I thought of the trapezoid room shape design as well. Many sub cabinets have that shape. I do not know if reviews have been been as to the perfect room shape and size. I believe commercial theaters have rectangular room shapes. From a CEDIA training seminar I attended in 1995 by Russ Herschelmann entitled "Home Theatre: Essential Elements" "The right room: Room size: 1000-CF (figure cubic feet Lx Wx H). Room shapes: a. rectangular preferred, b. dimensions should not be multiplies of each other (e.g. 8x16x20, 10x16x20, 8x14x28-are all bad!)
Other room shapes in the real world: square (bad), circular, bay windows, L-shaped rooms, the killer: open floor plans (kitchen/family room, etc.) Openings to other rooms (e.g. archways) increase the acoustic volume of the space, since the subwoofer "sees" the entire room area as ONE ROOM. Rooms that have arches/openings/alcoves to other rooms (with no doors) will require significantly more bass energy (both in raw drivers and amplification) than a room where you can close doors. In a medium-sized house with archways or no doors between the theater and the rest of the house, the theater could be well over 20,CF or so an absolute nightmare for bass reproduction!" (Herschelmann, 1995)
He goes on to suggest ways of dealing with odd shaped rooms and the key he said was to achieve balance. From what I critically read from his findings is that acoustic and light pollution problems occur with other than a proper room shape. I had a friend, just Sunday at church ask me if a round room was the best. I said it feel into an odd shaped, unideal room shaped acoustically. He said he meant a sphere room. I asked him how many times you see a sphere room. I can't answer if a sphere room is good, but round shaped room seem to not be ideal.
