Kim D., Wang S.

In previous studies on loudness calculation of time-varying sounds, loudness is not defined as a function of frequency since spectral summation takes place prior to temporal integration from Zwicker¡¯s and Fastl¡¯s certification. A sound like railway noise, however, has either time-varying characteristics or quasi-steady state ones because noises emitted from the train are defined within exposal time. In this study, time-varying loudness expression with respect to critical band rate is derived by percentile value for the quasi-steady sounds. After that, analyses through the comparison between one-third octave filtering and specific loudness will be discussed in order to see frequency contribution of noise sources with examples of railway noise.