A word of caution about any 10 inch subwoofer driver. In almost every case, a 10 inch driver cannot properly reproduce the two lowest octaves which is the entire purpose of a real subwoofer's existence. They end up distorting, popping, compressing, and just plain poopin' out. Therefore, some companies add a second 10 inch driver as in the case of NHT's Sub Two and then they call it a tight musical sub. I've heard the Sub Two in two different home applications, one home theater, one music with the JMLab Electra's. The sub's retail for about $1200, but after hearing them and trying to configure them for optimal bass reproduction, I wouldn't pay more than $100 for it. Just boomy and they do nothing more than what a cheap full range speaker already does except that now the entire room is filled with a boomy sound that has no musical definition whatsoever.
The cabinet size of a 10 inch sub is still three-quarters the size of an 18 inch sub. I believe the very smallest size one should consider should be 12 inches and even then unless it's the top of the line(i.e. Aerial's SW12), you will still experience much the same cheap affects I mentioned above.
Might I suggest you locate a used Bag End Infra-Sub on audiogon, purchase, and try for a few weeks? If it's too big or you simply don't like it, then you should have no trouble selling it for what you paid as long as you got a decent deal for about $900 or so.
IMO -John
