A single GX1 voice has four filters (HP, BP, and a HP-LP pair). There
are one voices per note (up to eight notes) per 61-key manual, a single
voice for the solo manual, and three voices for the pedalboard (though the
pedals are still monophonic). So, if you add it all up, there are 4
filters x 8 notes x 2 polyphonic manuals + 4 for solo manual + 12 for
pedalboard. That is 70 filters. Now you begin to see why the GX-1
weighs 300kg.
The GX1 filter module in 1U format is a single filter from the HP-LP
pair. You would need two of them to make the actual pair. Since I already
had a CS80 (state variable filter model) filter pair done on the MOTM-480,
I wanted to split the GX1-type (Sallen-Key diode ring) filters into two
modules so that 1) folks could insert other modules into the signal path,
and 2) if this was ever to be a MOTM 'micromodule' it would need to be 1U
and there isn't enough space to do a filter pair with enough basic panel
controls/jacks.
And yes, the CS80 and GX1 filters designs are not the same at all. You
can even do some ring modulator type sounds through the GX1 filter's diode
ring with resonance (I was doing that while testing the module ;), and
overdriving the filter input results in some interesting harmonic
'steps'.
Crow
/∗∗/
On Thu, 18 Mar 2004, edibennardo wrote:
> How many of these were in the GX1? I guess 8 for each of the two bigger
> manuals, just curious. Enrico