About 1.5 screen widths is required to achieve an acceptable sense of immersion. This is no bigger than the subtended field of vision in the farthest seat from the screen within a decent THX certified commercial theater.
I run a 9" CRT projector (no visible projection artifacts) on an 87x49" screen (100" 16:9 diagonal) with seating at 11'. This is small for nice DVD scope transfers, a little large for lower aspect ratios, and the best compromise for a standard screen shape. I'm leaning towards a change to 101x43" constant height.
Also note that it is impossible to visually resolve 1080 line HD sitting beyond 3.3 screen heights (about 1.8 widths).
I run a 9" CRT projector (no visible projection artifacts) on an 87x49" screen (100" 16:9 diagonal) with seating at 11'. This is small for nice DVD scope transfers, a little large for lower aspect ratios, and the best compromise for a standard screen shape. I'm leaning towards a change to 101x43" constant height.
Also note that it is impossible to visually resolve 1080 line HD sitting beyond 3.3 screen heights (about 1.8 widths).