Sub Recommendation

HSU VTF-15h if your a little flexible on the 800. I would save up a little more to get that sub if you already have 800. Would be well worth it.

Another option that will excel above 30hz is a CHT SS18.1 with a Behringer EP2000 power amp. That will also allow you to add a 2nd sub down the line for only $550.

Edit: This amps an even better deal and puts your right at your budget.
http://www.guitarcenter.com/Behringe...97-i2267784.gc

Suggestions provided so far have been good ones. Consider the Epik Empire also. It has excellent mid bass, only shipping costs put it over your budget. It would dust the Klipsch over 30 hz.

The subs you're considering are all better than your Klipsch, but may not exceed it by the order of magnitude you're looking for.

I agree except I think the sealed recommendations would run out of steam in that size room. Although I like the Chase idea since it would be very easy and cheap to add a second one down the road. Two of those would rock that room.

To answer the original question. $800 limit. That size room. Pb12-nsd all day

To get an idea of how the PB12 and Empire would compare, I'd suggest looking at the measurements here, using the Outlaw LFM EX with 2 ports open as a proxy for the PB12:
http://www.data-bass.com/data?page=systems
I've owned dual PB10's, which would exceed a single PB12 for output, and I can say above 30 hz or so its the Empire all the way. Between 20-30 hz they are comparable.

The PB12NSD can't keep up with the Empire. My Empire is in a bigger room than OP's and does just fine; the room's not sealed either. Empire has the advantage in the first place, and doesn't need to be ported. It does cost a bit more with shipping, tho. The 15H Hsu would also be worth spending a bit more on. Size does matter.

Either of the PB12-NSD or the VTF-3 MK4 would be just fine for that space. Check out this review from Audioholics of the PB12-NSD where it is rated in the end as good for rooms up to 5,000 cubic feet: http://www.audioholics.com/reviews/s...ofers/pb12-nsd

The VTF-3 MK4 is often compared to the Outlaw Audio LFM-1 EX, which got a similar rating from Audioholics and which has been demonstrated to have more output than the SVS. So all good there, too.

Two factors that you might consider are that the 3.4 should be able to get a little lower in frequency response when in maximum extension mode, and the PB12 has a limiter built in to keep you from accidentally pushing it too much. Personally, I think you could choose the one you want based on aesthetics and not do wrong.

I mean run out of steam in the lower end but that's still strong stuff from fhe Empire. but the Empire is over $800.

....Got one almost 2weeks ago and couldn't be happier. Sounds better everyday I listen to it!

They're all good choices and you'll be smiling with any of them. The differences are not great in any case. We're fans of what we know first hand for the most part...