Subject: Re: [linux-audio-dev] New release of my plugins
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Sun Dec 03 2000 - 04:41:17 EET
On Fri, Dec 01, 2000 at 10:21:59PM +0100, Benno Senoner wrote:
> Pretty disappointing the Xeon , considering the money you have to fork out
> for this CPU ...
> :-)
Yeah, the difference is pretty minor, but that CPU only has a small cache
(512k I think), you'd need to go to more cache to see much improvement I
think. IIRC you can't go to more than 2 CPUs with stock PIII's though, so
we don't have any choice for heavy SMP.
> 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 mean: usable to let's say slow down/speed up a techno tune in order to match
> its BPM with another one , or will you hear too much bg noise / clicks and
> pops when doing +-20% transpositions ?
You won't hear any clicks or pops, but it will mess up transients (make
them sound softer) I'm not sure how critical or severe that is. It's
good for up to +100%, -50% pitch shifts in theory.
> I know ... really good pitchshifters are both complex and mostly commercial
> only. (thus expensive),
> but it would really be handy to have a highquality and free pitchshifter
> available.
AFAIK It's not far off the state of the art in pitch shifters, the guy I
got the alogrithm off writes them for a living. A hardware box would use
a finer FFT, which sounds better, but it won't run in realtime on a
feasible machine then. The expensive part is making them run quickly in
general purpose cpus, I've cut a few corners, but I couldn't get it any
faster than it is. I will give it another bash when I know more about
optimising for Intel chips.
- Steve
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