Effect of perceived dominance and pleasantness on the total noise annoyance responses evoked by augmenting road traffic noise with birdsong/stream sound

Earlier studies suggested that sound preferences or soundscape quality could be improved by augmenting the acoustic environment originally dominated by road traffic noise by birdsong or water sound. However, little has been known on whether and how the total noise annoyance perceptions can also be moderated by augmenting road traffic noise with birdsong/water sound and there is a lack of models that can help portray the noise annoyance response of acoustic environments with traffic sound augmented by birdsong/stream sound. To this end, laboratory hearing experiments were designed to explore the moderating effects of augmenting road traffic noise with birdsong or stream sounds on the total annoyance responses. The responses collected from 94 human participants were employed to construct multivariate models for predicting the probability of evoking a high total noise annoyance response. Results show that multivariate models incorporating perceived level of road traffic dominance and pleasantness of birdsong or stream sound as perceptual factors can better portray the noise annoyance level rated by individuals. The probability of evoking a high total annoyance response tended to be lower when road traffic was not perceived as a dominant sound source, and/or birdsong/stream sound was perceived as pleasant. Of particular contribution of this study is the formulation of a model that can better portray the effects of augmenting road traffic noise with birdsong/stream sound on total noise annoyance responses by including perceived dominance and pleasantness as perceptual factors