The Peak parameter in the Filter section of Pulveriser controls the amount of Resonance of the Filter. And Self oscillation occurs when it is set to a high value, like it does in Thor. But with an additional feature: audio feedback! When the Peak is set to 100% the incoming audio signal will end up as a feedback sound sustaining endlessly.
Try that yourself, but be careful with the volume! Listen to the lowest volume, plug something in the Pulveriser, switch the Filter on and now turn the Peak all the way to 100% and the signal will start to feedback. When you change the Frequency of the Filter it will change the pitch of the signal. There you have it: an oscillator created with the Pulveriser!
Pulveriser only needs a short signal, which can be anything really, even noise, which will cause feedback when the Peak level is on 100%. Now if we found a way to tune the Frequency we can start playing like a synth…
Well, of course we can! We can also release the feedback so our synth doesn’t sound like a didgeridoo but like a real synth with attack and release.
Finding the right Frequency value and the right CV value so notes were pitched in tune, that was a challenge. But after some trial and error I found it: I could tune the Peak feedback pitch by playing the keys of my keyboard! And I didn’t even need to use a CV analyser for finding these values, it was all done by listening and comparing the tuning with a reference synth.
Listen to my demo track for this DIY Pulveriser Peak Synth I’ve created using one Pulveriser, one Thor and one CV Spider. It’s a one oscillator synth which sounds like nothing else. I made a Combinator for it with special modulation routings so I can control the synth by using the Combinator’s controls.
Musician and all around Reason wizard Selig created a complex synth last year, using the Pulveriser as an oscillator. His method is extremely complex, great sounding but different than mine. You can read about his model in this PUF thread.