In trying to pursue this Buchla-style experiment, I've found it almost
impossible to derive a decent audio-trigger from an ADSR envelope, no
matter how fast. Gates work nicely, but you're forced to have two
events: one on key-press and one on release.

I've got plenty of ADSRs, VCAs, Comparators and other things, and have
tried using the voltage comparator to create a gate from an ADSR
(close but no cigar). Can anyone suggest a way of generating a trigger