Revel B 15 sub,crossover question

I would set the Revel B15 subs to use a second preamp out instead of the high pass filters. I would rather have less in my speaker connections.
I have wood floors on pier and beam. My original down firing sub caused more rattles at lower volumes than the front firing B15s. I started with one B15 and then added the second one. Two are better than one. I use my B15s in a HT setup with 4 M-20 and 1 C30 center channel. The B15s and the M20s work very well together.

I'm extremely happy with a single B15. I'm running Revel M-20 monitors on good stands, and the clarity and imaging are world class. Also the equalised bass integrates seamlessly with the main speakers. Highly, Highly recommended.

I'm using a pair of Sub 30s. The high pass filter works quite well. The addition brought my system up a couple of levels. I'm told it is better than the B-15s.