Sub comparisons

[Raider]

I have narrowed my sub search to four possibilities.  First is to build a Rythmik Audio 12" or 15" servo kit. I have read reviews, all favorable, of these but cannot audition them.  Though they apparently give a very predictable result, I haven't had opportunity to hear them. Second is the Martin Logan Abyss.  I have heard these and really like them, but I suspect the Rythmik might offer more articulation at a slightly lesser price, since the ML's aren't discounted more than 5% off of list here.  Third is the RT12d which had good depth and output and adds the capability of the ARC circuit which is valuable, but raises the price point to double the first two alternatives.  Fourth is the JL Audio F112, which I found to be really articulate with a lot of clarity and with exceptional attack and decay response.  Unfortunately I was not able to audition the RT and F112 together. The street price of both the JL and the RT12d is basically the same. I briefly considered the F113 as well but the price point then would likely be into diminishing returns territory. I had actually also considered the Sub12, especially since a local dealer has them at $407 right now, but unfortunately the problems many are having with the Sub10 and 12 amps have caused me to eliminate this choice    

I am looking for articulation at low, moderate, and moderately loud outputs (up to about 100-105 db max, more typically 80-95 db), rather than extreme volume capability.  I have about a 3500 cubic foot room, open on one side to a stairway and hall. I'm also one of those weird guys that thinks a subwoofer or speaker should faithfully reproduce any signal input, so I make no distinction between music and HT.  I am using four RF82's and an RC62 for mains/surround/center.

So...my choices seem to come down to either the Rythmik or Abyss, later adding a second unit if necessary.  Or between a single RT12d or an F112. Any input or comparsion of these alternatives is appreciated, since Iwould like to nail this choice down very soon.

Thanks

[DrWho]

I have found that two subs always sounds better than one when you have the flexibility to choose multiple placement configurations that reduce modal issues. It also presents a more balanced stereo image, even if both sides are run off the same mono signal. With the 6dB additional gain from doubling up, I would imagine the output capabilities would be extremely close too.