Re: Upside down noise

["Charles S. Watson" <watson@xxxxxxxxxxx>]

Even a monaural person like moi can come up with an answer to Pierre's
question.  As the frequency of the bird's sinusoidal song varies, its
apparent position changes because the head shadow (there probably is a
meaningful one for the frequency range involved), as a constant interaural
difference in dB, is interpreted to mean a different azimuth at each
frequency.  (I suspect it would only work if you could not see the bird.)
I guess this explanation also means you would not experience it if you
happened to have your nose pointed at the bird.

Chuck

On Thu, 6 Aug 1998, Pierre Divenyi wrote:

> Personally, I don't find John Bates's question "noisy."  Actually, Fred did
> not answer the question -- I think that Fred's explanation "creating some
> sort of spatial effect" is too vague and off-the-cuff.
>
> The effect is predictable as one maps interaural phase difference into
> interaural time difference, but nonetheless cute (setting it up took
> exactly 30 seconds of my time and another 30 seconds to listen): the
> perceived locus shifts from right to left and back, as the frequency sweeps
> up and down.  However, depending on how low the frequency goes, the locus
> traverses ambiguous regions as well.
>
> I have a different question: Von Hornbostel is credited with describing the
> following situation: a bird singing (presumably sinusoidally) on a branch
> is perceived as if it were flying from right to left as the frequency of
> its song varies (presumably not too fast). Provided v. H. is right, how
> could that phenomenon be explained? I presume there were no reflecting
> surfaces near the bird.
>
> Pierre
>
>
>
> ****************************************************************************
> Pierre Divenyi             Experimental Audiology Research (151)
>                            V.A. Medical Center, Martinez, CA 94553, USA
> Phone: (925) 370-6745;     Fax: (925) 228-5738
> E-mail :                   PDivenyi@ucdavis.edu
> ****************************************************************************
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