Re: harmonic extraction

[Al Bregman <al.bregman@xxxxxxxxx>]

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..

Best,
Al
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Albert S. Bregman, Emeritus Professor
Psychology Department, McGill University
1205 Docteur Penfield Avenue
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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
>
>



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