My room is 18 x 19' with a vaulted ceiling that goes to 14'. There is tile on 1/3 of the floor space and a brick wall on one side with the wood stove. I've put throw rugs in a few spots including under the Sig IIs and a couple on the side wall. My room does benefit from two large openings on the rear wall. I certainly don't consider the Sig IIs as bright and don't think I've ever heard or read any other opinions that they are. Quite the contrary, Vandersteens are often said to err a bit on the warm, laid-back side. That said, I will offer three warnings:
1) With the AX-7, crazy SPLs are out of the question with a low-efficiency speaker such as Vandersteen. If you're like me, however, you don't require rock-concert levels. My set-up plays plenty loud for my tastes.
2) Break-in takes a couple of weeks. Take the time to dial in the speaker locations, including tilt and toe-in. Be patient (mine went thru' a phase for a couple of days where I thought I had made a mistake) and be sure to fill the stands with sand.
3) The midrange *can* be somewhat veiled depending on cabling. I was able to get a clear, open sound after I bi-wired with two pairs of Ayre Signature cables. That was an expensive upgrade that I would never have afforded except that I was able to get a good deal on demos. A few months ago, Vandersteen upgraded the midrange driver to the same unit as in the 5A (woven cone). Thus, it's possible that the midrange is now more open than with my iteration.
But let me finish by saying that, IMO, the Sig IIs are the best speaker in their price range. I think that you have to spend multiples of their price to get appreciably better sonics. Stuff like the 3A Sig and, maybe, Thiel 2.4, Avalon Idea, etc. *might* be a bit better. But if I ever upgrade, I want it to be a notable jump. I'm thinking Vandersteen Quatro or Thiel 3.7 or Vivid B1 will be needed to get to the next step. Those products are out of my budget for now.