TV VIEWING DISTANCE QUESTION

I have a 50" Plasma at just over 10 ft. and at first it seemed huge but now we are all used to it and it seems just right. I think 56 would be great at 11'6".

The headaches may not be due to the screen being big. Generally, the headaches are a result of getting used to another stimulus, whether it be the "sudden" change in screen size (going to a much bigger screen or a smaller screen than what you are used to), a brightly lit screen in a dark room (which you might not be used to), or some type of display artifact (plasma, LCD, and DLP each have their own types of artifacts). Sometimes you get acclimated to the change after time, and sometimes you don't (could you ever get used to listening to a "bright" system?).

The "accepted" values ave already been posted. 3:1 for TV viewing, and 2:1 for movie viewing. You could even go a step further and use 1.5:1 for high definition movie viewing (720p, 1080i, 1080p). But 2:1 or 1.85:1 is a nice distance to shoot for with movies.

But I can help but comment on something here. I do see a number of audiophiles seem to take pride in bucking the trend with videophiles and shooting for longer viewing distances and smaller screens, and being proud of that fact. That strikes me as odd. It's almost like a reverse snob thing. But then again one also sees similar parallels with non-audiophiles. One complaint from that side is that audiophiles listen to music "too loud." That's not meant to be overtly conclusive, but rather just a passing observation.

My point of reference.
-In the theater I sit 1.5 times the screen width back from the screen (about row 5 or 6).
-At home, I sit 1.85 times the screen width from a 800x600 front projector
-watching TV at home, I sit about 4:1 viewing distance (bedroom). it was about 3:1 when we had a bigger TV, which was sold for financial reasons.
-I listen to classical music between 60-72dB. And rock 68-76dB.

It really seems odd that a 42 inch at 11 feet, which is over 3.5:1 viewing distance, caused you that much problems. Your 34 inch at 11 feet is about 4.5:1. If anything, I'd think it was due to some other stimulus (alcohol, food, unfamilar setting, poor source material, display or display technology artifacts, too bright, too dark, etc). Or just the fact it was a sudden screen change in side (if that's it, you will get used to it after a while). Or maybe just laugh all the way to bank with a smaller screen. I dunno.

Aaron

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).

Re KJL: I doubt screen size had anything to do with the headache, but an obvious answer is to watch another movie at the friend's without ingesting anything.

We sit 92" from a Sony 36 XBR as a compromise set by an equalateral triangle determined by the separation of the front LR speakers. That's a ratio of 2.5, a bit too far away to be immursed in the picture. Although that's a near field listening configuration for stereo, I prefer listening at my desk chair, a bit over 11' from the center line of the speakers. An obvious solution for movies and HDTV is front projection, but I need to figure out a way to accomodate TV without running through expensive projector bulbs or sitting in a dark room.

db

As others have responded, light, flickering or sudden changes in light to dark can stimulate headaches. Also keeping your eyes focused on a single point for extended periods that are different than your usual focal length can do the same.

With respect to screen size, use your own subjective experience and taste. Going by the numbers is a good place to start, but you may find a smaller screen to be more comfortable if you regularly experience headaches. Room decor can also be a big difference. If a 42" screen is mounted on a dark background, you may get the same immersion as a larger screen on a light-color wall. I recently made this change, and the difference was spectacular.