Upside down -- Pitch perception

[Punita Singh <pgsingh@xxxxxxxxxxx>]

Dear List,

         Robert Zatorre's original query re: perception of direction of
pitch change referred to pure tones, -- so I did not pitch in earlier.
However, the issue seems to have become more complex lately, so I'd like to
point out some up-down confusions for pitch, when harmonic complex tones are
used.
         Dr. Ira Hirsh and I studied the influence of changes in spectral
locus of harmonics and/or fundamental frequency on perception of change in
both pitch and timbre.  For F0 changes > 2% (vis. 200 Hz) subjects reliably
reported the direction of F0 change as the direction of pitch change.
HOWEVER, -- for pairs of tones with no F0 difference, or differences within
2%, pitch changes were still reported, in the direction of change of
spectral locus...
    Listeners were evidently responding to the "spectral" rather than
"virtual" pitch in this case (vis. Terhardt's terminology), or "hauteur
brute" vs. "hauteur tonale" (vis. Risset's teminology,  or to the "tone
height", "spectral center of gravity", timbral "sharpness"  (choose your
favorite term !)
      So, for whatever it's worth (a couple of cents ?!), -- when dealing
with complex tones, you have to keep the dual nature of pitch in mind, and
be aware that the same spectral-temporal factors contributing to pitch, may
also contribute to timbre.

For details about our experiment and several relevant references, see:

Singh, P. G. and Hirsh, I. J.  (1992) " Influence of spectral locus and F0
changes on the pitch and timbre of complex tones", J. Acoust. Soc. Am.
92(5), 2650-2661.

Sincerely,
Punita
----------------------------------------------------------------------
Dr. Punita G. Singh,
Sound Sense,
20-A Aurangzeb Rd,
New Delhi 110011, India
Tel: (91-11) 379-2328 / 301-4068
Fax: (91-11) 301-8743
E-mail: pgsingh@hotmail.com


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