ADSR Envelope Shaper opinions

[lars-musik]

Hi,
on my quest for a slower slow-gearish swell (after some failed attemps with the Gator and even more with the EHX Attack Decay) I just stumbled upon this ADSR circuit on the great Paul-in-the-lab site :
ADSR Envelope Shaper Stripboard Veroboard Layout. I am not very good in deducing the results from staring at the schematics, so here are my questions: Do you think this would work for a guitar? Does it need to be triggered or does it detect the transients? Is it worth a try?
Thanks for your opinions.
Lars

[Mark Hammer]

If you are willing to press momentary switch S1, over in the upper left corner, whenever you strum or pick, it works fine.  If your hope was to have something that automatically produced volume swells as you play, that circuit will not do what you want.

[StephenGiles]

That looks like Practical Electronics print!

[lars-musik]

Thanks, Mark. That was what I feared. No, I don't want to press that switch. I guess I am about to put the Gator on my bench again...

[amptramp]

ADSR (attack decay sustain release) circuits are generally used for music synthesizers where there is a switch contact or logic input to multiply the tone generator output and get the typical envelope that many instruments use.  The use of ADSR corresponds to the sound of the analog synthesizers from the late 70's and early 80's.  These synthesizers used generic coefficients to shape the sound.  For example, the release state was often curtailed or zeroed for wind instruments which generally drop rapidly one the note stops.  Stringed instruments made use of all four parts of the envelope.

You would have to design a circuit to detect the sudden addition of sound from strumming the guitar in order to trigger it.