I recently started thinking seriously about building a modular synthesizer. I do, however, want it to be different from the rest of the modulars out there. At the moment, I plan to built it as a full keyboard-equipped synth, but one where almost all parts are modules.
The frame itself will contain the keyboard, a midi controller and a bus controller. The modules will be interconnected, not with jacks and cords, but through a digitally switched 16 or 32 channel analogue bus. This will make it possible to store and recall patches.
All pots and switches will be digitally controllable through a control bus, and I will use rotary encoders and keyboard buttons to control the sound modules. This means that I can save audio settings as well.
I intend to use the same size standard for the sound modules as the ones used by Doepfer, Cwejman and others, but instead of having them upright in an euro rack case, I will have six "wells", about 10 cm high and 13 cm wide, side by side, with access from the back of the synthesizer. All controlls will be on top of the synth, but on interchangable panels, making the synth a "platform" for all sorts of sound machines.
To begin with, I want to create a polyphonic synthesizer. I am thinking of a concept with 5 voice cards, vertically stacked, taking up 1 well, but using the same bus access connectors as other modules. Each voice card will contain 2 VCO's, a VCF and perhaps some other basic modules.
Now, if I could only find the time and the money to do this...