Preliminary study of relations between physical characteristics and psychological impressions of natural voices

To improve the naturalness of synthesized voices, the relations between the physical characteristics of the synthesized voices and the psychological effects should be established. The authors performed a psychological evaluation using natural voices of men and women as stimuli. The method of principal component analysis was applied to intercorrelations, the numerical ratings of the evaluation, and principal components were extracted which represented aspects ordinary people use to evaluate natural voices. Pitches of the voices used in the evaluation were analyzed as samples of physical voice parameters, and the relations between the pitches and the principal components were examined. Four principal components were extracted, representing aspects to which most people were observed to pay most attention when listening to voices. A significant relation was also found between physical pitches which were standardized by sex and the perceived pitches which were introduced from the principal component scores. This finding suggests that different criteria are used for perceptions of pitches of men and women.