Originally Posted by Dr. Gruv
COMPLETE Newbie to the home video thing...
I'm an audio guy and have that part down
Here is my space:
L 17.5 ft. - W 13 ft. - H 17 ft.
So this projector looks like an excellent start...
Do you have to get a screen? I've been looking at the The Elite ezFrame R100H1 (100" diagonal) I have flat white wall paint on now...
What would the best screen size for the room?
How far should the seats be away from the picture? My chairs are at 15 ft. and a couch on a side wall is closer... but not much watching from the side couch...
A 17 Foot ceiling?! - you are going to have problems. If you ceiling mount your projector, the top of the undistorted picture will be 1 - 2 feet below the lens of the projector depending on offset and distance (see lots of threads on this topic). If you tilt the projector to match your screen, you will end up with a "keystoned" (trapezoidal) picture. This can be corrected by the projector, but that process degrades the image somewhat.
You might want to hang a platform in the middle of the room (as someone said "like a pinata"). Otherwise, it probably needs to go on the back wall, and that will require a large screen. Optoma has not yet posted the full manual for the HD73, but it has a basic screen size calculator for the HD72 here
that you can use in the meantime. With a projection distance of 17.5 feet, you are looking at a minimum
screen size of 127 inches diagonal. Wow. Nice if you can do it, I guess. That means 111 inches wide, which with a 36-degree vewing angle (see below) means you sit 14.2 feet back (if my trig is right) - so might be Ok for you.
I think you really want a screen - even if it is just fastened to the wall. There are tons of posts on AVS about DIY screens using special paints, MDF boards, or real screen material stretched over a frame (you can get a good price from AVS) , or you can buy one ready-made, as you mentioned. I like pre-tensioned as opposed to pull-down, but each has its advantages.
There are a lot of interdependent variables. Most people want the biggest screen they can get, for bragging rights, but the important thing really is viewing angle. You don't sit in the front row at the cinema. Viewing angle, seating distance and screen size all vary dependently.
THX recommends 36 degrees as the optimum viewing angle for actual movie theaters; they also recommend that you sit with your eye about 1/3 of the way up the screen vertically. I used those numbers to size my setup (in a smaller room than yours)
This site also has a useful calculator.calculator