I'm with you on some level, as viewing distance is, IMO, the most overlooked aspect in our bigger is better world. However, Christer is right on THX spec w/ his screen/seating distance. As long as he's watching high-res material on good equipment, it'll look fine. In the end though, unless you have a acoustically transparent screen and have positioned speakers behind it, you'll likely be sacrificing acoustics for image size in THX spec.
The rule of thumb that I use is seating distance should equal 2 times the 16:9 screen diagonal. Now, THX specs will tell you that this is way to small. Check out this calculator here:THX Seating Distance Calculator
I currently sit 7.5 feet away from my 51" screen, a little closer than 2x the diagonal. THX tells me that I should either be sitting less than 6 feet away, or that I should have a 67" screen. But I won't bemoving closer, or buying a bigger TV, and this is why.
Let me start by saying that I'm throwing out approximate numbers here, just working off the back of a piece of scrap paper. I'm sure my math is a little off with rounding and what not, but close enough for our purposes.
Speaker placement: Dolby recommends front speaker placement 22-30 degrees off center. THX suggests similar placement. Many opinions that I've read say that for movies, you should shoot for the 22 degrees, for stereo music, the 30. Break out our 11th grade trig books and we see that the distance between speakers should be between 0.8 (for movies) and 1.15 (for music) of the seating distance.
My screen is about 45 inches wide, with the bezel my TV is 48. On my fronts (JBL S38II), the tweeters are atleast 14 inches from the side of the speaker. That means that if I butt the speakers right against the edge of my screen, the tweeters are 73" apart. Realistically, leaving an inch or two in between, we're at 75-77". At my THX recommended seating distance of 5.7 feet (68.4 inches), the tweeters of the speakers should be between 55 (movies) and 79 inches (music) apart. That doesn't leave a lot of wiggle room, and I found that in my room, the 79" was even too wide for music. I also needed a wider sweetspot, as I'd be watching most movies as at a pair, not a single.
So what did I do? Buy smaller speakers? Nah, I compromised. Good sound was more important to me than the biggest picture image (especially considering that I won't be watching HD exclusively, but also a lot of upscaled and processed 480P). I spent a lot of time listening, and moving, and listening, and measuring, and listening, and moving, and listening some more.
So, long story short, I postioned my speakers correctly and use a rule of thumb that you should sit slightly less than 2x the screen diagonal away from your display. No complaints yet.
Christer, with your current screen size, you'll probably be sacrificing acoustics for screen size. If that works for you, don't worry about it. Do what you can with your current setup, and sit back, and enjoy. However, if you want to improve your sound, positioning everything correctly is the start.
Originally Posted by Felgar
IMO the solution for you is to make the screen smaller. A large screen is not necessarily better.