Lovely room. My former home had a dedicated custom built listening room 25X23X11.5 max vaulted ceilings. My current (and final) home has only a 20X15X10 dedicated listening room which is decoupled except for the ceiling which has only 2X8 beams so I couldn't build-out my 16" to 17" thick wall/door structure. It does have a 12" thick, 3000 psi steel reinforced floor. (Construction visible under Fleschler on Audiogon).
Because of my speakers (and system) I don't miss having the larger, more spacious room for sound. The built-in bass traps in the walls help.
Yours looks fantastic with ample seating (I have only 5 seats across) and multi-purpose use.
