Hi Nick,
I compiled Bristol with the patch you provided (envelope.c) and the
--use-exp-attack configure flag and the pop is almost gone. I can still
hear it on some presets on the mini, for example. I can work with the
attack thing it as is :)
However, I'm now experiencing the same issue at the end of the notes.
It sounds just the same as before but when you release the key. Again
this is ost notable on some programs. Take a hear at program number 4
on the minimoog at 44100Hz.
Hope this helps, and thanks for sharing your work!