Tried the bypass. Tried the phase switch. Experimented with the "flat" and "half" settings on the EP-500 (kids make great remote controls...
). Made sure all speakers were at 'small' at turned off DRC in the Cambridge. Experimented a bit with different xo cutoffs in the Denon (60, 80, 100, 120). And there is some improvement - now there's a harsh cutoff from the EP-500 to the NHTs. What this needs is some blending... if only I knew how. Sigh.
The EP-500 just seems to 'boom' and not actually define musical notes. I have it sitting 3' from the side wall and 1' off the back wall. It's sort of mid-way between the center of the front speakers and the right front (the entire width of the front wall is 12').
It's awkward to do exact back-to-backs with my other system but the C-5 towers seem to blend a lot better with the other sub. BTW the AVR (a Sony ES series) is set to a 80hz xo and the front speakers to 'large' in that system.
Oh well.