applique à la présentation de toutes les informations auditives non liées à la sécurité, il n'inclut toutefois pas de recommandations spécifiques aux différents domaines d'application (par exemple, instructions audio pour biens de consommation).
Le présent document peut être utilisé au cours de l'ensemble du processus de conception (par exemple sous la forme de spécifications et de recommandations pour les concepteurs durant la conception ou en tant que base pour une évaluation heuristique). Ses dispositions relatives à la présentation des informations dépendent de l'approche de la conception auditive, de la tâche, de l'utilisateur, de l'environnement ainsi que des technologies, simples ou multiples, qui peuvent être utilisées pour présenter les informations. Par conséquent, le présent document ne peut pas être appliqué sans connaître le contexte d'utilisation. Il n'est pas conçu pour être utilisé comme un ensemble de règles prescriptives à appliquer dans son intégralité, mais suppose plutôt que le concepteur dispose d'informations appropriées concernant la tâche et les exigences de l'utilisateur et comprend l'utilisation de la technologie disponible.
Le présent document ne concerne pas la présentation visuelle ou tactile/haptique des informations, ni le transfert de modalité à une fin de présentation d'informations auditives dans d'autres modalités.
NOTE 3    L'ISO 9241-112 contient des préconisations ergonomiques de haut niveau qui s'appliquent à toutes les modalités.

Ergonomija medsebojnega vpliva človek-sistem - 126. del: Navodila za predstavitev slušnih informacij (ISO/TS 9241-126:2019)

Ta dokument vsebuje smernice za slušno predstavitev informacij, ki jih upravlja programska oprema, ne glede na uporabljeno napravo. Vključuje posebne lastnosti, kot so sintaktični ali semantični vidiki informacij, npr. tehnike kodiranja, ter določila za razporeditev informacij ob upoštevanju človeških zmožnosti zaznavanja in pomnjenja.
Ta dokument ne obravnava vprašanj posredovanja in pridobivanja slušnih informacij, povezanih s strojno opremo.
OPOMBA 1:   Glasnost je odvisna od strojne opreme, zato je ni mogoče vedno v celoti upravljati s programsko opremo. Na zmožnost zaznavanja zvokov lahko vplivajo tudi pogoji okolja, česar programska oprema morda ne more upoštevati.
Ta dokument se ne uporablja za slišne alarme, opozorila ali druga področja uporabe slušnih informacij, povezana z varnostjo.
OPOMBA 2:   Z varnostjo povezana področja uporabe slušne predstavitve informacij so zajeta v različnih posebnih standardih, ki se navezujejo na posamezne domene, na primer v standardu ISO 7731:2003, ki obravnava slišne nevarnostne signale za javna in delovna okolja, ter v standardu IEC 60601-1-8:2006, ki vsebuje zelo specifične zahteve za slišne alarme pri medicinskih pripomočkih.
Čeprav se ta dokument uporablja za predstavitev vseh informacij, ki niso povezane z varnostjo, ne vključuje smernic, ki bi se navezovale na posamezna področja uporabe (npr. zvočna navodila za potrošniške izdelke).
Ta dokument se lahko uporablja skozi celoten postopek oblikovanja (npr. kot specifikacija in smernice za oblikovalce pri oblikovanju ali kot osnova za hevristično vrednotenje). Njegove določbe za predstavitev informacij so odvisne od pristopa k zvočnemu oblikovanju, opravila, uporabnika, okolja ter posamezne tehnologije oziroma tehnologij, ki jih je mogoče uporabiti za predstavitev informacij. Tega dokumenta posledično ni mogoče uporabiti brez poznavanja okoliščin uporabe. Ta dokument naj se ne bi uporabljal kot zavezujoči nabor pravil, ki jih je treba v celoti upoštevati, temveč predpostavlja, da oblikovalec razpolaga z ustreznimi informacijami v zvezi z opravilom in zahtevami za uporabnike ter razume, kako se uporablja razpoložljiva tehnologija.
Ta dokument ne obravnava vizualne ali tipne/haptične predstavitve informacij ali spreminjanja modalitete za predstavitev slušnih informacij z drugimi modalitetami.
OPOMBA 3:   Standard ISO 9241-112 določa splošne smernice za ergonomijo, ki veljajo za vse modalitete.

General Information

• Status: Published
• Publication Date: 14-Jun-2022
• ICS: 13.180 - Ergonomics
• ICS: 35.180 - IT Terminal and other peripheral equipment
• Technical Committee: VSN - Safety of machinery
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 05-Apr-2022
• Due Date: 10-Jun-2022
• Completion Date: 15-Jun-2022
• Ref Project: CEN ISO/TS 9241-126:2022 - Ergonomics of human-system interaction - Part 126: Guidance on the presentation of auditory information (ISO/TS 9241-126:2019)

Overview

CEN ISO/TS 9241-126:2022 (ISO/TS 9241-126:2019) gives ergonomic guidance for the auditory presentation of information in human–system interaction. It focuses on the software-controlled presentation of non‑safety auditory information across devices and technologies, addressing how sounds can be coded, organized and delivered to match human perception and memory. The specification is intended as design guidance (not a prescriptive checklist) and must be applied with knowledge of the context of use.

Keywords: auditory information, ergonomics, human-system interaction, ISO/TS 9241-126, audio UX, sound design, accessibility, auditory presentation.

Key topics and technical guidance

The standard covers practical, perceptual and organizational aspects of audio presentation, including:

• Appropriate usage - when to use auditory presentation (e.g., visual unavailability, brief messages, attention capture) and when not to (it excludes alarms/safety signals).
• Auditory presentation principles - managing channel overload, concise information design, signal invariance and learnability, monaural options, logical sequencing, and support for short‑term memory.
• Detectability in noisy environments - ensuring signal distinctiveness, modifying frequency/ duration to improve audibility in real-world conditions.
• Auditory dimensions - requirements and guidance related to:
  • Frequency/pitch (identification, discrimination, ranges)
  • Intensity/loudness (control, minimum/maximum guidance, avoiding distortion)
  • Timbre (sound color and discriminability)
  • Localization (lateralization, front/back, distance and elevation cues)
  • Duration, rhythm and timing (minimum durations, rhythmic guidance for movement)
• Accessibility considerations - accommodating perceptual, cultural and environmental variability; recommendations for representative sounds and cross‑cultural use.
• Design process use - applies throughout design: specification, prototyping, heuristic evaluation and usability testing.

Note: the standard does not cover hardware transmission/production issues (volume is hardware-dependent) or safety-related alarms; domain-specific audio guidance (e.g., consumer product voice prompts) is outside its scope.

Applications and who uses it

This technical specification is useful for:

• UX designers and audio UX practitioners designing user interfaces with sound
• Human factors/ergonomics specialists and usability engineers
• Software developers and interaction designers implementing auditory cues
• Accessibility professionals specifying non-visual information channels
• Product managers and system architects defining multimodal interaction

Use cases include voice prompts, status feedback, navigation cues, and ambient information presented as sound (non-safety).

Related standards

• ISO 9241-112 - high-level ergonomic guidance across modalities
• ISO 7731:2003 and IEC 60601-1-8:2006 - cover safety‑related auditory alarms and domain‑specific alarm requirements (not addressed by ISO/TS 9241-126)

This guidance helps teams create effective, perceivable and learnable auditory interfaces while aligning audio UX with ergonomic principles.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2022
Ergonomija medsebojnega vpliva človek-sistem - 126. del: Navodila za
predstavitev slušnih informacij (ISO/TS 9241-126:2019)
Ergonomics of human-system interaction - Part 126: Guidance on the presentation of
auditory information (ISO/TS 9241-126:2019)
Ergonomie der Mensch-System-Interaktion - Teil 126: Empfehlungen zur auditiven
Informationsdarstellung (ISO/TS 9241 126:2019)
Ergonomie de l'interaction homme-système - Partie 126: Recommandations relatives à
la présentation d'informations auditives (ISO/TS 9241-126:2019)
Ta slovenski standard je istoveten z: CEN ISO/TS 9241-126:2022
ICS:
13.180 Ergonomija Ergonomics
35.180 Terminalska in druga IT Terminal and other
periferna oprema IT peripheral equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN ISO/TS 9241-126
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
March 2022
TECHNISCHE SPEZIFIKATION
ICS 13.180; 35.180
English Version
Ergonomics of human-system interaction - Part 126:
Guidance on the presentation of auditory information
(ISO/TS 9241-126:2019)
Ergonomie de l'interaction homme-système - Partie Ergonomie der Mensch-System-Interaktion - Teil 126:
126: Recommandations relatives à la présentation Empfehlungen zur auditiven Informationsdarstellung
d'informations auditives (ISO/TS 9241-126:2019) (ISO/TS 9241 126:2019)
This Technical Specification (CEN/TS) was approved by CEN on 13 March 2022 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 9241-126:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO/TS 9241-126:2019 has been prepared by Technical Committee ISO/TC 159
"Ergonomics” of the International Organization for Standardization (ISO) and has been taken over as
which is held by DIN.
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.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: 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/TS 9241-126:2019 has been approved by CEN as CEN ISO/TS 9241-126:2022 without
any modification.
TECHNICAL ISO/TS
SPECIFICATION 9241-126
First edition
2019-12
Ergonomics of human-system
interaction —
Part 126:
Guidance on the presentation of
auditory information
Reference number
ISO/TS 9241-126:2019(E)
©
ISO 2019
ISO/TS 9241-126:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO/TS 9241-126:2019(E)
Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Application . 3
4.1 Accessibility . 3
4.2 Applying the recommendations in this document . 4
5 Appropriate usage . 4
5.1 Visual system unavailability . 4
5.2 Inadequate or excessive light . 4
5.3 Inability to maintain visual attention . 4
5.4 Message brevity and simplicity . 4
5.5 Event-based messages . 5
5.6 Messages requiring immediate action . 5
5.7 Messages requiring verbal response. 5
5.8 Permanence of message relevance . 5
5.9 Attention capture . 5
5.10 Muting sound . 5
6 Auditory presentation . 5
6.1 General . 5
6.1.1 Auditory channel overload . 5
6.1.2 Information conciseness . 5
6.1.3 Avoid extreme dimensions . 5
6.1.4 Monaural option . 6
6.1.5 Ease of learning . 6
6.1.6 Signal invariance . 6
6.1.7 Signal similarity . 6
6.1.8 Two-stage signal usage . . . 6
6.1.9 Logical sequencing . 6
6.1.10 Supporting short term memory . . 6
6.1.11 Cross-cultural sounds . 7
6.1.12 Representative sounds. 7
6.1.13 Representative sound usage . 7
6.2 Detectability in noisy environments . 7
6.2.1 Signal distinctiveness . . 7
6.2.2 Change signal frequency . 7
6.2.3 Signal duration in noisy environments . 7
7 Auditory dimensions . 7
7.1 Frequency . 7
7.1.1 Absolute pitch identification . 7
7.1.2 Temporal proximity for pitch comparison . 7
7.1.3 Similarity for pitch comparison . 7
7.1.4 Minimum difference for pitch comparison . 8
7.1.5 Frequency range for pitch identification . 8
7.1.6 Frequency range for most accurate pitch discrimination . 8
7.1.7 Harmonicity for pitch identification . 8
7.1.8 Harmonic tones for pitch discrimination tasks . 8
7.1.9 Long-distance sound . 8
7.1.10 Obstructed sound . 8
7.2 Intensity . 8
7.2.1 Avoid distortion . 8
ISO/TS 9241-126:2019(E)
7.2.2 Separate signal control . 8
7.2.3 Loudness cues about the environment. 9
7.2.4 Minimal signal intensity . 9
7.2.5 Signal intensity for rapid response . 9
7.2.6 Relative maximal signal intensity . . 9
7.2.7 Absolute maximal signal loudness . 9
7.3 Timbre . 9
7.3.1 Timbre discrimination . 9
7.3.2 Musical instrument timbres . 9
7.4 Localization . 9
7.4.1 Guidance related to lateral sound localization. 9
7.4.2 Minimum angle for position discrimination .10
7.4.3 Frequency selection for sound localization .10
7.4.4 Minimum distance for front/back position identification .10
7.4.5 Guidance related to distance judgment.10
7.4.6 Doppler effect .10
7.4.7 Guidance related to elevation angle judgment.10
7.5 Duration .11
7.5.1 Minimum signal duration .11
7.5.2 Adjustable signal duration .11
7.6 Rhythm and accent usage .11
7.7 Timing .11
7.7.1 Event-based sounds .11
7.7.2 Sounds to guide rhythmic movements .11
7.7.3 Concurrent auditory streams .11
8 Speech .11
8.1 Appropriate usage .11
8.1.1 Complex messages .11
8.1.2 Source identification.11
8.1.3 Untrained users .12
8.1.4 Stressful context of use . .12
8.1.5 Rapid information exchange .12
8.2 General speech presentation .12
8.2.1 Eliminate non-relevant speech .12
8.2.2 Audio volume consistency .12
8.2.3 Monophonic speech presentation .12
8.2.4 Present messages serially .12
8.2.5 Information brevity .12
8.2.6 Message replay .12
8.2.7 Option phrase sequencing .12
8.2.8 Grouping information .13
8.3 Language .13
8.3.1 Language and dialect control .13
8.3.2 Avoid dialect-specific expressions .13
8.3.3 Vocabulary used in prompts .13
8.3.4 Consistency of terminology use .13
8.3.5 Unambiguous prompts .13
8.3.6 Simple linguistic forms .13
8.3.7 Minimum syllable count .13
8.3.8 Sentence usage .13
8.4 Voice .13
8.4.1 Use of synthetic speech .13
8.4.2 Source voice identification .14
8.4.3 Dialects and accents .14
8.4.4 Speech output rate .14
8.4.5 Intonation and prosody .14
9 Earcons .14
iv © ISO 2019 – All rights reserved

ISO/TS 9241-126:2019(E)
9.1 Meaningful earcons .14
9.2 Sound organization .14
9.3 Earcon usage .14
9.4 Earcon construction .14
9.5 Earcon duration.15
9.6 Consistency across earcons.15
9.7 Reversing earcons .15
10 Coding .15
10.1 General .15
10.1.1 Meaningfulness of codes .15
10.1.2 Access to meaning of code .15
10.1.3 Rules of code construction .15
10.1.4 Distinctiveness of codes.15
10.1.5 Consistent coding .15
10.1.6 Coding relative values .15
10.1.7 Ordered coding .16
10.1.8 Change of state.16
10.1.9 Combination codes.16
10.1.10  User training in codes .16
10.1.11  Counting simultaneous tones .16
10.2 Dimension-specific coding .16
10.2.1 Number of frequencies for pitch coding .16
10.2.2 Frequency selection for pitch coding .16
10.2.3 Need for redundant coding when coding based on frequency .16
10.2.4 Coding based on timbre .17
10.2.5 Coding based on intensity .17
10.2.6 Number of levels for loudness coding .17
10.2.7 Intensity spacing for loudness coding .17
10.2.8 Number of levels for pitch and loudness coding .17
10.2.9 Coding by position and distance .17
10.2.10  Coding position and distance with rhythm .17
10.2.11  Number of levels for duration coding .17
Bibliography .18
ISO/TS 9241-126:2019(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
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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).
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4,
Ergonomics of human-system interaction.
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.
vi © ISO 2019 – All rights reserved

ISO/TS 9241-126:2019(E)
Introduction
Interactive systems have used auditory information as primary sources and, more commonly, to
enhance interactions in primarily visual systems since about the time the digital computer was
invented. Even before that, one can consider telephone conversations to be a type of interactive system
where information is presented aurally. The way participants in a telephone conversation present
information to one another is largely based on learned and subconscious conventions. In the digital
realm, sound has been used in increasingly symbolic ways, straying out of necessity from the realistic
representations of objects and actions in the physical world.
Unlike visual displays, the information conveyed through sound is typically sparse, and it seems
more difficult to intuitively understand what makes a sound scheme usable, whether in its design or
its presentation. Since the main communication medium of modern interactive software is the visual
display, it is not surprising that a need was first identified for guidelines relating to presentation of
visual information. However, designers developing for both visual and auditory information would
benefit from guidelines rooted in scientific discovery, that lead to clear and usable communication of
information, while not inhibiting the creative process.
This document focuses on guidelines for presentation of information in the auditory modality.
The success of this document will depend on its positive impact on usability of future systems presenting
auditory information using these guidelines. However, this document is not necessarily designed to be
used by the direct beneficiaries of this desired usability increase. Instead, it serves the following types
of users:
a) the user interface designer, who will apply these guidelines during the development process;
b) the buyer, who will reference this document during the product procurement process, and whose
end users will gain from the potential benefits provided by the guidelines;
c) those responsible for ensuring products meet the recommendations in this document;
d) designers of auditory interface development tools to be used by auditory interface designers;
e) writers of software industry standard guides to be used by auditory interface designers.
TECHNICAL SPECIFICATION ISO/TS 9241-126:2019(E)
Ergonomics of human-system interaction —
Part 126:
Guidance on the presentation of auditory information
1 Scope
This document provides guidance for the auditory presentation of information controlled by software,
irrespective of the device. It includes specific properties such as the syntactic or semantic aspects of
information, e.g. coding techniques, and gives provisions for the organization of information taking
account of human perception and memory capabilities.
This document does not address the hardware issues of the transmission and the production of auditory
information.
NOTE 1 Volume is dependent on hardware and thus cannot always be absolutely controlled by software.
Environmental conditions can also affect the ability for sounds to be perceived, which can be beyond the ability
of the software to take into account.
This document does not apply to auditory alarms, warnings or other safety-related uses of auditory
information.
NOTE 2 Safety-related uses of auditory presentation of information are covered in various domain specific
standards, such as ISO 7731:2003 which deals with auditory danger signals for public and work areas, and
IEC 60601-1-8:2006 which provides very specific requirements for auditory alarms for medical devices.
While this document applies to the presentation of all non-safety-related information, it does not
include application domain specific guidance (e.g., audio instructions for consumer products).
This document can be utilized throughout the design process (e.g. as specification and guidance for
designers during design or as a basis for heuristic evaluation). Its provisions for the presentation of
information depend on the auditory design approach, the task, the user, the environment and the single
or multiple technologies that can be used for presenting the information. Consequently, this document
cannot be applied without knowledge of the context of use. It is not intended to be used as a prescriptive
set of rules to be applied in its entirety but rather assumes that the designer has proper information
available concerning task and user requirements and understands the use of available technology.
This document does not address visual or tactile/haptic presentation of information or modality
shifting for the presentation of auditory information in other modalities.
NOTE 3 ISO 9241-112 provides high-level ergonomic guidance that applies to all modalities.
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.
ISO 9241-171, Ergonomics of human-system interaction — Part 171: Guidance on software accessibility
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO/TS 9241-126:2019(E)
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
pitch
perception of the highness or lowness of a sound’s frequency (3.2)
3.2
frequency
number of complete oscillations per unit time of a periodic waveform
3.3
fundamental frequency
lowest frequency (3.2) component of a periodic waveform
3.4
overtone
higher tone (3.18) produced simultaneously with a fundamental frequency (3.3) and that, with the
fundamental frequency, comprise a complex tone
3.5
harmonic
overtone (3.4) that is an integer multiple of the fundamental frequency (3.3)
3.6
harmonicity
degree to which a sound’s overtones (3.4) are composed of integer multiples of its fundamental
frequency (3.3)
Note 1 to entry: A sound with high harmonicity is called “harmonic” while a sound with low harmonicity is called
“inharmonic”.
Note 2 to entry: The degree to which a sound’s overtones depart from being integer multiples of its fundamental
frequency is called “inharmonicity”.
3.7
pure tone
tone (3.18) composed of a single frequency (3.2) with no harmonics (3.5)
3.8
intensity
power per unit area of a sound wave in a direction perpendicular to that area
3.9
loudness
perception of a sound’s intensity (3.8)
3.10
masking threshold
sound pressure level below which a signal is not audible when in the presence of another specified
sound (i.e. a masking signal or masker)
Note 1 to entry: The masking threshold depends on the sound’s frequency (3.2), the type of masker, and the kind
of sound being masked.
3.11
timbre
quality given to a sound by its overtones (3.4)
2 © ISO 2019 – All rights reserved

ISO/TS 9241-126:2019(E)
3.12
reverberation
resonance
echo
prolongation of a sound through reflection off objects or structures in the sound environment
3.13
interaural
relating to sound reception and perception by each ear considered separately
3.14
monaural
relating to sound emanating from a single sound source or presented equally from all sound sources
3.15
rhythm
strong, regular, repeated pattern of sound
3.16
accent
increased stress or emphasis on a particular sound within a sequence, usually by increasing its intensity
(3.8) or duration relative to other sounds in the sequence
3.17
earcon
auditory icon
brief, distinctive sound used to represent a specific object or event
3.18
tone
discrete musical sound
3.19
prosody
rhythmic and intonational aspect of language
3.20
lateral sound localization
ability of a user to approximate the location where a sound originated
3.21
accessibility
extent to which products, systems, services, environments and facilities can be used by people from a
population with the widest range of user needs, characteristics and capabilities to achieve identified
goals in identified contexts of use
Note 1 to entry: Context of use includes direct use or use supported by assistive technologies.
[SOURCE: ISO 9241-112:2017, 3.15]
4 Application
4.1 Accessibility
Auditory presentation of information shall be in accordance with ISO 9241-171, which gives specific
requirements and recommendations for the presentation of information in the auditory modality and
the presentation of the same information in different modalities.
NOTE ISO 9241-171:2008, 10.6, contains significant guidance on the controllability and accessibility of
audio output.
ISO/TS 9241-126:2019(E)
4.2 Applying the recommendations in this document
It is recognized that different clauses in this document apply in different situations:
— Clause 5 contains recommendations on appropriate usage of auditory presentation of information;
— Clause 6 contains general recommendations on the auditory presentation of information;
— Clause 7 contains recommendations on auditory dimensions;
— Clause 8 contains recommendations on speech;
— Clause 9 contains recommendations on earcons;
— Clause 10 contains recommendations on auditory coding.
Each individual recommendation should be evaluated for its applicability and, if judged to be applicable,
should be implemented, unless there is evidence that doing so would cause deviation from the design
objectives, or would result in an overall degradation in usability. In judging whether applicable
recommendations have been met, evaluators should evaluate the product or observe representative
users of the product in the context of accomplishing the user’s task.
5 Appropriate usage
5.1 Visual system unavailability
If the user’s visual system is either unavailable or overburdened, then consider presenting information
aurally unless there is reaso
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