[linux-audio-dev] [ann] pvoc-0.1.0, caps-0.1.11
tim at quitte.de
Wed Mar 24 15:59:46 EST 2004
>Tim Goetze wrote on Wed, 24-Mar-2004:
> > the algorithm 'accumulates' energy from the pvoc frame bins into a
> > 'static' pvoc frame, thus the basic effect sounds a bit like an echo
> > or reverberation. (in fact i think it could be made to produce a
> > real nice reverb tail, with a _lot_ of tweaking though.)
> > of course this is combined with a decay mechanism so the stored energy
> > doesn't stay around forever. also, for some sound effects of the
> > stranger kind, Accumulate can also move the stored frequency
> > coefficients around, resulting in constant glissando of the 'sound
> > tail'.
>This is pretty much what FreqTweak's Delay module does, although
>I could not reproduce the exact Accumulate effect sound in FT upon
>some basic tweaking. Of course, FT has absurdly more control :)
it does indeed :)
>I've been waiting for someone to post a preset for FT that they
>hand built to produce a good reverb tail, but it appears no one's
>up to the challenge.....
i don't know how you feel about this, but my personal impression is
that the classic all-pass/comb reverbs are capable of producing very
fine sounding tails (especially with a slowly modulated delay line),
it's more the early and distinct reflections that i see as a weak
so, seeing the dramatic difference in CPU usage between the two
techniques, using FT/pvoc to produce a reverb tail would seem a rather
academic exercise to me. though, of course, "you won't know if you
don't go", maybe it's a particularly enlightening experience.
>The pitch scaling algorithm sounds quite similar to the one in
>FT (which is basically the Sprengler algo from SWH's pitch scaler),
>but Tim's sounds better, so I'm going to go code diving.
it would be more accurate to call it Richard's than mine -- i only
re-packaged the code from Richard Dobson's pvplugs in LADSPA shape.
(actually, the whole pvoc package is just a by-product; i needed the
phase vocoder for something completely different but found the plugins
good fun, and the stretch utility worth writing.)
to tell the truth, i haven't even spent much time deciphering the
Transpose algorithm. it did sound kind of OK with the guitar so it got
green light for shipping. :)
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