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Re: [motm] frustrated beyond belief

2000-03-09 by Paul Schreiber

You can't, in general, run audio into the GATE. What you need is something
external
to generate a GATE. There are 2 ways to do this:

a) use a keyboard or MIDI-CV with GATE out. It doesn't matter which key you
press :)

b) use a circuit called an Envelope Follower/Gate Extractor. The EF is a
rectifier followed by a
low-pass filter. This generates a DC level based on the input amplitude.
Then, a comparator is set
to be HIGH (ie at +5V) if this level exceeds a certain trip point (usually a
panel knob).

There will be a MOTM module that does this in about 8 weeks. There are
schematics at

www.synthfool.com/diy

for this as well. I think the old Polyfusion EF is there.

What's wrong with the '120??!

Paul S.

----- Original Message -----

Show quoted textHide quoted text

From: mark scetta <n0nspaz@...>
To: <motm@onelist.com>
Sent: Wednesday, March 08, 2000 11:11 PM
Subject: [motm] frustrated beyond belief


> From: mark scetta <n0nspaz@...>
>
> i am having the hardest time doing something that i think should be very
> simple: applying an ADSR to the volume of an audio signal. somebody,
> please, where am i going wrong:
>
> audio in is going to a preamp then into a mult block in my patchbay then
>    to the 110VCA and
>    gate in on my (older, gate-modified) 800EG
>
> and of course + out of the EG is going to the CV on the 110 and GAIN is in
> the 'bias region' with the CV pot maxxed.
>
> i just need to shape the volume envelope of a signal.
>

Re: [motm] frustrated beyond belief

2000-03-09 by J. Larry Hendry

Mark,
           Wrong hardware.  You need the soon-to-be-released and much
desired MOTM envelope follower.  The audio into your gate on the 800 EG
does nothing for you.  The EG needs a gate signal from a keyboard or
MIDI2CV converter to start its ADSR envelope DC control voltage.  To see
that your VCA is doing what you want, you could keep the same connection
(without the audio going to the 800) and hook an actual gate signal to your
800.  The EG should shape the level of the audio based on the ADSR settings
every time you hit a key on the keyboard ( if I am following your drift).

Larry (who loves his 120 sub-oct) Hendry


> From: mark scetta <n0nspaz@...>
> i am having the hardest time doing something that i think should be very 
> simple: applying an ADSR to the volume of an audio signal. somebody, 
> please, where am i going wrong:
> 
> audio in is going to a preamp then into a mult block in my patchbay then
>    to the 110VCA and
>    gate in on my (older, gate-modified) 800EG
> 
> and of course + out of the EG is going to the CV on the 110 and GAIN is
in

Show quoted textHide quoted text

> the 'bias region' with the CV pot maxxed.
> 
> i just need to shape the volume envelope of a signal.

RE: [motm] frustrated beyond belief

2000-03-09 by Dave Bradley

Actually, the circuit is here:

http://www.synthfool.com/schematics/polyef.jpg

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

Show quoted textHide quoted text

> -----Original Message-----
> From: Paul Schreiber [mailto:synth1@...]
> Sent: Wednesday, March 08, 2000 11:23 PM
> To: motm@onelist.com
> Subject: Re: [motm] frustrated beyond belief
>
>
> From: "Paul Schreiber" <synth1@...>
>
> You can't, in general, run audio into the GATE. What you need is something
> external
> to generate a GATE. There are 2 ways to do this:
>
> a) use a keyboard or MIDI-CV with GATE out. It doesn't matter
> which key you
> press :)
>
> b) use a circuit called an Envelope Follower/Gate Extractor. The EF is a
> rectifier followed by a
> low-pass filter. This generates a DC level based on the input amplitude.
> Then, a comparator is set
> to be HIGH (ie at +5V) if this level exceeds a certain trip point
> (usually a
> panel knob).
>
> There will be a MOTM module that does this in about 8 weeks. There are
> schematics at
>
> www.synthfool.com/diy
>
> for this as well. I think the old Polyfusion EF is there.
>
> What's wrong with the '120??!
>
> Paul S.
>
> ----- Original Message -----
> From: mark scetta <n0nspaz@...>
> To: <motm@onelist.com>
> Sent: Wednesday, March 08, 2000 11:11 PM
> Subject: [motm] frustrated beyond belief
>
>
> > From: mark scetta <n0nspaz@...>
> >
> > i am having the hardest time doing something that i think should be very
> > simple: applying an ADSR to the volume of an audio signal. somebody,
> > please, where am i going wrong:
> >
> > audio in is going to a preamp then into a mult block in my patchbay then
> >    to the 110VCA and
> >    gate in on my (older, gate-modified) 800EG
> >
> > and of course + out of the EG is going to the CV on the 110 and
> GAIN is in
> > the 'bias region' with the CV pot maxxed.
> >
> > i just need to shape the volume envelope of a signal.
> >
>
>
>
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