Acoustics -- Soundscape

This document specifies requirements and supporting information on data collection and reporting for soundscape studies, investigations and applications. This document identifies and harmonizes the collection of data by which relevant information on the key components people, acoustic environment and context is obtained, measured and reported.

Acoustique -- Paysage sonore

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ISO/TS 12913-2:2018 - Acoustics -- Soundscape
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TECHNICAL ISO/TS
SPECIFICATION 12913-2
First edition
2018-08
Acoustics — Soundscape —
Part 2:
Data collection and reporting
requirements
Acoustique — Paysage sonore —
Partie 2: Collecte de données
Reference number
ISO/TS 12913-2:2018(E)
ISO 2018
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ISO/TS 12913-2:2018(E)
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© ISO 2018

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
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ISO/TS 12913-2:2018(E)
Contents Page

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

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

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

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

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

4 Descriptors and indicators ........................................................................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Acoustic and psychoacoustic indicators ........................................................................................................................... 3

5 Data collection ........................................................................................................................................................................................................ 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Soundwalk ................................................................................................................................................................................................... 4

5.3 Questionnaire ........................................................................................................................................................................................... 4

5.4 Guided interview ................................................................................................................................................................................... 5

5.5 Sound source taxonomy .................................................................................................................................................................. 5

5.6 Binaural measurements .................................................................................................................................................................. 5

6 Reporting requirements ............................................................................................................................................................................... 6

Annex A (normative) Minimum reporting requirements ............................................................................................................... 7

Annex B (informative) Psychoacoustic indicators .................................................................................................................................. 9

Annex C (informative) Data collection methods ....................................................................................................................................11

Annex D (normative) Binaural measurement methods ................................................................................................................24

Annex E (informative) Good practice in reporting a soundscape study .......................................................................27

Bibliography .............................................................................................................................................................................................................................29

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ISO/TS 12913-2:2018(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, Subcommittee SC 1, Noise.

A list of all parts in the ISO 12913 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.
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ISO/TS 12913-2:2018(E)
Introduction

The ISO 12913 series on soundscape was developed in order to enable a broad international consensus

and to provide a foundation for communication across disciplines and professions with an interest

in soundscape. ISO 12913-1 provides the definition of and a conceptual framework for the term

“soundscape”.

The concept of soundscape was adopted to provide a holistic approach to the acoustic environment,

beyond noise, and its effect on the quality of life. Soundscape suggests assessing all sounds perceived

in an environment in all its complexity. To do this, soundscape studies use a variety of data collection

related to human perception, acoustic environment and context. Importantly, the study of soundscape

relies primarily upon human perception and only then turns to physical measurement.

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TECHNICAL SPECIFICATION ISO/TS 12913-2:2018(E)
Acoustics — Soundscape —
Part 2:
Data collection and reporting requirements
1 Scope

This document specifies requirements and supporting information on data collection and reporting for

soundscape studies, investigations and applications.

This document identifies and harmonizes the collection of data by which relevant information on the

key components people, acoustic environment and context is obtained, measured and reported.

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 532-1, Acoustics — Methods for calculating loudness — Part 1: Zwicker method

ISO 1996-1, Acoustics — Description, measurement and assessment of environmental noise — Part 1: Basic

quantities and assessment procedures

ISO 12913-1, Acoustics — Soundscape — Part 1: Definition and conceptual framework

ITU-T P.58:2013, Head and torso simulator for telephonometry

ANSI/ASA S 3.36:2012, Specification for a Manikin for Simulated in-situ Airborne Acoustic Measurements

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 12913-1 and the following 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 https: //www .electropedia .org/
3.1
background sound

sound which is heard continuously or frequently enough to form a background against which other

sounds are perceived

Note 1 to entry: Often these sounds are not consciously perceived, but they act as conditioning agents in the

perception of foreground sounds (3.3).
3.2
descriptor
term which is used to describe the perception of any acoustic environment
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ISO/TS 12913-2:2018(E)
3.3
foreground sound

sound to which attention of a listener is particularly directed and which can be associated with a

specific source
3.4
indicator
term which is used to predict a descriptor (3.2) or a part thereof
3.5
local expert

person who is familiar with the area under scrutiny either living in the area or having further daily

routines related to the area
3.6
noise
sound that is deemed to be unpleasant, unexpected, undesired or harmful

Note 1 to entry: Exceptions in this document are cases where the term “noise” is used as an established term, e.g.

broad-band noise or environmental noise.
3.7
soundwalk

method that implies a walk in an area with a focus on listening to the acoustic environment

3.8
total sound

totally encompassing sound in a given situation at a given time, usually composed of sound from many

sources near and far

[SOURCE: ISO 1996-1:2016, 3.4.1, modified — The figure and notes have been deleted.]

4 Descriptors and indicators
4.1 General

It is central to soundscape research, studies and implementation to fit descriptors and indicators to

the perception and the assessment of the concerned people. Classical indicators are known to show

strong limitations under certain sound conditions (low frequency sound, tonal components, multi-

source environments). The choice of indicators depends on the type of the investigated soundscape. It

is important that the fit of indicators reflects the situation and context (personal, social, cultural, land

use, economic, geographic) which define the acoustic environment, and also enables tracing dynamic

changes like time variances of the soundscape over the day or season.

Soundscape studies shall always consider the key components: people, acoustic environment and

context (see definitions and explanations in ISO 12913-1):
a) people:
— the participants shall be classified according to Annexes A and E;

— self-reported views of the participants (on the acoustic environment and on the context) shall

be obtained via questionnaires and/or interviews (see Annex C);

— in certain cases, if determined appropriate by the investigator or researcher, data collection via

non-participatory observations shall be obtained; this can include, for example, data collection

of subject(s)’ walking speed, proximity and/or openness to others (e.g. those not known to

themselves), head movements, and occupation time (e.g. time spent in the observation area)

[39][40]
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ISO/TS 12913-2:2018(E)

NOTE It is recognized that there are current limitations in feasible techniques. There can be

difficulties in trying to capture customary and holistic human response, by putting people into survey

contexts which can change their listening and related states.
b) acoustic environment:

— it shall be reported whether a real, recorded or virtual environment (indoor or outdoor) is

considered and whether it is a laboratory or field study (see Annex A);

— sound sources shall be described following a sound source taxonomy (e.g. Annex C);

— the acoustic environment shall be described using a combination of appropriate acoustic

indicators (e.g. see ISO 1996-1) and psychoacoustic indicators (see Annex B).
c) context:

— information on the context shall be reported in detail in accordance with Annex A.

This document specifies the data collection and reporting method(s) for each of these key components

in turn. The annexes provide further details of recommended (and any alternative) approaches for each

component.

The main requirements and some of the associated questions for descriptors and indicators shall

support:

— acoustical assessment: acoustic distinction of the variety of soundscapes (Why does this place

sound different? What is unique?);

— psycho-physiological assessment: assessment of the grade and type of neurophysiologic stimulation

(Is the soundscape stressing, supporting or relaxing? Which emotions are linked to it?);

— context assessment: assessment of the person-environment fit [Are there sounds or sound

components that interfere with the intentions/expectations of the meaning or support these?

Are there other sensory factors (visual, vibration, olfactory) that interact with the sounds in a

supporting or distorting way? Is the meaning of this place or the attachment to this place distorted,

undermined or supported?];

— design or remedial action: assessment of the holistic potential of the place (Are control/coping

options available/implementable? Can new meaning/emotions/attachment and social interaction

be created to support adaptation and meet expectations?).
4.2 Acoustic and psychoacoustic indicators

In order to describe the acoustic environment as the sound from all sound sources modified by the

environment and auditory sensations evoked by the sound, a set of acoustic and psychoacoustic

indicators shall be measured and reported as a minimum. Classical acoustic indicators shall be

measured and reported to be in conformance with ISO 1996-1. This includes equivalent continuous

sound pressure level L and L as well as percentage exceedance levels L and L .
Aeq,T Ceq,T AF5,T AF95,T

Psychoacoustic parameters play an important role with respect to auditory sensations. Such parameters

are functions of the time structure and spectral distribution and lead to results which yield information

with greater differentiation than the consideration of the sound pressure alone. Psychoacoustic

loudness indicators shall be reported in conformance with ISO 532-1, since acoustic environments are

time-variant sounds.

The consideration of further psychoacoustic parameters, like sharpness, tonality, roughness and

fluctuation strength, is recommended. If calculated and reported, the used calculation method shall be

reported. Some standards exist that can be applied to determine further psychoacoustic indicators, such

[6] [7]

as DIN 45692 for sharpness calculation or ECMA-74 for quantifying the tonality of discrete tones.

In general, the application of psychoacoustic parameters allows for an enhanced description of

acoustical environments (see Annex B). It has been shown that psychoacoustic parameters, like

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ISO/TS 12913-2:2018(E)

loudness and sharpness, correlate with the perception and assessment of environmental noise sources,

[25]

e.g. road traffic noise . However, acoustic and psychoacoustic indicators describe only the sound

and evoked auditory sensations; for example, whether the sound is perceived as loud, sharp or tonal.

These indicators are not intended to explain the level of pleasantness or appropriateness of sound in its

entirety.
5 Data collection
5.1 General

In practice there is still a significant gap between soundscape descriptors and indicators, which are used

in some standardized way in the “measurement by persons” and those applied in the “measurement

by instruments”. Psychoacoustic, ecological and landscape acoustics require techniques to be more

tightly integrated in such studies to mediate between personal experience and group-area-society

requirements and needs. Only through the proper integration of these techniques can the potential of

the soundscape approach be implemented in planning and design. The soundscape approach relies by

definition on this strategy. In this strict sense it can be said that any study that does not consider people,

acoustic environment and context in a combination of several differing investigative methods cannot

be seen as a full-featured soundscape study. So it is necessary to investigate each soundscape situation

from several viewpoints. This requires performing a soundwalk (see 5.2) and/or a questionnaire (see

5.3) and/or a guided interview (see 5.4) in addition to the binaural measurements (see 5.6).

Soundscape data collection tools and methods can be applied in situ and in situations where sound

is reproduced by headphones or loudspeakers. In the case of the reproduction of sound (e.g. for the

performance of listening experiments) an appropriate test design shall be applied.

5.2 Soundwalk

Over the past few decades, the focus of soundwalks has shifted from noting the researcher’s view to

determining the people’s understanding of places. The experiences and expectations of people, when

they are listening and observing during a soundwalk, are accessed primarily through the evaluation of

the rating scales and the annotation of the participants’ comments.

Soundwalk is a method to obtain human sensations/responses/outcomes (see ISO 12913-1).

Soundwalks are participatory group sound and listening walks through the environment. Soundscape

analysts observe and measure the perceptual responses of the participants to the acoustical, visual,

aesthetic, geographic, social and cultural differences. The participation of local experts and members

of relevant communities of interest in soundwalks enables researchers, practitioners, policy makers

and local authorities to collect and analyse ecologically valid acoustical as well as perceptual data. This

enhances the investigator’s sensitivity to the unique features of the examined areas.

Human sensations, responses and outcomes cannot be easily reduced to singular values of physical

units. The response to sound depends on the listener’s mental, social and geographical relation with the

sound source.
5.3 Questionnaire

When gathering data on human perception, the investigator should not interfere with the participants’

experience. Such data collection shall capture the general mood, restoration, appreciation, preferences

and overt behaviour to create an accurate representation of a specific location. Moreover, this type

of evaluation shall respect the way people are experiencing their environment. Data gathering via

questioning participants is a possible way to assess the whole path from acoustic environment to

soundscape, including the processes of individuals assessing and giving meaning to sound(s) and/or

demonstrating their responses to the acoustic environment. The final assessment shall be holistic,

covering all auditory sensations as well as all other context variables such as visual stimuli and personal

expectations.
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ISO/TS 12913-2:2018(E)
5.4 Guided interview

Data collection on human perception puts very strict requirements on managing attention processes.

Guided interviews shall be performed with the respective participants to explore associations, feelings

and emotions concerning the acoustic environment more deeply. The soundscape investigation

demands a holistic approach for the analysis of environments. This is why perceptual data (interviews,

questionnaires, non-participatory methods), psychoacoustic indicators (e.g. loudness, roughness,

sharpness) and physical parameters (sound levels) shall be used. Moreover, perceptual data collection

is particularly constructive because the context and information content of a soundscape can be

assessed as a result. It is important to use guidelines for narrative interviews to guarantee compatible

data collection related to the participant’s individual perception. Currently guidelines are available in

different formats. An example is provided in C.3.3.
5.5 Sound source taxonomy

To assist in source reporting for researches, a classification for all sound sources in any acoustic

[17]

environment in accordance with a common framework or checklist, is recommended , see Figure C.1.

The taxonomy shown in C.1 has been constructed on three levels: types of places, types of sound

sources and sound sources.

Categories of places are broadly considered either indoor or outdoor; within the outdoor environment,

they are divided between urban, rural and wilderness conditions. One can thus refer, for example, to

the acoustic environment of a wilderness place, or the acoustic environment of an urban place. Having

broadly characterized the type of the place, the taxonomy then categorises all sources of sound that can

be present. Most importantly, the nomenclature of sound sources has been carefully chosen to avoid

value judgements or connotations regarding these sound sources, irrespective of the type of the place

(for example, “motorized transport” is preferred to “intruding traffic noise” or “the passage of lorries”).

In some places, various sounds of human activities, say footsteps, can be present with only infrequent

sounds from roadway traffic; but in another location, roadway traffic can constitute the only sound

source. In each of these examples, the taxonomy of sources is applicable and encourages the description

of sources using a common terminology. The distinctiveness of particular acoustic environments lies,

amongst other things, in the presence or absence of these different sources and their relative intensities.

However, the framework for sound source identification assists in comparing the reporting of sound

sources across places and make other labels, value judgements and definitions more transparent, and

thus portable, across different studies.
5.6 Binaural measurements

Acoustical measurements related to a soundscape shall consider the way human beings perceive the

acoustic environment. For this purpose calibrated binaural measurement systems (artificial head)

shall be used to record an acoustic environment. Measurement conditions shall be chosen to measure

the acoustic environment as close as possible to the human auditory sensation. Binaural acoustical

measurements shall be performed in accordance with Annex D.

Each binaural measurement shall be described in a soundscape binaural measurement protocol. The

measurement protocol includes information about measurement time and interval, description of

measurement locations, measurement equipment, atmospheric conditions, notation of the influence

of topographical features, local shielding effects and description of sound sources. Reporting shall be

made in accordance with Annex A.

NOTE Further recording technology such as microphone arrays are frequently used in soundscape

investigations. It is acknowledged that those recording technologies can offer some advantages. In particular,

such technologies strive for a latter playback based on multi-loudspeaker arrays providing a certain level

of immersion. However, in contrast to binaural measurement technology these technological approaches lack

standardization and make it difficult to perform aurally accurate analyses to compute psychoacoustic parameters

and indicators.
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Binaural recordings are used for aurally adequate analyses, for the reproduction of acoustic

environments (e.g. in laboratory-based listening experiments) or for the purpose of preservation and

archiving.
6 Reporting requirements
The minimum reporting requirements that shall be adopted are given in Annex A.
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ISO/TS 12913-2:2018(E)
Annex A
(normative)
Minimum reporting requirements
A.1 General
The minimum reporting requirements in soundscape studies comprise the following:
a) the selection and classification of the participants;
b) a characterization of the studied acoustic environment;

c) the data collection with regard to human perception of the acoustic environment (including

context).
A.2 Participants

Soundscape studies are primarily conducted as field studies. However, sometimes laboratory studies

are also carried out. An example of a field study is a case study of a residential area where the acoustic

environment is redeveloped. In such a case it is common to select residents as participants in order to

learn how they perceive the acoustic environment and how they would like it to sound (indoors as well

as outdoors). Other examples of field studies are evaluations of parks or green areas. In these cases it

is common to select visitors in order to learn how they perceive the park and its acoustic environment.

It is also possible to select a panel of participants who are brought to the field study site to evaluate

its acoustic environment. Panels of participants are common in laboratory studies, which typically are

used to assess audio recordings of the acoustic environment from one or several sites.

As in any study design, the participants shall be identified and the following information recorded:

a) how they were selected;
b) whether the participants were residents at or visitors to the study site;

c) whether the participants were lay people, or experts in a field that is relevant to the study (e.g.

environmental noise or urban planning);
d) age and gender distribution;
e) other relevant information (e.g. hearing ability).
A.3 Acoustic environment

An acoustic environment can be real, recorded or virtual. A real acoustic environment is evaluated in

situ by means of a field study. A recorded or virtual acoustic environment is evaluated in a laboratory.

The two most common recording techniques in soundscape studies are binaural and ambisonics. The

former is typically reproduced by headphones and the latter by a multi-loudspeaker array. A virtual

acoustic environment can be based on recorded or synthesized sound sources that are mixed together

into an acoustic environment.

With regards to the characterization of the studied acoustic environment, the following aspects shall

be reported:

a) what type of acoustic environment the study concerns (real, recorded or virtual);

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b) the sound sources and the composition of the acoustic environment, including the total sound, the

background and foreground sounds;
c) weather and wind conditions;
d) time of the year and time of the day;

e) the measurement points (including height and orientation of the binaural measurement system)

and what acoustic measurements were taken;
f) the results of the measurements for the following:

— A-weighted equivalent continuous sound pressure level L ; C-weighted equivalent continuous

Aeq,T
sound pressure level L as well as percentage exceedance levels L and L ;
Ceq,T AF5,T AF95,T

NOTE A-weighting and C-weighting are specified in IEC 61672-1. Equivalent continuous sound

pressure level and percentage exceedance level are defined in ISO 1996-1.
— loudness exceeded in 5 % of the time interval N in accordance with ISO 532-1;
— loudness exceeded in 95 % of the time interval N in accordance with ISO 532-1;
— root mean cu
...

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