This article details a model for evaluations of sound quality in the human auditory system. The model includes an autocorrelation function (ACF) mechanism. Thus, we conducted physiological and psychological experiments to search for evidence of the ACF mechanism in the human auditory system. To evaluate physiological responses related to the peak amplitude of the ACF of an auditory signal, which represents the degree of temporal regularity of the sound, we used magnetoencephalography (MEG) to record auditory evoked fields (AEFs). To evaluate psychological responses related to the envelope of the ACF of an auditory signal, which is a measure of the repetitive features of an auditory signal, we examined perceptions of loudness and annoyance. The results of the MEG experiments showed that the amplitude of the N1m, which is found above the left and right temporal lobes around 100 ms after stimulus onset, was a function of the peak amplitude and its delay time or the degree of envelope decay of the ACF. The results of the psychological experiments indicated that loudness and annoyance increased for sounds with envelope decay of the ACF in a certain range. These results suggest that an autocorrelation mechanism exists in the human auditory system
