MOTM

bleep bleeped:
>>>>
hmm. how about a filter that's completely new? so far, all of the MOTM
filters are based on existing vintage designs, which is groovy and all
but... wouldn't it be excellent if in 20 years the chat on analogue 
heaven were all about "how do i get that MOTM filter sound in my 
quantum uber 3d virtual modular" etc. etc.??? 
<<<<

I sent Paul a cool unique filter design several years ago, but he's 
undoubtedly forgotten about it by now. It came from a design paper in 
the SSM databook. It could be generated from the discrete quad OTA 
cell design that already powers the 440.

It is....... ta da! a 4 pole state variable filter. Simultaneous LP, 
BP, HP, and notch, but with a steeper 4 pole response instead of the 
2 pole response in standard designs. In addition, it has a unique 
double feedback path: one called Q and one called R.

Q does what you would expect, while R separates the single peak into 
two peaks, and controls the spread between them. Allows for 
vocal/formant type sounds from a single state variable filter.

To the best of my knowledge, no synth manufacturer ever produced a 
filter of this type. How about it, Paul and everyone? Sound cool?

Moe

h3y all,
i'd be interested.  i like the sound o' the R feedback path...
have a good one...
peace,
doc


--- In motm@y..., mate_stubb@y... wrote:

> 
> It is....... ta da! a 4 pole state variable filter. Simultaneous 
LP, BP, HP, and notch, but with a steeper 4 pole response instead of 
the  2 pole response in standard designs. In addition, it has a 
unique  double feedback path: one called Q and one called R. 
> Q does what you would expect, while R separates the single peak 
into two peaks, and controls the spread between them. Allows for 

> vocal/formant type sounds from a single state variable filter. 
> To the best of my knowledge, no synth manufacturer ever produced a 
> filter of this type. How about it, Paul and everyone? Sound cool?
> 
> Moe

on Thursday, August 23, 2001 1:57 PM <mate_stubb@...> wrote:


> I sent Paul a cool unique filter design several years ago, but he's
> undoubtedly forgotten about it by now. It came from a design paper in
> the SSM databook. It could be generated from the discrete quad OTA
> cell design that already powers the 440.
>
> It is....... ta da! a 4 pole state variable filter. Simultaneous LP,
> BP, HP, and notch, but with a steeper 4 pole response instead of the
> 2 pole response in standard designs. In addition, it has a unique
> double feedback path: one called Q and one called R.
>
> Q does what you would expect, while R separates the single peak into
> two peaks, and controls the spread between them. Allows for
> vocal/formant type sounds from a single state variable filter.

This sounds VERY cool - and unique!  Separate VC of both Q and R would be
very interesting.  Just thinking off the top of my head here (good luck),
would the R control be similar to the freq CV input when two 2-pole
multimode filters are hooked in serial, and the Fc CV input for #1 is being
reversed from the Fc CV input for #2?

George

All this filter talk...

I've recently begun experimenting with the 420 in HP mode routed 
serially to the 440.  There are *many* timbral possibilities here, 
either filter static, the other modulated by an 800, or both 
modulated, etc.  The result through the 410 also widens the 
possibilities.

Filters are cool.

Mike

--- In motm@y..., "George Kisslak" <groovyshaman@s...> wrote:

> on Thursday, August 23, 2001 1:57 PM <mate_stubb@y...> wrote:
> 
> 
> > I sent Paul a cool unique filter design several years ago...

Yes. I should scan the response graphs and post them, but I'm still 
packing stooge panels at the moment.

Moe

>>>>
would the R control be similar to the freq CV input when two 2-pole
multimode filters are hooked in serial, and the Fc CV input for #1 is 
being reversed from the Fc CV input for #2?
<<<<