DIY tips for home theatre projects

Tip 1: Backlight your TV

I know you've been there: you're five hours into The Lord of the Rings marathon (watching the extended versions of each movie, of course), and your head begins to hurt. Your eyes get tired, and you can't understand what it is about those Uruk-Hai that's tiring you out. Well, it's not the movie; it's the lack of lighting in the room. More specifically, it's the lack of depth perception that the darkened room is causing.

When lights get dim, your television begins to "fade" into the back wall. Eventually, as lights go almost out (the optimal viewing environment), your eyes can no longer separate the picture on your screen from the wall behind it; but these two objects aren't the same distance away. If you're still unclear as to what I'm talking about, think about a camera trying to focus on two objects that are different distances away. Just as you seem to focus on one object, the other starts to grow blurry. That is what's happening to your eyes in a darkened room, and eventually, it'll begin to hurt. Your eyes need some way of distinguishing between the wall and the picture, which allows them to focus on just the picture, reducing eyestrain.

The easiest way to accomplish this is to backlight your television. Key to determining what light to use is the colour-rendering index (CRI), which measures light's ability to render pigments (perceived as colour) according to a prescribed standard. Most lights for your house don't even take CRI into consideration, so just grabbing a lamp and sticking it behind your TV won't help much -- in fact, you won't even see a CRI rating on most bulbs. However, you can make a judgment based on the light's Kelvins (K).

Ratings of 5,000K and higher are referenced to daylight, based on different times of the day; 6,500K is best for a home-theatre application. A white light rated at 6,500K will exactly match the white on a correctly calibrated TV set. You can pick up a 6,500K light from specialist hardware and electrical supply stores.

Place this light directly behind your TV set. You don't want the lamp visible, and you'll find the minimal light generated is not at all bothersome; in fact, as the hours roll by, it'll be quite pleasant.

Some nice side effects
In addition to reducing eyestrain, good backlighting often increases the perceived picture quality. Your eyes have a much more difficult time determining colour without any light source. In fact, this is why colours seem so bright when you walk out of a dark room into daylight: your eyes have lost their colour reference and have to adjust. The backlighting will provide just enough light for your eyes to get their colour reference, and you'll find that pictures seem a little crisper and colours more vivid -- quite a fringe benefit.

My light is too bright!
All the benefits in the world won't make you happy if your TV is small and your light is too bright. Suddenly, your lack of eyestrain is coupled with what appears to be an odd glow emanating from your TV; this isn't good. To lower the light level without losing the benefits, just place some aluminium foil over the edges of the light and work your way toward the centre of the lamp until you get acceptable light levels. The foil won't melt, and you'll get the same effect.

NB: If you don't want to go the DIY route, a more sophisticated, but slightly more expensive option would be to purchase a Philips plasma or LCD TV with Ambi light technology.

Ambi light is Philip's back-lighting system built into the rear side panels of the TV that adjusts ambient lighting around the television to match the colour of the content featured on screen. Ambi light can be set for real-time adjustment of light intensity and colour to complement the viewer's television programming or movies. It can also be fixed on a colour choice of the consumer's preference - red, green, blue, white or combination thereof - when the set is on or off. So it can be used for normal ambient room lighting when the TV set is in standby mode. To reduce glare and reflections on the screen, Ambi light technology is also coupled with an external light sensor to determine how much light there is in the room. It then can control the TV light output accordingly. A dark room will trigger less light, whereas a bright room will drive more light output.