[sdiy] Simpliest envelope follower

[harrybissell]

Yes... you could do that. You probably need an active full-wave
rectifier (opamps) not just a diode bridge here.

WHAT are you going to follow ? This is VERY important.  For instance, Rene's
circuit samples the peak then resets at the zero cross. A good technique if the

waveform has one zero cross per fundamental cycle.  Guitar, for example... does

NOT.   My design idea in EDN "envelope follower combines fast response, lowest
ripple works especially good for Guitar, beating the simple full-wave and peak
detect methods hands down.

iirc... I think Rene's circuit is much less complex than mine.  ;^P

otoh if you are going to follow DRUMS, a peak detector is the way to go.

The morphlag is a good filter circuit for either a peak detector or a fullwave
rectifier.

H^) harry

Johannes Öberg wrote:

> Hi! I'm finally going to put together a Rene Schmidt MS-20 filter, but
> I really want some envelope follower modulation on the cutoff. What's
> the simpliest / lowest part count design that produces acceptable
> results? The one on René's page looks simple enough, but I want lower
> parts count :-)
>
> I'm to stupid to isolate the envelope follower in the DrQuack schematics...
>
> What if I try a fullwave rectifier with Harry Bisells Morph-Lag? Or am
> I completely on the wrong track?
>
> If it matters, the filter would be used for uhr, "general purpose
> filtering", whatever that is. I guess I would be using it more on drum
> parts or 'the mix' rather than single instruments.
>
> /J