Fall is upon us, and for many it means World Series baseball and the start of football season. For others, autumn means that the newest episodes of our favorite fall TV shows that we set our DVR to record were, annoyingly, preempted by sports. Either way, the season means hours of new primetime programming. And what better way to spend those cold autumn nights than inside, sitting in front of a warm, new HDTV?
But before you take out that credit card, take a read through our LCD TV buying guide. It's like a cheat sheet that breaks down the most important features of today's best TVs. With this primer, you can nail down exactly which specifications are a must in your purchase, and which are either inflated marketing speak or more tech than you really need.
LCD TV Buying Guide
1080p HD Resolution
As of this moment, a 1920x1080 (1080p) resolution TV is the best bet for the average consumer. It can handle 99.9% of all HD video content that you'll find (cable, Blu-ray discs, etc.) and display it at the best possible quality. For the curious, a "1080p" TV can display up to 1,080 lines of vertical resolution; the "p" means that it can also show progressive scan video — as long as the input signal allows. Progressive scan video means that every line of a video image is output for every frame; this differs from interlaced video, or 1080i, which scans only half of the lines, then the other half, for each frame of video.
4K HD Resolution
The only commercially-available TVs that have resolution better than 1080p are 4K televisions (sometimes called QuadHD, UltraHD, or 2160p). These new-to-market panels offer a 3840x2160 resolution, which is four times that of 1080p HDTVs. Though this spec might sound impressive, there are very few sources of content available at such a resolution; most of the time you'd just be watching 1080p video on a screen that could handle much, much more.
Overall, 4K is best suited to early adopters who want in on the latest and greatest or next-wave of technology. But 4K isn't necessary for the everyday consumer — yet. If you're thinking of buying a new TV, don't put off buying a 1080p screen in fear of it becoming outdated by 2160p new technology any time soon.
Many basic LCD TVs refresh their images at a rate of 60 times per second, or 60Hz. This is perfect for video signals, as they come in at 30 frames per second and allows each frame to be refreshed twice. A 60Hz refresh rate clarifies the video image. However, since film is recorded at 24 frames per second, a 60Hz refresh rate can also get in the way. In order to properly display a movie, the TV's hardware does something called "2:3 pulldown;" essentially, it takes the 24 frames of film image (from a DVD or the like) and displays the first frame three times, the second frame twice, then the third three times, and so forth. When displayed on large TVs, this process can become very apparent, revealing itself through jerky motion called "judder" and a blurring of the image during scenes with fast motion.
Alternatively, 120Hz televisions refresh an image 120 times a second, which works out perfectly for both video at 30fps and film at 24fps because each frame can be refreshed at a constant rate: four times for video, five for film. A 120Hz refresh rate results in smoother and clearer images, especially during action scenes and sports events. Most brand-name TVs these days will have 120Hz refresh rates, although third-tier TVs are certainly not excluded from the spec.
TVs with a 240Hz refresh rate are currently being pushed by manufacturers as some of the best TVs available, but a higher refresh technology adds a premium price, too. However, for 99% of consumers a 120Hz refresh rate will suit all TV-watching needs just fine. And because 240 is also a multiple of 24 and 30 and the difference between 120Hz and 240Hz is not as apparent as the difference between 60Hz and 120Hz. In fact, side-by-side, the improved quality of a 240Hz over 120Hz is barely noticeable.
Brightness is a measure of the intensity of light that the TV panel is capable of emitting, and it's listed as candelas per square meters (cd/m2) or as "nits" (one candela per square meter). A candela is equivalent to the amount of light a single candle emits. Therefore, an LCD with a brightness of 300 cd/m2 (or 300 nits) is capable of emitting as much light as 300 candles do in a square meter of space. Naturally, a higher brightness number means a brighter picture. This specification is more important for TVs that will be viewed in an environment with a lot of light, as you'll want your screen to be able to overcome the ambient environmental light.
Technically, dynamic contrast ratio is the difference between the darkest dark and the brightest bright over time; static contrast ratio (sometimes called native contrast ratio) is the difference in luminance that can be displayed within one static image. However, the astronomically huge numbers the manufacturers present in these ratios are mostly meaningless for consumers to compare; there are no cross-industry regulations or measurement guidelines, and manufacturers can derive these numbers however they want.
The only instance where these ratios can be an effective comparison tool is between models of the same brand. Since one can assume that a manufacturer is using the same metrics to judge all of its TVs, its ratios are meaningful only within its own line of televisions. In these cases, consumers should look for a higher ratio.
However, even when comparing between the same brand, dynamic contrast ratio reporting is the least informative, as it's the sum total difference of what the panel can display (sometimes including the "off" state of the TV), not what it's capable of displaying within one static image. A better measure of contrast is the static contrast ratio. A higher ratio here will mean that when displaying content, a TV is better at showing dark images with small spots of light (or vice versa) without blurring or the image looking dim. The above image shows higher contrast ratio on the left and a lower contrast on the right.
Response time, measured in milliseconds (ms), is the time it takes a pixel to change from black to white, then back to black again. The smaller this number is, the better a panel is at handling video signals that contain a lot of motion or action scenes.
That said, the difference between a 10ms response time and anything faster is almost imperceptible to the human eye. Look for TVs that have less than 10ms, but don't pay a lot more for a faster response time. Anything slower than 10ms, however, could result in blurring or ghosting — leaving behind a fading trail — in video images with a lot of motion.
An additional note: Many manufacturers have begun listing response time as the time it takes for a pixel to go from gray-to-gray without the pixel ever entering a complete on or off state. This can lead to some wildly inaccurate information since there's no industry-wide guideline as to what a "gray" state is. To ensure better picture quality, look for a black-to-black response time.
ATSC (Advanced Television Systems Committee)
This digital method of image transmission allows for over-the-air reception of HD content with resolutions up to 1080i. If you do not subscribe to cable, satellite TV, etc., this is a very important tuner to have.
QAM (Quadrature Amplitude Modulation)
This tuner allows your television to display unscrambled digital cable signals without the aid of a set-top box. However, in many cases this will result in the ability to receive only your local network affiliate channels (there's a law against cable providers scrambling those), but not premium channels like HBO.
HDMI (High-Definition Multimedia Interface)
This cable carries both digital video and audio signals. Along with the benefit of decreasing the number of cords stuffed behind your entertainment center, this all-in-one solution can transport digital video resolutions up to 2560x1600 and up to eight channels of audio. HDMI your best bet for carrying high-definition content output from cable boxes, Blu-ray players, or set-top video streaming devices (like the Roku boxes.) It can even be used for connecting many of today's high-end laptops to your TV. The more HDMI ports your TV has, the more flexibility you'll have with connecting devices to your HDTV.
On a future-note, the HDMI 2.0 spec has just been approved, but won't be appearing in/on/around any TVs until well into 2014, so there's no need to worry about it yet. The new spec will allow transport of 3840x2160 (UltraHD/4K) resolutions.
MHL (Mobile High-Definition Link)
Only available on a handful of TVs so far, an MHL port is essentially a powered video input that does away with plugged-in devices' need for a separate power supply. Currently, only a couple of devices take advantage of this port; the most recognizable is the Roku Streaming Stick. But, since Roku also makes HDMI-connectable versions of its devices, having an MHL port isn't an essential feature.
This analog solution to video transport is a bundle of three wires, each carrying one of three colored information signals (Red, Green, and Blue.) As with HDMI, this type of cable carries HD video (up to 1080p), but its signal must get converted from digital to analog at the output source, then back to digital at the television. Many viewers claim that this creates poorer quality and a greater chance of "noise" in the displayed image. Moreover, because component cables only carry video, they needs to be paired up with analog or digital audio cables for audio transport; as mentioned before, HDMI does this all via one cable.
VGA (D-Sub 15)
If you want to use your TV as a media center, a VGA input is one to look out for, as such outputs are found on most computers. However, a VGA cable carries an analog video signal only; no audio information can be transmitted. Even though VGA can handle 2048x1536 video, the resolution displayed on a TV is dependant upon the type of graphics card your computer has: some export higher resolutions than others. Most TV panels will adjust their display resolution to accept the incoming VGA signal, but if you want a higher resolution, be sure to check your video card's maximum resolution output.
DVI (Digital Visual Interface)
DVI is another input to look for if you want to connect your TV to a computer. Unlike analog VGA, which often suffers from interference and distortion, DVI transmits all picture information digitally, pixel by pixel, and yields a higher quality image. Like VGA, this type of connection does not carry audio. A single DVI connection can transport video with up to a 1920x1200 resolution at 60Hz. (Dual-link DVI can carry up to 2560x1600, but it's primarily for use with computer monitors and is not found on TVs.)
10-Bit vs. 8-Bit Processor and Panel
The thousands of pixels on an LCD display are comprised of red, green, and blue sub-pixels. Each of the three are all capable of illuminating at various intensities. A sub-pixel on an 8-bit panel can generate 256 distinct levels of illumination. A 10-bit sub-pixel can create 1,024 levels. That means that in theory, a 10-bit display is able to produce more colors, smoother transitions between adjacent pixels, and can eliminate "banding" or "raster" images. The sunset image above and to the left is visibly less smooth with an apparent gradient, compared to the image on the right.
LED vs. CCFL vs. OLED Backlighting
An LCD screen, in order to be seen easily by the naked eye, needs to be backlit. (Think of when you tried to play a Gameboy in the dark.) Older LCD panels use CCFL (cold cathode fluorescent lamps) bulbs for illumination; many newer models use LED (light emitting diode) backlighting. Some high-end TVs have even started using OLEDs (organic light emitting diode). LEDs and OLEDs have the advantage over CCFLs for several reasons. First, CCFLs add more bulk than LEDs do — you can get a thinner TV with LED technology. Even better, since OLEDs are actually a new way of manufacturing a display without additional backlighting, they can be found in super-thin, more high-end TVs. Second, over time, the environmentally-dubious gases inside CCFL bulbs wear out, decreasing their effective output of illumination, but LED and OLED displays should remain bright for the lifespan of your TV.
There is one further differentiation within LED backlighting technologies to note. Most LED-backlit panels rely upon white LEDs for their illumination. However, RGB LED backlighting swaps out the white LEDs for clusters of red, green, and blue LEDs. This technology purportedly display sharper primary colors, more accurate color reproduction, and can produce darker blacks and brighter whites within the same image by selectively turning on and off individual clusters of LEDs. Above, the image to the left is LED-backlit; the image at right, OLED.
3D HDTVs require that each viewer wear special 3D glasses to add an extra layer of depth and dimension to selected programming. A 3D TV will either require active shutter glasses (battery-powered glasses that alternately block out the left or right lens in coordination with the video frames flashing on screen) or passive glasses (glasses that do not flicker and require no battery). 3D HDTVs have been around for some time and this past summer, 55" 3D LCD HDTVs dipped to prices that were about as low as their non-3D brethren, suggesting that the technology is becoming less of a price premium.
Hopefully after reading this HDTV buying guide, you feel comfortable enough to face the abbreviation-soaked techno-speak of the world of LCDs. While we normally recommend buying HDTVs during Black Friday and the holidays, if you're shopping today, be sure to check out our LCD HDTV section for deals on both high-end and entry-level models.
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