[sdiy] harmonic generator & megaloopers

[Andre Majorel]

On 2002-02-28 19:48 +0100, mark verbos wrote:

> Grant Richter wrote:
>
> >It seems something like that should also apply to a continuous time
> >transform. Changes in the shape of the discontinuity (edges of the window)
> >should appear in the output of the transform and change the short term
> >harmonic spectra.
> >
> >The only time I have seen this mentioned is Electronotes #45 Page 21
> >"Transform methods in musical engineering" where Bernie talks about how the
> >Fourier series fails for gated sine waves. But he does not say what does
> >happens exactly, or why fading in a sine wave vs. gating it removes the
> >clicks mathematically.
> >
> wouldn't that suggest that the sine wave should be synched to the note 
> start? That way beginning of a note is always comming from a zero point. 
> Then the click that results from a short attack would be eliminated. 
> Assuming that the abrupt jump to the zero state doesn't cause a click at 
> the end of the previous note ;)

Yes, but that won't be enough. That removes the discontinuity in
the value but not the discontinuity in the derivative. In other
words, the curve does not jump from one value to another but it
still has a sharp angle and it translates as a short burst of dull
noise. Listen to it for yourself :

  http://www.teaser.fr/~amajorel/gatedsine/

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
std::disclaimer ("Not speaking for my employer");