Home Theater Projection Screens

in Home Theater Design, Home Theater Projection Screens

So your big TV might be nice, but when you are ready to really step up to all that a home theater can be, you need a projector and a screen. A screen that is measured in feet, not inches! When it comes time to pick a screen, you have lots of choices. At the higher end, you have fully motorized screens with masking to provide you multiple aspect ratios. At the lower end you have manual pull-down screens. Screen Size Screen size is a hotly debated issue in the world of home theater. There are two main groups of thought on this subject. One is that you should try to get the best possible image for your space, even if it means the screen is smaller than your neighbors. The other is that you should try to get the biggest possible screen to maximize your theater and make your neighbors envious! The choice is yours, no one other than you can decide this issue; it must be what you are comfortable with and what your goals are in your theater. For many folks, the way to determine the screen size is to go to your local movie theater. Find your favorite seat. Then, take some time and estimate the screen size, and the distance you picked from the screen. Often the ceiling tiles in the theater will be 2×4 feet, so you can count the tiles to estimate your seating preference. You might find that you like to sit at 1x or 2x the screen width. Knowing your personal preference, you can then take that home and determine your ideal seating distance for the screen width you will use. You normally want the screen to sit so that the audience isn’t looking down, so your screen will sit higher on the wall than you might first expect. If you have one to two rows of seats, your screen will likely end up 24 inches from the floor of the theater. If you have many rows, do not be surprised if the bottom of the screen ends up several feet from the floor of the theater. Generally, you want the center of the screen to be no more than 15 degrees higher than the eye-level of the viewer, with the top of the screen no greater than 35 degrees higher than the eye-level of the viewer. Later in this course you will see a section that discusses viewing angles in relation to seat risers. Many projector manuals also include a chart that shows screen height calculations. There are two related articles, in the Home Theater Learning Library, about screens and viewing. Check them out here:  Home Theater Viewing Angles and Home Theater Viewing Distance Screen Material When it comes to the actual screen material itself there are several more issues to consider. The primary two of these are screen gain and viewing angle. You should account for both of these when choosing your screen. The screen gain, as you will read in a moment, is related to the brightness of your projector. This means you should make your projector and screen decisions together. A single screen will react differently for two different projectors, one brighter than the other, so keep this in mind. Every screen these days has a listed ‘gain’, and can range from low gain to high gain screens. Most of the screens that are white and used in the home theater have a gain of between 1.0 and 1.3. Screens that are gray in color tend to have lower gains, including numbers lower than 1.0, although it is not unheard of for a gray screen to have a gain higher than 1.0. The gain of the screen is measured by noting the reflectivity of the screen material. The measurement is in comparison to the amount of light that is reflected from a pure white board. A screen with a 1.0 gain has the same reflectivity as the white board, while a screen that has a 1.5 gain reflects 50% more light than the white board. Screens that are lower and have a gain of .80 reflect 80% of the light of the white board. These gains above 1.0 are not to imply that light is “added”, only that by using technology in manufacturing, more light is reflected to the viewing position than would normally occur. If you shine a flashlight against a flat white wall, light will be reflected in all angles, even the ceiling and floor. Imagine now that the wall were created so that some of the light that would normally reflect to the ceiling and floor is now reflected towards you, it would seem that there is an increase in the actual light. The measurement itself is taken at the brightest point on the screen, which is usually the center of the screen and perpendicular to the projection source. This is the peak gain of the screen. As you move to the side of center, you may reach a point where the brightness of the screen lowers. The distance you move with the picture remaining bright is the viewing angle of the screen. When you move beyond this point, the picture will continue to get dimmer as you move further and further to the side. While it might seem that you should pick a high gain screen to get the brightest image possible,...