Pitch shifts associated with partial masking

Abstract

The change in pitch of a pure tone induced by the simultaneous presentation of a broadband noise is often thought to be related to the “partial masking” (loudness reduction) of the tone by the noise. This assumed relationship was investigated by determining partial masking and pitch shifts for equivalent conditions in the same subjects. Both the reduction in loudness and the reduction in (nonsimultaneous) masking effectiveness of fixed intensity pure tones were measured as a function of noise spectrum level (N0) and were found to be roughly equivalent, as shown by Houtgast [Acustica 30, 214–221 (1974)]. The pitch shifts of the tones, as a function of N0, were also determined. Finally, pitch-intensity functions were obtained for the pure tones. The results show a definite correspondence between the amount of pitch shift and the amount of partial masking. However, neither the magnitude nor the direction of pitch shift is predictable from the pitch-intensity functions by assuming that the partial masking is equivalent to a simple reduction in intensity of the pure tone. [Research supported by NINCDS.]