Re: [Fwd: Re: [iiwusynth-devel] update and todo list]

[Peter Hanappe]

Tim Goetze wrote:
> Bob Ham wrote:
>
>
> > On Mon, 2002-06-03 at 09:09, Tim Goetze wrote:
> >
> >
> > > i'm linking against libiiwusynth and using more than one iiwusynth
> > > instance, with chorus and reverb applied within my own code, if at
> > > all. on this 450 MHz k6-III, the cpu usage of one instance with no
> > > voices playing is about 1.5 % cpu, with iiwu_synth_write_float called
> > > every 64 audio frames. imo it's not too much.
> > Will it still not be too much if there's 10 iiwusynth's running, with 4
> > ladspa plugins applied to the output of each?  This is the kind of thing
> > my projects seem to end up with in logic audio in windows.  Besides,
> > IMHO, even 1% of *unnecessary* CPU use is too much.
>
> agree.

I agree it can be improved. I started profiling the synthesizer to
analyse where most of the time is spent. I also experimented with
doing part of the DSP in fixed point arithmetic. It seems that the
signal processing takes an acceptable amount of CPU. It seems rather
that the release phases of the notes are generally quite long which
means a lot of voices are being synthesized that you don't really
hear. For 10 notes being played, there can be 40 notes in the release
phase! Anyway, it clearly needs more work.

Peter


> tim
>
>
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