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>From tothl Thu Feb  5 16:50:04 +0100 1998 remote from inf.u-szeged.hu
Date: Thu, 5 Feb 1998 16:50:04 +0100 (MET)
From: Toth Laszlo <tothl@inf.u-szeged.hu>
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Subject: Re: effect of phase on pitch
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On Thu, 5 Feb 1998, R. Parncutt wrote:

> ...
> Straightforward evidence of the ear's insensitivity to phase in the sounds
> of the real human environment has been provided by Heinbach (1988). He
> reduced natural sounds including speech (with or without background noise
> and multiple speakers) and music to their spectral contours, which he called
> the part-tone-time-pattern. In the process, he completely discarded all
> phase information. The length of the spectrum analysis window was carefully
> tuned to that of the ear, which depends on frequency. Finally, he
> resynthesized the original sounds, using random or arbitrary phase
> relationships. The resynthesized sounds were perceptually indistinguishable
> from the originals, even though their phase relationships had been shuffled.

"Perceptually indistinguishable" means here only that their PITCHes were
perceptually indistingushable, am I right? Considering other aspects,
changing the phase relationships definitely has effects on sound quality.
In phase vocoders, for example, uncorrect decoding of phases results in
really annoying artifacts.

*               Toth Laszlo                   *                              *
*        Hungarian Academy of Sciences        * "In our life there's if      *
*  Research Group on Artificial Intelligence  *  In our beliefs there's lie  *
*                                             *  In our business there's sin *
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