When using AR mk2 with OB, you can send any Audio Track from your DAW to any of the 8 Voices of the AR and use the Parameters of that Voice (Filter, FX, Compressor…) to process the Audio Track.
Let’s say that you have a Drum Loop in your DAW. You can now filter it, use FX and then, compress it with the other AR drums using a Voice (or 2) from AR.