Perception of complex-tone pairs mistuned from unison: Waveform relations determines whether pitch slides or iterated complex auditory patterns are heard
Richard M. Warren, Brad S. Brubaker, Daniel A. Gardner · The Journal of the Acoustical Society of America · 1984
When a broad-spectrum complex tone (CT) (whether derived from a voice, musical instrument, pulse train, or randomly generated waveform), having a stable frequency and containing harmonics above the 7th or 8th, is mixed with itself after a slight (1 Hz or less) change in the waveform repetition frequency, listeners hear a rising glissando when fine structures of the correlated waveforms approach alignment and a falling glissando as they move away. If harmonics above the 8th are removed, multiple beats are heard (not glissandi) with the dominant repetition frequency equal to the difference (in Hz) between the CTs. When two broad-spectrum uncorrelated CTs mistuned slightly from unison are mixed, complex periodic patterns rather than glissandi are heard: Multiple beats dominate following removal of harmonics above the 8th (the dominant repetition frequency heard in each case equals the difference in Hz between the uncorrelation CTs). These observations provide information concerning the nature of spectral and periodicity analyses of iterated acoustic patterns. [Work supported by NSF.]