| On Sat, 20 Mar 1999, Blake Markle wrote:
> Good day fellow Csounders,
>
> We're still getting bad quality resynthesis using Hetro/adsyn. We are
> analyzing a sustained piano note in hetro, and resynthesizing it with
> adsyn. Even with many (50+) harmonics included and many (1024)
> amplitude breakpoints checked, we get bad transient response (attack)
> and distortion. We have an "owl" sounding hoot in the attack and lots
> of high frequency noise distortion.
>
> We are using the latest csound edition (csound_con.zip) with winsound
> for the adsyn process. The file format is wav. We would welcome any
> wisdom on the subject. If it is possible to create a reasonably
> realistic analysis/resynthesis, please let us know.
>
The effect you experience is normal due to the nature of hetrodyning
analysis and additive resynthesis. First the attack portion contains a
lot of noise which cannot be reproduced by only 50+ partials, second the
partials of a piano sound are not exactly harmonic overtones. A high
quality resynthesis should usa a dual approach such as additive synthesis
for the steady part and subtractive (filtered noise) for the residual
part.
For a good discussion of the subject see
Musical sound modelling using sinusoids plus noise
in
Musical Signal Processing edited by C. Roads et al
Swets and Zeitlinger Publishers
ISBN 90-265-1483-2
Hope that helps
Thomas
--
Thomas Neuhaus(neuhaus@folkwang.uni-essen.de) Phone (49)-201-4903-333
ICEM Institut fuer Computermusik und elektronische Medien
Folkwang-Hochschule Essen, Klemensborn 39, D-49239 Essen
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