HDTV Buying Guide: Making Sense of the Specifications

Alfred Poor, PC World
PC World
Thursday, November 26, 2009; 12:19 AM

Whether you're buying your first HDTV or replacing an older model, you'll find all sorts of new specifications and features to consider when shopping. Some of these apply to both LCD and plasma sets, while others are significant for LCDs in particular. Here's a quick overview of the different choices and what they may mean for you.

Important Specifications for LCD and Plasma HDTVs

Almost all sets 40 inches or larger have 1080p resolution, which is 1920 by 1080 pixels. The 1080p resolution will give you the maximum detail available for almost all HD content. For some smaller HDTV sizes, 1366 by 768 pixels is often a lower-cost choice, but a 720p set has to scale 1080p images down to match its native resolution. This interpolation may introduce imaging artifacts, and the image may not appear quite as sharp or have the depth of the picture on a 1080p set.

While 720p models are available in many sizes as a lower-cost option, they remain prevalent in the 40-inches-or-smaller category. If you're shopping for a small HDTV, expect to pay about a 20 to 25 percent premium (as of this writing) for a 1080p set over a 720p set. All else being equal, we recommend that you pick a 1080p model, which will better match much of the content you can now get from broadcast, streaming, and satellite services, and will match the native resolution of a Blu-ray Disc player.

This spec refers to the difference between the darkest images and the lightest images that a screen can produce; in general, it is determined by how dark the blacks are. Contrast is probably the most important factor in determining image quality after resolution. If the blacks are gray and the contrast is lower, the whole image can look washed out. If the blacks are deep and strong, however, the image will look sharper and the colors will pop. Unfortunately, manufacturers' methods for measuring and specifying contrast are almost useless for helping you predict how the screen will look. Manufacturers use full-screen measurements, all black and all white, in a darkened room. An all-black or all-white screen is not what people watch, and in computer terms it conveys precisely zero bits of information. When you have actual content on the screen, you get internal reflections, ambient lighting effects, and other optical crosstalk that results in the light from one section of an image affecting the light levels of another.

You have to get the image from your disc player or set-top box into the TV set, and to do so you need to use a video connection. Only three connectors--HDMI, component video, and "VGA"--can deliver HD-resolution images, and of those only HDMI is capable of providing full 1080p HD over an HDCP-protected connection.

In addition to those three connectors, you are also likely to find two others: S-Video and composite video. They can carry only standard-definition video images, typically from older devices such as a DVD player, a camcorder, or a VCR. Depending on how you set your HDTV, it can scale standard-def images up to HD (interpolation).

How many connections do you need? Most HDTVs today offer at least three HDMI connectors, while many provide four, and some have even more. Get as many HDMI connections as you can; doing so will allow you the most flexibility in attaching devices. For instance, you'll probably want to connect a set-top DVR, a Blu-ray player, a camcorder, or other gadgets like Western Digital's WD TV Live HD media player, which links a hard drive and your network to your TV for displaying media content. If possible, use HDMI for your high-definition connections, and try to buy an HDTV that has one more connector than you currently need, to allow for the future expansion of your home entertainment system.

If you have too few HDMI ports on your set, you can always add a switch that will multiply how many devices you can connect to a single input on your HDTV; but this device adds a level of complexity and one more remote control to keep track of.

The U.S. Department of Energy and the Environmental Protection Agency jointly operate the Energy Star logo program, which sets energy-consumption standards for appliances and consumer electronics. The current standard is Energy Star 3.0. Version 4.0, with more-stringent requirements for televisions, is slated to take effect in May 2010. Manufacturers are eager to promote a TV's energy-efficient status, so it's a safe bet that sets with the Energy Star logo will consume less power than ones without.

This function will adjust the brightness of your set's image depending on the amount of light in the room; it can be a significant power-saving feature.

This feature will reduce the difference in volume levels, especially between TV programs and their commercials, which tend to be much louder.

Many people now hang their flat-panel TVs on the wall, and they often do the installation job themselves instead of hiring someone. Most wall mounts are designed to match the standard VESA hole patterns, so you may find it easier to mount a flat-panel TV that offers one or more of these patterns on its case.

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