Abstract
We, human being, hear 'twitter of birds', 'stream sound' etc. as comfortable sound. On the other hand, we hear 'sound scratching window', 'sound scrubbing styrene foam' etc. as uncomfortable noise. What is the difference between them? In this paper, the uncomfortable rates of 16 daily hearing sounds were evaluated at first, using method of paired comparison. Then, those sounds were analyzed by the human auditory model and wavelet analysis in order to find out causes of discomfort. Such characteristics of comfort and discomfort were found out that the former has calm rising up and down and the later has steep rising up and down, and that the former has sinusoidal vibratos in high frequency region and the later has irregular ones. But the auditory indexes which can evaluate the noisiness of machines were proved hardly to have correlation with uncomfortable rate.
