Well, I'm building out the room in my basement, so my measurements are not "exact" as of yet, but it will be pretty close to 12' x 19' x 7'6". The ceiling height varies because of support beams and HVAC equipment. Some parts are 8', some are 7'.
I'm happy to hear that the responses are so overwhelmingly in favor of the M22s and its capabilities. I was also quite impressed with the response I received from Axiom directly. So, things are looking good! I'm looking forward to adding the 22s with the 150 and the QS8s. I may opt to do the 22s and the 150s in the "on-wall" version as that is primarily what I'm looking for. I may have to add a pair of smaller bookshelves to my office as well.