EmailWhat's the difference between plasma and LCD?
Both plasma and LCD flat-panel displays are capable of delivering high-definition TV within a thin case, but there are differences between the two:
- LCD TVs are available in many more screen sizes than plasma. Plasma TVs are available mainly in sizes of 40 inches and up (typically to 65 inches), but LCD TVs can be as small as 7 inches, and manufacturers have demonstrated LCD TVs with screen sizes of up to 108 inches. For home theaters, LCD TVs with screen sizes from 32 inches to 65 inches are most popular.
- LCD TVs work better in bright rooms. Plasma TVs are known for their ability to display dark colors and deep blacks better than LCD TVs, but they can look washed out in bright rooms. LCD TVs appear brighter, so the screen won't wash out in daylight. Many LCD screens have an adjustable backlight, so you can control the brightness of the screen. Some high-end LCD TVs use LED backlighting instead of cold-cathode fluorescent lamp backlights. These LCD TVs are better able to compete with plasma TVs.
- Plasma TVs are more prone to glare when viewed in a bright room. However, some plasma TVs have screens that do a better job of handling reflections, while some LCD TVs use a panel that's more reflective than others.
- Plasma screens have wider viewing angles than LCD flat screens. That means you can sit at more of an angle and still get the best picture, one reason why reviewers (such as CNET's David Katzmaier) say a plasma screen gives you "better home theater performance than LCD." With LCD televisions, sitting too far to one side will result in a loss of brightness. Reports say that some LCD TVs have fewer issues with limited viewing angles, but still fall short of plasma in this regard. Some of the best LCD TVs with LED backlights have limited viewing angles as their chief drawback.
- LCD TVs are much more efficient than plasma TVs. Plasma TV manufacturers are working on improving energy consumption, but right now, LCD TVs are at least 40 percent more efficient to operate.
120 and 240 Hz processing: Useful feature or marketing ploy?
Image blur can be an issue in some LCD TVs. Pictures can look softer or appear to smear with fast action. The newest LCD HDTVs are using faster 120 Hz and 240 Hz refresh rates -- the rate at which individual images are placed on the screen -- instead of the more traditional 60 Hz in an attempt to overcome image blur. However, the signal processing involved is fairly complex because the source material has its own frame rate (the number of individual images per second), typically 24 or 60 frames per second (fps) depending on whether it is film or video, and reports say some LCD TVs do better than others at overcoming blur.
While faster refresh rates seem like a great idea in theory, experts say that that motion blur in most modern LCD HDTV televisions is minimal to begin with. While faster refresh rates improve things when looking at test patterns, when it comes to typical program material, little if any improvement can be seen by most people. However, most set makers combine faster refresh rates with signal processing circuitry to reduce judder, a small shaking artifact that pops up because of the mismatched frame and refresh rates when watching movies -- or anything else originally shot on film -- on a TV. That generally is effective in smoothing out motion when watching movies -- though some say it robs movies of their film-like qualities, making everything look like it was originally shot on video. Some TVs let you use one feature or the other, but some make you use both or nothing at all.
Important Features
In addition to the points made elsewhere in this report, there are lots of things to consider before purchasing an LCD TV. Here are some that experts say often get overlooked:
- Look for lots of HDMI inputs. This connection keeps the signal all-digital, avoiding degradation that can occur as the signal passes through other components (such as a cable box). HDMI carries high-definition audio as well as video. Some satellite receivers and DVD players connect through this port, and it is a must for viewing the output of a high-definition Blu-ray player. HDMI also supports HDCP, a copy-protection standard that prevents people from making copies of high-definition movies. Blu-ray players can't pass on their signals in 1080p resolution except through HDMI, and most upconverting standard-definition DVD players will only pass upconverted movies via this connection.
- Match TV size to the size of your room. Because HD LCD screens have higher resolutions than older TVs, you can sit closer to them, meaning you can get away with a bigger screen. Even so, 52-inch screens that look great in a showroom may overwhelm a small room.
- Shop around for price. In our research, we found big price differences from retailer to retailer, so it pays to look around.
- Verify that the TV comes with a stand or mounting hardware. Most LCD TVs come with a basic table stand; some stands swivel, but others do not. Wall-mounting hardware is rarely included and could cost an additional $100 to $200.
- Check the manufacturer's policy before buying online. Some manufacturers have strict policies regarding authorized dealers. For example, if you buy a Sharp LCD TV from an unauthorized dealer, you'll probably void the manufacturer's warranty. However, the retailer may offer a substitute warranty. We found a substantial price differential between Sharp's authorized dealers and discounters. Be sure to calculate your threshold for risk on such a large purchase and ask the dealer about warranty coverage.
Goodbye analog TV
This past June, most analog broadcasting (low-power and repeater stations designed to serve limited areas and rural populations being the exceptions) ceased in the U.S. in favor of digital broadcasting. All current TV models come with a digital tuner, so you need nothing except an antenna to receive digital signals over the air. If the digital tuner is QAM-capable, cable subscribers can also receive nonpremium, unscrambled HDTV and other digital programming. (QAM is the method cable companies use to distribute digital TV signals.) Premium programming will still require a cable box or another external decoder.