This one looks pretty cool, with included descriptions of how modular synthesis works. Seems a bit hard on the cpu, though.
"Modular is a powerful sound design tool which allows you to build your own custom synthesizer by connecting different sound modules together. By separating each synthesis process, modules can be connected in any way. You are no longer limited to fixed synthesizer design, you are now in full control of your sound. This is the beauty and power of modular synthesis. Whether you are a professional musician or a beginner who just loves sound, modular offers you an incredibly powerful synthesizer experience.
Modular looks, acts, and sounds like a hardware modular synthesizer to give you features that musicians want such as pulse width modulation, oscillator sync, 4 pole ladder filters, and 1v/oct filter tracking. Traditional modular systems are expensive and out of reach for the average artist. Modular is here to bridge that gap and allow everyone the opportunity to use these powerful synthesizers."http://www.idesignsound.com/modular-syn ... universal/http://www.idesignsound.com/update-modu ... h-sharing/