My room is 18 feet wide and it goes from the family room all the way into the kitchen, so the back of the room is open. I have 9 foot ceilings too.

If you look at the pics I posted, the small openings I was going to put the sub woofer in are 22" wide x 16" tall x 16" deep.

So I'm thinking of getting a small sub to put in one of those spots for now, and then get a second one later on. I think that will give me enough on the low end of things.

So is one large sub woofer better than 2 smaller subs, or will I even really notice a difference if I'm not going to A/B test them?