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sine waves with envelope in poly~ clipping

Jun 18 2013 | 8:48 pm


I am having troubles with the poly~ object.
Basically I built a sampler for sustaining sine waves. I have a cycle~ with envelope inside a poly~ and I am giving it different frequencies through a $1 message.
This works fine for a few minutes then suddenly it starts clipping and sometimes even the sound stops. I then have to turn off the audio and switch it back on to continue playing.

Anyone any idea why this is happening? (see attachment)



Jun 19 2013 | 2:21 am

I think it’s getting too loud – running up to 1000 voices of anything typically requires quite controlled envelopes.

The breaking up you’re hearing might also be caused by heavy cpu load? I know that if I max out your patch my 2.66ghz i7 mbp reaches at least 140% cpu.

It seems as if the only thing that’ll truly stop a note in the patch is note stealing… and that happens @ 1000 poly. Reducing that to 100 seems to completely solve the problem.

Jun 19 2013 | 3:34 am

Thanks for your answer!

I had reduced the voices to 100 before – without success though. Even if I reduce to 20 I still get the hearing knock out, while my CPU (in Max) shows no more than 1 or 2 %.
The overdrive / knockout happens faster when I am using higher frequencies (like above 8000Hz). It seems as if they are "ganging up" among themselfs like a feedback loop.
So my guess would be that they somehow create intermediate tones. I don’t understand it though.

Jun 19 2013 | 3:51 am

I definitely am not seeing that response here.

The ganging up, does that still happen if you deactivate the adc~-triggered notes? As in, starting some notes, and then not letting more get triggered?

I’d also start looking at the envelope – that function looks very odd indeed, all the values are bunched up off to the side, and if I’m reading it correctly it’s a very fast envelope, too? – try swapping it out with a straight "0, 0.05 1000" message, perhaps?

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Forums > MaxMSP