MOTM

(1) Just taking my first look at the motm-480 panel, noticing the BP and
LP outputs.  Is the configuration of this filter as follows: audio enters
the low pass filter first (so is available for output) and then the low
pass filtered audio enters the high pass filter (so audio is now band pass
filtered)?  Hence, this is the reason that a high pass output is not
available. If so, seems like a similar audio setup to the Korg MS20 filter
section (though different filter designs, I assume).

(2) Are there any "module connection additions" on the drawing board (or
in someone's imagination) that make this feature worth the advertisement
space?

Thanks, Jeff

Details are coming in about 4 weeks.

Paul S.

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

From: "Jeffrey Pontius" <jpont@...>
To: <motm@yahoogroups.com>
Sent: Monday, February 11, 2002 8:09 AM
Subject: [motm] motm-480 cs-80 filter configuration?


> (1) Just taking my first look at the motm-480 panel, noticing the BP and
> LP outputs.  Is the configuration of this filter as follows: audio enters
> the low pass filter first (so is available for output) and then the low
> pass filtered audio enters the high pass filter (so audio is now band pass
> filtered)?  Hence, this is the reason that a high pass output is not
> available. If so, seems like a similar audio setup to the Korg MS20 filter
> section (though different filter designs, I assume).
> 
> (2) Are there any "module connection additions" on the drawing board (or
> in someone's imagination) that make this feature worth the advertisement
> space?
> 
> Thanks, Jeff
> 
> 
> 
>  
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 
> 
>

On Mon, 11 Feb 2002, Jeffrey Pontius wrote:

> (1) Just taking my first look at the motm-480 panel, noticing the BP and
> LP outputs.  Is the configuration of this filter as follows: audio enters
> the low pass filter first (so is available for output) and then the low
> pass filtered audio enters the high pass filter (so audio is now band pass
> filtered)?  Hence, this is the reason that a high pass output is not
> available. If so, seems like a similar audio setup to the Korg MS20 filter
> section (though different filter designs, I assume).

  The CS filter is made up of two 2-pole state-variable filters with
open-loop gain limiting for each integrator and for the resonance 
feedback.  The first filter is high-pass and the second filter is 
low-pass.

  THe input signals go into the first filter. The BP output jack is from
the FIRST filter.  This output exists on the IG00156 filter chip as used
by CS machines, but is not used.  The high-pass output of the first filter
is hardwired to the input of the second filter.  The LP jack is the
lowpass output of the SECOND filter. This is the stock CS configuration.

Input -> SVF1 (HP) -> SVF2 (LP) -> LP jack
          |
         (BP) -> BP jack

Crow
/**/

Jeff,

I believe a couple of other differences from two cascaded MOTM-420s would be
voltage-controlled resonance and if I remember the original CS-80 filter
correctly, the fact that it may not self-resonate.  Hopefully the Old Crow
will chime in here - Oh, looks like he just posted while I was typing. :)

Not sure what a "Future Companion Module" is either, but I am quite curious!
Possibly something like Tony A's OMS-series?

George

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

From: Jeffrey Pontius <jpont@...>
Sent: Monday, February 11, 2002 9:09 AM


> (1) Just taking my first look at the motm-480 panel, noticing the BP and
> LP outputs.  Is the configuration of this filter as follows: audio enters
> the low pass filter first (so is available for output) and then the low
> pass filtered audio enters the high pass filter (so audio is now band pass
> filtered)?  Hence, this is the reason that a high pass output is not
> available. If so, seems like a similar audio setup to the Korg MS20 filter
> section (though different filter designs, I assume).
>
> (2) Are there any "module connection additions" on the drawing board (or
> in someone's imagination) that make this feature worth the advertisement
> space?
>
> Thanks, Jeff

Not to proove just how dense I am, but how does this make sence?  If you
input a tone with freq. content from 80Hz to 800Hz, and set the HP to
100Hz and the LP to 400Hz, then the BP out should give you 100-800Hz and
the LP out should give you 100-400Hz.

One of us hasn't had enough coffee, and it's probably me.  Help?

--PBr

-----Original Message-----
From: The Old Crow [mailto:oldcrow@...]
Sent: Monday, February 11, 2002 6:46 AM
To: motm@yahoogroups.com
Subject: Re: [motm] motm-480 cs-80 filter configuration?

  THe input signals go into the first filter. The BP output jack is from
the FIRST filter.  This output exists on the IG00156 filter chip as used
by CS machines, but is not used.  The high-pass output of the first
filter
is hardwired to the input of the second filter.  The LP jack is the
lowpass output of the SECOND filter. This is the stock CS configuration.

Input -> SVF1 (HP) -> SVF2 (LP) -> LP jack
          |
         (BP) -> BP jack

On Mon, 11 Feb 2002, Brousseau, Paul E (Paul) wrote:

> Not to proove just how dense I am, but how does this make sence?  If you
> input a tone with freq. content from 80Hz to 800Hz, and set the HP to
> 100Hz and the LP to 400Hz, then the BP out should give you 100-800Hz and
> the LP out should give you 100-400Hz.
> 
> One of us hasn't had enough coffee, and it's probably me.  Help?

  It is the jack labeling that is confusing everyone.  Perhaps Paul can 
have the outputs labeled 'BP1' (for BP output of 1st filter) and 
'HP1->LP2' (for first filter HP output chained 2nd filter from which is 
taken the LP output.  This is how the CS filters are configured).

  Note: if one is just using the BP output, then the 2nd filter's controls 
(FREQ LP, RES LP) aren't going to affect anything.  The "super-bandpass 
filter" that Paul describes only happens when using the LP output and 
adjusting both filter sections accordingly.

Crow
/**/