Pondering Your Next TV

Like many Connected Home readers, I've started looking at TVs again. As my wife is fond of pointing out, we don't actually need a new TV. But it's pretty clear that, after years of empty promises, TV makers are finally starting to adopt the digital, wide-screen, high-definition formats that will make DVD movies look low tech by comparison. I'm still some months away from a purchase—the completion of our basement-refinishing project pretty much guarantees that—but here's what I've learned so far.

Today's TV Technology
Until fairly recently, consumers had only a few choices when it came to purchasing reasonably priced TVs: the familiar direct-view sets (which essentially use the same picture-tube technology as the earliest sets) and projection TVs (which ship in rear- and front-projection varieties). I own a couple of TVs that represent both technologies: a 4-year-old 43" rear-projection set that still provides surprisingly good picture quality, albeit it in the old 4:3 screen format, and a 27" direct-view TV that sits largely unused in our bedroom.

Today, the choices are much broader. First, many TVs now support 16:9 or similar wide-screen aspect ratios, providing for a theater-like viewing experience with the appropriate source material. With newer high-definition television (HDTV) picture qualities available, old-fashioned TV is now called Standard Definition TV (SDTV) and is often denoted by 480i (interlaced) and 480p resolutions; that is, each mode supports 480 horizontal scan lines of resolution. HDTV, confusingly, supports two additional modes—720p/i and 1080p/i—each of which can be delivered interlaced or noninterlaced. Unlike 480p/i, these modes are also delivered in widescreen and not in the old 4:3 format. (For more information about interlaced and noninterlaced TV signals, see the sidebar "The Beauty of Progressive Scan.")

The Beauty of Progressive Scan
In the main article, I discuss the various resolutions that today's TVs support. But what's really the difference between an interlaced TV signal (e.g., 480i) and a noninterlaced TV signal (e.g., 480p, in which "p" means "progressive")? An interlaced TV signal draws the picture every other line at once, drawing the odd-numbered lines first, and the even-numbered lines next. Every half-screen drawing takes about 1/60th of a second, so a full screen image on a 480i, 720i, or 1080i display will be drawn in 1/30th of a second. Progressive scan (noninterlaced) technology is newer: With this method, the TV signal is drawn in a single pass, from top to bottom. If your TV supports progressive scan, you should try the progressive modes first. And some modern AV components, such as newer DVD players, also support progressive scan display. Coupled with a compatible TV, progressive scan gives you the most stable picture now possible.
If you're looking for the best possible picture, you want 1080i. But because the HDTV standard also supports 720p/i, many so-called HDTV sets don't actually output at the highest possible resolution, so you'll need to pay attention to these numbers when shopping. Most TVs today can downconvert HDTV signals to lower resolutions, which is the TV version of instant transcoding. Unlike transcoding, however, the effect is excellent: Even on my 480p rear-projection set, 1080i signals, downconverted to 480 lines of resolution, look stunning.

TV Types
You've probably seen—and been potentially lured by—the amazing flat-screen TVs you see in ads and in consumer electronics stores. But what might surprise you is that these sets are almost never the appropriate choice, unless you value real estate over picture quality and price. Here's what I've discovered about the types of sets that are available today.

  • Direct-view—Still the champion in the picture-quality category, direct-view TVs are much deeper (often 2' or so) than most other TV types and therefore can take up a lot of space in a room. On the other hand, direct-view TVs are limited by physics, and the sets are generally available only in sizes as large as 36" (4:3 sets) or 34" (16:9 sets). But not only do direct-view TVs offer the best picture, they also are generally the cheapest option. Look for units with flat screen surfaces, not curved, and be sure to get an HD-ready or HDTV-compatible unit if you want to future-proof your purchase.
  • Rear-projection—Hulking rear-projection sets take up the most space in a room, but they also offer the largest screen sizes and impressive pictures for a great price. Like direct-view TVs, rear-projection sets are available in 4:3 and 16:9 formats, but they come in sizes as large as 65" or so. If you're looking for the largest possible picture for the best price, rear projection is the way to go. An offshoot of rear projection called Digital Light Processing (DLP) offers even better picture quality but costs more. Most rear-projection and DLP sets are HDTV-ready or HDTV-compatible now.
  • LCD—LCD TVs offer flat form factors and good pictures but sacrifice size to plasma (see below) and picture quality to direct-view and rear-projection sets. Based on the same technology that drives laptop and computer displays, LCD sets are also fairly expensive, given the size of the displays. LCD TVs are available in sizes between 14" and 30".
  • Plasma—The sets that everyone drools about are also, by far, the most expensive. And you can get gargantuan plasma sets, if you desire. But surprisingly, plasma doesn't offer very good picture quality, and there are mounting concerns that plasma displays dim over a short period of time, compelling me to issue a warning to anyone considering such a set. (For more information about this concern, see the sidebar "Plasma 'Half Life' Issues Bedeviling Early Adopters.") Sure, they're cool. But plasma TVs have too many problems for me to even think about such a product, and they're far too expensive.

Plasma "Half Life" Issues Bedeviling Early Adopters
Buyers of expensive plasma TV displays are discovering the dark side of early adoption: Not only were their beautiful, flat displays extremely expensive, they apparently don't last very long. Numerous plasma TVs are starting to dim, according to users, who have started complaining to TV makers. Apparently, plasma TVs have a "half life" of 10,000 to 20,000 hours, during which time the brightness of the display panel degrades to half its original brightness. The result, of course, is a washed-out, less vibrant TV picture—exactly the opposite effect consumers were looking for when they purchased the sets. So what's a consumer to do? First, do some research: Apparently, this has been a known concern in plasma sets for some time, and the only recourse you have is an expensive repair.
Source Matters
The greatest TV in the world is only as good as the source input you provide, so don't be surprised when your $10,000 plasma display looks horrible when it's connected to a nondigital cable signal or a VHS tape. To get the best performance out of your new set, you'll need the very best source inputs. From a technical standpoint, yesterday's technologies—VHS players, standard cable boxes, DVD players—connect to TVs by using yesterday's connectors: coaxial cable, composite video cable, and S-video. Today's higher-resolution sources support better connection types, such as Digital Visual Interface (DVI), a digital computer standard, and component video, which HDTV requires.

To get the best picture quality, consider digital cable at the least, and—even better—an HDTV cable source, such as that offered by RCN or VOOM. Alternatively, get satellite TV, which also offers excellent picture quality. Make sure you use the best possible interconnect cables for each device you're connecting. That means going with component video (or, if that's not available, S-video) for a DVD player, and not composite video.

The Future Is Bright
When my basement is finally finished, I'll be moving my rear-projection set and its HDTV cable box downstairs, but we'll be purchasing some kind of 16:9 direct-view TV for the den to replace the old 27-incher. I'm not sure exactly which set that will be—right now, we're looking at a 34" Sony WEGA—but the search sure is illuminating. Whatever happens, this much is certain: Between on-demand digital cable, HDTV-compatible cable channels, DVD movies, and even the Xbox, our TV experiences are decidedly more high-tech than they were just a few short years ago. They're also a lot more enjoyable.

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