I want to do guitar effects that start an ADSR on a note-on trigger. I have done it in the past (on an FV-1) by generating an envelope, delaying it 10 or 20ms, and comparing the dry and the delayed envelopes. I see if they are above a threshold (say 10mV), and their ratio is above another threshold (say 6dB). It is reasonably robust, but I was wondering if there is a more sophisticated approach that is better.
(Searching the forum, I am surprised that this hasn’t come up.)