Ultimate sub?


So I have been in a slight upgrade stage recently. I just purchased a b&w HTM2 and I'm shopping for a sub. There is never much talk about subs it seems and so right now my two options are the Velodyne DDPlus 12 and the JL Audio Fathom 112. Are there any other manufacturers I should check out? This sub is an ultimate system purchase so I don't want to make a misstep.
dark_elation
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Never much talk about subs? Search the archives, you'll find plenty of talk about subs.
Careful Tpreaves, I got told on another thread that suggesting that someone search the archives is rude and unacceptable behaviour. ;)

I didn't see a price range in the OP's initial post, it was titled "Ultimate sub", so I took him at his word and assumed he was looking for the ultimate sub, not a budget sub.
This one from Rhythmik has about as much low end extension as you could ever require. It's down 3db at 14hz. It's a sealed box with a 600wpc dedicated amp. I use a pair of their 300wpc 12" subs in a pretty large space and have apparently limitless clean SPL available. (I say "apparently", because tho they stay clean - to my ear - and go louder than I'd ever care to approach, I've never measured for THD).

Although I've never heard this model, I suspect that you'd need a giant room and some very unusual program material to find the limits on a pair of these guys.

http://www.rythmikaudio.com/F15HP_specs.html