We have a 25 foot by 16.75 foot (by 10.7 foot average height) room that is dedicated to being a home theater, library/study and music listening room. We only run movies in total darkness, except for light that comes off of the screen. Seats for 5 people are permanently placed in a fixed position. My desk is directly behind them, so if we have 5 guests, I can sit in the 6th (centered) seat behind the desk.
We have a true width (not diagonal) 130 inch 'scope (2.35:1) acoustically transparent screen. Of the 10 aspect ratios I counted, our projector can fill the screen (+/-
about1"), top to bottom, with 8 of them, i.e., "common height," while providing the maximum width for Panavision, and most other true wide screen formats. The only fly in the ointment is Christopher Nolan.
To use the TV industry's deceptive metric, the diagonal is about 141 inches.
The center channel is behind the screen and EQ'd so that the screen doesn't diminish the treble, since "acoustically transparent" is a bit like "clean coal." IIRC, the EQ required was only about 1.5 dB to boost at 16 K Hz.
We sit about 12 feet away. Distance from any screen is an important variable, since it, and the screen size and the aspect ratio dictate the perceived size of the image. My friends and I used to use visual height as measured with a detachable viewfinder of a 35 mm still camera to estimate the perceived height of an image on a screen from a given seat in a commercial theater. As is true in most theaters, 'scope is wider, with the same height. When the viewfinder was set for a 50mm lens, the image height that just barely fit in the viewfinder from top to bottom became our unit of measurement. This height could be seen from the 20th row in one theater (a 70 mm venue, with seats that went all the way down to the curved screen), but to get an image that tall in another (a movie palace with a good size gap in front of the front row, an organ that took up a fair amount of space, with the screen placed well back from the front of the stage), we had to move up to the 6th row. Our home theater's common height image is that same height (just fills the finder, top to bottom) from our 12 foot distance.
The projector is a Panasonic.
Our Left Front and Right Front speakers are stock upgraded Klipschorns. The Center is a modified Belle Klipsch. The modification involves a new top hat, making room for the same midrange horn as in the Klipschorns, for uniformity of timbre (all drivers and mid and tweeter horns are the same in all three front speakers). Surrounds are Klipsch Heresy IIs. They are fed by NAD amps (separates) and a Marantz pre-pro, with an Oppo universal player. The sub is a Klipsch RSW 15.
Audyssey improves the smoothness of the response. We use Audyssey Flat for most movies and music disks, and Audyssey (Reference) for a few. The room is moderately treated with absorbers, a rug, and diffusers. The book shelves, books, and art objects provide some additional diffusion and absorption.