How to Buy a Flat-Screen HDTV

Introduction

Before you drop hundreds or thousands of dollars on the wrong flat-panel HDTV, read our comprehensive breakdown of everything you need to know. Our advice might just help you save some money.

The Big Picture

The supersizing of the American TV continues--but as screens grow ever bigger, tube sizes are going on crash diets. The once-popular 32-inch CRT-based set is a major hog, weighing well over a hundred pounds and requiring a couple of feet of space behind it. Today, thin is in, and flat-panel displays are your best bet for the best picture.

So which kind of flat-panel HDTV should you buy: a plasma model or an LCD set? Both technologies have made it possible to build very shallow, relatively lightweight TV screens with large picture areas. Both carry higher prices than their bulkier brethren, although the gap has shrunk over recent years. In the end, however, you must weigh the differences between plasma and LCD TVs, and determine which works better for your viewing conditions.

The first thing you should know, whether you look at plasma or LCD, is that almost all the sets on the market now are wide-screen models. Translation: Such sets have a 16:9 ratio of screen width to screen height (also referred to as the aspect ratio), which is the standard for HDTV and very close to the ratio used for most modern movies. As a result, the displays are more rectangular than the traditional, almost-square 4:3 sets of the past.

You can find the latest prices on both plasma and LCD TVs in PC World's Shop and Compare center.

Plasma

Essentially all current plasma displays offer HDTV resolution. Screen sizes begin at 42 inches diagonal and typically range up to about 70 inches (occasionally moving up to the downright ridiculous 150-inch sets that companies trot out for trade shows). Prices start at around $1000 and can reach about $15,000.

You get what you pay for in plasma, which means you can't expect to see the same picture quality from a $999 42-inch display that you would from a same-size model selling for $2000, a more typical price. The budget model will usually have lower contrast and poorer reproduction of black and of dark grays, yielding a picture with less punch and detail. A bigger problem with a bargain set is that it may do a worse job of upconverting regular standard-definition (SD) TV programs and DVDs to its native resolution. The resulting picture could look softer, coarser, or noisier than if it had better processing.

The most expensive plasmas in a given screen size are typically 1080p models, which offer 1920 by 1080 resolution. Whether this provides a visible improvement in picture quality over lower but more typical plasma resolutions, such as 1366 by 768 or 1024 by 768, depends on screen size and viewing distance. The smaller the screen, the closer you must be to it to see the benefit of a higher display resolution. For example, with a 50-inch screen you would have to sit within about 10 feet to perceive the difference between 1080p and 1366 by 768.

Like CRTs, plasmas use phosphors to generate light, which means they can be subject to "burn-in"--or, at least, the older plasma sets are susceptible. Burn-in occurs when a static image stays on the screen for a long time; for example, it could be the score box for a ballgame on ESPN, the health meter in a video game, or an annoying network logo that squats in the corner of your screen.

Fortunately, you can minimize the risk by keeping contrast and brightness settings reasonable (virtually all TV sets come out of the box with their contrast, brightness, color, and sharpness controls turned up too high) and by using stretch modes to fill the screen when you're watching 4:3 programming. And for the most part, today's TVs use pixel-shifting strategies that continually move the image on the screen in imperceptibly tiny increments to help prevent burn-in. Such technology should help--that is, unless you plan to watch NCAA March Madness nonstop. Then you have bigger issues.

One last thing to bear in mind with plasma sets is the audio. Most sets now come with speakers either built in or attached to the sides or bottom of the panel, but some remain strictly video displays with neither speakers nor any integrated TV tuner. In such cases you will need to factor those additional costs into your home-theater budget.

You can find the latest prices on plasma TVs in PC World's Shop and Compare center.

LCD

LCD screens range from desktop-friendly 15-inch models up to 70-inch wide-screen wonders complete with speakers and TV tuners. At screen sizes smaller than 42 inches, HDTV LCDs still come at a premium price, but the category is falling into a much more reasonable range. A 32-inch high-definition LCD, for instance, could cost anywhere from about $600 to $2000 depending on its manufacturer and features. (A 32-inch wide-screen display has about the same screen height as a 27-inch TV with a conventional 4:3 aspect ratio.) Once you start craving something larger than 50 inches, though, LCD shopping becomes a little more cost-prohibitive.

LCDs are continuing to play catch-up with plasma models in visual performance. LCD sets often come under criticism for having lower contrast ratios than their plasma counterparts do, as they have a tougher time reproducing deep black and dark grays. That's saying nothing of slower screen response times (aka the refresh rate), which causes on-screen blurring with fast-moving action scenes; sports and video-game fiends are the people most likely to find that problematic.

However, new advances in LCD technology are attempting to resolve the refresh-rate issue. We're seeing more models that refresh the display 120 times per second instead of the standard 60. Sets accomplish this by interpolating between frames to create new frames with pixels illuminated at levels midway between those of the preceding and succeeding real frames--in other words, by faking it. If you're buying a new LCD HDTV, make sure that it has this 120-Hz feature.

LCDs are often one to several inches thicker than plasmas and have a somewhat narrower effective viewing angle. (Plasmas, like CRTs, are easily viewable from well off to the side and do not exhibit any change in brightness as you stand up or sit down.) On the other hand, LCDs are completely immune to burn-in, are easier to view in brightly lit rooms, and more often include all the standard features of a conventional TV. LCDs also run cooler than plasmas, minimizing the need for potentially noisy cooling fans.

Another bonus of LCDs is that they give you the freedom to set them up wherever you please. LCDs work equally well in the dark or in bright-light situations. Or maybe you want to have your TV serve double duty as a huge monitor. LCD panels are light--way lighter than plasmas of the same size--and won't require a team of Clydesdales to haul between rooms.

You can find the latest prices on LCD TVs in PC World's Shop and Compare center.

The Specs Explained

Gone are the days when you figured out how big a screen you wanted, looked at some sets, and bought the one with the best picture that fit your budget. An options explosion has littered the shopping landscape with numbers, features, and terminology that even experts sometimes have trouble tracking (not us, though). We've cut through the chaos to give you the information you need to get up to speed. When you're finding your way in the high-def, A/V world, don't just go for the gaudiest numbers--sure, some are important, but others aren't. Let's quickly walk through a few.

Important: Contrast Ratio

Contrast ratio refers to the brightest and darkest light values a display can produce at the same time. All else being equal, the higher the contrast ratio is, the better. All else is seldom equal, however.

Pumping up the maximum light output, for example, will increase contrast, but it won't do anything to help pitiful black levels--that, in our opinion, is a much greater concern. LCDs in particular have a tougher time dealing with darks. So take contrast ratings as a very rough guide to be supplemented by eyes-on evaluation. LCD contrast-ratio specs start at about 600:1, while those for plasmas start at about 1000:1. Although ratings of 10,000:1 or better are becoming common for both types of displays, you should approach such claims with a healthy bit of skepticism. Trust your own eyes. Keep in mind that when you're on a showroom floor, you're checking out the HDTVs under the store's lighting conditions, not yours. Will you watch in a dark cave or in a well-lit, open space? Probably the smartest idea is to check the store's return policy before buying.

Important: Aspect Ratio

The aspect ratio describes the relationship of screen width to screen height. Conventional sets have a 4:3 aspect ratio, whereas wide-screen models are 16:9. Wide screens are the future. HDTV is a wide-screen format, for one thing. For another, DVDs usually look better on wide-screen displays because nearly every movie made in the last 50 years was filmed in an aspect ratio of either 1.85:1 (very close to 16:9, which is 1.78:1) or 2.35:1 (even wider than 16:9).

Important: Video Inputs

The number and type of video inputs determine which sources you can use with the display.

Composite video: This input type has the lowest quality but the broadest compatibility. Any device that has video outputs will include composite video among them. Connection is made with a single 75-ohm coaxial cable between RCA jacks.

S-Video: S-Video offers better quality than composite video does, and most video sources except standard VCRs now have S-Video outputs. Connection is made with a special cable and multipin sockets.

Component video: This high-quality option is the minimum standard for connecting high-definition cable and satellite set-top boxes and progressive-scan DVD, Blu-ray Disc, and HD DVD players. It requires three 75-ohm coaxial cables of the same type used for composite video.

VGA (Video Graphics Array): This high-quality analog RGB connection is used primarily for computer connections.

DVI (Digital Video Interface): One of the highest-quality types of inputs. This digital video connection can attach to devices with HDMI outputs (see below) by means of an adapter. It may also be used for computer connections. Requires a special cable and multipin sockets. Some displays with a DVI input may work only with computers, so watch out for that if you plan to connect an HDTV source, such as an HD digital cable box or a Blu-ray Disc or HD DVD player. Another thing you need for guaranteed HDTV compatibility is compliance with the HDCP (High-bandwidth Digital Content Protection) system.

HDMI (High-Definition Multimedia Interface): Also of the highest quality, this is basically DVI plus a digital audio and control link. The big draw here is that you get a one-wire setup that pumps HD content into your other home-theater components too. This connection is provided on almost all current HD satellite receivers, HD cable boxes, and upconverting DVD players (those that provide 720p, 1080i, or 1080p output from regular DVDs), and it is the standard video connector for Blu-ray and HD DVD players. The exact version of the HDMI input (for example, 1.1 or 1.3) is of little consequence on TV sets currently on the market. If you have, or plan on getting, a Blu-ray Disc or HD DVD player, it is desirable, though by no means essential, that the TV's HDMI inputs be capable of accepting 1080p signals (we'll get to 1080p in a second). Don't have HDMI components? Don't sweat it: Simple adapters turn HDMI into DVI connectors. Finally, for what it's worth, movie and TV studios love HDMI because it incorporates HDCP to combat piracy.

Somewhat Important: Resolution

Non-CRT displays, such as plasmas and LCDs, are fixed-pixel arrays, which means they have rows and columns of individual picture elements that turn on and off to produce the necessary patterns of light. Resolution is specified as the number of pixel columns by the number of pixel rows--640 by 480, for example, or 1280 by 720. Resolution and, to a somewhat lesser degree, contrast ratio determine perceived picture detail.

Digital content currently is delivered in one of five formats: 480i, 480p, 720p, 1080i, and 1080p. The 480i format is the same as that used for standard analog TV, and when programming originally in 480i is delivered by digital cable or satellite to your home, it retains that format. DVDs are sometimes mastered in 480p, but mostly they are 480i; a progressive-scan DVD player can deinterlace 480i DVDs to create 480p output, however. The 720p and 1080i formats are used by satellite, cable, and over-the-air-broadcast high-definition content providers, as well as some advanced DVD players that upconvert 480i and 480p content. Blu-ray and HD-DVD discs carry 1080p video, though their corresponding players can deliver the content in 1080i or 720p format for displays that do not accept 1080p input.

Generally speaking, a display is considered high-definition if it is wide-screen and has a total pixel count approaching 1 million. So 1920 by 1080 (1080p), 1280 by 720 (720p), 1366 by 768, and 1024 by 1024 are all examples of high-definition display resolutions.

Somewhat Important: Screen Size

Size matters, don't get us wrong. But just because you can afford a 65-inch monster doesn't mean you should buy one. You need to factor in the screen size and where you plan to watch the TV. Having your nose pressed up against the display in a broom closet of a room is hardly "ideal viewing conditions."

To determine the best viewing distance, and therefore how much space you'll need in your TV room, remember this simple bit of math: Note the screen size in inches and multiply it by 2. Calculators ready? Take, for example, a 52-inch set. The sweet spot for viewing is 104 inches away, or a little more than 8.5 feet from the screen (8.66666667 feet if you want to be nitpicky about it). You don't have to be exactly on target. Just bear this in mind as you plan where to place your new set.

Somewhat Important: Built-In Tuners

Most current flat-panel displays include a tuner for conventional analog broadcast and cable-TV reception and for broadcast HDTV. A few, however, are strictly business--they're monitors with no built-in tuner (more common for plasmas than for LCDs). That may not matter if you receive all your TV programming via satellite or cable, but if you want to watch broadcast TV over an antenna, be sure that the set you buy includes a TV tuner. Many sets also have built-in tuners for digital cable TV. Although such tuners have a standard for handling scrambled premium channels (for example, HBO), many sets do not support it, so be sure you know exactly what you are getting. If you want that capability, make sure the set you buy has a CableCard slot and that your cable provider can give you the necessary electronic ID card. Cable pay-per-view and satellite TV currently require external set-top boxes.

Minor: Comb Filter Type

Comb filters are necessary in analog TV to separate color and luminance information without losing too much detail, but that's not an issue in HDTV. The only time the comb filter comes into play is for analog TV reception or any signal coming in via a composite-video connection. For all other connections, it's out of the loop. In any case, the comb filters in flat-panel TV sets are routinely very good these days.

Flat-Screen TV Shopping Tips

All right, you've made it this far. Here are key points to consider before you take the HD plunge.

Consider the alternatives: If you can live with a tabletop set that's 10 to 18 inches deep rather than 4 to 7, LCoS (liquid crystal on silicon) and DLP (digital light-processing) rear-projection sets can deliver solid performance in similar screen sizes and at lower prices. You just don't hear about them as much because they're not as sexy.

To learn about other big-screen TV options, check out "How to Buy a Rear-Projection TV."

Think HDMI: If at all possible, you should get a set with an HDMI (High-Definition Multimedia Interface) input. This will ensure maximum compatibility with HDTV sources such as HD digital cable boxes, HD satellite receivers, and Blu-ray Disc and HD DVD players.

Compare displays using a variety of material: Just about any flat-panel display will handle HDTV and DVD signals well, but mediocre cable and satellite signals will give some of them fits. Don't make a buying decision based solely on pictures generated from pristine sources.

Look for good blacks: When you're comparison shopping, bring along a DVD of a movie containing some dimly lit night scenes. Use it to check for good black reproduction and ability to render detail in near-darkness.

Get to know the remote: A good remote can be your best friend, a bad remote your worst enemy. (Well, okay, we're exaggerating a little, but you get the idea.) Does it have backlighting or glow-in-the-dark buttons to help you see what you're doing when the lights are turned down? How easy is it to find commonly used buttons by feel?

Check the video settings: Now that you have the remote, pull up the video-adjustment menu and look at the settings. If you thought the picture looked a little (or a lot) off on first viewing, try selecting the median settings for contrast, brightness, color, tint, and sharpness. Those probably won't be optimum, but chances are they're closer than what you found originally. A good display can easily look worse than a lesser one if it's poorly adjusted. Repeat your tests using a variety of sources, including a dimly lit movie, if necessary. Also keep in mind that you'll likely have to readjust the color settings for each source. Most HDTVs these days have input memories, so your set should keep the ideal settings for high-def movies on one input and your video games on another.

You can find the latest prices on both plasma and LCD TVs in PC World's Shop and Compare center.