Envelope filter?

[ethrbunny]

Im wanting to find a board that would truly let me control the envelope (ADSR). More than just an auto-wah. Im thinking that adjusting anything beyond the attack is getting into the domain of a synth but Im hoping that I can get at least that part.

Any pointers?

[Mark Hammer]

Attack/decay manipulation is reasonably easy to do with changes to passive components in a standard envelope-controlled filter like a Doctor Q or Mutron.  While extra long decays are easily achievable, extra long attacks are not (although musically useful variation in attack time IS achievable, and it was precisely that feature/capability that sustained my love affair with the MXR-EF since 1978).

The ADSR type envelope cycle, however, is one which depends on a sort of standardized signal event that a "normal" envelope generator cannot produce.  In particular, the "S" part of that cycle is a divided-down version of the gate signal, such that after the initial attack/decay cycle, the voltage produced falls to some predesignated voltage for as long as the gate signal lasts.  That relies on having something that falls into an on-vs-off dichotomy, not a more vs less one like the standard envelpe follower produces.

There is more discussion about this in the thread below: http://www.diystompboxes.com/sboxforum/viewtopic.php?t=27022

[ethrbunny]

OK - double caveat:

1) Im still on the steep side of the electronics learning curve
2) my kids are having a 'sleep over'- IE there are 'extra children' in my house - so there is 'extra red wine' in my brain

*but* given that -

could the 'attack' part be controlled similar to the volume oscillation in a tremolo? what if one were to start charging a cap when the signal hits, and the cap were used to drive an LED which shone onto a light sensitive resistor which (somehow) ("then a miracle occurs)" limited the volume.

(In retrospect this is v "rube goldberg" sounding.  After building the commonsound "tremulus lune" Im v enamoured with led/resistor combos)

(and apparently with "'" marks tonight too.. sheesh)

If the charging circuit to the capacitor was limited by a variable resistor would it be possible to dial in the attack rate?

Ill probably regret this post in the morning.. but thats a whole sleepless sleepover night from now.

[Ge_Whiz]

Sounds like you should have given the red wine to the kids.