Screen Size & Viewing Distance

SMPTE recommends about a 30 degree viewing angle; THX prefers 36 degrees. Screen width times 1.5 to 1.9 gives a good seat distance.

A 120 inch 16:9 screen (about 105 inches wide) works well from roughly 12 to 15 feet. Sitting closer than the low end of that range shows pixel structure with 1080p sources.