On the study of noise perceptions caused by mixed noises and visual environment

Annoyance caused by road traffic noise is increasingly concerned in urban environments. Many studies have been conducted to understand how the annoyance caused by road traffic noise can be moderated by an additional sound. In particular, there are a number of studies focusing on using water sounds, e.g. fountain or stream sounds, to moderate noise annoyance caused by traffic noise. However, no solid statistical relationship between the mixed sounds and annoyance level has yet been established. Little is known about the relationship between the preference of masking sound and its masking capability. Also visual perception was not included in the considerations of these studies. Indeed, both visual and audio components should be taken into account since individuals in reality will not be exposed to the environment with audio components alone. Although there were studies focusing on the audio-visual effects on noise annoyance, there is a lack of research studies on noises mixed with water sound in the presence of visual environment. To this end, this study attempted to develop a statistical model linking the mixed water and road traffic sound with the noise annoyance rating at home. The effect of visual environment in combination with the mixed noise on annoyance rating would also be revealed. It is expected that results arising from the study can facilitate both site planning and building design decision making in terms of noise annoyance moderation. The results can also be adopted by relevant local authorities to formulate urban planning guidelines so as to provide a better acoustical environment in dwellings.