Synth-DIY Yahoo! Groups Archives

Thread

RE: [motm] lag processor question...

2000-06-20 by Tkacs, Ken

A lag is an integrator, which in a mumbo-jumbo way is a one-pole low-pass
filter.

I'm no EE, so I can't explain this as well as others might.

Even a fluctuating DC voltage has a "frequency" identity to it. A
steady-state voltage is a signal with an infinitely long period, hence it is
like zero hertz. A slowly moving voltage has a super-low sub-audio
frequency. So the 1-pole (6db) integrator is making that voltage 'lag'
because it is filtering out all of the "high frequencies," which may be very
very low in audio terms. High frequencies mean fast movement and low, slow.
(This is a terrible explanation but I've just had two Starbucks Vente
Frappuccinos and my brain is all over the place).

The opposite of a lag integrator is a differentiator, which rolls off low
frequencies and emphasizes high ones, or in the CV case, faster-changing
voltages. I wish I could play with a differentiator... probably will make a
simple one some day. I don't think it's nearly as useful as a lag but
anything that does something to CV's or sound is useful.

Show quoted textHide quoted text

 -----Original Message-----
From: 	Chad Conger [mailto:lordgrimley@...] 
Sent:	Tuesday, 20 June, 2000 3:14 PM
To:	motm@egroups.com
Subject:	[motm] lag processor question...

A while back there was some discussion about the uses of a Lag processor,
and I remember one of the uses was using it as a 6 db filter...  How does
a lag processor act like a filter?  I'm rather foggy on that.

Re: [motm] lag processor question...

2000-06-20 by Paul Schreiber

A lag is a simple RC filter (where the R is variable). So, if you put in
audio, it acts as a 1-pole
lowpass filter. This is a 6dB/Octave slope.

Paul S.

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

Show quoted textHide quoted text

From: "Chad Conger" <lordgrimley@...>
To: <motm@egroups.com>
Sent: Tuesday, June 20, 2000 2:14 PM
Subject: [motm] lag processor question...


>
> A while back there was some discussion about the uses of a Lag processor,
> and I remember one of the uses was using it as a 6 db filter...  How does
> a lag processor act like a filter?  I'm rather foggy on that.
>
> Chad.
>
>
> ------------------------------------------------------------------------
> Find long lost high school friends:
> http://click.egroups.com/1/5535/5/_/529958/_/961527487/
> ------------------------------------------------------------------------
>
>

Re: [motm] lag processor question...

2000-06-20 by jwbarlow@aol.com

In a message dated 6/20/2000 11:59:39 AM, lordgrimley@... writes:

>How does
>a lag processor act like a filter?

Yet another explanation:
Suppose you input a square wave to the LAG PROCESSOR INPUT.
Then adjust the output curve to be linear.
In the ideal case, adjusting the LAG TIME (or amount) will vary the output 
from completely flat (i.e., the lag time greatly exceeds the wavelength of 
the square wave input ), to an unadulterated square wave.
There will be one spot on the LAG TIME control which would result in the 
output having the same period as the square AND the output will show a 
triangle wave output but phase shifted by 90 degrees wrt the square input.
Now by careful adjustment of the curve control (and probably some 
recalibration of the other controls too) the output can be made to a sine 
wave.

In each of these examples it can be seen that one is filtering out harmonics.

Now another idea for the 820 LAG PROCESSOR module:
1) Take a CV source to the input of the 820 (e.g., noise).
2) Take the 820 output to the input of the 100 (or 101) S/H. 
3) Take the 100 output to a CV input (say a 1v/oct of an oscillator).
4) Set the lag time to be rather long (like say a 5 octave sweep in thirty 
seconds).
5) Set the S/H level all the way up.

This great patch (which I learned from the old Serge manual) keeps step size 
small but allows for a full 10V peak to peak swing for the total voltage 
output over time. This means that (in the patch example given above) any two 
adjacent notes must be close together, but over time a full ten octaves would 
be covered. I use this patch with the S/H output going to a VC PANNER 
(instead of a VCO) so that a signal may start on the left and slowly pan to 
the right and back again. I'm thinking that with judicious use of the curve 
control you could make the sound source stay at the extreme left or right 
positions with little time in the center. I often use either my sequencer 
clock (or keyboard gate) to clock the S/H so that there is no movement while 
a sound source is audible.

Try it when you get the chance! It'd be nice to see a simple VC LAG and a 
simple S/H module made available to use for these types of uses.
JB

Re: [motm] lag processor question...

2000-06-20 by jwbarlow@aol.com

Damn! This patch won't work in the way I described since the 820 appears to 
have no HOLD input (a gate input which holds the output constant regardless 
of the input). You'd have to have another S/H in front of the VC LAG input in 
order to keep the input from changing (and the output slowly following that 
input).

Now it's getting expensive!
JB

In a message dated 6/20/2000 1:27:38 PM, jwbarlow@... writes:

Show quoted textHide quoted text

>Now another idea for the 820 LAG PROCESSOR module:
>1) Take a CV source to the input of the 820 (e.g., noise).
>2) Take the 820 output to the input of the 100 (or 101) S/H. 
>3) Take the 100 output to a CV input (say a 1v/oct of an oscillator).
>4) Set the lag time to be rather long (like say a 5 octave sweep in thirty
>
>seconds).
>5) Set the S/H level all the way up.
>
>This great patch (which I learned from the old Serge manual) keeps step
>size 
>small but allows for a full 10V peak to peak swing for the total voltage
>
>output over time. This means that (in the patch example given above) any
>two 
>adjacent notes must be close together, but over time a full ten octaves
>would 
>be covered.

Re: [motm] lag processor question...

2000-06-20 by Nathan Alan Hunsicker

and if remember correctly, i don't think the 820 lag has a lag time as
high as 30 seconds. I think it was around 5 sec or shorter. -Nate

jwbarlow@... wrote:

Show quoted textHide quoted text

> Damn! This patch won't work in the way I described since the 820
> appears to
> have no HOLD input (a gate input which holds the output constant
> regardless
> of the input). You'd have to have another S/H in front of the VC LAG
> input in
> order to keep the input from changing (and the output slowly following
> that
> input).
>
> Now it's getting expensive!
> JB
>
> In a message dated 6/20/2000 1:27:38 PM, jwbarlow@... writes:
>
> >Now another idea for the 820 LAG PROCESSOR module:
> >1) Take a CV source to the input of the 820 (e.g., noise).
> >2) Take the 820 output to the input of the 100 (or 101) S/H.
> >3) Take the 100 output to a CV input (say a 1v/oct of an oscillator).
>
> >4) Set the lag time to be rather long (like say a 5 octave sweep in
> thirty
> >
> >seconds).
> >5) Set the S/H level all the way up.
> >
> >This great patch (which I learned from the old Serge manual) keeps
> step
> >size
> >small but allows for a full 10V peak to peak swing for the total
> voltage
> >
> >output over time. This means that (in the patch example given above)
> any
> >two
> >adjacent notes must be close together, but over time a full ten
> octaves
> >would
> >be covered.
> -----------------------------------------------------------------------
>
> -----------------------------------------------------------------------
>

Re: [motm] lag processor question...

2000-06-20 by Paul Schreiber

Sure, 30-40 seconds easy!

Paul S.


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

Show quoted textHide quoted text

From: "Nathan Alan Hunsicker" <nate@...>
To: <motm@egroups.com>
Sent: Tuesday, June 20, 2000 5:35 PM
Subject: Re: [motm] lag processor question...


> and if remember correctly, i don't think the 820 lag has a lag time as
> high as 30 seconds. I think it was around 5 sec or shorter. -Nate
> 
> jwbarlow@... wrote:
> 
> > Damn! This patch won't work in the way I described since the 820
> > appears to
> > have no HOLD input (a gate input which holds the output constant
> > regardless
> > of the input). You'd have to have another S/H in front of the VC LAG
> > input in
> > order to keep the input from changing (and the output slowly following
> > that
> > input).
> >
> > Now it's getting expensive!
> > JB
> >
> > In a message dated 6/20/2000 1:27:38 PM, jwbarlow@... writes:
> >
> > >Now another idea for the 820 LAG PROCESSOR module:
> > >1) Take a CV source to the input of the 820 (e.g., noise).
> > >2) Take the 820 output to the input of the 100 (or 101) S/H.
> > >3) Take the 100 output to a CV input (say a 1v/oct of an oscillator).
> >
> > >4) Set the lag time to be rather long (like say a 5 octave sweep in
> > thirty
> > >
> > >seconds).
> > >5) Set the S/H level all the way up.
> > >
> > >This great patch (which I learned from the old Serge manual) keeps
> > step
> > >size
> > >small but allows for a full 10V peak to peak swing for the total
> > voltage
> > >
> > >output over time. This means that (in the patch example given above)
> > any
> > >two
> > >adjacent notes must be close together, but over time a full ten
> > octaves
> > >would
> > >be covered.
> > -----------------------------------------------------------------------
> >
> > -----------------------------------------------------------------------
> >
> 
> ------------------------------------------------------------------------
> Get 6 months of FREE* MSN Internet access!
> http://click.egroups.com/1/5725/5/_/529958/_/961540368/
> ------------------------------------------------------------------------
> 
>

Re: [motm] lag processor question...

2000-06-20 by Nathan Alan Hunsicker

oooops, my mistake. -nate

Paul Schreiber wrote:

Show quoted textHide quoted text

> Sure, 30-40 seconds easy!
>
> Paul S.
>
>
> ----- Original Message -----
> From: "Nathan Alan Hunsicker" <nate@...>
> To: <motm@egroups.com>
> Sent: Tuesday, June 20, 2000 5:35 PM
> Subject: Re: [motm] lag processor question...
>
>
> > and if remember correctly, i don't think the 820 lag has a lag time
> as
> > high as 30 seconds. I think it was around 5 sec or shorter. -Nate
> >
> > jwbarlow@... wrote:
> >
> > > Damn! This patch won't work in the way I described since the 820
> > > appears to
> > > have no HOLD input (a gate input which holds the output constant
> > > regardless
> > > of the input). You'd have to have another S/H in front of the VC
> LAG
> > > input in
> > > order to keep the input from changing (and the output slowly
> following
> > > that
> > > input).
> > >
> > > Now it's getting expensive!
> > > JB
> > >
> > > In a message dated 6/20/2000 1:27:38 PM, jwbarlow@... writes:
> > >
> > > >Now another idea for the 820 LAG PROCESSOR module:
> > > >1) Take a CV source to the input of the 820 (e.g., noise).
> > > >2) Take the 820 output to the input of the 100 (or 101) S/H.
> > > >3) Take the 100 output to a CV input (say a 1v/oct of an
> oscillator).
> > >
> > > >4) Set the lag time to be rather long (like say a 5 octave sweep
> in
> > > thirty
> > > >
> > > >seconds).
> > > >5) Set the S/H level all the way up.
> > > >
> > > >This great patch (which I learned from the old Serge manual)
> keeps
> > > step
> > > >size
> > > >small but allows for a full 10V peak to peak swing for the total
> > > voltage
> > > >
> > > >output over time. This means that (in the patch example given
> above)
> > > any
> > > >two
> > > >adjacent notes must be close together, but over time a full ten
> > > octaves
> > > >would
> > > >be covered.
> > >
> -----------------------------------------------------------------------
>
> > >
> > >
> -----------------------------------------------------------------------
>
> > >
> >
> >
> ------------------------------------------------------------------------
>
> > Get 6 months of FREE* MSN Internet access!
> > http://click.egroups.com/1/5725/5/_/529958/_/961540368/
> >
> ------------------------------------------------------------------------
>
> >
> >
>
> -----------------------------------------------------------------------
>
> -----------------------------------------------------------------------
>

Re: [motm] lag processor question...

2000-06-20 by Chad Conger

Aha..... thanks for the explanations and ideas Ken & JB & Paul S.

A big cartoon-like light bulb has appeared above my head....

Chad.


On Tue, 20 Jun 2000 17:27:48 EDT jwbarlow@... writes:
> Damn! This patch won't work in the way I described since the 820 
> appears to 
> have no HOLD input (a gate input which holds the output constant 
> regardless 
> of the input). You'd have to have another S/H in front of the VC LAG 
> input in 
> order to keep the input from changing (and the output slowly 
> following that 
> input).
> 
> Now it's getting expensive!
> JB
> 
> In a message dated 6/20/2000 1:27:38 PM, jwbarlow@... writes:
> 
> >Now another idea for the 820 LAG PROCESSOR module:
> >1) Take a CV source to the input of the 820 (e.g., noise).
> >2) Take the 820 output to the input of the 100 (or 101) S/H. 
> >3) Take the 100 output to a CV input (say a 1v/oct of an 
> oscillator).
> >4) Set the lag time to be rather long (like say a 5 octave sweep in 
> thirty
> >
> >seconds).
> >5) Set the S/H level all the way up.
> >
> >This great patch (which I learned from the old Serge manual) keeps 
> step
> >size 
> >small but allows for a full 10V peak to peak swing for the total 
> voltage
> >
> >output over time. This means that (in the patch example given 
> above) any
> >two 
> >adjacent notes must be close together, but over time a full ten 
> octaves
> >would 
> >be covered. 
> 
>
------------------------------------------------------------------------
> Free Conference Calling with Firetalk!
> Host your next egroup meeting live on Firetalk.
> Click here!
> http://click.egroups.com/1/5478/5/_/529958/_/961536523/
>
------------------------------------------------------------------------
> 
>

Re: [motm] lag processor question...

2000-06-21 by J. Larry Hendry

If you use the combination of both the UP& DOWN and the UP and the DOWN to
maximum, the lag time can probably be measured in hours,  many minutes for
sure.  I got tired of waiting for it it can be made so slow.

Larry (who has been crying solid for 24 hours since I had to send the beta
test lag processor back to Paul yesterday.  I can hardly wait to get the
two I have on order) Hendry

Show quoted textHide quoted text

From: Paul Schreiber <synth1@...>
To: motm@egroups.com
Subject: Re: [motm] lag processor question...
Date: Tuesday, June 20, 2000 5:56 PM

Sure, 30-40 seconds easy!

Paul S.

----- Original Message ----- 
From: "Nathan Alan Hunsicker" <nate@...>

and if remember correctly, i don't think the 820 lag has a lag time as
high as 30 seconds. I think it was around 5 sec or shorter. -Nate