Addendum: After a couple searches online, I can't find any hardware Eurorack modules that have an absolute value function. That seems weird―software modulars always have it.

As a substitute, you can square the feedback signal with a four-quadrant multiplier, but this is less effective. The square function further attenuates quiet signals (making the chaotic behaviour harder to initiate), and further amplifies loud ones (which tends to peg the filter to +10 volts) so the range of filter parameters that will produce noise becomes very narrow.


Yesterday I found a surprising way to generate noise: Feed an HPF or BPF's input with the absolute value of its output at a high gain. Depending on the filter and parameters used, it will generate white noise, brown noise, narrowband noise, regular or random bursts of noise, crackly sounds, etc.

I did this in Softube Modular (it works with the Korgasmatron II and the Doepfer VCF-8), and was wondering if someone could try it IRL and let me know if it works. I don't own anything in hardware that has an absolute value function. The two above-mentioned filters have input gain knobs that go to clipping, which helps a lot.

Is this already a known trick?