THX recommends that when viewing good quality full HD on a 16:9 display, you should be sat between 2.4 x the image height (optimal) to 3.68 x IH (back row).
So, for the optimal seating distance, that would be a 4.2 foot tall, 7.5 feet wide screen - that's a diagonal of 102 inches.
For the back row, it would be a 2.7 foot tall, 4.8 feet wide, 66 inch diagonal screen. Not very big from where you sit.
A 92" diagonal screen will give you a seating distance to height ratio of 2.66 - closer to optimal than back row, so you should be fine, though you may want it a bit larger.
Vertical viewing angle is important for comfort when watching movies for a period of time, so having the eyes fall around a third of the way up the screen is a good rule of thumb to ensure comfort. Lower is OK, but the higher the screen, the more fatiguing it may become to watch. A vertical viewing angle of 15 degrees is recommended, with no more than 35 (viewing from normal seating position height to top of screen).
Originally Posted by elmalloc
Who says Cameron is "right" and why do we care about him so much - lol!
I trust Gary Lightfoot more than James Cameron.