Besides sound level measurements, perceived acoustic quality and preferences are often evaluated through interviews, questionnaires and soundwalks. During sound level measurements A-weighted equivalent continuous sound level (LAeq) is measured and statistical sound levels (Leq90, Leq50, and Leq10) are calculated. Equivalent continuous sound level presents the average level of noise over a time period, while statistical sound levels are used to define maximum, intrusive, median and background sound levels (Kang, 2007). Identification of the sounds which are perceived by the user is generally the first step of soundscape preference research. This procedure provides researchers an insight to perceived foreground sounds, background sounds and soundmarks. Rating scales are frequently employed in preference research. Participants are asked to rate the acoustic environment or a particular sound. The rating scale generally involves bipolar verbal descriptions such as like-dislike, noisy-quite, favorite-unfavorite etc. Semantic differential analysis is another tool which is commonly used to investigate people’s emotional responses towards sound types and acoustic environments. These techniques can easily be applied any time to anyone without a hearing deficit or disorder. However, the soundwalk technique depends on more conscious listening state. During soundwalks, participants observe and listen to their environments very carefully while walking along a path and make judgments on the acoustic environment.
Previous studies have been carried out either in laboratories or in-situ. Binaural recordings are preferred for laboratory studies. Laboratory conditions are also suitable for assessment of the interaction between visual and auditory stimuli with different characteristics. However, if the soundscape of a particular place is to be assessed, considering primarily that visual perception affects perception of acoustic environment. it is best to carry out the study in-situ. Furthermore, for researchers from design and planning disciplines it might be difficult to establish and maintain laboratory conditions for acoustic evaluations due to lack of technical and scientific knowledge. Therefore, a multidisciplinary approach might be helpful in designing and conducting more effective research on soundscapes.
Zhang & Kang (2007) proposed a detailed system for investigation of urban open space soundscapes. They identified four facets; (i)characteristics of each sound, (ii)acoustic effects of the space, (iii)characteristics of users and (iv)other aspects of physical and environmental conditions. Description of each facet is summarized below.
Sound: For each sound, it is recommended that both steady state and the statistical SPL, spectrum, temporal conditions, source location, source movement and the psychological and social characteristics should be taken into account. Temporal conditions include variation (hour, day, season), duration and impulsive characteristics. Meaning, natural or artificial sounds, relation to activities, soundmarks and listening state (descriptive or holistic) should be considered in context of psychological and social characteristics.
Space: The shape of the space, boundary materials, street and square furniture, landscape elements, reverberation, reflection pattern and/or echogram, general background sound and sounds around the space are the characteristics to be considered related to the space.
People: Social, demographic, cultural characteristics of users and acoustic condition at users’ home, work etc. should be assessed.
Environment: Microclimate conditions, lighting, visual, landscape and architectural characteristics are among the environmental characteristics that need to be taken into consideration.
Jennings & Cain (2012) propose a framework which uses Kano model in order to provide designers and planners a tool for predicting impacts of design interventions on soundscape. Kano model is generally used in product development for determination of customer needs and satisfaction. Jennings & Cain (2012) suggest that Kano model can help to clarify thinking, since perception of the soundscapes is a complex process. To summarize their proposal, there are three attributes to be assessed in Kano model; basic requirements, performance requirements and excitement (or attractive) requirements. The first step is to satisfy basic requirements, such as fulfilling legislative requirements for noise control. Then performance requirements need to be assessed in order to find out user needs and expectations. Use of emotional perceptual dimensions, interactive simulations and soundwalks might be helpful in this step. Finally for the excitement requirements, the authors suggest that culturally significant sounds or sonic art could be introduced to give a unique character and to increase excitement or attractive quality. The authors state that Kano model is successfully used in automobile industry for sound quality assessments. However, this model might seem confusing for spatial designers and planners. The authors also emphasize the need for application of the framework through real-life examples. Please see the reference for further details of the framework.
Solene (2011) applied cognitive mapping technique in her study on urban soundscapes. Participants were asked to draw graphical representations of sonic ambiences of three urban squares. They were also asked to describe their preference for ideal sonic environments in squares. Boundary was found to be an essential element in perceived ideal sonic environments since most participants described closed or semi-open squares. On the contrary, open squares were associated with negative sonic ambiance. Depending on the results, the author inferred that there is a strong bond between urban typology and perceived sonic ambiance. She concluded that sonic mind maps were appropriate for studying psychoacoustics of an urban environment.
Despite the short history of soundscape research on outdoor environments, there seems to be a variety of research techniques and methodologies which can be adapted to the researcher’s objectives. Still, many issues such as interrelationships between factors that affect soundscape preferences and the effects of spatial design on acoustic comfort need to be further investigated. Spatial designers and planners can contribute to the soundscape research by developing new models and methodologies in order to display and emphasize their role on creating livable and high quality environments.
2. Conclusion
Our landscapes are natural and cultural heritage of our societies. With the rapid urbanization and development processes, change has become an inevitable outcome for our landscapes in global scale. Unfortunately, landscape change often occurs in negative ways. Loss of diversity and identity should be the main concern for future design and planning research for landscape architects. However, the role of perception and its effects on spatial behavior and attitudes must be realized first.
If landscape architecture aims to create livable and effective environments for people in the community, people’s perception and interpretation of environments must be investigated. One can argue that landscape assessments should be made by experts because of their knowledge and experiences and general public can’t judge environmental quality. On the other hand, environmental quality issues are still on the agenda. To some extent, local, national and even international authorities can be blamed for ignoring knowledge and suggestions of environmental designers and planners in sustainable development. Certainly, professionals have a lot to offer in terms of knowledge and skills. However, knowing and understanding the basic relationships between people and their environments is a necessity.
This chapter has summarized basic information and approaches on landscape perception both in visual and auditory context, aiming to provide an insight on perceptual and cognitive dimensions of environmental research. However, there are more to landscape perception research. Reference list can provide readers with valuable resources to read.
Although there is a vast amount of research on landscape preferences, there are still theoretical and methodological issues that have not been clarified yet. The outcomes of environmental psychology research can guide planners and designers in creating and managing our landscapes. Therefore, it is crucial to establish a multidisciplinary cooperation. The relevance and importance of landscape perception research has been neglected in Turkey so far. Most undergraduate curricula in landscape architecture programs do not cover perceptual dimension of the landscape. I hope this chapter draws an attention to the significance of the subject. Finally, I’d also like to emphasize the need for strengthening the role of landscape design and planning on landscape perception research.
