I'm all but positive it does something up high. We had an install with a couple hangs of these. The processor was back-ordered for a few days. I decided to fire them up w/o the processor (mainly just to make sure everything was wired correctly) and noticed they were lacking in the low end (no subs in this system) and when pushed a little harder, the 4-5k range seemed to get out of hand. I also noticed the hole in the lower mids that Evan mentioned. Not at all what I expected.
When the processor came in, I went right down and racked it up. I played the same music I played without the processor and it sounded like a completely different system. Plenty of low end, and the high-end didn't get abrasive when played loudly. The low mids (say 250-400ish) all the sudden had a nice presence without muddying things up. All this without a single change in the other DSP in the system.
Maybe it is a mind thing. I wish I had performed actual measurements both before and after the processor was wired in. I have no proof as to why, but they definitely sound better with the processor.