The impact of sound quality on annoyance caused by road traffic noise: an influence of frequency spectra on annoyance

This paper describes a laboratory study of the influence of sound quality on the annoyance caused by road traffic noise. To measure the annoyance caused by road traffic noise, two kinds of subjective evaluation tests were carried out under the exposure of artificially modified road traffic noise which was originally recorded in an urban area. One is a subjective evaluation test using a categorical scale of five steps for annoyance, and the other is a listening interference test for matching the loudness of replayed classic music under the existence of road traffic noise of various loudness. As a result, we found that (1) Contribution of high frequency contents of road traffic noise on annoyance was significant. (2) When noise exposure level was 70 dB(A) in Leq, the contribution of high-frequency noise to the listening interference was equivalent to 3 dB(A) under the exposure of various modified road traffic noise in their high-frequency contents. (3) Multiple regression models of annoyance were constructed by roughness and sharpness as well as Leq as their explanatory variables.