Whoa. That is one heckuva nice diagram. Hope you didn't just tool that up for this little conversation. That's got to be a fantastic room!
On the AV123 v. Axiom question, there are a few things I'd like to assert.
1. It's not an apples v. apples comparison. The x-mtm is more comparable to the M50 than to the M60 in size and driver complement. The M50's could also be an excellent choice for you.
2. Nobody has heard the x-mtm yet. It's not available. So, there's no way for ANYBODY to "know" how YOU might think it compares to the M60. I would say that - in most things in life - you get what you pay for. With both Axiom and AV123, most customers feel that they got good value (i.e. a bit MORE than they paid for). So, it's going to come down to your personal preference and your assessment of value. Arrange auditions if you can.
3. For HT use, the Axiom QS surrounds are - I believe - far superior in design and performance to just about any small, directional bookshelf speaker.
4. Shipping is free at Axiom. It is NOT free at AV123.
Regarding the sub - you might want to consult the folks at Hsu. You could always start with a VTF-2 and then add a second one if you find that you need "more".
Regarding speaker placement, thanks for the diagram. (barrage of disclaimers follows). There are still unknowns. Personal tastes vary. The room is important. You don't know until you try. Only your opinion matters. There are several different approaches that you might find satisfying. A rolling stone gathers no moss. Kilroy was here. Wait...
As I understand your room, I'm not sure that ANY of the specified "surround" locations are really optimal.
You're pretty much locked in (and nicely so) on the display and seating.
Do I understand correctly that the bar is basically all at/below bar height? That is, there are no "upper cabinets" or walls hanging over the "bar" section that juts into the room, right?
First off, I think this room SCREAMS for 7.1 (eventually). I would absolutely plan for a pair of REAR QS speakers (or even maybe M2's) on the long wall parallel with the pool table. That implementation is going to make your 25% music time go from blah to great. It's also going to fill out the HT experience significantly since it is such a big room.
As to the surrounds, that's a tough one.
I think positions 1 and 2 are too far forward to do you any good. I think positions 3 and 4 being right on top of the listening position could be problematic, too.
The QS surrounds are pretty forgiving in placement, and given your room, are an especially good choice.
It's not absolutely essential that the surrounds are symmetrically placed relative to the listening position. Your receiver will have settings for you to calibrate the distance and volume. Symmetry is good, but I don't see how you can make it work. The low ceiling height is going to make it problematic if not impossible for you to ceiling mount the speakers; I think having the QS8's wall mounted will be a much more elegant approach.
You could put the surrounds on the back wall (spaced wider than the "rear" speakers).
I would try the right surround on the wall to the left of the opening to the office over by the bar.
The left surround is more problematic. At the end of the wall with the cubby door might work, but it might have to be a bit low because of the beam. Or, you could try either side of the door on the wall where the stairwell comes down, but the wall with the cubby door is going to get in the way.
The existing wired speaker locations would work really well if your viewing distance was 6' instead of 12'.
