Role of sounds in perception of enclosure in urban street canyons

Abstract

This study aims to examine the influence of sound on the perceptions of enclosures in urban street canyons with varying height-to-width ratios (H/Ws). Two typical urban streets, one narrow and one wide, were modelled with street widths of 6 m and 27 m, respectively. The H/W was varied from 0.5 to 6 in seven steps by changing the heights of the buildings on both sides of the street. Three-dimensional visual images were created in a virtual reality (VR) environment, and a synthesised car pass-by sound was convolved with impulse responses extracted from acoustic computer simulations as the sound stimuli. Laboratory experiments were conducted with a total of 41 participants. The experiments consisted of three sessions: 1) a visual-only condition, 2) a combined audio-visual condition, and 3) an audio-only condition. The subjective responses to the stimuli were rated in terms of the perceived enclosure, perceived spaciousness, perceived pleasantness, and perceived source width. The results from the experiment revealed that the perceived enclosure, perceived spaciousness, and perceived pleasantness of the visual stimuli decreased as the H/W increased. The presentation of sound significantly influenced the perceived enclosure and perceived spaciousness, whereas the perceived pleasantness was less affected by sound. The effects of sound on the subjective responses were greater for narrow streets than for wide streets.