[sdiy] Famous Fixed Filters - FFF PCB ?

[JH.]

Hi -  I've been thinking about PCB projects for 2008.

What dou you think about a collection of "Famous Fixed Filters"?

I think fixed filters are much underrated. Sure, the first thing you need in 
a synthesizer, is a variable filter - a VCF. Several VCFs, actually. The 
next step are fixed filters like filter banks, graphic and parametric 
equalizers, for formant shaping.
But then there are the "preset filters" that have been optimized in ensemble 
keyboards, electronic organs, the Polymoog, the Vocoder Plus, you name it. 
These filters can be emulated with parametric EQs to a certain degree, but 
it would still be nice to have the original filter, in dedicated hardware, 
with all their complexity, all their special overload behaviour, all their 
character.

But there's a problem:
A few years a go I built a rackmount FX to emulate the Human Voice filters 
of the Roland Vocoder Plus VP330.
This is an example for such a filter - but IMO it's not worth to make a 
dedicated module for this. It's a waste of front panel space to make a 
dedicated module for such a small filter circuit.

So I had the idea to combine many such fixed filters in one module.

Right now I try to find out how many "famous" fixed filters I can put on a 
single 160mm x 100mm PCB - and which filters are your favorites.

The Polymoog comes to mind.
All kinds of Formant filters in electronic organs.
A "manual" filter like the SH-5 BPF.
...
Anything that needs a minimum of front panel controls and has a lot of
character.

Let me know what filter you would like to see included.
And if you're interested in such a PCB at all.

The idea is to offer a board for 27.00 Euro with all the filters on it, and 
then allow various configurations:

(1) Each filter may have its dedicated input and output jack.

(2) You have one general input and output, and a set of switches, or a 
rotary switch, to choose your favorite fixed filter.

(3) You could also connect potentiometers to each filter output and mix them 
all together.

(4) You could have normalized input and output jacks, to use certain filters 
separately, and still mix some of the others together.

(5) You could feed different waveforms into dedicated filter inputs, and 
then mix the outputs.

(6) or any other combination that comes to mind.

Let me know what you think about this idea.

Would you buy such a board?
What classic filters would you consider mandatory in such a collection?

Looking forward to hear from you!

JH.