Measuring the sound perception of citizens on the Chahar Bagh sidewalk in Isfahan

Urban open spaces play an important role in improving the quality of urban life. In the past, urban designers mainly focused on the visual esthetics and physical aspects of urban spaces, but neglected acoustic elements. Ignoring the role of sound in urban planning has led to an increase in environmentally disturbing sounds, which ultimately leads to an unclear human perception of sounds. To avoid these issues, acoustic research to create high-quality spaces has become one of the current aims of urban planners and environmental designers.

This study investigated the soundscape quality of the Chahar Bagh Abbasi pedestrian Axis in Isfahan, one of the most valuable historical-cultural urban spaces in Iran. The study aimed to answer the following questions:1. What are the sound components that affect the pleasantness of the soundscape of the area? 2. How is the overall quality of the soundscape on the Chahar Bagh Abbasi pedestrian Axis? 3. What are the sound imageability components in the Chahar Bagh Abbasi pedestrian Axis?To determine the dominant sound sources in the space, non-interventional observation and audio recording were used. To clarify the perception of different people of the pedestrian Axis soundscape, a questionnaire was distributed. To ensure the reliabilityof the questionnaire, Cronbach’s alpha test was used. The obtained rate was equal to 0.731, which shows the adequate reliability of the questionnaire. The statistical population of the research is all people present on the Chahar Bagh Abbasi pedestrian Axis. For this purpose, 384 questionnaires were randomly distributed among the people. To analyze the results of the questionnaire, SPSS software and the analytical method of correlation coefficient and step-by-step regression were used.

The findings of this research showed that simply reducing negative sounds in the environment does not lead to the formation of a positive sound environment. Physical background sound levels are also important factors in the sound assessment of public spaces in cities. Other findings showed that some groups of people did not consider some sounds to be undesirable. This depends on people’s habits regarding the current state of the environment soundscape and the low intensity of hearing these sounds in the space. The findings also showed that the frequency of people’s presence in urban spaces is among the factors affecting how people perceive and the quality of the urban soundscapes. In fact, in this research, it was found that the higher the exposure to the soundscape, the less pleasant it is. Therefore, merchants, due to long-term exposure to the soundscape during the day, perceived the soundscape of the pedestrian Axis as less satisfactory compared to others, while tourists due to short exposure to the soundscape of the area, found the soundscape more pleasant. Furthermore, it was found that the duration of people’s exposure to the soundscape is also effective in assessing the sound imageability of the area so that citizens and merchants can better identify sound imageability components in the area due to the longer exposure to sounds.

The results of the questionnaire suggest that exposure to sounds in the short or long term can affect people’s perception of the sound imageability of a space. Overall, merchants and citizens in this space, due to their longer exposure to sound sources, have a better recognition of the components of sound imageability than tourists. For example, the sounds that merchants and citizens of Chahar Bagh Abbasi pedestrian Axis mentioned as characteristics of this area are largely similar. This also applies to the identification of sound signals in the space, such that merchants in this area and citizens at the next level have better performance in detecting loud and close sounds in the space due to their frequent visits to the space compared to tourists. A significant point in people’s answers regarding the identification of background sounds is that the length of time people are exposed to the soundscape of the pedestrian Axis does not have much effect on the correct identification of background sounds. This is because background sounds are the combination of several individual sound sources that are attenuated due to distance, making it difficult to distinguish them from other sounds.