Instead of one big sub, why not look at getting a bunch of small subs? That will net you a flatter response overall. Look at the less expensive subs from Hsu, Monoprice Monolith, Outlaw Audio... You could get four VTF-2 MK5s for the price of a single PB16-Ultra, and you would get the same SPL with a much flatter response across all listening positions, and unpacking and moving them isn't nearly as difficult.