Selecting a Video Display

It used to be that a tv was a tv . . .

Whether it's a flat-panel TV, an old-school CRT TV, or a digital video projector, your video display takes center stage at the home theater.

Video-Jargon Jungle

Advances in display technology have unleashed a crazy quilt of competing video display types. Each display type has not only has its advantages and disadvantages, but it also has its own perplexing acronym such as DLP RPT, just to name one. Yoinks!

These days you not only have to worry about the type of display, but you also have to worry about which type of programming you want to watch and -- especially if you want to watch the new higher definition formats -- which TVs will play which types of programming formats.

But fear not. All of the displays can be classified into a few basic types. This lesson will discuss each kind and will also look at support for high-definition video. It'll conclude with advice about how to make the final judgment about which picture suits you best.

The Sky's the Limit

It's an especially good idea to have your budget in mind before you do too much investigating on the video front. This is because the upper price limit of displays is in the stratosphere -- if you're so inclined you can spend more than $30,000 on a front-projector! The good news, though, is that the competing technologies have driven the prices down on many regular models, and you can get very good video TVs for a reasonable amount of money.

Video-Display Formats

Here's a quick look at the types of video displays:

CRT TVs
LCD (liquid crystal display) and plasma TVs (also known as flat panel TVs)
Rear- projector TVs
Front-projector TVs

CRT TVs

This is your parents' TV, sort of. The old cathode ray tube TV. CRTs are built around a large vacuum tube, which makes them bulky and heavy (and makes them implode when dropped off buildings on Late Show with David Letterman). The larger they come, the deeper the tube has to be, and these types of sets max out at about a 38-inch screen. (There are also CRT projectors that display at a larger size; those are discussed alongside other video projectors later.)

Be aware that television manufacturers measure screen size diagonally across the screen to make sizes sound bigger.

Despite their bulk and weight, CRT TVs have become quite affordable compared to the newer display formats. CRT screens often have a greater color range and contrast than flat-panel TVs. When looking at CRT TVs, notice that some have flat screens and others have convex screens (like old-fashioned rounded-screen TVs). Flat screens are generally more expensive but are also more pleasing to watch and are better at reducing light reflected in your viewing room.

Flat CRT screens are not the same as flat-panel displays, which are discussed on the next page.

LCD and Plasma: Flat-Panel TVs

LCD and plasma TVs are still in their adolescence, but are transforming the television industry. The main advantage of these TVs is that they're thin -- just a few inches deep -- and lightweight compared to conventional televisions.

Both of these types of TVs are advancing rapidly and becoming available in larger sizes, from big to huge. The following sections cover the pros and cons of both, but the fact that they come in elegant thin designs that can be hung on a wall without dominating your viewing room can be a major advantage.

Another sensory trick: In a test of video resolution, subjects thought that flat-panel TVs had higher resolution than bulkier CRT TVs simply because the thin, wall-mountable design of the LCDs is more pleasing to the eye than the bigger CRTs.

LCDs

LCD screens are what you see in laptop computers and are now available as thin flat-panel TVs. LCDs have some disadvantages, but many watchers extol the virtues of their elegant thin design.

LCDs are more expensive than plasma screens, but it's expected that LCDs will emerge as a dominant format and become less expensive as more television factories shift to producing them and away from older screen types.

Sometimes, especially for less expensive LCDs, you can notice the grid of pixels (the tiny little dots of color that make up the picture) on the screen, which makes it look like you're looking at the picture through a screen door (known, not surprisingly, as the screen-door effect.)

LCDs don't have as strong a contrast as other displays (sometimes black can look more like a dark gray), and it's possible for some pixels to go bad and show up as blank (which cannot be reversed).

Plasma

Plasma TVs look somewhat similar to LCD TVs although they operate on a different principle, which involves gas sandwiched between two panes of glass. Plasma screens have deeper contrast and brighter brights than LCDs, and go to larger sizes (as big as 80 inches!).

There are some drawbacks to plasma TVs, the main one being that they're still expensive. A plasma TV costs several times what the same sized CRT TV costs.

Sometimes you can see color trails behind some kinds of on-screen motion and what are known as digital artifacts, or little visible ghosts that don't belong in the picture. Screens can suffer from burn-in, whereby an image that shows up repeatedly (say the ABC television logo) actually burns itself into the screen so that you see a semblance of it even when you're on another channel.

Rear-Projection TVs

If you want a large-screen TV that won't break the bank, consider the new wave of rear-projection sets, or RPTVs. They're not as thin as plasma or LCD screens, but they generally display an excellent picture in a package that's often not as bulky or as heavy as CRT TVs. Often, these televisions are designed to sit on the floor.

Rear-projection TVs project the picture onto to the TV's opaque screen from inside the box. When you watch the picture from the viewing side, it looks like a big, flat TV screen. These may not be as sexy as the wall-mountable large plasma and LCD screens, but are good-looking and are more affordable.

The confusing aspect of shopping for a rear-projection TVs is that they use several internal projection formats: CRT, LCD, and two new formats called DLP (for Digital Light Processing) and LCoS (Liquid Crystal on Silicon). The reason for all these standards is that different television manufacturers are promoting different standards, and it's not yet clear which will win out. Let's take a brief tour of these different types:

CRT rear-projection TVs: The bulk of rear-projection televisions are CRT-based and have a light for projecting each of the primary light colors of red, green, and blue. The three colors are aligned just right so that they combine into one picture. CRT models can suffer from burn-in. They're also heavier and bulkier than the other types.

LCD rear-projection TVs: LCD rear-projection sets are good-looking, thin, and use the LCD technology. They also can share regular LCD screens' lack of dark blacks and lower contrast than other screen types.

DLP TVs: DLP rear-projection TVs are more expensive than LCD TVs, but offer better contrast and representation of very dark colors. They're also slightly more expensive than LCD models.
LCoS models: These are a little pricier yet than DLPs, but also offer exceptional picture quality in a not-too-bulky box.

Front Projectors

Just like at the movies, front projectors project an image from the audience-side of things onto a stand-alone screen. Basic projectors have come way down in price over the last couple of years, but still are not cheap. The expensive end of the spectrum can bring you brilliance for a price -- the higher end can cost more than $30,000.

Front projectors are not for everyone. They're more susceptible to light interference than other kinds of display (lower-end projector pictures can be rendered unviewable by direct sunlight). They require not only that you have a place to mount the projector (from the ceiling or in your seating area), but also that you buy or prepare a stand-alone screen to project onto.

On the other hand, there's something about the experience of watching a front-projected movie that makes it feel just a little more like the movie house.

Higher Definition

Color television was first introduced to the masses in the 1950s and 1960s, and in the intervening decades, the resolution of the picture that you see did not improve significantly. Television sets had a certain number of horizontal scan lines that would get painted by an electron gun, shooting electrons onto phosphorescent elements on the screen that would glow in colors. The lines (these are the horizontal lines you can see on your TV screen when you look up-close) get painted and repainted so fast that the entire screen refreshed faster than you could see it, giving you the illusion of the moving picture that brings TV to life.

The number of lines on a television screen remained constant for decades. Now, however, this is all changing fast. TV shows filmed at the standard lower resolution can only be viewed at that resolution, but movies and new higher-resolution shows are bringing unprecedented picture clarity to screens near you. Enter HDTV.

High-definition television displays more than twice the visual information of regular-old TV, and this makes video look significantly more crisp and lifelike.

To display HDTV, you need both a video display that can handle it, and a digital tuner to interpret the high-definition signal and send it to the video display. Most TVs that can display HDTV now are HDTV-compatible, meaning they can show the picture but do not include the tuner.

This is usually for the best because the technology for getting an HD signal is just emerging and it will be easier to change your tuner later than having to replace your whole television.

HDTVs don't display more visual information than old school TVs, but use a technology called progressive scan to smooth out the picture even more.

If you want to watch HDTV, you also need an HDTV source, which can be cable, satellite, or broadcast. Coverage is still spotty so investigate through your local cable company, satellite providers, and broadcasters.

How to Decide

Each kind of video screen -- CRT, the various rear-projectors, LCDs, plasma screens -- have a different feel. Some criticize LCDs as being too pixelated, which means you can see the little dots of color on the screen, whereas others don't mind a bit; some need a flat screen for video bliss, others don't mind a rounded CRT. Some people complain of a rainbow effect on some displays screens where you can see individual colors when you're supposed to see a blend, but only a small percentage of viewers even see them.

The bottom line here is that there's no formula to find the screen that is right for you. It's a good idea to go to an electronics retailer or a specialty home theater store and spend some time looking at the different types of displays. If you can go in the middle of the day on a weekday, you'll have to fend off more salespeople but you'll be able to concentrate without the weekend crowds.

TIP - If you have friends who have big-screen TVs of one type and another, invite yourself over for some watching and ask them what they like and dislike about their TV.

Another element that you should be aware of is that TVs do not uniformly have the same proportion of height to width, or aspect ratio. The key to making sure your picture doesn't look squished this way or that is to buy a TV that has aspect ratio control, where you can alter a program to fit correctly on the screen.

Finally, think about whether your watching habits help you determine what kind of TV to buy. If you love sports, you may want a set that can play multiple channels at once so you can keep track of all the games. If you're a hardened movie-lover, perhaps a front projection screen will give you that special feeling. You say you just can't stand a cluttered room? Flat-panels are pretty elegant and out-of-the-way.