Is It Really HDTV?
One of the first things you’ll notice when you walk into a store is that most HDTVs have screens that are almost twice as wide as they are tall — in other words, the screen’s aspect ratio is 16:9 instead of the squarish 4:3 you’re used to. (For explanations of “aspect ratio” and other key terms, see “The Lingo.”) When it comes to watching movies, wider is definitely better since it resembles the shape of movie-theater screens. Widescreen is also great for sports, delivering more of the action — a third more!
Pay close attention to how the sets are labeled. Some say “HDTV,” while others are called “HDTV-ready” or “HDTV monitors.” While HDTVs have a digital tuner built in, HDTV-ready sets get their high-def images either from an external source like a cable box or satellite receiver, or from a separate digital tuner (these start around $350) that you hook up to an antenna.
You should also be aware of HDTV’s lower-resolution sibling, enhanced-definition TV, or EDTV. Many plasma TVs that sell for less than $4,000 and LCD (liquid-crystal display) sets smaller than 20 inches are EDTVs, not HDTVs. The 480p (progressive-scan) images these sets deliver are better than regular TV’s 480i (interlaced) images — in fact, they’re the same quality you get from a DVD played on a progressive-scan DVD player connected to a digital TV. But they don’t have the fine detail of HDTV’s 720p or 1080i images. (For help in sorting out what all these numbers mean, see “Resolution Basics.”) EDTVs can accept high-def signals from an outboard tuner, satellite receiver, or cable box — they just convert the image to the set’s lower resolution.
What the Specs Mean
You’ll run across several numbers while researching which TV to buy. One of the most important is screen size. HDTV screens are measured on the diagonal, just as with regular TVs.
A technical spec that many manufacturers tout is contrast ratio, and it’s not unusual to see outrageously high claims, like 3,000:1 or higher. Unfortunately, marketing departments have glommed onto this spec, so the numbers should be taken with a grain of salt. These measurements are often not done uniformly or under “real world” viewing conditions. A properly calibrated TV will yield a contrast ratio of 300:1 to 700:1, while some of the newer technologies like LCD and DLP (Digital Light Processing) can deliver up to 900:1. These figures are a lot lower than the hyped specs because the color temperature and white levels have been adjusted correctly and because they’re calculated using a checkerboard pattern rather than alternating between bright and dark screens.
In order to deliver pictures that can jump out on a showroom floor full of TVs and hold their own against harsh store lighting, most TVs are set too “hot” when they’re shipped from the factory. Useful technical specs that are unlikely to appear in a company’s ads or literature are those for color temperature, which tells how reddish or bluish its whites are, and grayscale tracking, or how well the TV reproduces shades of gray between white and black (for more on these, see “The Color of Gray”). All Sound & Vision test reports include this information in a panel titled “in the lab.” The readings before and after calibration will give you a good idea of the performance you’re likely to see when you get the TV home — the first reading indicates how it will look “out of the box,” while the second shows what kind of picture you’ll get after it’s properly set up.
