Real soon I plan to pull the trigger on a subwoofer setup for my growing home theater. The room is 4,300 cubic feet with 2 openings one of which I can close off with a door. The subwoofer(s) have only one spot in the room for placement that works and that is the front left corner. The opposite corner has a room mode that is a problem so I avoid placement there. When I do listen to movies it is near reference so I require more of a subwoofer than most. Budget: ~$2k. My friend bought a dual SVS 25-31CS+ package. He went that route to maximize the 25hz output as many agreed that 25hz was where the majority of movies tend to be in terms of low end output. He suggests I do the same. I however want more down low. Questions: For this amount I am considering Dual SVS CS Ultras, Dual PC Ultras or 1 PB12Ultra/2. If I get the final veto on the tubes(unlikely) I'll have to step up to the Pb12Ultra and get 2 of them. 1. SVS wise: am I on the right Track? 2. Am I sacrificing that much or at all in the 25hz region to gain more in the 16-20 range? If so would it be that noticable or is it a case of me forgetting about it because it is already good enough and the lower end will make up for it? 3. Do I need 2 subs? I figured since the dual cs/pc ultras have more port area and a little more power I'd gain more output? 4. If I go the dual pc ultra route, how would I calibrate that given both have the EQ? 5. Is a BFD or similar device necessary or will the EQ in the SVS suffice you think?