My wife and I are in the process of finalizing the plans for our new house. It will be located on the 2nd floor, above the attached garage, and the dimensions ar 15X20 feet, and with 9 foot ceilings). Plans are below. You have to step down at the entrance; the HT floor will be 1 foot lower than the floor of the hallway. I anticipate having 2 rows of seating, and the 2nd row will be stepped up. The screen will be on the 15 foot wall at the top of the picture.
At this stage of the design, I can't move the room or make it bigger but I can choose to close off open areas with wall and doors - and that's one thing I'm seeking advice on. The biggest issue I see is the study. I'm thinking the best thing will be to put in a single door that is as close to the center of the back of the theater as possible (but it won't be dead center). This should help with placement of the rear speakers. I also think I should place a door at the opening from the hallway - to keep the left and right walls similar, and also to help with sound isolation from the rest of the house.
The other thing I'm not quite sure of pertains to placement of the seating. The level of the second row will be the same level as the hallway - which could become awkward because of where the entrance is located. I'd appreciate any ideas you might have about this.
Is that the only space you have available for a theater? Above the garage? I ask because I did the same thing, in Michigan, and temperature swings were ungodly. I can't imagine how hot it might get for you in TX in that room. Are you planning on doing a proper load calc for the room?
My bonus room was added a couple years after my house was finished so I really couldn't plan the HVAC for it.
Another thought is can the bed location of the lower bedroom be moved to another wall?
The theater door could stay where it was, and use a simple opening into the theater. That way, there is no door swing and seating
clearance issues to deal with. Once again, you enter the theater at riser height.