Well more is always better than less I have full range mains that are transmission line sat/subs, two separate cabinets. They are flat down to the upper 20's. I have the system crossed over at 60HZ at the pre amp, so I am down 6db at 45 HZ (12 db per octave slope). I am getting some good reinforcement from the mains as well. They say it is always easier to dial in a good bass response and minimize room modes with two subs versus one. You might be in overkill mode, but I predict it is gonna sound phenominal!