Relationship between the geometric profile of the city and the subjective perception of urban soundscapes

Large urban areas are very prone to be contaminated by different pollutants beyond safe limits. In recentyears, it is not only pursued that these environments comply with all the regulations in this regard, butalso to make them as comfortable as possible for their inhabitants. Being noise one of the most harmfulpollutants, researchers and administrations are focusing their efforts in understanding and improving thesubjective perception of the urban sound. This understanding could allow to make better decisions in theplanning of large urban areas or in the efficient management of the traffic flow.The main purpose of this study is to evaluate if urban places with similar geometrical features areacoustically perceived in a similar manner. The study was conducted in the city centre of Madrid(Spain), where the sound was recorded in 13 places, and their geometrical features studied. In some ofthese places the recordings were performed more than one time, in different recording sessions, to studythe acoustic stability of the environments. Psychoacoustic indicators were extracted and statistical anal-ysis as well as clustering analysis were performed. A listening test was conducted to evaluate the agree-ment between the quantitative results and the perception of a sample of 16 participants. Both thequantitative and the qualitative analysis reported that urban places with similar geometries are per-ceived in a similar way. Also, it was proven that a recording performed a particular day in one place ishighly representative of that place for similar working conditions. These results point out the benefitsof incorporating the psychoacoustic indicators in the planning of large urban areas in order improvethe acoustic comfort besides reducing the noise pollution.