Subwoofer for Ayre AX-7e?

I run two JL Audio E112’s in a 12’ x 11’ x 9’ room and they provide smooth musical bass with my 805S mains. Without the subs the bass was boomy and unnatural. Prior to moving this system into this new “small” room I was concerned the subs would be impossible to use in such tight quarters. To the contrary, they pulled the sound together and drastically improved the rooms sonic attributes. 

I have a very large room, it's about 9000 cubic feet and I have tried quite a few subs.  I brought in four different subs from SVS including the fancy Ultra SB16, a massive Paradigm 2000SW, an older vintage Def Tech 15 inch sub and finally two different offerings from Axiom Audio out of Ontario.    The reason I wanted to try the Axiom subs was because they are the manufacturer for the Bryston speakers and I have a pair of Bryston Model T's for my main speakers and they are absolutely outstanding and can take whatever you want to feed them with (I am feeding each speaker with 2000 watts RMS with a pair of M1 mono blocks running off of dedicated 240V 15 amp inputs).   The build quality of the Brystons is as good as it gets and they are built with all parts made in Canada at the Axiom facility, no Chinese parts please.   

So I first ordered in the EP500 V4 which is a sealed cabinet 12 inch driver and a 500 watts class D amp.  What I like about the Axiom amps is that the power supplies are not switching design as SVS, JL Audio, etc... most everyone uses actually; the Axiom uses a Toroid/high capacitance supply as is found in amps like the Bryson monster amps.  In fact Axiom builds the sub amps and cross overs for Bryston speakers.  Bryston of course builds all of their own power amps and they are beasts.  The dynamic head room in the Axiom Subs is amazing, the subs do not run out of gas at all.   I was so impressed with the EP500, that I decided to get the EP800, which is a huge towering sub.  It has dual 12 inch drivers and an 800 watt rms amp.  I will tell you that these subs with power ratings which are half of the others out there which I tried, are just massively more powerful.  

Compared to the SVS subs, well there isn't a comparison, the Axiom's are far more musical, more controllable and don't have odd one note bumps in the range.  These are flat, and I mean perfect.   Plus with the phase control, I can dial the subs in with the main speakers in under 15 seconds for the most perfect syncing.    I am extremely impressed and very pleased.   Plus Ian built my EP800 with a custom DSP algorithm which is switchable for a 6 db boost in the middle bass for those times I want to really put the sub into high gear.    These subs are all hand built to order, you cannot beat it.   I highly recommend reviewing their website before you spend a lot of money on any particular brand.   And by the way, there are speaker level inputs/outputs on the back in addition to unbalanced or balanced input (I use the balanced inputs, it made a substantial difference over the unbalance).

the thing that folks really need to keep in mind when dealing with subs is how well they mate wiht their speakers.  This is a very difficult thing to do since there are just so many variables.  What works for some may not work for others.  I love how the Vandersteen EQ will smooth the response in any set up, plus his amp will take on the same sound as your main amp, but will they sound coherent with your speakers?  They may or they may not.  

The same thing goes with anyone else subs.  I have found so many folks using subs to just give more bass in a system.  All too often the subs can be heard as that's what so many want. My personal feeling is that you will never hear a sub person say.  This is why I feel strongly that any sub really needs to be used by overlapping an octave with the main speakers similar to the way a crossover may work.  

As someone who loves his AX-7e so much he had Ayre install high-pass crossover caps so he could use it to drive a pair of Quatro CTs, I’d build your system around this component. I used to drive a pair of monitors + subs, but my GMA Callistos could play -3 dB @ 47 Hz (I think), so my subs (plural) would cross-over around 40 Hz. Subs would cross-over much higher to augment the Epos. I’d spend your sub budget on fuller-range speakers. I’m also a big fan of the Ayre / Vandersteen combo. 

As someone who has ownand used a pair of Vandersteen 2WQ's for many years I don't think either they or the new Vandersteen subs would ever work with the speakers you have now that have a minimal bass response in the 50's hz range.That is not the type of speaker they were designed to work with.  I like other posters would recommend you look into a full range speaker first whether it be the venerable Ici or even a used 2CE Sig.  There are also many others so you need to get out and listen for yourself.