Better Subwoofer for 2 channel Music: Focal Utopia Sub or JL Fathom f113

@akg_ca , what a great synopsis of the subwoofer and quite truthful in many ways.............................all the way to the blatent plug or advertising for Vandersteen, I stopped reading at that point.
Are Vandersteen good? Probably. Are they the absolute best? I doubt it. .Are they the only sub in the marketplace of audiophile subwoofers that will satisfy the discerning audiophile? I'll leave that answer to the discerning audiophile. Subwoofers are one of those animals where you get what you pay for at least for now. I don't know what your Vandersteen cost but am pretty darn sure there are equally capable  products from other manufacturers.

These are all great response. thank you. 

I surmised a couple of things..

1) To perhaps focus on REL or JL but its a bit harder for me to get ahold of a REL
2)The RCA hookups from preamp is fine.
3) That perhaps two smaller 'good quality' subs may be better for 2 channel music than one larger one.  (i.e two f112s better than a single f113).  I just don't think that going to a three or four sub configuration is practical for me.  I might just get one sub and see how it works by itself and with my Monitor Audio.  

One person mentioned to stay away from the JL Version 1.  Does anyone have  a good account of exactly what JL upgraded in the V2s? 

My room is like 20'x20'x8'.  Two couches, carpet.  Should I be concerned that a single f113 may be two 'large' or overwhelming or can it always be dialed down?

@gillatgh,
Though Akg's post might sound like a plug for Vandersteen, the post does show how such a simple way to incorporate a sub not only makes sense, but works.
Yes, there are other subs out there, but few are built to last like the Vandersteen's. My 2w's were probably over 20 years old, yet still functioned as they should. I would ask the OP to look up previous threads regarding JL subs and the parts they use.
I also own a pair of HSU subs. They are quite good for the money, but took a long time to get integrated properly- Unlike my Vandy's which only required adjusting the impedance on the crossover.
@jmarshak , 
I would also consider the Audiokinesis Swarm. I haven't heard it, but people I consider knowledgeable on the subject, swear by them. 
Bob

The issue with sub size is integration.

Smaller subs are just less problematic than larger subs. The higher cut off prevents you from waking the dragons that live in the depths. Less chance of exciting nasty room modes, therefore, they sound better if you don't have adequate EQ and room treatment.

However ... given good EQ, treatment, and exact calibration, larger subs can be breathtaking.

.“....@akg_ca , what a great synopsis of the subwoofer and quite truthful in many ways.............................all the way to the blatent plug or advertising for Vandersteen, I stopped reading at that point.
Are Vandersteen good? Probably. Are they the absolute best? I doubt it. .Are they the only sub in the marketplace of audiophile subwoofers that will satisfy the discerning audiophile? I’ll leave that answer to the discerning audiophile. Subwoofers are one of those animals where you get what you pay for at least for now. I don’t know what your Vandersteen cost but am pretty darn sure there are equally capable products from other manufacturers....”

@gillatgh

I’m not pushing Vandersteen subs as the “best”.... there is no one “best” in my opinion. This was the full audio reporter article, and his comments on a specific brand fave may or may be noteworthy to a reader, but they are his editorial comments alone.

i totally agree that there are many other brand equals and superior choices as long as one remembers that everything is entirely bespoke/ unique system dependent...,, full stop.

my takeaway from that article is simply twofold as highlighted in his article:

$$ alone as a decision criteria is a pathway to a failed experiment, He has a valid comment that general audio mass market buyer has sticker shock at a under $1000 level,and its nigh on impossible to get a quality performer at that modest level. ANd similarly, simply throwing a large $$ at a sub is a pure gamble at best with a a high likelihood on system incongruity and poor integration regardless of price,

his best takeaway is that BOTH the design and the build of the crossovers are key...

Have I personally auditioned VANDY subs? Yes.
are they good? Yes.... VERY GOOD.and a contender and no pretender .
are they different with a very fast sonic signature ? Yes
Do I think it’s the only Yellow Brick Road to my audio OZ? NO... ,I still have a CASTLE CLASSIC sub ( a quality build and good performer built by ATC) for now.

There is no “Best” ...this crazy hobby choice of auditioning contenders and pretenders is a bespoke journey and NEVER a destination