The Hsu subs have a phase switch which I have tried. The 2 bass systems have worked together pretty well IMO. I took my speaks back to the dealer again and a faulty amp in one speaker was finally discovered and replaced by the dealer. The bass in the system has definitley improved and the case seems to be solved. Now I'm looking at a new set of IC's to make further improvements.
Thanks to all for your valuable input!
Thanks to all for your valuable input!