ISO/TS 12913-2:2018

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 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

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
Foreword
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.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.
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iv © ISO 2018 – All rights reserved

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.
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
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]
.
2 © ISO 2018 – All rights reserved

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
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.
4 © ISO 2018 – All rights reserved

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.
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.
6 © ISO 2018 – All rights reserved

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);
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 cubed loudness N in accordance with ISO 532-1;
rmc
NOTE The root mean cubed loudness (cubic mean), Nrmc, is computed by determining the mean of all
loudness values raised to the power of 3 with a subsequent application of the exponent 3 as shown in the following
formula:
n
N =3 N
rmc i
∑
n
i=1
where
N is the single measurement value of the loudness;
n is the number of measured loudness values.
g) for a field study or a study based on audio recordings, a description of the study site, including the
type of site (e.g. indoors or outdoors; residential, plaza or a park);
h) for a recorded or virtual acoustic environment, how it was recorded or created and how it was
reproduced.
A.4 Data collection
Data on how a person or people perceive or experience and/or understand the acoustic environment
shall be collected by interviews or questionnaires or rating scales, or by observations of behaviour or
combinations of those. The following shall be reported:
a) the methods used;
b) the questions asked, how they were formulated and how the responses were documented;
c) for a study based on rating scales, how the questions, response alternatives and response format
were constructed and formulated;
d) what language was used in the study and examples of questions written in the original language as
well as in translation;
e) for observations of behaviour, how they were conducted and documented.
A copy of the data collection instrument (e.g. questionnaire or scales) shall be included in the report.
8 © ISO 2018 – All rights reserved

Annex B
(informative)
Psychoacoustic indicators
[8]
According to ISO 532-1 and ISO 532-2 , loudness and loudness level are two perceptual attributes
of a sound describing absolute and relative sensations of sound strength perceived by a listener with
otologically normal hearing under specific listening conditions. Since the loudness parameter considers
human signal processing effects like spectral sensitivity (frequency weighting), masking, critical bands
and nonlinearities, it shows a higher correspondence with the sensation of volume (loudness) than
[23]
any sound pressure level based indicators . For example, the psychoacoustic parameter loudness
indicates a loudness difference between a narrow-band noise compared to a broad-band noise, even if
both sounds have the same A-weighted sound pressure level. The broad-band noise is clearly perceived
as louder, which is indicated by the respective loudness value.
For calculating the psychoacoustic parameter loudness, different models and procedures have been
developed with the aim to represent the human signal processing as closely as possible. In particular,
procedures for computing the loudness of steady sounds are already established and have been in use
[3] [9] [2]
for several years (DIN 45631 , ISO 532 , ANSI/ASA S 3.4 ). However, almost all sounds in acoustic
environments are time-variant in general and loudness computation models for time-variant sounds
[4]
should be used. ISO 532-1 and DIN 45631/A1 allow for determining the loudness of steady as well as
time-variant sounds.
Sharpness represents the sensations of timbre with emphasis on high frequency content. It is influenced
[23]
by the spectral envelope of the sound and increases with increasing high frequency content .
The calculation of the psychoacoustic parameter sharpness as independent from total loudness is
[6]
standardized in DIN 45692 .
There is an alternative computation method for sharpness with a slightly different weighting function,
[62]
but without any influence of the total loudness on sharpness as well . Other computation methods for
[11]
sharpness exist, which apply a certain total loudness dependent weighting . For example, the noise of
waterfalls produces a relative high sharpness sensation.
With respect to modulated sounds, different sensations exist and are modelled by different indicators.
At very low modulation frequencies the loudness changes slowly up and down leading to a sensation
of fluctuation. The parameter fluctuation strength describing this phenomenon has its maximum
near a modulation frequency of 4 Hz. For example the sound of sirens possesses a high fluctuation
strength. Fluctuating sounds usually attract attention. At higher modulation frequencies a sensation
of roughness takes place. Roughness is related to relatively quick changes of sound with a maximum
[23]
near a modulation frequency of 70 Hz . Moreover, the parameter roughness is influenced besides
the modulation frequency by the sound pressure level, carrier frequency and degree of modulation.
For example, a motor scooter equipped with a two-stroke engine produces a relatively high roughness.
Standardized computation methods of roughness or fluctuation strength are not available yet. However,
[11][23][44][56]
different models for the computation of roughness exist .
[12]
Tonality is another sensation of timbre, which indicates whether a sound consists mainly of tonal
[12][59]
components or broadband sound . Although standards for the determination of tonal content
[5] [1]
in sound exist (DIN 45681 , ANSI/ASA S 1.13 ), these standards do not model the psychoacoustic
impression of tonality, but rather focus on the derivation of penalties. However, different approaches
[11][57][59]
exist to compute the perceived amount of tonality of a sound . Several publications have
[38]
observed an increase of annoyance for technical sounds with increasing tonality .
[55] [21]
Other hearing related parameters are available, e.g. impulsiveness , gravity centre of spectrum or
[27]
relative approach as an indicator of the perceived amount of noise patterns .
In general, it is important in the case of the determination of a single value representing an auditory
sensation to consider the human cognitive processing of sound. For example, in case of a time-variant
sound, the determination of a single value representing a “sensation magnitude in average” over a certain
period should follow the typical human cognitive stimulus integration. Frequently, the arithmetic mean
of the function of a parameter over time does not reflect the human cognitive processing of a sound.
For example, surveys have shown with respect to loudness that the perceived overall loudness of a
[23]
time-variant sound is well represented by the percentile loudness N . This is the loudness, which
is reached or exceeded in only 5 % of the measuring time interval. Prominent and loud sound events
dominate the overall loudness and should be emphasized.
Since binaural measurements provide signals representing the left and right ear of a listener, any
acoustic parameter can be calculated for both ears separately. Since an acknowledged model for
combining dichotic situations causing inter-aural differences into one global sensation is missing,
[4]
different strategies for determining a single value are reasonable. For example DIN 45631/A1 and
[8]
ISO 532-1 recommend using the maximum value of both ears or in ISO 532-2 a binaural loudness
[43]
model is proposed .
In general, if psychoacoustic parameters are analysed the applied computation method and potential
post-processing steps should be indicated.
NOTE In psychoacoustics, the term "parameter" is commonly used for established psychoacoustic metrics
instead of the term "indicator".
10 © ISO 2018 – All rights reserved

Annex C
(informative)
Data collection methods
C.1 Taxonomy
To assist in source reporting an information structure that is aligned with a classification for all sound
sources in acoustic environments can be used. A proposed taxonomy is shown in Figure C.1 and is
intended to be used only by investigators and is not intended to be used by participants.
C.2 Soundwalk procedures
C.2.1 General
The purpose of a soundwalk is to evaluate the soundscape in a given area. Usually a soundwalk
should be led by a moderator who also conducts a narrative interview or discussion session after the
soundwalk. The participants may be led along a predefined route or be asked to walk where they prefer
within a predefined area. They may be asked to stop at predefined locations to listen or to select any
place they like in order to listen more attentively. The moderator should instruct the participants to pay
attention to what sounds are heard during the soundwalk, what they liked and disliked, why, and how
they believe the acoustic environment could be improved. The participants are expected to report on
these aspects in their personal narratives, comments or statements. For examples, see C.3.1 and C.3.2.
C.2.2 Soundwalk: Obtaining human sensations/responses/outcomes
C.2.2.1 Instructions to the participants about to undertake a soundwalk
a) Conduct the walk in silence in order to pay attention to surrounding sounds and to avoid disturbing
the concentration of the other participants.
b) Try listening to “sound as sound”, suspending any attempts at “source identification” and source-
related value judgements in favour of listening to the innate qualities of the sound.
c) Alternatively, try to identify the maximum number of separate sounds audible at any one time.
d) Identify which sounds are entirely natural and which are man-made and by what or whom.
If attention should also be paid to the movement, body awareness and sensitization within a soundwalk,
it is proposed to add the following instructions.
e) Listen to the sounds that your body creates while moving. These are the sources of sounds closest
to you and establishing the first interaction between you and the environment.
f) Lead your attention away from your own sounds and listen to the sounds nearby.
g) Lead your attention away from the nearby sounds and listen beyond, into the distance.
h) Select a continuous moving sound (e.g. footsteps or a vehicle) and try to listen to it until it becomes
inaudible. This can help “recalibrate” the ear to pick up detail.
i) Closing your eyes (when safe to do so) can help to improve listening.
j) Alternatively, try to train your hearing to focus on sounds which have positive associations for you,
even if they are only just audible above sounds which normally have negative associations.
k) Assess how the changing environment alters sounds; for example, absorption by some surfaces,
reflection from others, especially multiple reflections within narrow alleyways, tunnels,
colonnades or below bridges. Judge where any of the sounds are coming from. Assess the effects of
screening by buildings, walls, or changes in sound level.
C.2.2.2 Questions to the participants of a soundwalk
a) What was your favourite sound on the walk? Why and where was it?
b) What sound did you dislike the most? Why and where was it?
c) Where would you make improvements to the sounds you heard? which would be the most important
and why?
d) Did the sounds you heard match your expectations of the area? why/why not?
C.2.3 Soundwalk: Obtaining quantitative data
A questionnaire with predefined questions and response scales should be used to describe the most
essential aspects of the soundscape. At least twenty participants should assess the soundscape with the
questionnaire at exactly the same sites in the area under scrutiny. The selection of the assessment sites
depends on the purpose of the study. Sometimes the researcher or investigator selects the assessment
sites alone, and sometimes the researcher or investigator selects them together with the participants,
who can be stakeholders in the study.
For each soundwalk a group of up to five participants walks together along a predefined route.
Therefore, the procedure should be repeated a number of times to reach at least twenty independent
observations of each assessment site under similar conditions (e.g. time of the day, weather, ambient
conditions). The participants should not discuss their assessments or experiences with each other
during the soundwalk. In order to reduce a systematic influence of order effects on the assessments it
is necessary to bring the different groups of participants to the assessment sites in different orders, if
possible.
A soundwalk with predefined assessment sites should have the following aspects.
— The soundwalk area, including assessment sites, is predefined.
— The soundwalk is led by a moderator.
— A questionnaire with predefined questions and scales is used.
— The participants walk in silence and listen freely for the duration of the soundwalk.
— All participants fill in the questionnaire at the predefined assessment sites.
— At least twenty independent observations are collected at each assessment site.
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a
The urban/rural distinction is not always readily defined, but remains useful.
b
The wilderness category includes national parks, undeveloped natural and coastal zones and large
recreation areas for example, though the wilderness/rural divide is not always clear-cut.
c
While “nature” and “domesticated animals” sources are shown as being “not generated by human
activity” there are many areas of overlap, e.g. the sounds of running water in constructed water fea-
tures or the sounds of wind on buildings. Domesticated animal sounds are generally from animals
associated with a human activity/facility.
d
Recording, replay and amplification can occur for any type of sound, e.g. in installations playing
nature/wildlife sounds.
e
Because of the different acoustic impedances in air and water, many of the terrestrial sound sourc-
es would not normally be observed under water, but overall the same classification system is still
applicable.
f
Coughing, for example.
NOTE 1 Bold boxes = types of places; dashed boxes = types of sound sources; italics = sound sources.
NOTE 2 See Reference [17].
Figure C.1 — A taxonomy of the acoustic environment for soundscape studies
C.2.4 Local expertise
Local experts are those people — e.g. the daily inhabitants of an environment or the stakeholders in the
investigation area — who provide their expertise to researchers, investigators and project designers
through such processes as soundwalks and open interviews. The listener’s attitude, expectations and
experiences are significant parameters which can be used to comprehend the different perceptions and
evaluations of the acoustic environment of a place due to
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