Where do you get the digital X-over from?

Interestingly enough my Onk has two separate outputs per channel for the front. One of the outputs is for bass and mid-range and the other is for the tweeter. You can configure your own X-over in the setup. I've never tried it but have always wondered how well it works.

A-LFR/1000-8 & 2/500v4x2
Air Force, Freedom
had v2