If I have a room with interior dimensions of about 13 feet wide, 19 feet long, and 8 feet tall, is it worth looking at a CIH screen?

My previous screen was 16:9 104", so it would take about a 132" 2.35:1 screen to get the same height as I had before, but I would gain a lot of width.

Anyway, with my M60 fronts needing some room to breathe, and the desire for bass traps in the corners, could a 132" 2.35:1 CIH screen even work? I am not opposed to framing something up that actually is forward a little bit from the wall behind the screen to give the bass traps more room, but I am just wondering for my planning of V4.0 of the theater.

Seems like you'd need to do a calculation on viewing angle, too.

i.e. (and I know this is un-American), bigger may not always be better. You could get to a point where - at your viewing distance - the screen so wide that it requires you to move your eyes or head "too much" to enjoy the image.

Seems like there is a calculator out there somewhere. THX?

You can beam the image from your projector on your plain wall to get an idea of how big it will look, and build the screen later. My 2.35 screen is 10ft wide, and sometimes when sitting in the front row on fast action movies you find your eyes darting around to much. Now that my room is going to be smaller, and the front row closer, I may reduce the size of my screen a bit. Haven't decided on aspect ratio yet, but since the new panny's have auto AR adjustment, I may stay with 2.35.

Randy, how close are you to your screen? Because my plan is to put a 10ft wide screen in a room that's 11 to 11.5 ft wide. I'll be sitting about 10-11 feet back.

Apparently, THX says 40 degrees. FWIW.

The front row used to be about 12ft back and at times if you were watching a movie that was full 2.35 ratio, and had a lot of back/forth fast paced action, your eyes would have to dart back/forth and could often be to much. Standard DVD ratios are fine, just the full screen stuff. Slower paced or "chick" flick type movies are fine.

With my new setup I have to move the seating about a foot closer, so only time will tell, but I might redue my screen size a little to accomodate for the closer seating. The back row is fine for all types of movies.

OK. So how far back is 40 degrees if the screen is 122 inches wide? I have the ability to make the room deeper since it is currently unfinished basement space.

I need to work up some geometry I guess...

122" wide would give you about a 133" diag, slightly bigger than my screen Nick, which you've seen. So using Tom's link dividing the diag by .84, so about 13ft back. But, I am not sure THX is looking at 2.35 screens, this might be for 16:9 images. In either case, that might be a huge screen for your room.

Good catch, Randy. Obviously, THX is using a 16:9 ratio to calculate the screen width, which is what really matters here. But I'm not sure that the given formula becomes invalid. There is a separate one for height (15 degrees).

Like Randy said, I think THX provides an optimum viewing distance for a screen that size of a little over 13 feet away (which might be fine for your room, eh?). People who sit appreciably CLOSER than that will have more than 40 degrees of horizontal image to process, which might be "too much".

I mean, seriously, 11 FEET diagonally? You guys make me sick.

I currently sit about 14.5 feet back from my 106" 16:9 screen and like the height of it, but could definitely be OK with wider. Just not sure by how much. Of course, since I have 2 of the 4 walls that I have to build, I have some flexibility with the depth if need be. Max depth of the room is about 26 feet. My wife would like it to be about 20 feet max. I was going by the "golden ratios" for home theater sizes and my height and width are set to about the maximum that they can be.

When figuring max width, you should really figure that width using 16.9 dimensions, not 2.35. Vertical screen height will have more of an effect on your vision (negative) than width.

I sit 12' away from a 8' wide 2.35 screen. I sized my screen for a 'comfortable' vertical height and have been extremely happy with it. Some folks bitch about the black bars to right / left when not viewing 2.35 material, but if your room is dark, I don't mind at all. Certainly not enough to spend the money and curtains.

Be advised that 2.35 CIH set ups do come with extra costs. I think they are worth it, others don't....