[sdiy] Enveloping Envelopes

[John Mahoney]

At 04:17 AM 9/24/2009, Kyle Stephens wrote:
>Envelopes envelopes envelopes...
>
>... How do you use them aside just running VCAs and VCFs? ...

So many ways to use them.

Envelopes can be used for modulation -- anyplace you might use an LFO.

Modulating pulse width with an EG is cool.

Pitch envelopes are fairly common. An easy to understand example is 
the cliche 1980s Syndrum sound in which the pitch starts at a high 
value and drops (DOOoooooo....). This is an A/D (attack/decay, with 
no sustain) envelope with very short (instantaneous) attack and 
moderate to long decay. In this patch (not that you really want to 
use it, noooo! LOL), one envelope can usually handle pitch, VCF, and 
VCA modulation.

EG-controlled pitch bend in a VCO that is hard synced to another VCO 
is a classic sound.

Delayed vibrato is another old standard. Route the vibrato LFO 
through a VCA (it's nice to have 2 or 3 VCAs), and control that VCA 
with an EG that has a slow attack and full sustain. As you hold down 
the not, the EG will open up the VCA, thus fading in the vibrato over time.

A different application for that extra VCA+EG is using it to fade 
part of a patch in and out during a note's duration. Like, you can 
add a little extra something to the attack of a note. Or, have some 
element fade in, as with delayed vibrato.

Take a slew limiter (lag) with separate up and down rates, patch the 
gate signal through it, and you've got an A/R EG. Cheap and simple.

John