Posted May 11, 200718 yr I know this is a car audio forum so please excuse the HT question. I tried to get an answer out on the main forum but I wasn't getting any responses.I've heard great things about Fi and want to get a pair of 18s for my HT setup. I was told over on the Cult that some tweaks can be made to make the drivers IB friendly. So, the question I have is, what diffence could I expect between the SSD series and the Q series? I expect it to be loud, but I'm looking to hit the bottom octave with some authority. Opinions?