Phase Effects in Monaural Perception

Abstract

Experiments are reported demonstrating that the enveloped-wave shape of a complex steady-state tone is an important factor in audible perception. In particular, it strikingly influences sensations of roughness or smoothness and is related to a sensation of apparent pitch. As envelope-wave shape depends on the phases as well as the amplitudes of the components, these differences of sensation can be produced by changes in the phase alone of but a single component or group of components. The results provide general verification of a limitation placed by Helmholtz, on theoretical grounds, as to the degree to which his phase rule might be expected to be true. The experiments were conducted at such levels that subjective tones produced by non-linearity in the ear are not believed to influence the results. It is suggested that these results emphasize the importance of time factors in the phenomena of aural perception.