Investigation of the Relation Between (t_e)_min and Operatic Singing with Different Vibrato Styles
Kosuke Kato, Takatsugu Hirawa, Keiji Kawai, Takashi Yano and Yoichi Ando

This study investigates the relationship between operatic singing and opera house acoustics in terms of the minimum value of the effective duration of the running autocorrelation function (t_e)_min of voice signals. It has been shown that (t_e)_min of source signal is closely correlated with the subjective response of both listeners and performers to the temporal conditions of sound fields [Y. Ando: "Architectural Acoustics" AIP/Springer-Verlag, New York (1998)]. In order to examine the variability of (t_e)_min by means of variation in musical expressivity, we analyzed the steady-state part of anechoic recordings of variably pitched vowels sung with different subjective degrees of vibrato for ten trained singers performing operatic-style sung vowels. The results showed that (t_e)_min values can be varied by an appropriate selection of the subjective degree of vibrato, tone pitch, and vowel selection. Significant findings are that (1) the contribution of the subjective degree of vibrato to the (t_e)_min value was typically more significant; (t_e)_min decreased with increasing subjective degree of vibrato; and (2) the contribution of each musical expression to the value of (t_e)_min depended greatly on the individual singers.

Key words: autocorrelation function, operatic singing, opera house, vowel, vibrato, individual singer variation