Routing OSC 2 to the filter in the modulation section results in a pretty cool type of distortion.
What kind of modulation is this?
I have a really cool patch that only uses OSC 1 set to a very pure waveform. As I bring up the mod wheel (OSC 2 routed to the filter) I hear lower tones come in. Using the mod wheel from high to low sounds kind of like a distorted guitar going into feedback. Too cool.
Bryan
it’s audio frequency modulation as opposed to low frequency modulation, that’s all really. you can get sounds similar to this w/ the actual LFO since it can oscillate up into audio range, too.
does sound wonderful though. 
Yes, but it has the added benefit that it tracks pitch. I’ve come up with some amazing bass sounds using this trick.
yea, it’s a fun mod dest. Try sweeping the OSC2 freq around while you have this mod set for more fun.
Also try using Oscillator Sync and then play with OSC2 freq and waveform. And then there is high resonance filter self-oscillation with OSC2->Filter mod. Lots of possibilities. Watch this if you haven’t already: http://www.youtube.com/watch?v=S45jRMdpFu0
Low frequency mod can also be achieved with OSC 2. Set the octave of OSC 2 to 16 and drop it’s frequency even lower with the frequency knob. Now you have a variable waveform LFO and it tracks with the keyboard.