Subjective evaluation of sound images of air-conditioning system in a vehicle

In this study, we attempted to evaluate air-conditioning sounds in a vehicle from the viewpoint of sound quality. First, we carried out an experiment to select suitable words for evaluating air-conditioning sounds in the compartment of a vehicle. The subjects of the experiment selected several words that were appropriate to represent images of the air-conditioning sounds from a list of adjectives. As a result of a cluster analysis of the experimental data, the seven evaluation words "quiet,'' "refreshing,'' "heavy,'' "wide,'' "muddy,'' "violent,'' and "dry'' were selected as the evaluation words. Next, we carried out a subjective evaluation experiment by the rating scale method. The subjects of the experiment evaluated each presented sound in seven degrees for the seven evaluation words. As a result of a factor analysis, the air-conditioning sounds were found to be represented by three factors: "rough,'' "space,'' and "refreshing.'' Finally, we carried out an experiment to evaluate the air-conditioning sounds using psychoacoustic parameters such as loudness and sharpness. As a result, we found that the rough factor correlated with loudness and space and refreshing factors correlated with sharpness.