Page 9 - January 2007

SOUNDSCAPE:
AN APPROACH TO RELY ON HUMAN PERCEPTION AND EXPERTISE IN THE POST-MODERN COMMUNITY NOISE ERA
Brigitte Schulte-Fortkamp
Institute of Technical Acoustics, Technical University Berlin Berlin, Germany
Bennett M. Brooks
Brooks Acoustics Corporation Vernon, Connecticut 06066
Wade R. Bray
HEAD acoustics, Inc. Brighton, Michigan 48116
The term “Soundscape” seems like
magic compared with standard
measurement methods in com-
munity noise, since it considers people’s
minds as measuring instruments hav-
ing the same relevance as “real” meas-
urements. However, even in the 1970s,
Murray Schafer’s message about noise-
abatement legislation brought aware-
ness of the necessity and opportunity to
consider not just noise alone, but also
its perception by the experts who are
affected by noise: those who live in the
soundscapes—a term Schafer coined.
He clearly stated, “early noise abate-
ment legislation was selective and qual-
itative, contrasting with that of the
modern era, which has begun to fix
quantitative limits in decibels for all
sounds...the study of noise legislation
is interesting, not because anything is ever really accom- plished by it, rather because it provides us with a concrete register of acoustic phobias and nuisances. Changes in leg- islation give us clues to changing attitudes and perceptions, and these are important for the accurate treatment of sound symbolism.” 1
During the past 30 years, advances in policy develop- ment include the introduction of community-based environ- mental protection. This process makes the locally-affected community a major stakeholder in the crafting of effective public policy. The techniques of Soundscape are ideally suit- ed for the development of community-based noise policy.
After consensus had been reached about the European Union (EU)-directive on environmental noise in 2002, there remain several major challenges to overcome:
(1) Presently, only the effects of a single noise source are assessed, while typically several sound sources are present simultaneously.
(2) Only mono-sensory sound perception is taken into account, while in reality other sensory qualities (e.g., visual or very low frequency vibrations) contribute. (3) On the basis of the present standards, it is not yet possible to predict the effects of changes in the urban
“The soundscape approach provides a method to develop acoustical indicators and parameters into a database that describes urban and other outdoor living areas with respect to their physical conditions and their relevance for life.”
soundscape—difficult because data are only valid for “steady-state” condi- tions.
(4) It will become necessary to make generalizations—but there are very substantial differences in context.
(5) Presently, noise mapping is state of the art—but what is really needed is some form of annoyance mapping.
For more than ten years the multi- disciplinary approach has been applied to the study of community noise to explain people’s reaction to noise, including context related evaluation. The context-bounded approach was the crucial step to reach the definition of “Soundscape,” using its fundamental knowledge and procedures.
The soundscape approach provides a method to develop acoustical indica- tors and parameters into a database that describes urban and other outdoor living areas with respect to their physical con- ditions and their relevance for life. Those parameters will reli- ably allow the measurement of outdoor sound quality, which will take into consideration not only the sound pressure but also the characteristics of the sounds which lead to specific human reactions, both positive and negative: calmness, inspi- ration, annoyance, discontentment, anxiety, etc. as well as the pathogenic effects. Emission and immission measurements must be performed to document the physical conditions of the examined living area. In particular, the contribution of important sources like traffic noise to the overall sound expo- sure and its influence on the evaluations by residents must be determined. Moreover, the question is, to which degree does a single source determine the soundscape of the environment with respect to perception and evaluation? Therefore, diverse boundary conditions should be taken into account to reflect
adequately the circumstances of everyday life.
The application of Soundscape in community noise is
rapidly evolving, and has been discussed at numerous recent conferences within the Acoustical Society of America (ASA), and at a workshop on methods for com- munity noise and annoyance evaluation held at the149th
Soundscape and Community Noise 7