Clave From a Self-oscillating LPF
Here’s a patch that makes a clave out of the LPF.
User ‘The Real MC’ on Modwiggler figured out how to turn Cascadia’s non-resonant LPF into a resonant filter here. I’ve modified that to make the LPF self-oscillate. You can tune it using the LPF CV amount knob. You can modulate its pitch by patching into the LPF CV in, but it doesn’t track V/Oct.
To make the LPF self-oscillate, create an amplified feedback loop:
1: Turn the output volume down and protect your ears when playing with feedback.
2: Turn the VCA-B/LPF control switch down.
3: Patch LPF out to a mult in.
4: Patch mult out 1 to VCA-A audio in.
5: Patch mult out 2 to the mixuverter main in (the one on the left).
6: Turn the mixuverter x2 switch up.
7: Turn the mixuverter polarity switch down (bipolar).
8: Turn the mixuverter knob fully counter-clockwise.
9: Patch the mixuverter out to the LPF audio in.
10: The LPF should start self-oscillating. Tune it using the LPF CV amount knob.
11: ENV-B to VCA-A level in.
12: Set ENV-B rise to 0 (immediate attack). Adjust fall and shape to taste.
Adjust drive to taste.
Try it with and without soft clipping.
For some alternate sounds: try patching a copy of ENV-B to the LPF CV in. There are a lot of nice plonks and zaps in here.
Further Reading
Synthesizing Cowbells & Claves (SOS)
Gordon Reid explains how to reproduce classic cowbell and clave sounds. Scroll down to get to the clave.
Pg. 6 has a brief description of the combined clave/rimshot circuit (RS/CL).
Pg. 7 has a block diagram (top right, under the BD).
Pg. 9 the circuit (bottom right).
Pg. 14 has a chart displaying the frequency, and decay time (C).
A short blog post on the 808 Clave.
EDU DIY SYNTH VCF Part 2: Active Filters & Resonance
Moritz Klein has a good explanation of how to add resonance to a filter in this video.
Scroll down to download the manual and read page 15.