Just another side note to this brother story. My brother is purely a classical listener. I venture he must have approx. 2000 classical CDs. Basically it's a classical library.
Anyways. He always felt that a sub wouldn't be of any benifit in his system. One day he started some serious listening, on my system, to some of his cherished classical CDs he brought; while I was out. When I got back he says "I think I DO need a sub in my system!" He felt he was missing a lot of presence in the low end. The music with the sub was much richer and fuller. Here is a classical (as in music) guy with Paradigm Ref 80s wanting a sub. Being the nice brother I am, I offered to build the same version of Tempest that I have (Octagon shape and sealed). He gladly accepted. I'm happy too, because I love woodworking.
Moral of the story is: I would venture a lot of systems would reap the benefits of a good subwoofer.
my 2 1/2cents