"Funny Quicke!"
Actually Lokie, just for your info, seeing that it sounds like such a large entertainment room would be, just that, large, I thought I'd mention that you really wouldn't have to work to hard on the acoustics of such a place!
If you simply had a low pile carpet floor(no pad is probably good), you would have to do very minimal acoustical work in that room to make things sound good all around! that room is goign to have a long reverb time in the midrange/trebble, and aborb a lot of bass. You want to balance the lower reverb time in the bass, by absorbing the mid/trebble reverb with pannel absorbers spaced out around the front and sides of the room a bit specifically.
In such a large acoustical space, you could simply concentrate on putting pannel absorbers spread out all around the front/sides of the room between you and the front speakers. Also, some on the ceiling are good, but not as critical. Also add some diffusion, maybe a few absorbers on the back wall. (more absorbers in front, more diffusion in the rear). IN such a large space, you just want to balance out reverb between bass and mid/trebble, and your good. Doing what I suggested would do just that. It would also break up first reflections from many listening possitions, which you will likely have in a game room with unspecified seating(if applicable). Also put aborbing pannels directly behind main speakers on front wall, with spacing in between. Your overall balance should be good, and you shouldn't have a slap echo problem, and good overall imaging with the speakers out away from the walls. Also, get enough subwoofers for the room(2 large one's at least are adequate). I'm assuming at least a 25x25 foot room with vaulted ceilings here, right? If so, your bass modes(although don't have 25x25 exactly) will be stacked up, frequent, and no so much of an issue as with smaller rooms. So you're good. I'd just concentrate on pannels(see HT magazine's previous issue, which I think was Feb or March, entitled "the ultimate Echo chamber".
Use something like large Def Tech BP2000tl's with powered subs built in, and you shoudl have some excellent HT sound(f you use dipolars/bi-polars don't put absorbtion behind speakers however!).
This ends my quick acoustical assesment of your potential room.
With this simple approach, and proper gear/setup(just keep speakers away from walls in front a bit out in room) in that room, and you will be fine. Again, in such a large space, with so many listening possitions likely, many many speaker, seating locations will be good/possible! So, if your thinking major acoustical consultation, the basic one will do just fine...it's smaller rooms and more critical set up rooms that require a balls-to-the-wall" engineering from each seat, etc. good luck if you really do this room!
