Attic room too small for Hi End Speakers??

I am considering finishing a walk-in attic space from the second floor of my home over the garage. The finished space will have 4 foot knee walls and the ceiling height at its center is 8 feet. The length is 16 feet and the width only 12 feet. Would this room be too small for a high end system. Thinking along the lines of either Wilson WP 7 or the Vandersteens 5's with tube amps.?

I will need to have some acoustic treatments to deal with the slanting wall/ceiling. Is there any special padding for under the wall-to-wall carpeting to reduce reflections??
I am skeptical. What is the floor? I have been in such a room, although it was much larger, and the flexible floor, even with supporting jacks, sucked the bass right out. Try to measure the room before investing heavily.
I have a similar sized space, dimension wise, I'm dealing with right now. The usable length is about 21 feet and it's primarily an office w/ a subfloor amd new HW floors (need to get a rug)/skylights, etc. I'm running a much smaller system than the one you're contemplating - Vandersteen 2CE w/ SS on the bottom and tubes on top. I think with a room your size, you'll wind up doing nearfield listening with larger speakers.

So, it does sound good, plenty of bass, good balance, but there is alot that can be improved via the ROOM. I'm looking into room treatments right now and don't want to go crazy with padding up everything. I've been eyeing eighth nerve and michael green, they seem to have their acts together. Good luck.
i've used soundlabs and WP6s in a room 11* 12; is it optimal? no, but w/ proper placement and sufficient room treatment (!), it will sound quite nice.
I would check the floor joists size, if they are spanning the 12 foot width they should be 2x10 doug fir or better. If not, the joist could be changed to silent floor I-joists or sistered them up to beef up what ever is there. The subfloor should be 3/4" plywood glued to the joists.

The average height of the room sounds like 6 feet, so here possibly you could dormer one side of the roof for a better average height. Raising the entire roof is another, though, more expensive option.

Other construction items to consider are electric(dedicated outlets), AC, Heat, insulation, windows, skylights, doors, rough & finished carpentry, siding, roofing, wall and ceiling sheetrock and acoustic treatments.

I know it's alot to think about and pay for, but for the system you are thinking about, it's best to get the room right before you start moving in with expensive equipment.

One other heads up is that the room dimensions are problematic 16' x 12' x 8'?(average 6'). Room modes are stacking up so that base response will suffer. I would check out the site at Audio Asylum on Room Acoustics and see what Richard(Rives)and the others have to say.

Given all of this, I agree with Lbex2 that its probably best to set speakers up on the long wall. If the speakers are 3 feet off the back wall, 4 feet off the side walls and 7 feet apart, they will be approximately 7-8 feet from the listening position (assuming your listening seat is pinned to the wall). My point is make sure the speakers you select can integrate well in that distance. Best of luck with you plans. Ken

If you can pick up a used pair of Platinum Audio Solo's, you can sit anywhere from virtually touching the speakers to as far back from the speakers as your space allows. The sound is truly full range, without requiring physically imposing appearance. You will have great flexibility in positioning the speakers, and yourself in what seems to be a relatively distinctive, confined listening space.
I have used tube amps as low as 35 watts per channel, although the Aronov LS-960I with 60 WPC provided awesome naturalness, musicality, and bass control.
Check out the Gershman Avant Garde RX 20's for this size room. I have a pair in a similar situation with a Ss amp but have had an EAR 534 pushing it with great sounding results.