Rear-Projection TV & HDTV Buying Guide: Powered by ConsumerGuide and HowStuffWorks

The Basics: Rear-Projection TVs & HDTVs

The term "big-screen TV" once described 27-inch and 32-inch televisions, but that torch has long since passed to rear-projection (RP) televisions and flat-screen LCD and plasma monitors. Today, big-screen televisions start at 41 inches, and even these are in danger of losing the big-screen title (Pioneer unveiled a 103-inch plasma screen at CES 2006). Nevertheless, 41-inch and larger RP TVs, and especially HDTVs, are in great demand today.

Short of plasma and LCD flat-panel sets (also discussed on ConsumerGuide.com), rear-projection TVs provide the ultimate big-screen performance, and they are intended for viewers who plan to make this their primary set for watching programming and movies. Rear-projection sets offer all of the same built-in features and enhancements that are found in direct-view TVs, as well as many more that are specific to rear projection.

In general, traditional CRT (tube) TVs top out at 36 inches, and anything larger falls into the realm of either rear-projection televisions or flat-panel sets. Rear-projection televisions provide exceptional picture quality and performance while costing significantly less than their same-size plasma and LCD flat-panel cousins. RP sets come in several distinct flavors that can be grouped into two categories: CRT sets and microdisplays (DLP, LCD, and LCoS).

The oldest and most inexpensive rear-projection technology, CRT (cathode-ray tube) RP televisions offer excellent picture performance for budget-minded big-screen shoppers. CRT sets have a number of drawbacks compared to their more technologically advanced kin, such as excessive cabinet size and weight, narrow viewing angles, the need for periodic convergence maintenance, and less-than-ideal image brightness. Still, these sets provide the best black levels of all rear-projection televisions, and their relatively low price will keep CRT RP televisions around for at least the near future.

Microdisplays are rear-projection sets that use various forms of computer chips illuminated by lamps to produce on-screen images. They are much thinner (depth) and lighter than traditional CRT RP sets, although they usually need to be placed on a stand or table to bring them up to a proper viewing height. Microdisplays do not require CRT's convergence adjustments, and they produce brighter images.

The current leader in microdisplay technology is DLP. Developed by Texas Instruments, DLP (digital light processing) provides a very detailed and bright picture, and it currently has the best black levels of RP microdisplays. Some people complain of rainbow effects, which are caused by DLP's color wheel, but technological innovations are reducing this problem. LCD rear-projection televisions do not suffer from rainbow effects, but LCD RP sets generally aren't as bright and have poorer black levels compared to DLP, and they can suffer from pixilation (visible spaces between pixels). LCoS (liquid crystal on silicon) is a relatively new technology to the microdisplay market, and it is currently sold under a variety of names including SXRD (Sony), HD-ILA (JVC), and simply LCoS. These sets have poorer black levels than DLP, although this is expected to improve. On the other hand, LCoS doesn't suffer from DLP's rainbow effects.

Virtually all rear-projection televisions available today are either HDTVs or HD-ready TVs. HDTVs include integrated HD tuners, allowing them to display over-the-air, cable, and satellite HD signals without the need for an additional set-top box. However, if you are not yet planning on converting to high-definition viewing, it would be wise to opt for a set that is HD-ready (without the integrated HD tuner), as this will save you some dollars while future-proofing your investment. Both HDTVs and HD-ready TVs can also display standard content, whether analog television signals or digital DVD progressive scan movies.

How to Shop

The rule for TV shopping used to be, "buy the biggest TV you can afford," and that was fine when the size of the TV was the main deciding factor. But with all the newer display technologies, available features, and wildly varying price ranges even for similar-size TVs with comparable technologies and features, today a lot more goes into a TV purchase decision than size. The wisest course of action is to determine the features you need and the screen size you want (within reason, of course), select an approximate price range, and take some time to research and learn about the different technologies and what is offered. Then go see the TVs for yourself. The worst thing you can do is go to an electronics store with no preparation.

When shopping for a new TV, examine potential purchases to ensure the picture is clear and bright. Stores usually crank the brightness up on display models, so ask the store's floor staff to let you adjust the picture settings to a more realistic level. It is a good idea to bring along a favorite DVD to test. Also take a listen to a TV's audio system, especially if you won't be connecting the set to a larger home theater speaker system. If you intend to hook up numerous components to the set (DVD player, sat receiver, video game console, etc.), make sure the TV has sufficient input and output jacks to accommodate your components. Often overlooked, try out the remote control to ensure it is comfortable to use and not confusingly laid out.

16:9 Aspect Ratio TV

These sets are designed to provide widescreen pictures without the letterbox effect (black bars found on the top and bottom of the screen). This is great for wide-format movies, but for conventional pictures you will either end up with a cropped picture on the top or bottom, or black bars on both sides of the picture, or picture-outside-picture on one side. Some projection sets will stretch a standard 4:3 picture to fit the screen, although this usually results in some picture distortion.

Audio and Video Inputs/Outputs

Normally there are more audio outputs than video ones. More audio and video outputs are desirable, as they allow you more versatility in signal switching of multiple VCRs, DVD players, and the like. Depending on how you decide to hook up your A/V system, either the TV or your A/V receiver can be used for video switching. Audio and video input jacks are more desirable for hooking up a VCR than putting the signal through your RF antenna connector, as they will provide you with better audio and video quality.

Cable Terminology

A common cause of confusion for shoppers is the term cable-ready. Many people incorrectly believe that a cable-ready set will allow them to receive pay services free of charge. A cable-ready set only eliminates the need for a converter box to receive basic cable programming. Except for a few 13-inch and smaller sets, every TV sold today is cable-ready. To receive premium channels, which are scrambled, you might need the converter box. To this end, many higher-end sets offer dual antenna inputs. Through the use of a signal splitter (available from your cable company or Radio Shack), you split the signal before it goes into the cable box. One signal goes directly to your TV, and the other to your cable box. The second signal then goes out from your cable box and into the second antenna input of your TV. In this way, all unscrambled programming is available on antenna A, and scrambled/premium services are available on antenna B. As long as your TV has a universal remote, it will control your cable box. Therefore, you do not need your cable company's remote (which is normally provided at an additional cost). Several years ago, a standard interconnect was agreed upon and the TV manufacturers built this interconnect into their sets. IEEE-1394 "Firewire" is a specialized digital computer cable that allows information to be passed in either direction. It is currently used in the computer industry to pass and capture digital video images from digital still cameras to your computer. Firewire lets you connect your digital TV with a myriad of digital accessories, and is instrumental in the development of new services, including digital video programming.

Comb Filter

A feature that improves resolution, picture quality, and reduces objectionable color patterns. Low- to mid-line sets use a glass comb filter. High-end sets use a CCD or digital comb filter, which greatly enhances resolution.

Component Video (Inputs/Outputs)

Also called Color Difference or ColorStream, this is the latest (and best) input/output to date. While similar to RGB (red/green/blue) connections, it separates the luminance and chrominance even further providing superior images over S-VHS. Most step-up DVD players now include component video outputs, which will also be included on most HDTV set-top boxes. Many TV manufacturers are now including these inputs on their mid- to upper-line TVs.

Dual-Antenna Inputs

This feature means your set can accommodate two antenna sources, such as a master antenna and cable box or master antenna/cable box and DSS decoder. By having dual inputs, it allows you to switch easily between antenna sources.

DVI and HDMI interfaces

There are two all-digital video connections for HDTV set-top boxes, monitors, DVD players, and some audio/video receivers: DVI (digital visual interface) and HDMI (high-definition multimedia interface). DVI sends digital video data from a source (such as an HDTV set-top receiver or progressive-scan DVD player) to a display (such as an HD-ready television), and it eliminates the need for digital-to-analog decoders. HDMI builds on DVI by adding multichannel digital audio to the digital video, so digital audio and video can be transmitted in one cable. Both DVI and HDMI incorporate HDCP (high-bandwidth digital content protection), a data encryption method that prevents video piracy. DVI and HDMI both support uncompressed data transfer, and neither is constrained by cable length limitations (up to 500 meters). HDMI is fully backward-compatible with DVI, and with its incorporation of multichannel audio, HDMI is expected to completely replace DVI in the near future.

External Speaker Jacks

These devices allow you to attach separate speakers directly to a TV for improved sound quality, or to attach rear speakers, allowing you to experience surround. The downside to this equation is based on the wattage of your internal television amplifier.

Front A/V Jacks

These jack packs found on the front of a TV (usually hidden under a panel) are a handy feature, especially for hooking up a camcorder or a video game console.

HDTV/HD-Ready

HDTV refers to a television with an integrated high-definition tuner, allowing it to display ATSC (high-definition) broadcasts. An HD-ready set has the ability to display HD content, but it requires an external HD receiver or set-top box. EDTV (enhanced-definition TV) describes a television that can display HD content but at lower resolutions than true HDTV. Nevertheless, EDTV displays are still far superior to standard analog displays.

Horizontal Resolution

Horizontal resolution is the number of horizontal lines that the television can display. Theoretically, the more lines that can be displayed, the better the picture. Broadcast television displays 330 lines, VHS tapes about 240 lines, S-VHS tapes about 400 from a pre-recorded video (330 from broadcast), and DVD about 425 lines. When broadcast, satellite, DSS, and video sources become available with greater resolution, sets with higher horizontal resolution will be able to receive an enhanced signal.

Invar Shadow Mask

Invar shadow mask gives the picture more brightness and punch. Invar is considered to be a premium feature. When sets are very bright, a side effect called "blooming" occurs. To counteract this bleeding of colors, some manufacturers include the invar shadow mask.

Notch Filter

This filter helps remove a small part of the signal that contains excess color information. By doing so, it helps eliminate some objectionable color effects. However, using this circuit creates a slight loss in picture resolution.

Number of Speakers

Indicates the number of speakers found on a particular television set. Obviously, for people who do not plan to attach additional speakers, more is better.

Parental Lock-Out or Channel Block

All sets larger than 13 inches now include a V-chip (V for violence) that allows parents to lock out certain programs if they have too much violence or sexual content. By punching in a special code (that you as the parent devise), parents can lock out children (or anyone else) from viewing specific channels or disable the TV from being used during a specified time of day.

Picture-in-Picture (PIP)

PIP lets you view two image sources simultaneously. The primary picture displays full-size on the screen, while the second picture is normally placed in a smaller box located in one corner of the screen. To use PIP, you need a second video source such as a VCR. A handful of upper-end sets include a second tuner for PIP, thereby eliminating the need to use the VCR tuner as the second video source. Advanced PIP lets you display multiple PIXs (or channels) on the screen at the same time (all are frozen except the channel that it is presently scrolling through), change the size or location the smaller box, and swap back and forth between main and PIP. Picture-outside-picture (POP; also known as picture-out-of-picture) allows the screen to be split into two equal-sized, side-by-side pictures. POP is sometimes considered a function of PIP, and many manufacturers do not distinguish between the two.

Premium Sound Systems

Manufacturers are looking for ways to come up with better sound enhancement systems. RCA and Sony, for example, include SRS (Sound Retrieval System), developed by Hughes for use in their high-end sets. SRS adds depth and more realistic sound without adding additional speakers. Similar systems have been developed by Toshiba with their Cyclone Sub-Bass System with 4-channel DSP, and Zenith with SEQ. Some manufacturers are now adding Spatializer sound to enhance their audio.

Remote

Sets have either a basic, standard, unified, universal, or learning remote. There are also a few combination universal/learning models. A basic remote controls basic functions, such as volume or channel up/down and power on and off. A standard remote is an enhanced basic model with a keypad for direct access and access to on-screen menus and displays. Universal remotes are becoming the most common remotes. They come with pre-programmed codes for both VCRs and cable boxes. Some brands offer models that are ergonomically designed with keys of different shapes, colors, and sizes. On top of that, a handful of brands include devices with illuminated keys. That's a feature you'll appreciate when trying to read those buttons in a semi-dark room. Learning remotes can be taught codes from other types of components, such as A/V receivers and surround processors. If you are trying to tie all of your components together, a learning remote might be the best option. However, at best, they can learn only primary functions for each component. Normally, you cannot get into menus from other products to adjust surround settings, for example. A learning remote from an A/V receiver or an aftermarket universal/learning unit might be a better bet for trying to tie all of your components together.

S-Video (Inputs/Outputs)

Many components besides S-VHS VCRs now include S-video jacks. S-video separates the luminance (Y) and chrominance (C) signals, offering better picture quality than standard video inputs. S-video jacks increase resolution, help color reproduction, and help reduce jitter at scene transitions. To get the most out of your video source, you must use an S-video jack for the highest resolution.

Scan Velocity Modulation

Scan velocity modulation adjusts the rate of horizontal movement of the beam as it "draws" the scan lines, which gives black-and-white picture transitions more punch. This results in a sharper picture.

Special Picture Tubes

A better grade of picture tube is normally found in larger sets. A recent innovation that has taken the industry by storm is the inclusion of either dark-tint or dark-glass picture tubes. By offering darker faceplates, these picture tubes provide greater contrast between black and white. Those brands that include darkened picture tubes have had to increase brightness levels so that the picture does not appear too dark. Most consumers prefer brightness to color accuracy. Other advancements include flattened picture tubes, which offer less distortion on the outer edges of the picture. Some manufacturers use a combination of techniques to tweak out the highest performance from their picture tubes. These sets, while costly, offer the viewer a picture with the highest resolution and provide the most lifelike appearance.

Stereo (Watts Per Channel)

Many sets include a multichannel television sound decoder (MTS), which receives and decodes all stereo signals broadcast by the networks or cable channels. Watts per channel refers to the wattage of the set's stereo amplifier. Some manufacturers' literature can be a bit deceptive if it indicates that the TV has a 20-watt amplifier. This normally means that the set can produce 10 watts per channel.

Surround

Many manufacturers include matrix surround sound or other psycho-acoustic effects to enhance the audio. It might also be called ambiance or extended stereo effects. However, more and more sets are now including Dolby Pro Logic as a means to greatly enhance the audio quality. Obviously, you must add rear speakers to obtain the desired effect. A major drawback with these sets is their underpowered amps. Even with 5 or 10 watts per channel, these amps just don't cut it. Many sets include variable audio outs for connection to an A/V receiver, but few sets offer ample wattage. Some sets also include a center-channel input, which allows you to use the TV's internal speakers for the center channel. Other manufacturers, such as Sony, Toshiba, and RCA, offer special speaker systems that are compatible with their sets for an additional cost.

Rear-Projection TV & HDTV Buying Guide

The Basics: Rear-Projection TVs & HDTVs

How to Shop

Glossary

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