Best Big Sub? or duals?

I own a single F113 and all I can say, WOW! There isn't anything it can't do. I have tried it in three different locations in my living room, none of them being where it should go (my living room is wierd), and it sounded amazing in all three positions. It is the one piece of my system that I don't think will ever be outperformed.
I can't even imagine what a pair of them would do!

Christian_coach, I agree. I have only one Fathom F113 for a couple of weeks now, but it blends in great with my main speakers.

You can hear the bass lines walk through the music.
Even older music has a defined bass line.

I have several other Subs that I use for HT, but the Fathom F113 is used strickly for 2 channel audio.

Highly recommended!

Value goes to the HSU. I would do 2 15's in that room, upfront near mains, possibly in center on front wall behind/near the center, run in mono (.1 channel). Better would be two Paradigm Servo 15's (musically even more accurate).
Other dual sub options available, obviously, (yes, I like dual subs for you, EQ'd, up front for best integration....FORGET THE SUBS AROUND THE ROOM TO SMOOTH RESPONSE WITH TODAY'S TECHNOLOGY - besides, it looks unsightly and cluttered around the room) but would likely run more for the quality. Earthquake dual 15's will run more, and not out-do the Servo 15's.
Did I leave any out?

Hey Coach, my room is big. 18'w x 40'd x 10h and one on each side of the speaker is ideal. Adds great bloom, depth and stage. Nice controls which makes them very versatile and integrate nicely with time. They don't disappoint that's for sure.

Jp1208, my room is comparable size except I have 8 foot ceilings. The adjustments, and automatic calibration is well worth it when it comes to sound quality are worth whatever it might cost above some of the other subs people have mentioned. I thought is sounded good, then I ran the auto calibration and it was like night and day! I used to have a Paradigm PDR12 which I thought sounded good with my fronts, but the Fathom blends even better with them.
Some day I hope to have a space that can handle 2 Fathoms. I think the structural integrity of my home would be compromised if I had 2 in it!