Repetition pitch with a continuously gliding rigid spectal envelope

Abstract

The noise stimulus for repetition pitch has a spectral envelope consisting of an unlimited number of identical broad peaks. The frequency spacing between the peaks is 1/τ, the reciprocal of the repetition time. With appropriate digital techniques it is possible to cause the spectral envelope to glide slowly and indefinitely along the frequency axis, while maintaining a constant envelope shape and peak spacing. The pitch generated by this stimulus does not ascend or descend indefinitely, as in the illusions of Risset and Burns. Instead, there are several pitches, which follow repetitive sawtooth patterns. One pitch glide follows the pattern conjectured by F. A. Bilsen [Acustica 17, 295–300 (1966)], with a discontinuity from about 1/τ, ± 12% to 1/τ ∓ 12% near the cos− condition. Another pitch, heard for some positive spectral glides, has a discontinuity near the cos+ condition, beginning at 1/2τ and rising to 1/τ. There are sometimes other gliding pitches, not necessarily weaker than the above, for which we have no ready explanation. [Work partially supported by the NSF and the NIH.]