Subject: Re: [linux-audio-dev] New release of my plugins
From: David Olofson (david_AT_gardena.net)
Date: Sun Dec 03 2000 - 19:30:05 EET
On Sunday 03 December 2000 12:45, Steve Harris wrote:
> On Sat, Dec 02, 2000 at 10:34:30PM -0500, Paul Barton-Davis wrote:
> > >> Anyway Steve can you tell us more about your pitchshifter (the
> > >> HQ version):
> > >>
> > >> how does it sound on +-20% pitch transpositions ?
> > >
> > >You tell me, my working-in-linux soundard is terrible! In theoru
> > > it should be good, (its an algorithm used in high end
> > > hardware/software). Early next year I plan to get an RME for
> > > home, then I can actualy tune these plugins properly.
> >
> > I'm not sure how much impact your soundcard has. For me, both the
> > pitch shifters are not particularly good as transposers in that
> > they cause substantial alterations in the timbre of the sound,
> > not just the pitch. compared to the very-non-real-time stuff done
> > by the SCRIME guys (Inspect is the s/w), its really awful.
> > Compared to what by Quadraverb does, its fine. I've always viewed
> > these things as colorants as well as shifters - transposition
> > needs to be done via a different mechanism (hence the excitement
> > about Acid when it came out).
>
> Well, that algorithm is supposed to scale the harmonics
> proportianly to the fundamental, and it preserves phase, but I
> suspect that the coarse FFT, and small oversample I have to use to
> get it running in realtime causes a lot of problems. Writing a good
> pitchshifter requires a lots of maths, and I just don't know enough
> to do it, and there's no shortage of off-line pitchshifters out
> there.
>
> It all depends on what you want from a pitchshifter really. It
> sounds a lot like the one in my lexicon multieffect, but I only
> ever use them to mess up harmonics myself. Maybe I just need a good
> one ;)
>
> My soundcard is noisy and it distorts slighty and muddies up the
> sound a lot. It's an antient SB16, I could probably help a lot by
> just bunging in something which isn't 4 or 5 years old.
AWE64 Gold, AudioPCI and Live! (any version), is a good scale from
"ok" to "quite good" I think, as long as we're talking about consumer
cards from Creative. However, forget about the AWE64 Gold in this
case - it doesn't do (real) full duplex, and I'm not very impressed
by the frequency response. (Large dip in the middle, probably to give
an impression of higher quality than it really has... Common trick
for cheapo stereos with crappy speakers and amplifiers.)
I don't have any personal experience of Hoontech, but they seem to
provide incredible price/performance in the full range from consumer
to semi-pro cards.
Don't know if their higher end systems are up to it, but the specs
look great, even without considering the very low prices. According
to the cards list on the ALSA site, there are sufficient docs for
those systems, but no drivers yet.)
Anyway, Hammerfall + converter still seems to be the best way to go
for the serious setup, IMHO. I really like the idea of not being tied
to a non-standard interface for the converters. (ADAT + S/PDIF
instead of some "proprietary serial interface.")
For the low end, AudioPCI based cards are solid, cheap, clean (no
synth chips and other crap), and there are stable drivers for them.
Also, they perform very well in lowlatency systems, and the MIDI
interface seems to be OK. (I'd have to look more carefully at the
code to tell for sure WRT IRQs, but at least there are some 8 bytes
of buffering.)
//David
.- M u C o S -------------------------. .- David Olofson --------.
| A Free/Open Source | | Audio Hacker |
| Plugin and Integration Standard | | Linux Advocate |
| for | | Open Source Advocate |
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`-----> http://www.linuxdj.com/mucos -' `---> david_AT_linuxdj.com -'
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