The imput impedence of the X150 is 22 kohm balanced x2=44kohm I have the M5-HP set at 50 htz now. I would guess that it will be calculated at 88 htz so I would try 75 htz and 100 htz. What I meant to be asking was should I come out of the pre into the Xover and split the run right behind the xover or run a single cable into the xover near the amp then split right in front of the amp. If double biwireing gives a cleaner signal in speaker cable wouldn't it be true if I ran 2 interconnects from a split close to the pre, wouldn't that help the quality of signal? I'll have to check with some one to see if in fact I should use 88htz, you bring up a good question thanks.