From the soundscape to the architectural redevelopment of an outdoor public space

From the soundscape to the architectural redevelopment of an outdoor public space

Francesco Asdrubali, Francesco D’Alessandro, Giorgio Baldinelli

Department of Engineering, University of Perugia, Perugia, Italy.

Brigitte Schulte-Fortkamp

Institute of Fluid Mechanics and Engineering Acoustics, Technische Universität Berlin, Berlin,

Germany.

Summary

The historic urban centers often undergo redevelopment, restoration and enhancement activities

aimed at the preservation of the historical and artistic heritage and at the improvement of the

citizens’ quality of life. Usually these interventions are mainly focused on architecture and urban

planning, favoring the visual appearance and not considering adequately the multidimensionality

of the environment perception, not least the sound environment. For this reason, the choice to

adopt the "Soundscape Approach" in the design is linked to the desire of adding a significant

contribution to the regeneration of urban areas, in order to make them more enjoyable and to meet

the needs of all the people who really and in different ways "live" the area (dwellers, storekeepers,

tourists and night lifers). The case study of the present paper is located in the historical center of

Perugia, in Italy. The acoustic analysis was performed through binaural recordings and

soundwalks involving residents of the area, in order to obtain respectively objective and subjective

evaluations of the soundscape. After this stage, Piazza Danti, a small square located in the very

heart of the historical center, was chosen as the project area. This decision was taken together with

the Municipality of Perugia since there are several problems afflicting the square, such as difficult

routes for motorists, lack of urban design and, above all, nightlife noise. A comprehensive

historical and architectural survey of the square allowed to understand all its morphological and

functional characteristics, while a noise monitoring showed night noise levels significantly higher

(even 30 dBA) than the law limits. These aspects guided the renovation project of the square: a

particular focus was put on the interaction between the architectural and the soundscape design, in

order to enrich the square with new sounds, while reducing some noise issues considered highly

annoying by part of the citizens.

PACS no. 43.50.Qp, 43.50.Rq, 43.66.Pn

1. Introduction

1

The redevelopment of a square mainly involves

returning to the place its values and promoting the

different uses, even considering the most modern

ways of living the city. The square is the place

where people speak, exchange ideas and goods,

meet and manifest, where shows and events are

staged; it is the crossroads of paths along which

the story is remembered, the culture of the area is

layered, the citizenship is built.

The historic urban centers are often the subject of

redevelopment, restoration and enhancement,

aimed at the preservation of the historical and

1(c) European Acoustics Association

artistic heritage and at the improvement of the

quality of the citizens’ life. These interventions

consist usually of architectural and urban planning

that favor the visual appearance but do not

adequately consider the multidimensionality of

perception of the environment, not least the sound

context, an essential component of the urban

landscape.

At the legislative level environmental noise is

regulated through redevelopment plans in order to

control and reduce its effects on human health.

This approach is without doubt correct and

necessary when noise can be detrimental to health

[1], but in other cases a wider approach aiming at

exploring and, in case of urban and architectural

planning, designing soundscapes can be profitably

applied.

FORUM ACUSTICUM 2014 Asdrubali, D’Alessandro, Baldinelli, Schulte-Fortkamp:

7–12 September, Krakow From the soundscape to the architectural redevelopment of an outdoor public space

Several methodologies for soundscape design have

been proposed so far [[2], [3], [4], [5]], but, since

the soundscape is strictly linked to the activities

and the functions that are (or are planned to be)

present in a place and to the expectations of the

users (variable in space and time), general

guidelines are hard to be provided. What is

important is the involvement in the urban planning

(including the soundscape planning) of all the

stakeholders through a participatory process [6].

2. Evaluation of the soundscape of the historic center of Perugia

The first stage of the work was devoted to the

evaluation of the soundscape of the historical

center of Perugia, in order to identify one area for

its architectural and acoustic redevelopment. This

activity was performed by means of a soundwalk;

the path was selected through a participation

process with the Municipality of Perugia (Figure

1).

The soundwalk was performed in December in a

warm (average temperature 12 °C) sunny Friday

morning from 10:00 to 13:30, and it was organized

with two groups of six people, chosen on the

condition that all of them were resident in Perugia

and local experts [6], led by two operators.

The two groups followed the path in opposite

directions. This had some influence on the results,

so the average results of the two groups are

reported in the paper. The only discrepancies were

found at P5 (Piazza Cavallotti), because of the

presence of a bus at the stop during one session;

however, this aspect will not be further

investigated in the paper.

During the walk the participants were asked to

stop in six sites with different characteristics. A

short description of each site is provided:

P1 Giardini Carducci: panoramic gardens

offering one of the most fascinating views of

the city; presence of a green area with benches

and temporary child games.

P2 Corso Vannucci: the most important

pedestrian street of the city, characterized by a

strong vitality and dynamism and by the

presence of different types of activities: bars,

theaters, shops and boutiques of any kind.

P3 Piazza Matteotti: small square built on an

artificial terrace hosting many commercial

activities and the direct access to the elevator

that connects to the Minimetro station and to

the city market.

P4 Piazza IV Novembre: monumental center of

the city, located at the end of Corso Vannucci,

surrounded by elegant and interesting

buildings: on one side the Cathedral of San

Lorenzo and on the opposite the Palace of

Priori, in the middle the wonderful Fontana

Maggiore.

P5 Piazza Cavallotti: a small square frequented

especially by young people for the presence in

the vicinity of the University Campus. It hosts

a bus stop.

P6 Piazza Fortebraccio: small square

characterized by a strong presence of the urban

traffic (cars and buses). The building of the

University for Foreigners, a small green area

and a basketball court overlook here.

Figure 1. Path and sites selected for the soundwalk in

the historical centre of Perugia.

In each location, along the chosen path, the

participants were requested to examine the local

soundscape writing down, in situ, their

impressions and assessments on an evaluation

sheet. The items of the evaluation sheet were

selected on the basis of those used in [7][8], [9].

The participants were asked to give their

judgments on each attribute (such as subjective

loudness, annoyance, pleasantness, relaxation,

vibrancy, quietness) crossing out their choice on

Likert five-point rating scales. In addition, the

participants were requested, with the open-ended

question “What goes into your mind”, to write

down the feelings they felt during their presence,

as well as the sound sources and soundmarks they

were able to recognize there.



In the meantime, one of the two operators carried

out recordings three minutes long, using a mobile

frontend with a binaural headset (Head Acoustics

MHS III). Both the measurements and the

participants’ hearings were executed with a fixed

orientation and with a fixed position; the

participants had to stay in silence during the three

minutes focusing on the sounds of the

environment and they had not a deadline to fill in

the questionnaire. In addition, panorama-photos

were taken by the second operator in order to have

an image of what the participants were looking at

during their hearing.

The elaboration of results obtained from the field

survey was developed in three stages: the first

concerning the analysis of the subjective

assessments (both for the first and for the second

group) and their subsequent comparison, the

second concerning the analysis of the objective

assessments (psychoacoustic parameters, SPL

measures, analysis of the spectrograms, acoustic

zoning limits) obtained by the binaural recordings,

the third concerning the comparison between the

results derived by the previous two phases. For

brevity sake, only some results are reported.

Figure 2 summarizes the results of the

questionnaires.

1

2

3

4

5

Not Loud / Loud

Notdisturbed/Disturbed

Unpleasant/Pleasant

Stressful/Relaxing

Quiet/Chaotic

Boring/Vibrant

P1.Giardini Carducci

P2.Corso Vanucci

P3.Piazza Matteotti

P4.Piazza IV Novembre

P5.Piazza Cavallotti

P6.Piazza Braccio Fortebraccio

Figure 2. Results of the questionnaires in the six locations (the black dashed line represents the neutral judgement).

The sound sources indicated by the participants

were collected in three main categories

(mechanical, human and nature): the results are

reported in Figure 3.

Table I reports the acoustics (A-weighted sound

pressure level LAeq and spectrum centre of gravity

G) and psychoacoustic (Loudness N, Sharpness S

and Roughness R) parameters measured in the six

locations: the results are expressed as average of

the left and right channels in both the soundwalks.

The participants’ feedbacks as written down in the

open-ended question “What goes through your

mind?” – were also taken into account and

summarized in keywords to create a tag cloud.

Examples related to the location Giardini Carducci

and Piazza Fortebraccio are reported respectively

in Figure 4 and 5, together with the spectral

analysis and the individuation of specific sound

events.

Table I. Acoustic and psychoacoustic parameters

measured during the soundwalks.

Locations LAeq

[dB(A)] N

[sone] S

[acum] R

[asper] G

[Hertz]

P1.Giardini

Carducci 54.6 9.98 1021.0 0.0221 109.2

P2.Corso

Vannucci 59.9 13.15 1028.5 0.0283 99.6

P3.Piazza

Matteotti 62.0 15.05 1053.6 0.0293 119.0

P4.Piazza IV

Novembre 63.9 16.9 1266.3 0.0282 133.4

P5.Piazza

Cavallotti 64.5 15.7 1198.7 0.0280 183.9

P6.Piazza

Fortebraccio 68.0 17.95 1211.2 0.0303 172.5

The results of the investigation can be summarized

in the following assumptions:

as expected, the quietest, most relaxing and less

annoying location is Giardini Carducci, where

the lowest SPL were recorded and natural

sources constitute an important feature;



27.7%

17.0%

6.3%

21.0%

11.5%

33.7%56.3%

47.0%

53.0%

43.5%

39.5%

38.7%35.3%

46.8%

26.0%

56.5%

49.0%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

P1.Giardini Carducci P2.Corso Vanucci P3.Piazza Matteotti P4.Piazza IVNovembre

P5.Piazza Cavallotti P6.Piazza BraccioFortebraccio

Mechanical

Human

Nature

Figure 3. Categories of the sound sources.

Figure 4. Tag cloud and spectrum (FFT: 4096, 50%

overlapping, Hanning) at Giardini Carducci.

Figure 5. Tag cloud and spectrum (FFT: 4096, 50%

overlapping, Hanning) at Piazza Fortebraccio.

Corso Vannucci and Piazza IV Novembre are

the most pleasant and vibrant locations, despite

sound pressure levels reaching 64 dB(A): this

is mainly due to the limited presence of

mechanical sources in comparison to human

sources (such as people walking or talking,

sounds from the shops or bars, street music);

Piazza Fortebraccio is assessed as the square

with the highest SPL and loudness value

(generated mainly by mechanic sources), with

the highest subjective loudness and annoyance

level and with the lowest pleasantness level.

3. Case study: Piazza Danti

Piazza Danti was chosen as the project location

inside the area of Perugia historic center. Although

this square does not constitute one of the six

locations where binaural recordings were made, it

is inserted along the previously described

soundwalk path.

The selection was guided by the outcomes of the

project “Magica Bula”, realized by Municipality

of Perugia, aimed at defining planning strategies

and interventions to improve the liveability of the

historic center of Perugia through the opinion of

the citizens, divided into the three main categories

- residents, merchants and students / young

people. The main objective was to investigate and

understand the needs, opinions and judgments of

those who live every day in the area, the major

issues related to the livability and the use of public

space, as a physical place where anyone has the

right to move.

For the purpose of this work, the most interesting

issues that emerged during the focus groups on the

liveability and use of public space were:



1. noises at night, especially in summer, due to

the presence of bars and shops;

2. difficult routes for the motorists, mainly in the

evening and night hours in summer and on

holidays, when the square is crowded;

3. poor utilization of public space and lack of

urban décor;

4. lack of attention to the secondary roads of the

centre: poorly lit alleys become the scene of

drug dealing and vandalism.

As far as the description of Piazza Danti, the

square has a surface-area of about 1400 square

meters, it is characterized by an uneven triangular

shape and it is sited in the northern part of the

historic center (Figure 6).

The historic center, including also Piazza Danti, is

a restricted traffic zone; the square has only one

entrance, one that comes from Piazza IV

Novembre and it is a one-way driveway, but it can

be travelled in the opposite direction only by

vehicles of public service.

The buildings surrounding Piazza Danti on its

three sides differ for their intended use and for

their state of repair of their façades:

the Cathedral of Perugia occupies the west side

of the square;

the Palazzo Conestabile is located at the east

side; it hosts commercial activities at the

ground floor (shops, bars, clubs, etc.) and

houses and offices at upper floors;

the north side is occupied by the Turreno

Theatre (now closed) and by shops and bars at

the ground floor.

During spring and summer the bars are equipped

with outdoor tables and umbrellas. Another

occupation of public land is reserved to temporary

markets and is located on the west side of the

square.

The historic analysis allowed to investigate the

morphological and functional evolution of the

square. The market appeared as a particularly

significant function (for bread before and for straw

later), which featured the area until it was moved

to Piazza IV Novembre. Today, this activity is

revived on a smaller scale and in an inadequate

space.

The architectural survey allowed to capture all

those characters of the square and surrounding

buildings (planimetric, entrances on the ground

floors, buildings height, architectural details,

presence of street furniture, etc.) and offered an

important starting point for orientating the

redevelopment.

The acoustic survey was performed by means of a

measurement campaign with a sound level meter

(01 dB dB4) installed in a box in Piazza Danti

during a late spring weekend. The results are

reported in Table II and Figure 7.

Table II. A-weighted SPL.

Period LAeq

(dB)

Daytime Friday 18:00 pm – 22:00 pm 62.4

Saturday 06:00 am – 22:00 pm 63.3

Nighttime Friday 22:00 pm – Saturday 06:00 am 74.8

Saturday 22:00 pm – Sunday 03:00 am 77.5

Results show how the complaints expressed in the

project “Magica Bula” are legitimate: during the

night, especially between 11 pm and 3 am, there is

a quite constant (see Figure 6, L1 and L90 are very

close) SPL equal to 75-78 dB(A) generated by the

voices of the people attending the bars and clubs

of the square. The law limit for the area in the

night period (10 pm – 6 am) is 50 dB(A). Hence,

the need to mediate between the different needs of

those who "live" the square has provided an

additional input for the design.

Figure 6. Aerial image of the historic centre of Perugia (right) and zoom of Piazza Danti with indication s of streets.



Figure 7. L90 (blue line), L50 (red line) and L1 (green line) trend in dB(A).

Results show how the complaints expressed in the

project “Magica Bula” are legitimate: during the

night, especially between 11 pm and 3 am, there is

a quite constant (see Figure 6, L1 and L90 are very

close) SPL equal to 75-78 dB(A) generated by the

voices of the people attending the bars and clubs

of the square. The law limit for the area in the

night period (10 pm – 6 am) is 50 dB(A). Hence,

the need to mediate between the different needs of

those who "live" the square has provided an

additional input for the design.

4. Redevelopment of the square

Intervention strategies were defined starting from

the identification of constraints to be respected

and then defining the objectives to be pursued

correlated with the suggestions. The constraints

for the design procedure are the outcomes of the

“Magica Bula” project, already introduced in

section 3, while the strategies are following

reported:

design of a new configuration of the square

according to the destinations, design of the

system of the street furniture and resting

places;

integration of the current soundscape with new

sounds according to the new function of the

square;

protection of the residents from unwanted

sounds (at night).

Under the idea "Pushing the limits, Creating

opportunities" the square was divided into four

areas (Figure 8).

By means of the division into sub-areas, the

square expresses the most of its potential, with a

better organization of space to facilitate the

permeability of the site and to carry out the

functions, increasing opportunities for using, in

favor of a fluid identity. Only the covered and the

rest/relaxation area will be described in this paper.

4.1 Covered area

The idea of a covered square aims at solving the

problem of the noise, especially at night, caused

by the activities in the square itself, which are

concentrated mainly on the east front.

The design solution was directed towards the

installation of a translucent cover, lightweight and

flexible, consisting of a series of umbrellas (made

of PMMA, Rw = 32-33 dB) whose height however

leaves space for view of the square in its limited

extension (Figure 9). The umbrellas will serve as

outdoor spaces for the bars, limiting the sound

propagation to the houses located at the upper

floors.

This proposal does not want to be a complete

solution for the nightlife noise issues of the area,

which can be obtained only with a combined effort

of policy actions and awareness campaigns.

4.2 Rest/relaxation area

This idea comes from the will of offering the users

of the square an area destined to pause and relax,

therefore, a quiet meeting place, in which people

are not forced to use the stairs which border the

facade of the cathedral as seats.

The seats placed in the rest/relax area have two

different designs.



Vehicular area Covered area Rest area Market area

Figure 8. Proposed division of functions of the square.

Figure 9. Section of the covered area with the umbrellas.

The first (Figure 10), located in the closest area to

the driveway, have been shaped to include a sound

absorbing panel with the function of reducing the

sounds coming from vehicular traffic; the latter

(Figure 11) are the so called "audio islands”: seats

but also places for reading, meditation or simply

for resting. They are equipped with sources that

transmit sounds deemed beneficial to this type of

activity, for instance natural sounds [7].

The area where they are inserted is bounded by a

mark on the ground that runs along the wooden

platform, including Feonic speakers [10] that, in

addition to the installation of the speakers in the

seats, recreate a quieter, more private and more

relaxing atmosphere by the reproduction of natural

sounds.

Figure 10. First type of benches in the rest area.



Figure 11. “Audio islands”.

5. Conclusions

The results of the work and the applied

methodology show the role of integrated planning

and participatory processes, whose interaction

becomes of fundamental importance in the recent

urban development processes.

The acoustic design should be included in a more

general integrated management approach of urban

planning. The approach based on the soundscape

can be a good solution for the design of urban

areas, taking into accounts not only the numerical

constraints of legislation, but also the acoustic

comfort of the places, in order to improve the

quality of life of people living and using a place.

The intention is therefore to shift the focus of

urban planners and landscape architects towards a

participatory planning approach, aimed at

upgrading the spaces, at the enhancement of the

sound elements as a vehicle for socialization, and

at making urban sound spaces central elements of

the social and aesthetic quality of our cities.

Thus, the use of the Soundscape Approach can add

a new acoustic consciousness to the visual

dimension and the involvement of the citizens, and

represents the condition that a proper design of the

modern city must take into primary consideration.

Acknowledgement

The authors would like to thank the Municipality

of Perugia for providing the outcomes of the

“Magica Bula” project and Francesca Catalucci

for her assistance during the work.

References

[1] J. L. Bento Coelho, K. Chourmouziadou: Soundscape of European Cities and Landscapes - Creating and Designing. – In COST Action TD0804 - Soundscape of European Cities and Landscapes, 2013, e-book version available at: http://soundscape-cost.org.

[2] L. Brown, A. Muhart: An Approach to the Acoustic Design of Outdoor Space. Journal of Environmental Planning and Management 47 (2004) 827–842.

[3] B. De Coensel, A. Bockstael, L. Dekoninck, D. Botteldooren, B. Schulte Fortkamp, J. Kang, M. E. Nilsson: The Soundscape Approach for early stage urban planning: a case study. Proc. InterNoise 2010, 2333-2342.

[4] S. Olafsen: Using planning guidelines as a tool to achieve good soundscapes for residents. Proc. InterNoise 2009, 4070-4075.

[5] G. W. Siebein: Creating and Designing Soundscapes. – In COST Action TD0804 - Soundscape of European Cities and Landscapes, 2013, e-book version available at: http://soundscape-cost.org.

[6] B. Schulte-Fortkamp, K. Genuit, A. Fiebig: Developing a public Space in Berlin based on the Knowledge of New Experts. Proc. InterNoise 2008.

[7] F. Asdrubali, F. D’Alessandro, A. Sberna, G. Baldinelli: Redevelopment of an urban open public space using the soundscape approach: A case study in Città di Castello, Italy. Proc. InterNoise 2012, 10211-10221.

[8] A. Fiebig, V. Acloque, S. Basturk et al: Education in soundscape - A seminar with young scientists in the COST short term scientific mission "Soundscape - Measurement, analysis, evaluation". Proc. 20th International Congress on Acoustics 2010, 3492-3498.

[9] G. Brambilla, V. Gallo, F. Asdrubali, F. D'Alessandro: The perceived quality of soundscape in three urban parks in Rome. The Journal of the Acoustical Society of America 134(1) (2013) 832-9.

[10] www.feonic.com, last visit May 28th 2014.

http://soundscape-cost.org/

http://soundscape-cost.org/

http://www.feonic.com/

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From the soundscape to the architectural redevelopment of an outdoor public space