Evaluation of air-conditioning sounds in a vehicle to determine thermal feelings using psychoacoustic parameters

In this paper, we investigated subjective impressions of air-conditioning sounds in a vehicle by using the psychoacoustic parameters of loudness and sharpness. First, we carried out a subjective evaluation using a rating scale method and investigated the relationships between the psychoacoustic parameters and nine evaluation words, quiet, refreshing, heavy, wide, muddy, violent, dry, warm, and cool, that represent impressions of air-conditioning sounds. As a result, we found that the impressions of ``violent'' and ``quiet'' strongly depended on the loudness, and the impressions of ``heavy,'' ``dry,'' ``warm,'' and ``cool'' strongly depended on the sharpness. Next, we performed a factor analysis. As a result, we found that the air-conditioning sounds can be explained by two factors, a volume factor and a thermal factor, which were strongly correlated with the loudness and sharpness, respectively. This result shows that the feelings of heating and cooling perceived from air-conditioning sounds are related to the sharpness. Therefore, a synergetic effect on the heating and cooling performance can be expected by improving the sharpness of air-conditioning sounds.