Developing method describing impression of unknown sounds through non-acoustic event - for a sound design of electric vehicle

Most of people have not had experience to see, listen to, or drive electric vehicles (EVs). Even though the sound of EVs are unknown for most of people, it is important, however, to know the factors that make sounds to recall EVs particularly to design the warning sounds for EVs to ensure awareness of them. To understand these factors, we developed a method to know an impression of unknown sounds through non-acoustic events. We assumed that if the impression of the non-acoustic events, in this study those were impression of road environments or driving impression, were highly related to running EVs, the sounds that had similar impression could harmonize with each other.At the first, we conducted a large scale social survey to collect enough number of words that correspond with the non-acoustic events. The collected answers were divided some groups which represent the non-acoustic events by by hierarchical cluster analysis using the mutual occurrence frequency between two words. Then the impression of the place that evoked by each word group was examined through the SD-method subjective evaluation experiment. As a result, we described the impression of the sounds that would potentially harmonize with driving EVs.