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Re: harmonic extraction

Dear James,

This example of duplex perception, outside the domain of speech, and
clearly not involving two distinct mental "modules", is very
interesting, throws a different light on duplex perception of speech,
and is certainly worth further development and publication..

Albert S. Bregman, Emeritus Professor
Psychology Department, McGill University
1205 Docteur Penfield Avenue
Montreal, QC, Canada H3A 1B1.
Office:  Phone: (514) 398-6103
              Fax: (514) 398-4896
Residence phone & fax: (514) 484-2592

On Wed, Mar 25, 2009 at 10:35 AM, James Bashford <bashford@xxxxxxx> wrote:
> Dear Xueliang Zhang,
>    I was intrigued by the interchange between you, Yoshitaka Nakajima, and
> Al Bregman, and did some listening, diotically through headphones, to
> stimuli consisting of the first 10 harmonics of 100 Hz alternating with the
> 5 even harmonics of that stimulus (all harmonics were presented at the same
> level).  With on/off times for each complex matched at either 0.5 sec or 1.0
> sec (10 ms rise/fall), I hear a fully continous 200-Hz tone that matches the
> intensity and timbre of the isolated even-harmonic complex.  More
> interesting, however, is that the 10-component “all-harmonic” stimulus,
> which is heard intermittently, has not only the 100-Hz pitch of that complex
> but also retains the loudness and timbre of the all-harmonic stimulus as
> heard when it is presented in isolation.  Were the even harmonics of the
> all-harmonic complex exclusively allocated to support perception of the
> continuous 200-Hz complex tone -- leaving only the odd-harmonics to support
> perception of the 100 Hz tone -- we would expect both a reduction in
> loudness and a clear shift in timbre to the “hollow” quality characteristic
> of odd-harmonic signals.  This suggests that the “priming” or “capture”
> effect observed with complex tones provides an example of duplex perception
> that requires neither a verbal stimulus nor dichotic presentation.  As I
> recall, Al Bregman has previously suggested that such an effect might occur
> when nonverbal stimulus input is strongly ambiguous.
>       This use of the even-harmonic components to support two simultaneous
> percepts (that of both the intermittent “all-harmonic” tone and the
> continuous even-harmonic tone) contrasts sharply with the processing
> underlying the general phenomenon of illusory continuity that is observed
> when one sound alternates with a higher-intensity, potential masking
> sound.  The latter effect, which has been called auditory induction (Warren,
> 1972), occurs with a wide variety of signals, such as tones alternating with
> other tones, noise alternating with higher intensity noise, or speech
> interrupted by noise (phonemic restoration).  This type of continuity, in
> which there are no exactly matching components to be found between the
> alternating signals, does appear to involve subtractive or exclusive
> allocation.  For interrupted tones, noise, or speech, continuity is obtained
> at the expense of the interrupting signal, which is reduced in loudness by
> an amount proportional to the extent the illusion (Warren et al., 1994).
> Warren, R. M., Obusek, C. and Ackroff, J. M. (1972). Auditory induction:
> Perceptual synthesis of absent sounds. Science, 176, 1149-1151.
> Warren, R. M., Bashford, J. A., Jr., Healy, E. W., and Brubaker, B. S.
> (1994). Auditory induction: Reciprocal changes in alternating sounds.
> Perception & Psychophysics, 55, 313-322.
> James Bashford
> On Mar 19, 2009, at 5:24 AM, xlzhang wrote:
> Dear list,
> A pure tone can extract corresponding harmonic from complex sound when
> appearing alternatively. I wonder if a harmonic sound can do the same job?
> For example, a complex sound with F0=200Hz appears with a complex sound
> with F0=100 Hz, can we get a continuous perception for F0=200Hz?
> Thank you for your answers in advance.
> Xueliang Zhang