A Study of Evaluating the Button Sounds for Car Audio Main Units

In recent years, a lot of attention has been directed at designing various sounds that are treated as noise, such as automobile acceleration sounds and cleaner sounds. The idea of sound being a normal part of product operation has permeated society. We focused on sound design and evaluated it with 11 kinds of button sounds for car audio main units. At present psychoacoustics metrics (loudness, sharpness, etc.) which took the frequency characteristic of the complicated human auditory system into consideration, has come to be used for evaluation of the various sounds. However, button sounds are not steady and continuous. In order to accurately represent button sounds, it is necessary to analyze time characteristics as well as frequency characteristics; this is known as time-frequency (t - f ) representation. In this study, an impression was extracted by the semantic differential (SD) method, and the relevance of that impression was investigated by the wavelet transform (WT). The t - f resolution features of WT are similar to an auditory t - f resolution feature. As a result, the button sound impressions were classified into an esthetic factor, metallic / clarified factor and powerful / massive factor on the basis of these results, and these impressions could be visualized by the WT distribution. Next, we confirmed whether or not the impression changed when a sound that generated a bad impression was processed using an adaptive control into a sound that generated a good impression.