A bouncing-ball envelope turns a single gate into a series of decaying hits. You can build one with a function generator that exposes its end-of-rise stage — the technique works on any slope generator with an EOR output and a modulatable fall time.
The patch
- Take the end-of-rise (EOR) output of one channel.
- Send it to the trigger input of a second channel.
- Route the second channel’s output to modulate the first channel’s fall time.
Why it bounces
Each time the first channel reaches the top of its rise, the EOR pulse retriggers the second channel. The second channel’s voltage shortens the first channel’s fall, so every successive bounce is quicker than the last. The result is a decaying series of pulses from a single gate — the same shape as a ball losing energy against a floor.
Tuning it
Set the fall modulation amount to control how sharply the bounces decay. A small amount gives a long, gradual roll-out; a large amount gives two or three fast hits and a stop. Slow the rise slightly to make each bounce read as a distinct event rather than a smear.
From there, patch the first channel’s output to a VCO’s pitch for a melodic bounce, or to a filter cutoff for a percussive one.