HDTV buying guide

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HDTV buying guide: Select the right flat-panel technology

High-definition television is truly different from the standard-definition television that it replaces. The screen is wider, and since many more pixels make up the image, you get greater detail. And these days, many television shows and sports broadcasts, as well as Blu-ray disc movies, can deliver this more-detailed image.

You want to buy a new big-screen HDTV for your home. Where do you start? You have so many options, features, and specifications to choose from that it can be confusing. And since you're likely to keep this set for at least the next five years, you want to make a smart choice that you can live with for a long time. In this HDTV buying guide, we'll break the process down into some simple steps that will help you pinpoint the best HDTV for your needs and budget.

In selecting a flat-panel screen, you must first choose between plasma and LCD technology. You also need to determine what size to buy. You may also have to think about resolution, but that will depend on the size you're considering. If you're buying a set that's 35 inches or smaller, you may find 720p models available, but sets measuring 40 inches or larger will almost all be 1080p. The difference is that the 1080p sets have more pixels that make up the image, and thus they are capable of providing the highest detail possible. If you're viewing a smaller screen from a distance, you'll be too far to notice the added detail of a 1080p set, so in many cases 720p will be just fine for smaller TVs.

Flat-panel HDTV technologies

You have two technology choices: LCD and plasma. (Note that in spite of what some manufacturers would have you think, "LED TVs" are not a different technology; they are simply LCD TVs with LED backlights.) The two approaches differ in the way that they create the image on the screen. LCDs use a bright backlight that shines through a layer of liquid crystals, which move to transmit or block the light. Plasmas use an electrical charge to make a gas give off ultraviolet light, which in turn causes phosphors to glow. (This is the same process that a typical fluorescent lamp uses.)

Another alternative, rear-projection (DLP) TVs, exists, but we're not discussing such sets here. Rear-projection models can offer incredible value (especially when you're looking at sizes of 60 inches or larger) but they're not popular because they're bulkier than flat panels. And flat panels are now available in comparable sizes.

Selecting the right HDTV size

All HDTVs are "wide format," which means that their proportion resembles that of a movie screen more than that of a traditional, standard-definition TV screen. In technical terms, the widescreen aspect ratio is 16:9 (for every 16 units of width, the screen is 9 units tall) while standard-definition screens have a 4:3 aspect ratio.

The widescreen format should fill more of your field of view, much as a movie theater screen does. As a result, the answer to the question "How big a screen do you need?" is probably "Bigger than you think."

If you decide that you can get by with an HDTV smaller than 40 inches, you're limited to buying an LCD HDTV; plasma screens are not efficient to manufacture at sizes below 42 inches. If you're setting your sights on something larger, however, you have to choose between plasma and LCD. To make that decision, you need to consider other factors.

Your budget

Retail prices for flat-panel televisions have fallen by more than 20 percent already in 2009 (similar to the price-drop trends in recent years), so your HDTV dollars will go a lot further now than they would have just a couple of years ago.

If your budget is tight and you want a set larger than 40 inches, you'll probably get the best deal on a plasma screen because such models cost less to make in large sizes than LCDs do (though the difference is shrinking all the time). Fewer companies offer plasma now, but you can still find good-quality models at prices that often beat the cost of LCD sets of the same size, especially in the 50-inches-and-larger range.

But what if your budget gives you a bit more leeway? How can you pick between LCD and plasma models? One way is to compare the specifications and features, but you have some other fundamental issues to consider.

Plasma televisions continue to have an advantage in reproducing blacks. LCDs continue to enjoy an edge over plasma sets in brightness, which makes LCDs better suited for well-lit environments. In general, LCDs produce a brighter image, so they are less likely to look washed out in a room with bright ambient lighting. (This is also why LCDs sometimes look better than plasmas do in the well-lit showrooms of big-box stores and buying clubs.) On the other hand, plasmas tend to generate deeper blacks, which should result in better image quality in darkened rooms.

Early plasmas had a problem with images' becoming permanently burned into the screen. The latest plasma sets are no longer susceptible to permanent damage, but such image echoes can persist for as long as a few hours before fading away. If you tend to leave the television on for hours at a time on the same channel, you may want to select an LCD instead.

The nature of LCDs leaves that technology prone to motion blurring. To create an image, the LCD's tiny, cylindrical molecules of liquid crystal material respond to electrical charges and move to either transmit or block the light from the panel's backlight. Making the molecules move takes time, however, and if they don't move quickly enough, they can produce motion blur on the screen. This effect can be most noticeable during sports broadcasts in which you're trying to follow a small object on the screen, such as a baseball or a hockey puck. Generally it isn't a problem for typical movie or television-program images. Some LCDs now have higher refresh rates of 120Hz or 240Hz, designed to reduce motion blur.

Note that some TVs are advertised as "LED TVs." This is not a new type of TV; it's simply an LCD panel that uses LED as its backlight instead of the traditional fluorescent tubes.

LCDs tend to have the advantage in physical dimensions, as they are typically thinner and lighter than plasmas of the same size. LCDs also tend to consume less electricity than plasmas of the same size do. The difference in power consumption can be difficult to assess, however, and some plasmas using newer display technologies can compete well with LCDs in this respect (and the comparison changes yet again if you factor in LED LCDs, which consume the least energy of all). Though a plasma screen uses almost no power when it's showing a black screen, an LCD uses about the same amount of energy whether the screen is all black or all white, so its power consumption will depend on what you watch.

[Alfred Poor is a freelance writer.]

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