One of the most critical elements of home theater design is the screen. But for many shoppers, deciding how big a screen to buy usually boils down to settling on a budget first, then comparing TVs from trusted brands within that price range and opting for the one with the best mix of features and size. In the end, though, many new TV buyers eventually end up wishing they had saved up for a larger display.
To ensure that consumers get the most impact and immersion from their displays (and to ensure that viewers can actually appreciate the resolution of 1080p HD), two different organizations have developed recommendations for screen sizes relative to viewing distance.
- SMPTE (the Society of Motion Picture & Television Engineers) recommends a minimum viewing angle of 30 degrees.
- THX (yes, they do more than just create seat-rattling trailers) previously recommended a 36-degree optimal viewing angle for TVs, and 40 degrees for home theaters with projection screens. But with the advent of 3D in the home, THX has started suggesting 40 degrees for all home viewing.
There's no need to bring a protractor with you when shopping for a new display, though. It's easy enough, with a little math, to convert these recommended viewing angles into something that makes more practical sense: diagonal screen size in relation to viewing distance.
To find SMPTE's recommended minimum screen size for your room, measure the distance between your seat and the empty spot you plan to fill with a TV (or projection screen) in inches. Multiply by 0.6, and you'll be pretty close-taking into consideration that screens generally only come in a finite number of sizes. For THX's ideal screen size, take that distance in inches, and multiply by 0.84.
Let's say you sit five feet away from your display. According to SMPTE's guidelines, you should be shopping for a TV at least in the 36-inch range, and THX would recommend up to a 50-inch display.
Move a little farther back, say to eight feet, and SMPTE would suggest at least a 58-inch TV, whereas THX would recommend up to 80 inches. And at that point, you may way to start giving serious consideration to a projection system instead of a TV.
That doesn't mean that bigger is always better, though; sit too close to too large a screen, and you'll start to be distracted by the pixels in the image, even with the best of high-definition sources like Blu-ray.
And these guidelines generally work under the assumption that you do most of your movie-watching on Blu-ray. If you stream the bulk of your movies via the internet, a larger screen is going to make the lower resolution and increased video artifacts of such sources more noticeable. And if you plan on building a more multi-purpose media room, it may also make more sense to stick with SMPTE's smaller size recommendations.
Or, for the ultimate in flexibility, you could opt for a multi-screen system, with a smaller TV for general use, and a drop-down motorized screen for a more immersive movie-watching experience. Your local CEDIA home technology professional can talk with you about how you use your room and the type of content you watch the most, and will work with you to determine the optimal screen size and type for your home theater system.