I think that it is recommended by many that you set the cross over in the pre-amp and bi-pass the crossover in the subwoofer amp. I tried this for the first time tonight and hate it!!! I was playing with my dads new Rotel 1066 pre/pro, and when I ONLY rely on the sub setting in that unit (even way down at 40Hz) I get way tooo much mid-bass hmmmm. it sounds like crap. I actually tried this way back with a Yamaha receiver with the same results. Why do people recommend doing it that way, obviously (in theory) it should work better, but it didn't the 2 times I have tried it, what gives???