Need Help Choosing A Subwoofer

The Onix rocket UFW-10 would serve well in your room. You might try corner loading the sub you wind up choosing. You are likely going to have some interesting null/peak challenges in your room.

Yeah...a 10x10' room? You definitely can forget the 4x15" subs with mono's! Call it a hunch(lol).
Yes, you need quality well integrated fast solid bass. I think it's reasonable to say you'll be staying with mass marketed, and forgoing the custom DIY, ya think? And, actually there's enough good subs out there that, set up well (the key), will do you proud really.
For that room, I like dual fast 8" subs (even push/pulls, like MX stuff from M&k, for instance MX70), or subs with a tight "Q", even more musical vs, monsterously sloppy and boomy. Read a reivew or two...then choose wisely

Not to sound snipity but bass is not fast.If the "Q" is low enough and the F3 is typical of an eight inch driver what is deemed fast is rolled off bass, in other words it's a woofer not a subwoofer.

DIY is not for everyone, that is a fact.Yes, there are enough mass market subs out there.Vandersteen got around this with (3) 8" drivers with separate amps for each driver.The "Q" is adjustable also.A couple of these used would do you well.

The (4) 15's is an example of what I needed to acheive a response in my room.All the subs I listened to failed to dig as deep as my DIY system.Laughing out loud fails to help and only creates problems.Lets learn from one another and help this member find a sub that creates sound he can enjoy for years to come.

Good luck with your search. KG

Kgveteran,
I see that you brought up the (3) 8" Vandersteen. I have been looking at that sub also. How do you think that it would stack up to the Def. Tech. Supercube II? To give you a little more info about my system; I have Boston Acoustic VR950 front speakers, VR940 rear speakers, and the VRC center speaker. I watch mostly action/sci-fi movies and the music I listen to swings more toward rock. And additional subs worth looking at? Thank you for everyone that has provided me with some help!

The Vandersteen really does music well.It has that fast feel with the help of a steep high pass at the tuning frequency.Add to that variable "Q" which can roll off more of that low 20hz signal and you will have what people call a fast sounding sub.The 2W has never gotten good reviews for hometheater.I have heard of multiple stacked versions but that doesn't make much sense.
Can you drop by a Def Tech dealed to give a listen.Since I began building my own I seem to know less and less of the commercial brands these days.SVS is a huge favorite on the AV science forum.There is a true cult following.I have heard the Ultra12 and it really packs a punch.

Try your hardest to get into a dealership and do some real listening.You will answer your own questions about subs after a short time in a good videoroom.