I'm building a sub for our new dedicated HT using JBL's 2245H. The vented, 6th-order alignment yields F3 of 24Hz and ruler-flat 121db(!) output. But it requires a 9+ cu ft box. I'm struggling with where to put it. There's a spot about halfway down the side wall but the path length from the sub to the listener would be about 7' shorter than from the LCRs. Is this a problem? 1/2 wavelength at the crossover frequency is about 7'. Does this mean I should invert the sub polarity? If I use a 2nd order crossover, there is already a 180 deg. phase shift at the crossover frequency. Or I could use 4th orer Linkwitz-Reilly crossover to minimize the overlap and interactions. Thoughts?