Rear Projection TV Buying Guide

Rear Projection TV Myths

If you owned one of the early rear projection HDTVs, you might think you need a ton of floor space and the time to fiddle with the settings to make it work. Not anymore. Rear projection TVs utilizing DLP or LCD technology average a depth of about 18 inches for screen sizes up to 73 inches diagonal, and they don’t require convergence adjustments.

The viewing angle on a rear projection TV is still more limited than that of flat-panel sets. Rear projection TVs look their best from a chair or sofa straight ahead of the screen. The horizontal viewing angle of rear projection TVs is typically less than 130 degrees. Vertical viewing angles vary between rear projection TV models, but you’ll get the best picture while seated.

Rear projection TVs are heavier than plasma or LCD flat panels, weighing up to 200 pounds for the largest floor models. Even a 50” rear projection TV can weigh 40-60 pounds, so you’ll need a sturdy stand.

Rear Projection TV Technologies

All rear projection TVs are self-contained units that shine an image on the inside of a plastic screen. These screens are fragile, and a scratch can distort the image, so it’s a good idea to keep pets and children away. There are four types of rear projection TVs, each with strengths and weaknesses.

CRT - Cathode Ray Tube rear projection TVs are still being made, but the technology is less common today. These sets use red, blue, and green picture tubes to create the image. CRT rear projection TVs are heavier and have more front-to-back depth than other technologies. They also require periodic convergence tuning and are very susceptible to image burn.

DLP - Digital Light Processing comes in two forms: single chip, which uses a spinning color wheel to add the color information, and three-chip, which has a separate chip for red, green, and blue. In both of these rear projection technologies, a tiny image is bounced off a chip coated in millions of tiny mirrors. These rear projection TVs deliver a sharper picture and excellent black levels. A small percentage of viewers are sensitive to the color wheel used in these rear projection TVs and experience an effect called “rainbowing.”

LCD - These rear projection TVs have three tiny liquid crystal displays (one red, one blue, one green) that a lamp shines through to create the image. Because the source image is so small, an LCD rear projection television has fewer problems with image blur or ghosting than a full-screen LCD flat panel. Noted for their vivid colors, some LCD rear projection TVs suffer from the “screen door” effect, where the grid that separates the pixels appears on the screen. As with rainbowing, some viewers are more sensitive than others.

LCoS - Combining elements of LCD and DLP, these rear projection TVs shine a light through the LCD chips, off a mirror, then back through the chips to the screen. The resulting image has more vivid color, but advances in standard LCD technology are making LCoS less common in rear projection TV.

Things to look for

Lamp life and replacement cost should be weighed for any rear projection television. Lamps can cost in excess of $300, and the average life ranges from 3,000 hours at the low end to 20,000 hours at most. Rear projection TV manufacturers are experimenting with light emitting diodes (LEDs) and lasers to eliminate the lamps, but these technologies are a few years off.

If you’ll be playing video games, avoid CRT rear projection TVs. Their tubes are easily burned by static images, leaving a ghost of the image permanently etched on everything you watch.

One big plus on rear projection TVs is their superior sound systems. While it’s seldom worth paying for sound on flat screens, some rear projection TVs can match the performance of higher-end sound systems and double as your home theater receiver.

Look for a rear projection TV with a high contrast ratio. This number, typically expressed in a thousands to one format (6000:1, for example), tells you the difference between the brightest white and the darkest black. A rear projection TV with a higher contrast ratio always delivers a sharper picture.

Rear Projection and HDTV

2007 saw the introduction of rear projection TVs supporting 1080p. Useful if you’re a videophile with a Blu-Ray or HD DVD player, 1080p is not currently in use for television, so it may not be worth the extra money. Let your eye be your guide—most viewers are happy with 1080i or 720p resolution.

To get the most HDTV out of your rear projection set, look for one with multiple HDMI and Composite Video inputs. It’s always worth it to have more than you think you need.

At a minimum, choose an HDTV with an ATSC digital tuner that can receive HD broadcasts, and an NTSC tuner that receives standard analog broadcasts. You can get by with an HD-ready rear projection TV if you know the set will always be hooked up to a cable box, but you might miss out on local HDTV programming. Rear projection TVs with QAM tuners can decode encrypted cable signals. You won’t get free cable, but you might be able to control cable channels with the rear projection TV’s remote, cutting down on the side-table clutter.

Screen Size

Rear projection TVs offer superb image quality at larger sizes, but don’t buy more set than you need. A good rule of thumb is to measure the distance from the front of the set to where you’ll be sitting and divide by 2.5 to get the screen size.

Need to know more?

• How Projection Television Works
  http://electronics.howstuffworks.com/projection-tv.htm
• Rear Projection TV Technology Primer
  http://www.hometheatermag.com/advicefromtheexperts/707rptvprimer/
• Display Technology
  http://en.wikipedia.org/wiki/Television