As mentioned in the voice architecture overview, Poly-Mod can be a little tricky to wrap your head around. The conceptual difference between "standard" LFO mod and poly mod is that with LFO mod, a single LFO mod source gets routed to all selected mod destinations, whereas Poly-Mod makes use of each individual voice's filter envelope and/or Oscillator B to modulate parameters within the same voice. This results in each voice having its own modulation path. Depending on how it's used, this can have very different sonic results than with basic LFO modulation.
Source Amount- These knobs determine the level of polyphonic modulation. They can be used singly or in any combination.
Filter Envelope- Sets the amount of modulation from the filter envelope. Depending on amount and destination settings, this is capable of a lot of sounds; perhaps the most familiar is the legendary "Cars Sync" swept sync patch. This can be created by turning up Filter Envelope, setting Destination to Freq A and enabling the Oscillator A Sync button.
Oscillator B- Sets the amount of modulation from Oscillator B, effectively turning Oscillator B into a powerful low-frequency (or audio-range) oscillator.
A couple of things to keep in mind: if you'd like to use Oscillator B for typical low-frequency oscillator duties, make sure to enable the Lo Freq button; this shifts Oscillator B's overall frequency range below audible range. If the Lo Freq button is off, the result will be "audio-range" modulation. This can be used for all manner of clangorous beating, bell and "FM" type sounds (or insane lasers when combined with Filter Envelope mod).
You'll also notice that the mod frequency rises as higher notes are played on the keyboard; disabling the Oscillator B Keyboard button will disconnect the keyboard control voltage resulting in a constant frequency. Conversely, you can leave the Keyboard switch on if you'd like mod speed to increase as ascending keyboard notes are played.Finally, you'll most likely want to set Osc B level to zero in the Mixer section when Oscillator B is used for poly modulation.
Destination- These toggle buttons determine how aftertouch mod is routed. They can be used singly or in any combination. Destinations are as follows:
Freq A- Poly-Mod modulates Oscillator A pitch.
PW A- Poly-Mod modulates Oscillator A Pulse Width control.
Filter- Poly-Mod modulates filter Cutoff frequency control.
Amp- Poly-Mod modulates overall amplitude.