Archive of the former Yahoo!Groups mailing list: MOTM

previous by date index next by date
previous in topic topic list next in topic

Subject: RE: Anybody like Fixed filter banks?(new mod)

From: Mark Pulver <mpulver@...
Date: 1999-10-05

Dave Bradley (09:42 AM 10/5/1999) wrote:

>> Intresting stuff, can be done with a parametric eq, but as with all
>> filters, the sound will depend on the actual circuit used and there
>> are plenty of variables here :)
>
>The MOTM 420 is 3 resonant bandpass filters. Fixed resonance, but
>individually tuneable filters so you can do similar interesting things. I
>plan to use mine a lot for formant types of things, not just swooshing
>around with the LFOs.

Is someone was gonna go nuts on a filter bank, my vote is for a full
Formant filter. I have a custom 4-band in my Moog modular, and it's awesome.

(I know you know this Dave, but...)

A Formant filter is basically a number of bands (4 is common, I've seen
overkill at 8) where each band has a variable center freq, a cut/boost
control, and a fine control for resonance - usually a 10 turn pot.

The point is to mimic the nasal sounds of the oral cavity. The 10-turn pot
on resonance is required in order to be able to hang the filter stage
∗right∗ on the edge of feedback - RIGHT on the edge.


>> I am not too familiar with these other "fixed filter banks" . What
>> are the controls per section/band, if freq is fixed, what center
>> frequencies are used ?
>
>The Moog fixed filter banks are fixed frequency AND resonance, so no better
>than a common graphic eq. Just a gain control for each band. If I remember
>right, there is an 8 band and a 12 band version, each with an additional low
>and high shelving control.

I remember the Moog filter bank being only cut, no boost. Sweet sounding
stages though. :)


Mark