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Fig. 1. Possible relationships linking sound pressure level (vertical, dB(A)) to psy- choacoustic loudness (horizontal, the linear measure Sone) depend on spectral shape (there is no single rule). The inner ear, assigning frequencies to locations of hair-cell excitation along a physical structure (much different than the way a microphone works), responds as loudness to the total area being excited. For exam- ple, tonal centers close together have merged excitation areas and generate lower loudness than tonal centers more separated in frequency, for the same sound pres- sure level. Another major factor in loudness sensation: for constant sound pressure level vs. frequency, loudness is much higher (approximately double)—around 4 kHz due to a strong acoustic resonance of the outer ear near the ear canal entrance.
the identification of the relevant indicators that have an essential impact on the perception and evaluation of envi-
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“Soundscaping”—Combined soundscape analysis technique
“Acoustic coloration” from the environmental sound sources carries information that may either block or stim- ulate human activities, thoughts, and feelings. Therefore, soundscape evaluation will include acoustical as well as other sensory, aesthetic, geographic, social, psychological, and cultural modalities in the context of human activity. The aim is to get access to the social, psychological, and cultural conditions that are important to determine a par- ticular individual’s and/or collective behavior, attitudes, and emotions relative to the given noise under scrutiny.
In daily life, parameters and phenomena enter into interrelation and interaction that can be investigated with regard to their acoustic-ecological, psycho-acoustic, socio- acoustic ascription. Detailed analysis of the typology, mor- phology, and topology of potential test sites must include, criteria like land use and function, urban fabric and its state or condition, qualities of private, semi-private and public zones, analysis of neighborhoods in terms of archi- tectural shape and scale, specific issues of any existing site development strategies, and specific features related to the site, i.e. differentiating patterns and situations.
Soundscapes are defined with respect to their scope. This can be done by sound walks that are participatory sound and listening walks with respect to the acoustical, visual, aesthet- ic, geographic, social, and cultural modalities.
Data collection—Short term
A brief demonstration of the combined soundscape analysis technique (“Soundscaping”) was given at the 151st Meeting of the Acoustical Society of America, in
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close to office and shopping destinations.
One location is known as the “Riverwalk.” This river-
side area is popular with residents of the city and the sur- rounding communities for its attractive setting and for its famous Saturday night event “Waterfire,” which is held throughout the summer months. In this event, fires are built and displayed in a series of metal stanchions placed in the river and the surrounding plazas are alive with music, food and other entertainment.
Measurement and interviews
For this soundscaping demonstration, measurements and interviews were conducted during an afternoon of fair weather, while the Riverwalk Plaza was busy with lunch hour pedestrian traffic (see Fig. 2). Although the sound level in dB (A) was consistently in the mid 60’s, with high- er excursions due to nearby construction activity, the reac- tion of pedestrians to the sound was universally positive. This was primarily due to their positive personal associa-
ronmental noise.
During a walk in the urban area near the meeting hotel, physical sound measurements and perceptual interviews were conducted at two downtown locations. Both of these locations were
Providence, Rhode Island, June 2006.
Perceptual measurements
The key to understanding, and ultimately to applying these physical measurements, is an evaluation of the per- ceptual effects induced by the various magnitudes of those
8 specific physical and psychoacoustic parameters. Since
soundscapes have to be considered as two-component environments, comprising certain sound sources as well as the way people feel about those sounds contributing to the identity of those residential areas, these essential “human weighting” effects may be analyzed through the use of sci- entifically-developed interviews, questionnaires and other means to determine the frank and honest appraisal by
4 community members of their sound environment. Only
through the accurate evaluation of this cause-and-effect relationship may successful strategies be developed and implemented. It is important to recognize that among varying soundscape types the relationship between physi- cal and perceptual parameters will have similarities, but the relationship will also have unique properties tied to each specific community and living context, related to socio-economic background and specific lifestyle.
For example, the contextual conditions are important when people are evaluating noise annoyance. The combi- nation of methods with different sensibilities for subjects’ work during a process of perceiving, describing and/or evaluating noise in such an environment is necessary for a reliable and valid analysis and interpretation of data.
Another aspect is that the annoyance of exposed indi- viduals rises with increasing traffic density. In a situation with low traffic density, single noise events stand out. This results in a high level of annoyance although the Leq is low. These parameters must be adequately considered in meas- urements. The broad approach using acoustical diaries and both indoor and outdoor measurements guarantees
Soundscape and Community Noise 9