Abstract
Monaural phase effects (MPE's) in steady-state musical tones were experimentally studied for two-and three-component tones. The two types of stimulus pairs used were : {sin 2π·ft+A2/A1 sin 2π·2ft, sin 2π·ft+A2/A1 sin (2π·2ft+θ); and {sin 2π·ft+A2/A1 sin 2π·2ft+A3/A1 sin 2π·3ft, sin 2π·ft+A2/A1 cos 2π·2ft+A3/A1 sin 2π·3ft.
Timbre discrimination between the stimuli of each pair was investigated as a function of f, A2/A1, A3/A1, and θ at a constant sound pressure level (about 30 dB). The AB method was applied, and the information rates were calculated and used as a measure of discriminability.
The most important findings are :
(1) MPE's can be perceived for two-and three-component steady state musical tones under certain conditions of f, A2/A1, A3/A1, and θ.
(2) For stimulus pairs with a frequency beyond 1248 Hz, no timbre difference can be heard.
(3) Maximal discriminability of two-component tones with f of 193 Hz is obtained when A2/A1 is about 0.5. For three-component tones maximal discriminability is reached at a certain value of A2/A1, which increases with A3/A1. And a great difference is observed between the stimulus pairs with A3/A1>1 and with A3/A1<1.
The experimental results suggest that MPE's are related to differences in the waveform of the vibration patterns of the basilar membrane, and are particularly related to the corresponding differences in the temporal patterns of the nerve impulses near the peak point of the envelope of the basilar membrane vibration caused by the higher component of the stimulus.
