As the title states, i am trying to decide between this 2 subs. Room is 5400 cubic feet. Sr7013, focal aria 906 front stage and micca mb42x surrounds. Carpet over concrete floor. X15 is from a local dealer and is only $50 more than the HSU once everything is all said and done(im in Canada, so exchange and taxes). I know the Hsu is better down low, but leaning towards x15(with a plan of getting a second one in a year). Thanks for any input