ON SOUNDSCAPES AND THEIR MEANING REGARDING NOISE ANNOYANCE MEASUREMENTS

Transcription

1 ON SOUNDSCAPES AND THEIR MEANING REGARDING NOISE ANNOYANCE MEASUREMENTS Brigitte Schulte-Fortkamp, Wolfgang Nitsch University of Oldenburg D Oldenburg, Germany INTRODUCTION The World Soundscape Project was carried out by the Canadian composer R. Murray Schafer and his colleagues at Burnaby, British Columbia during the 1970's. Their interests included studying the interactions between people and sound. The way people were perceiving their environment consciously and the chance to change the orchestrating of the global soundscape was in the focus of the project. (Schafer, 1977) When interviewing people about their experiences with noises in their residential area descriptions of the area could be identified which have been connected with their visual impression as well with an impression of the noise sources fitting or not fitting with the area (Fyhri, Klaboe, 1999). Additionally the history of the area and the changes which lead to the nowadays structure built the focus of the description. The assessments of the quality of the area depended e.g. on how long people have been living there, how they defined the area in dependency from the infra structure, how much they have been involved in the social life in those areas or integrated in their neighborhoods (Nitsch, Schulte-Fortkamp, 1997). Firstly criteria for defining soundscapes and the relevance concerning with noise annoyance measurements will be discussed. Then findings from an explorative study will be presented to discuss the importance of soundscapes as a new approach towards a theory of noise annoyance. THEORETICAL BACKGROUND Noise annoyance measurement usually refers to situations where people feel disturbed, or annoyed because of activities which are interfered by noise which is unexpected or moreover not wanted. However, the same noise probably will for some people be annoying for some other people kind of lifestyle, kind of sound belonging to an area. When judging noise every noise evokes processes of auditory structuring, because people are always looking, consciously and unconsciously, for orientation. This includes different processes of analysis and in result it mainly allows people to identify the source of a given sound, the distance to this sound source, its characteristics etc. Simply said while analyzing people do a lot of comparison work: they compare the in-going information with

2 stored sound or sound patterns, e.g. they are listening to a sound and spontaneously they remember a similar sound which is often connected to a special situation and/or to past experiences. Those experiences usually will be remembered as a situation which is embedded in a real environment. People usually remember in scenes, they have images about a situation in their mind. Processes of auditory structuring as part of sound analysis are necessarily connected to memories, which are remembered in associations and imaginations, acoustically and visually, and related to their social situations: context constructions are built which are partly based of past autobiographical experiences.(muckel et al.,1999) To know something about these contexts is essential to explore the judgements about how much annoying is a noise or synergistic noise event. Analyzing noise annoyance it is important to separate analytically the typical objective structure of such sound events related to their specific characteristic from the subjectively defined structure by judgments e.g. of loudness, unpleasantness. (Neisser, 1979). Therefore it is helpful to have descriptions of the sound events and the perceived effects by different groups of people, e.g. inhabitants, researchers, testpersons, and physical acoustical measurements. EXPLORING THE SOUNDSCAPE A study to explore the soundscapes was conducted to clarify the measurement features on synergistic noise effects. Firstly there was the strategy to select residential areas, living styles, and people to built from the acoustical point of view ecological and sociological samplings. There was a team of students with architectural knowledge and acoustical experts who went around the different areas and gave a description of noise events regarding road traffic noise and air traffic noise. For each area and road section different houses, apartments and people living there have been selected by this procedures. Regarding the concept of theory-building research work criteria and procedure of theoretical sampling (Strauss, 1991) was guiding the selection of groups being involved in this investigation (Flick, 1995). The field study should contribute to explain the socio-cultural background of noise effects as well as to explore methodologically the conditions for a representative study developing prediction models. Another important issue here was to focus on synergistic noise immissions, e.g. the distance to different noise sources characterizing the soundscape of an area: road traffic noise, air traffic noise, and railroad noise. The strategy of selection was motivated by some hypothesis of noise effects. For systematic comparison people have been selected regarding to their social status: one group with higher status segments profession, education, and living comfort, the other group was on lower levels to the same status segments. The selection for each group included the frequency of noise events as well as whether there were one source or different sources dominating the noise events. During the scouting it was helpful to combine the acoustical-ecological and sociocultural indicators to define the relevance of the chosen parameters regarding to lifestyle phenomena and synergetic noise events. DESCRIPTION OF SOUNDSCAPES Acoustical, ecological, and socio-acoustical evaluation of the areas pointed out that the concepts of gestalt-theory and ecological- psychological- perception (Gibson, 1982; Neisser, 1979) and in the same way the typology of a cultural-historical and ecological-acoustical phenomenology of Schafer, 1977 Amphoux, 1994 and Meier / Meier Dallach, 1992 were

3 compatible theoretical elements to describe soundscapes. It was important to discriminate between evaluation of inhabitants and some similar test persons on the one hand and experts of a perhaps multidisciplinary research team on the other. Inhabitants had to follow their tasks by instructions and guidelines, whereas the experts had to go by different strictly defined tasks as to follow acoustical-physical aspects, sociological aspects of urban areas, and socio-acoustical criteria. For the expert group it was necessary too to communicate frequently in order to compare and to discuss the different observed items. Different variations of the new evaluation procedure have been developed and practiced: each expert had to write an acoustical diary, to record the noise events and to comment on them regarding time, duration and impression; they had to do minutes of each event, and to record and comment the discussion on those topics in the team. Moreover the schedule included to give comments on the auditive perception while being active in different everyday-activities, to go around in the chosen areas, just listening and describing, to compare the own voice with different acoustical events, to describe the acoustical and visual impression, to be aware of their reaction to attention attracting noise events, to describe the observing position. To go further than to descriptions the combined procedures enabled theoretically to define the correlation between noise events. The physical measurement gave the acoustical information outside the houses and apartments to have an objective description of the subject s environment. Analyses of noise events, e.g. as a traffic jam at a barrier as shown in the fig. 1 and fig.2 below, made it possible to describe the soundscape based on subjective perceptions, reactions and judgments db(a) Zeit 9,9 19,9 29,9 39,9 49,9 59,9 69,9 79,9 89,9 99,9 109,9 time fig.1 Traffic jam at a barrier: road traffic, warning signal, rail road traffic, opening of the barriers, start of road traffic.

4 db(a) ,1 10,1 20,1 30,1 40,1 50,1 60,1 70,1 80,1 90,1 100,1 110,1 120,1 time fig.2 Traffic jam at a barrier: road traffic, warning signal, rail road traffic, opening of the barriers, start of road traffic, jet over flight. Such data could be used to be compared with the description of the acoustical environment by the subjects. The aim was to relate the subjective judgments and kinds of habituation to the objective measurements, in order to step forward to prediction models. Also the data base offered to have some explanation regarding noise sensitivity when comparing the subjective judgment with the objective data. Analysis of recorded noise events of the evaluated areas have been added to the reports to have the opportunity to analyze methodologically using the objective-hermeneutic textsequence analysis (Englisch, 1991) to reconstruct or demonstrate the structure of noise events within the soundscape. SUBJECTIVE MEANINGS ON SOUNDSCAPES When the subjects described different parameters on noise perception in their environment their description was based on scenes and images and there was an associative context in each of the comments by the subjects. There were some subjects relying with their judgments definitively on the combined noise event and a special compensation of annoyance was found when natural noises (e.g. from birds) were part of the noise events. Some profiles of noise events could be identified which were symptomatic for the chosen areas and describing the soundscapes: regarding the areas defined mainly by air traffic there were the take-off and landing situations with their typical structure attracting much more attention than the road traffic noise. Traffic jam at barriers was another special indicator regarding the soundscape which had been described. Air traffic noise events have been judged as attention attracting and annoying in soundscapes defined without flight events, but there was no special attention regarding those noise events when they were embedded in such a noisy soundscape like the one defined as shopping area. Some kinds of cluster effects of subjective descriptions have been found where the noises have been integrated in the living area such as descriptors of a soundscape and where the same noise have been described only from the point of view of disturbance and annoyance. For example one interviewee mentioned: oh, you know, we have the jets here. But they are here since I am living here, they do not disturb, they belong to our place and another

5 one I feel so much annoyed, I feel powerless, I panic because of the jet-noises, it is so terrible, I feel disturbed and helpless all the time because of the noises here. When the noises the have been presented to judge the unpleasantness in the laboratory by a five-point-scale (Rohrmann, 1978) to the people living in the area where the noises have been recorded and to the people not living there, differences in the judgment up to one category could be analyzed (fig.3) categories Leq [db(a)] fig.3: median values for different groups of subjects: upper graph subjects living in a different area - lower graph subjects living in the area where the noise have been recorded - middle graph all subjects DISCUSSION The described effects showed that the analysis had to go in two different direction: to the macro level and to the micro level. The macro-level was defined by descriptions embedding the noise events into the comparable soundscapes of streets, places, urban areas, and towns. The microlevel meant the analysis of qualitative acoustical composition of noise events following psycho acoustical parameters with regard to the subjectively defined context differing by socio-cultural issues. Regarding to Schafer and to Meyer / Meyer-Dallach it was possible to identify at the macro-level noise events and the different constitutions as a basis for soundscapes, which usually have been accepted because they belong to the area. People living there usually will not be able to escape. As an example a comment of an interviewee: You know, sometimes I am really getting angry of the jet noise, but, you know, I can not run away from my home, I am living here. While on the micro-level the subjective judgment will be depending on the sociocultural background: but of course the more common the perception on psycho acoustical parameter is the more common the judgment will be. To give an example: noises on high loudness level will of course being judged very similar regarding loudness whereas noises with some sensory pleasantness may evoke different

6 feelings and will be judged differently. Sometimes there is even a difference in such judgments when people refer to different contexts. McAdams (1993) characterizes this kind of perceivingand evaluation-procedure as a multi-stage-process. CONCLUSIONS The evaluation procedure to detect and to analyze soundscapes in their meaning regarding noise annoyance measurement is a new step and a very complex procedure. Going towards the evaluation of noise annoyance in urban areas, environmental noise is focused on different aspects like the structure of urban areas, people living in those areas, architectural and social parameters designing those areas, and acoustical and visual parameters. For analysis it is necessary to discriminate between macro- and micro levels, prediction on noise annoyance will be possible by triangulation of objective and subjective data. As a next step it will be useful to explore soundscapes in their meaning for noise annoyance by analyzing socio-cultural and lifestyle related elements of soundscapes. Following Schafer s message that if people are perceiving their environment consciously they will have the chance to change the orchestrating of the global soundscape, researches on soundscapes regarding noise annoyance have to be focused on in the future. REFERENCES P. Amphoux, Die Zeit der Stille, Welt auf tönernen Füßen, Göttingen, p , 1994 F. Englisch, Bildanalyse in strukturhermeneutischer Einstellung. Methodische Überlegungen und Analysebeispiele. p , Garz, D. (Ed.): Qualitativ-empirische Sozialforschung, Opladen, 1991 U. Flick, Qualitative Forschung, Reinbek, 1996 A. Fyhri, R. Klaboe, Exploring the impact of visual aesthetics on the soundscape, Internoise 99, USA J.J. Gibson, Wahrnehmung und Umwelt. Der ökologische Ansatz in der visuellen Wahrnehmung, München, 1972 S. McAdams, Recognition of sound sources and events, Thinking in Sound. The Cognitive Psychology of Human Audition, McAdams, S. & Bigand, E. (Ed) Oxford: Claredon Press, 1993, pp H.P. Meier-Dallach, H. Meier, Die Stadt als Tonlandschaft: Beobachtungen und soziologische Überlegungen., Lipp, W. (Ed.): Sociologica Internationale: Gesellschaft und Musik. Wege zur Musiksoziologie, Berlin, 1992 P. Muckel, L. Ensel, B. Schulte-Fortkamp, Exploration of associated imaginations on sound perception (AISP): A method for helping people to describe and to evaluate their sound perceptions, in J. Acoust. Soc. Am., Vol. 105, No.2, Pt 2, 1279, (1999) U. Neisser, Kognition und Wirklichkeit, Stuttgart, 1979 W. Nitsch, B. Schulte-Fortkamp, Geräuscheinwirkungen in Stadtvierteln. Eine sozio- und psychoakustische Feld- und Laborstudie, Loeber-Pautsch, U., Nitsch, W., Rieß, F., Schulte-Fortkamp, B., Sterzel, D. (Ed) Quer zu den Disziplinen, Hannover, 1997 B. Rohrmann, Empirische Studien zur Entwicklung von Antwortskalen für die sozialwissenschaftliche Forschung, Zeitschrift für Sozialpsychologie 9, p , 1978 R.M. Schafer, The Tuning of the World, New York 1977 ACKNOWLEDGEMENT The authors thank for support by AGIS - Arbeitsgruppe für Interdisziplinäre Sozialforschung, University of Oldenburg, Germany