Re: [fluid-dev] static in output

[jpyle]

I am using a 2.08 Ghz Athlon XP with a 333Mhz FSB, 1G "dual channel"
memory, nForce2, 2.4.21 with preemptible and low-latency patches.  I run
fluidsynth as root, through jack and sometimes ardour.  I would describe
the static as occuring whenever fluidsynth is trying to process too many
voices: either when I am pressing eight keys, using the sustain pedal,
or playing something complicated.  It isn't limited to the low octaves,
but it is much more audible there, perhaps because decays are longer
there on the grand piano soundfonts.  I've tried turning down the gain,
but that doesn't make a difference.  Using the -z parameter also didn't
help much.  Someone at:
http://www.altlinux.ru/pipermail/music/2003-January/000617.html 
described it as "crackly static distortion."  It doesn't sound like
clipping, but something more random, like dropouts occuring at random
intervals.

Quoting Josh Green <address@hidden>:

> Also make sure you are running FluidSynth as root for low latency
> SCHED_FIFO scheduling, or alternatively increase audio card buffer
> size
> and count (thus increasing latency). Like Garett mentioned, some
> more
> info about when static is heard (particular to certain instruments,
> related to system load, constantly heard, etc) would be helpful.
> Regards,
>       Josh Green
> 
> 
> On Mon, 2004-02-16 at 19:07, Garett Shulman wrote:
> > Can you give more info about you setup? Processor, Memory, OS,
> sound 
> > card? Can you be more specific about the unwanted sound you are
> hearing? 
> > It only occurs in the lower octaves with sustain? Could it be
> clipping 
> > from having the gain to high? Have you tried adjusting the gain in
> 
> > fluidsynth to something low like 0.6 or 0.3? I doubt changing the
> code 
> > will be of much help. I run a 600MB rhodes sound font (used to be a
> 
> > .gig) fine on an athlon 1700 with 750MB of ram, a delta66, and
> alsa. 
> > Sounds great even with lots of voices. The latency is unnoticable
> to me 
> > even though I don't have kernel preemption enabled and some of the
> 
> > sample data is being swapped.
> > -Garett
> > 
> > address@hidden wrote:
> > 
> > >I hear static from fluidsynth when I use ~40 megabyte grand piano
> > >soundfonts and I play in the lower octaves with the sustain pedal
> down.
> > > (I've noticed CPU usage is pretty high when I do that, too). 
> Does
> > >anyone know ways to get around this (command line switches, code
> > >changes)?   I'm willing to sacrifice latency or number of
> simultaneous
> > >voices for a clean performance.
> > >
> > >
> > >_______________________________________________
> > >fluid-dev mailing list
> > >address@hidden
> > >http://mail.nongnu.org/mailman/listinfo/fluid-dev
> > >  
> > >
> > 
> > 
> > 
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>