Osc sync, how does it affect the signal path

[iProg]

and how does it work in general? New in that area...

[Synthaholic]

Sync doesn't change the signal path to the filters/VCAs. What it does do is send the output of the master oscillator into the sync input of the slave oscillator. With sync enabled, the slave doesn't start generating a waveform until the master oscillator's waveform reaches zero (or some threshold). Then the slave generates one cycle of its waveform, and then waits for the master oscillator to reach zero again.

This is a fairly simplified explanation, and probably not 100% correct but it gets the basic idea across.

[Big Gnome]

It doesn't affect the signal path in the slightest--it locks the phase of one oscillator to another's. The first bit of this article will tell you everything you could possibly wish to know about oscillator sync.