PROCEEDINGS of the23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Soundscape Cognition for User Behavior in Urban Parks
Hyun In JO1; Jin Yong JEON1; Jean-Dominique POLACK2
1Hanyang University, South Korea
2

Sorbonne University, France

ABSTRACT
To investigate the cognitive components of urban park soundscape design, we evaluated soundscapepreference based on visual object change factors for the background and people within the virtual reality(VR) environment. We investigated the changes in the sound pressure level and frequency characteristics
among 18 evaluation points selected from three parks in Paris. For the investigation, sound environments of
two minutes and 30 seconds during the daytime (10:00-14:00) were selected from each point using a 360degree camera (Insta360) and SoundField (SPS200) microphone. To investigate the behavioral characteristics
of urban users, the image of each selected point was divided into 30-second segments, and objective
characteristics, such as activity, group, posture, and density, were analyzed. We also evaluated subjective
responses, such as soundscape evaluation factors, landscape evaluation factors, and overall satisfaction, toinvestigate the differences in soundscape cognition as behavioral characteristics changed at the same pointin the park. To realize an immersive environment, the subjects were allowed to move freely in VR byreflecting the direction of the sound source and head rotations. Assessments of the level of immersion andsense of reality were used to verify the experimental environment.
Keywords: Soundscape, human behavior, soundscape quality

1. INTRODUCTION
Soundscape has a close relationship with the landscape, and there are many previous studies thatthe perception of the soundscape perception depends on the composition of the landscape (1, 2).
Furthermore, the effects of audio-visual components on recognition of soundscape and audio-visualinteraction have been studied (3). In recent years, there has been an attempt to investigate the changeof the sound environment according to the behavioral characteristics of the urban users in addition to
the simple audio-visual effect investigation (4). However, there is little research on the relationshipbetween the soundscape quality in a space and the human behavior of urban users. Although arecognition model for soundscape perception has been proposed, further study is needed because there
are limitations on the consideration of user behavior and application of visual i ndicators (5).
Virtual reality technology is widely used to reproduce the visual and acoustical conditions of a realenvironment. In recent years, there have been a lot of applied studies on indoor and outdoor noise,and methodological researches on the implementation of VR environment for soundscape evaluation
have been made (6 - 8). Therefore, it is possible to implement similar conditions in the laboratoryenvironment through the VR technology in a situation where control of the exper imental conditions
is required, and the results of the previous studies show that the subjective evaluation results in theVR environment are similar to the actual ones, so they need to be practically used (9, 10)
In this study, we implement the evaluation environment by applying the virtual reality technology
and evaluate the soundscape of the urban park. First, we examine the perceived sound sources of eachpark's evaluation points, observe the behavioral characteristics of the park users, evaluate thesoundscape quality, and finally examine the relationship between human behavioral characteristics
1

best2012@hanyang.ac.kr
jyjeon@hanyang.ac.kr
2jean-dominique.polack@sorbonne-universite.fr
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and soundscape recognition.

2. METHODS
2.1 Site Selection
To investigate the effect of human behavior characteristics on soundscape recognition in urban
parks, Arènes de Lutèce (A), Jardin des Tuileries (J), and Champ de Mars parks (C), which havedifferent acoustic and visual characteristics around the Seine River in Paris, were selected. The Arènesde Lutèce park is located near the residential area and is surrounded by buildings and has a green area.
And it has a circular square in the center. The Jardin des Tuileries park has a large open space and agreen area, surrounded by tall buildings, and there are distinctively different sized fractions. The
Champ de Mars park also houses the landmark Eiffel Tower in Paris and features a large green area.
Subjective response and objective measurement results were obtained at 12 points in total, and eachevaluation points is shown in Fig. 1.
The A-weighted sound pressure level (L Aeq ) was calculated to determine the sound strengthcharacteristics. LCeq-Aeq was calculated to investigate the relative low-frequency characteristics withrespect to the sound spectral contents. Finally, LA10-A90 was calculated to investigate the temporalvariability of the sound environment (See the table 1).

Figure 1 – Panoramic view of selected evaluation locations
Table 1 – Mean value of acoustic parameter of each evaluation locations
Sites

LAeq

LA10-A90

LCeq-Aeq

Sites

LAeq

LA10-A90

LCeq-Aeq

Sites

LAeqLA10-A90

LCeq-Aeq

A1

54.5

12.4

21.8

C1

67.6

21.9

17.8

J1

65.0

24.4

18.5

A2

42.5

5.0

28.4

C2

72.1

22.4

16.1

J2

64.2

18.9

19.3

A3

54.8

22.1

22.4

C3

69.6

19.7

17.5

J3

56.1

12.1

21.9

A4

60.4

23.9

20.7

C4

67.9

22.1

18.4

J4

66.0

17.5

19.6

869

2.2 VR soundscape recording and reproduction
Soundscape data were recorded at 12 points at 10 am – 2 pm in October 2018. A spherical
panoramic camera (Insta 360 camera), an ambisonic microphone (Soundfield SPS 200 microphone),and portable recording device (MixPre-6) were used to measure the audio-visual environment data.
The recordings were recorded in A-format first-order ambisonic (FOA). A-weighted sound pressurelevels were measured using a calibrated 1/2-inch microphone (G.R.A.S AE46) to calibrate the soundpressure level when reproducing recorded sources in a laboratory environment.
A 360° camera image recorded with six channels was implemented with a head-mounted display(HMD). For the implementation of headphone-based 3D stereo sound, the sound source recorded with
the A-format FOA was converted into B-format FOA using Unity software and down-mixed with abinaural track and reproduced using and open-type headphone (Sennhiser HD-650). The length of theevaluation source was set to 30 seconds, which is sufficient to an swer the question through the pilot
test. The sound pressure level of the recorded ambisonic audio at each evaluation point was calibratedusing a head and torso simulator (Brüel & Kjær 4100) based on the value of the A-weighted equivalentcontinuity sound level of the 150 sec (LAeq,150-sec).
2.3 QuestionnaireSoundscape data were collected using a questionnaire and observation, and the questionnaire
consists of 3 parts. The dominance of the perceived sound sources was evaluated using a 5-point likert
scale, and the types of sound sources were classified into four categories: traffic noise, sounds fromhuman activities, water sounds, and birdsong. The perceived affective quality at each location wasalso evaluated using eight adjective attributes. Human behaviour characteristics were investigatedusing observation method. The behavioural characteristics of every 30 seconds frame of the videotaken at each evaluation positon were classified into three categorize: Activity (chatting, eating,loitering, talking on the phone, stroll with dog, talking a picture, walking, jogging, riding, stroller),group (alone, group) (11).
2.4 Procedure
A total of 30 subjects (20 males, 10 females) participated in the evaluation of the soundscape, andall subjects had normal auditory capabilities. The test subjects were aged between 20 and 29 (meanage = 24.8, standard deviation = 1.98). The evaluation was conducted in the semi-anechoic room andthe background noise was sufficiently low to be 30 dBA. The order placement of the evaluation points
in the same park was set to coincide with the actual walking path, and the order of the park was set tobe random. The length of the sound source was set to 150 seconds for each evaluation point, and eachsound source was divided into 5 sections in 30 second intervals. Subjects were asked to answer thesame questionnaire for a total of 60 sound sources (12 points ൈ 5 sound sources). To minimize thephysical fatigue during the evaluation period, the subjects were allowed to have a sufficient restingtime of about 10 minutes every 30 minutes.

3. RESULTS
3.1 Perceived sound sources
The sound sources prominent at each evaluation point are shown in Figure 2. Percentage is thepercentage of people who answered "heard a lot" or "dominated completely" out of the 5 -point scale.
First, Park A is dominated by birds, because it is quiet and well-organized compared to other parks.
In the case of Park C, the sound of people was predominant, which is considered to be due to the flowof people because Park C is a sightseeing spot and plays a landmark role in Paris. Park J showed that
traffic, human, water, birdsongs can be heard well. Thus, it can be seen that the three parks havedifferent acoustic characteristics.

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Figure 2– Temporal variation in the dominant sound sources types for 5 different sampling period
3.2 Human behavior
The results of the observation of human behavior are analyzed and the overall characteristics areshown in Figure 3 and the specific activity types are shown in Figure 4. First, Figure 3 (a) shows thatPark A has a higher percentage of people staying in the space, and (b) shows that many people arecoming alone. Park C had a higher percentage of passers, as it was one of the tour courses, becauseof the high percentage of people who came and went for a while, most of them coming to the group.
Park J showed the characteristics of Park A and C. The ratio of passer to stopper wa s similar. However,considering the size of the park, similar to Park C, the proportion of people coming to the group ishigher than that coming alone.

Figure 3 – Overall human behavior characteristics in different sampling periods
As shown in Figure 4, there were many people who went to Park A without taking any special
action. In Park C, the closer to the Eiffel Tower, the higher the percentage of people walking andtaking photos and staying in the space. In Park J, the percentage of people who walked in the park
was high regardless of the location.

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Figure 4 – Specific human behavior characteristics in different sampling periods
3.3 Soundscape quality
Table 2 shows the results of the principle component analysis for eight soundscape attributes. TheKaiser-Meyer-Olkin (KMO) measures of sampling adequacy was 0.71, respectively, indicating
optimum levels. The Bartlett’s test of sphericity was clear (p<0.01). The soundscape quality of thepark is expressed by three factors (Tranquil/Peaceful, Dynamic/Lively, Confusing/Uncomfortable).
Table 2 – Rotated component matrices of the PCA using semantic attributes response
Attributes

Tranquil/Peaceful

Dynamic/Lively

Confusing/Uncomfortable

Explained variance

26.30

24.00

18.48

Pleasant

0.23

0.75

0.14

Unpleasant

0.01

0.12

0.84

Eventful

-0.32

0.78

0.12

Uneventful0.74

-0.28

0.19

Exciting

-0.22

0.78

0.15

Monotonous

0.82

-0.10

-0.07

Calm

0.83

0.08

-0.20

Chaotic-0.10

0.19

0.80

The factor scores for each evaluation point are shown in Figure 5. Park A was relatively tranquiland peaceful, and in the case of A3, it was found to be negative in the vicinity of the road. Park Cshowed a high percentage of people and was rated as dynamic. In the case of Park J, there was no
significant difference between factor factors. All three parks showed no significant difference withtime.

872Figure 5 – Temporal variation of the mean PCA component scores

4. DISCUSSION
4.1 Relationship between sound-sources and soundscape quality
Table 3 shows the results of the spearman rho's correlation between the soundscape component
results derived from PCA and the sound-sources perceived in the park. Traffic and human sounds werepositively correlated with Dynamic / Lively, but they were found to be somewhat confusing. On theother hand, natural sounds (birdsongs, water) showed a positive relationship with Tranquil / Peacefuland showed positive contribution to soundscape evaluation. This is in agreement with the results ofprevious studies (3, 9)
Table 3 – Spearman rho’ correlation between perceived sound sources and perceptual components ofsoundscapes (Bold < 0.01, underscore < 0.05)
Attributes

Tranquil/Peaceful

Dynamic/Lively

Confusing/Uncomfortable

Traffic

-0.57

0.41

0.39

Human-0.69

0.68

0.30

Birdsongs

0.56

-0.02

-0.71

Water

0.29

-0.08

-0.31

4.2 The influence of human behavior characteristics on soundscape recognition
Table 4 shows the correlation between human behavior and soundscape quality. When we look at
each group first, it shows that Tranquil / Peaceful is more influential when several people are in group.
In the case of Stay, it was found that the higher the ratio of stopper, the more dynamic and lively theperson staying in the space is. In the case of specific activities, the degree of walking or stay ing lightly
rather than jogging / running or riding has a greater effect on Dynamic / Lively.

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Table 4 – Spearman rho’ correlation between perceptual components of soundscapes for different humanbehavior characteristics (Bold < 0.01, underscore < 0.05)

Group

Stay

Activity

Criteria

Tranquil/Peaceful

Dynamic/Lively

Confusing/Uncomfortable

Alone

-0.39

0.48

0.28

Group-0.44

0.45

0.28

Passer

-0.39

0.35

0.28

Stopper

-0.48

0.53

0.29

Stopping

-0.48

0.54

0.33

Loitering

-0.26

0.39

0.22

Walking

-0.43

0.43

0.25

Jogging/Running

0.03

0.17

0.18

Riding (Bicycle)

-0.21

0.25

-0.03

5. CONCLUSIONSIn this study, the effect of human behavior characteristics on soundscape recognition wasinvestigated through a VR environment in the laboratory to improve soundscape quality throughinducing the human behavior in the urban parks. As a result, we identified three factors for soundscapequality and identified the relationship with human behavior. However, there is a need to investigate
the differences in behavioral changes with time, and it would be more meaningful to study the effectof noise level or psychological density, such as perceived loudness or perceived crowd density. The
results of this study can be effectively and practically used from the viewpoint of human behavior indesigning and improving the city park.

ACKNOWLEDGEMENTS
This work was supported by a grant the Science and Technology Amicable Relationship (STAR)
program, from the National Research Foundation of Korea (NRF) grant funded by the Korea
government (MSIT) (2018K1A3A1A21043775)

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