That just means it's time to upgrade the Denon to a newer unit that allows multiple crossovers. I just saw Outlaw has the 970 PrePro/7125 Pwr Amp for $1385 delivered to my door(I was so close to buying it, but the sub must come first)
I just tried to get my sub to match up the M80s at the 40hz mark yesterday and I couldn't even get my sub to match the SPL! I had to increase the level in the receiver to do it and it sounded incredibly awful!
I could have swore I saw something about Santa Ian offering 20% off on the EP500 to those of us with such sucky subs