Help picking a sub

For your price range and room size, I would get this one:
http://www.outlawaudio.com/products/lfmEX.html

+1

The EX is an excellent sub, and it sounds great with my Energy RC-50s, RC-LCR, and Veritas Surrounds

+2 as well on the Outlaw EX.... fantastic sub, love mine!!

To save a few dollars to can take a look at these as well

Outlaw Plus
www.outlawaudio.com/products/lfm1plus.html

HSU VTF-2mk4
www.hsuresearch.com/products/vtf-2mk4.html

I'm bias thou as I would go with the PLUS over the VTF-2 as I know what the Outlaw can do . You can always check the "B" stock at Outlaw as they can save a few dollars as well BUT they always sell fast so you almost have to be right on top of it daily to check.

^^^^^^^ either or.

butter and jelly please.

The F12 is a sealed sub a won't have the output the others will in a room that size. A pair of $300 subs might give a more even bass response but they won't go as deep and generally won't sound as good. They're almost all boom with little control or definition. But boom is mostly OK for many movies. It's your preference.

Agreed.

The F12 would likely be challenged in your size space at louder volumes. And I would not consider subs in the $300 to $400 range the same caliber as the Veritas setup you just bought.

For the price of the F12, either the HSU VTF-3 MK4, the Outlaw Audio LFM-1 EX, or the SVS PB12-NSD would be my choice, and you'll be very surprised at how well they perform for HT usage. Here are reviews for two of them:

http://www.audioholics.com/reviews/speakers/subwoofers/lfm-1-ex-review
http://www.audioholics.com/reviews/speakers/subwoofers/pb12-nsd/pb12-nsd-measurements

I agree with Cel4145 as the HSU VTF-3 MK4, the Outlaw Audio LFM-1 EX, or the SVS PB12-NSD would be a great choice, not to mention when time/money allows to can add another.