The relationship between subjective preference for sound fields with vocal music and brain activity

The purpose of this study is to reconfirm the theory that the subjective preference for music sound fields depends on its autocorrelation function (ACF) of the source signal by means of analyzing continuous α-brain waves. Ando’s theory describes that the most preferred delay time of early reflections and reverberation time are calculated by the effective duration (τe) of the ACF of music signals [Y. Ando, J. Acoust. Soc. Am. 74, 873–887 (1983)]. On the other hand, it was demonstrated that the τe of the ACF of the α-brain wave range (8–13 Hz) from the left and right temporal lobes was changed by temporal factors relating to the subjective preference of sound fields [Y. Ando and C. Chen, J. Archit. Plann. Environ. Eng. AIJ 488, 67–73 (1996); C. Chen and Y. Ando, ibid. 489, 73–80 (1996)]. When a sound field has a constant delay time as a usual condition, it is assumed that continuous α-brain waves may be affected sequentially by the different running τe values of the ACF of the source signal.