Author Topic: operator feedback  (Read 91 times)

solipsvs

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operator feedback
« on: December 01, 2019, 04:27:21 PM »
i understand that this is too much for the cpu to produce, but what if we understood that the polyphony would diminish when using a ‘feedback enabled patch’?  is it possible to do?  i often use preenfm2 as a mono bass synth anyway.   if i dont need all that polyphony, can i have feedback?  i would dearly love to use it with preenfm2!   :P

matrix12x

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Re: operator feedback
« Reply #1 on: December 01, 2019, 05:37:47 PM »
I don't think its a CPU/polyphony issue.

The PreenFM2 does FM. Operator feedback in FM changes the pitch of the sound. I recommend using other waveforms to get the sound you want. For example, when I want to simulate an operator feedback sound I use the saw waveform. It works really well for the types of sounds I'm doing. There are also some user waveforms on the forum with varying amounts of feedback.

The Yamaha DX series actually uses Phase Modulation.

However, along these lines, what might be cool would be having for example, a new algorithm, something like Algorithm 1, but have a modulation index (IM4) to allow OP1 modulate OP2.

Xavier

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Re: operator feedback
« Reply #2 on: December 01, 2019, 05:59:12 PM »

The pitch shifting could be avoided with a High pass filter. As it's already implemented when 3 or more operators are in cascade.

Yes, that would be interesting to add new ALGO with some feedback capability.
ALGO1 is here, if anyone want to modify some wirings :
https://github.com/Ixox/preenfm2/blob/master/src/synth/Voice.cpp?ts=4#L314
Line 350 is the HP filter for OP2.

observer

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Re: operator feedback
« Reply #3 on: December 03, 2019, 05:15:45 AM »
ooh, this would be a very welcome addition! Anyone up to the task of creating new algorithms? I'm loving the new filters!

solipsvs

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Re: operator feedback
« Reply #4 on: December 03, 2019, 06:44:19 AM »
my mistake, iguess i thought i read that it was a cpu issue.

boy this thing is lovely with those new distortion filters and feedback would just make it that much more awesome.  i will try the saw waveform however