AW(2): adsr and lfo abolish

[jh]

Excuse my ignorance, but I still don't understand what the problem
of ADSR and similar envelope generators is. 

"Not only accept rectangular pulses" ? Restricted to trigger events ?
Who says that you have to use it that way.
You can build an ADSR so that in its gate-on phase it will react to
continously changing voltages at its Sustain input. In fact most
ADSR circuits do, even when the other parameters are not voltage contolled.
Asuming a Gate = On condition, a changing Sustain CV will control
the ADSR output voltage, with positive changes being slewed by the
attack time, and negative changes being slewed by the decay time,
"Like a filter/lag circuit, but nonlinear, with different Attack and Release 
settings."

My intention is not to defend an old style means of contour generator.
I think that the basic concept, reacting to gates / triggers *and*
to continuous CVs (sustain input) at the same time, is already implemented
in the classic ADSR, and it's hard to beat. What else could you imagine 
than performing integral and d/dt operations on certain CVs 
(including Gate CVs) ?? The trigger -> Attack/Decay stuff is nothing
but a nonlinear operation on the d/dt of a CV called "Gate",
and the Sustain -> Attack/Decay stuff is nothing but a nonlinear 
integration on a CV called "Sustain". I know I'm not *precise*
in my wording here, but you surely get the idea.

Not slitting hairs, here - use multiple decays / breakpoints etc if the
basig ADSR structure is to simple (You need at least two decays
for a piano-like envelope, for instance) - I'm aware of that.
You just do the classic envelope generator circuit wrong if you see it
as "only" a trigger controlled device. It may have some possibilities
still to explore.

JH.

-----Original Message-----
From:	Martin Fay [SMTP:martin at manikin.force9.co.uk]
Sent:	Saturday, April 10, 1999 9:33 PM
To:	debus at cityweb.de; synth-diy at mailhost.bpa.nl
Subject:	Re: adsr and lfo abolish

>I'd love to have a synth with an envelope generator that does not only
>accept rectangular pulses, for my Wind Controller. Like a filter/lag
>circuit, but nonlinear, with different Attack and Release settings.
>Something like the envelope generators found in compressors or noise
>gates. The "artificial" envelope of an ADSR (or something like that) is
>one extreme; the pure breath controlled envelope of the Wind Controller
>is the other. I'd like to have something in between too.

At a simplistic level this is a slew limiter with seperate rise and
fall times, I guess an exponential response would be close to what you
are looking for? I'm definately interested in getting hold of a wind
controller and I expect that would give me the impetus to sort out
MIDI output on VAZ Modular (i.e. MIDI in ->digital CVprocessing->MIDI
out)



Martin

VAZ+/VAZ Modular
www.software-technology.com