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Re: stereo mixer (not synth) / music device bug?
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Re: stereo mixer (not synth) / music device bug?


  • Subject: Re: stereo mixer (not synth) / music device bug?
  • From: Bill Stewart <email@hidden>
  • Date: Mon, 16 Dec 2002 16:54:51 -0800

The main thing that this changes actually is the reverb - so the difference in CPU load you're seeing is so significant because you're turning down ***4*** reverbs.

I'd strongly recommend that you do a more complex graph where you have 1 reverb unit and take the feeds from each of the synths into that reverb, then do the dry wet mix...

If you look at the PrintSequence code in the SDK there's an example of doing this (it does an deinterleave/interleave for a multi-channel reverb - which you don't have to do) - but its very similar code to that.

Bill

On Monday, December 16, 2002, at 04:20 PM, chris corbell wrote:

On Sunday, December 15, 2002, at 01:51 PM, Chris Rogers wrote:

Chris,

It sounds like your problem is simply that you're overloading the
CPU when you have three or more MusicDevices running at the same
time. [....]

[....]
The misbehavior is, if I add more than three MusicDevices, everything
gets 'strange'. The app begins responding sluggishly, playing of instrument
sounds is mangled (it sounds like sounds are being rendered at a
much lower frequency), and eventually the app can hang. However
if I limit myself to three MusicDevices everything works perfectly including
mixing through the mixer unit. If I create the graph with four
music devices,

Thanks very much for this clue! It was CPU usage, which I'm now checking
in my test app regularly.

Turning off reverb did not help that much - 4 music devices still pushed
90% of CPU just idling (on a G3 500 iBook) - but chaning the render-quality
to high (must be max by default) improved this significantly. I can now have
multiple notes sounding on 4 music devices without ever breaking 50%.

Thanks again,
Chris
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