Phase Error Reflects Subjective Sound Quality

It is suggested that the local maxima of spectrally dissociated vibration are detected in the cochlea of the inner ear for coding all the acoustic information of pitch, loudness and timbre in the auditory nerves. The margin of errors in time and amplitude on the extrema in the narrow-band waveforms of the equivalent vibration in the cochlea were emphasized in the previous study, ascer- taining that all sounds have been successfully reconstructed by using the sinusoidal interpolation between two successive extrema. In order to elucidate further the neuronal extraction process of acoustic attributes, we collated the statistics of phase and quantization errors in extrema and the measurement of subjective scores and event-related potentials, in response to synthesized sounds using manipulated extrema with either phase error or quantization error and estimation of probable extrema. The observations could be interpreted as supporting the assumption that the band-limited structure of sounds is restorable in symmetry about the time-axis, in which reduction of phase error is prior to quantization error, suggesting the most suitable index that is sensitive to the sound qual-