On December 31, 2006, the government is going to pull the plug on all VHF television channels, and people with old analog sets who don’t have cable or satellite will not have TV,” warns Mike Wood, editor of Digital TV magazine. “On the other hand,” Wood maintains, still referring to the FCC’s mandate for all television broadcast stations to switch over to digital transmissions, “that date might be pushed back, so nobody really knows when the change will take effect.” (Actually, a converter box can be added to our old sets, making them capable of picking up new digital broadcasts.)
Wood’s startling proclamation and the confusion surrounding the impending changeover, not to mention the fact that most consumers have no idea that such an event is looming ever-closer on the horizon, makes the task of buying a television these days a mind-boggling maze.
A numbing alphabet-CRT, LCD, DLP, EDTV, RPTV, HDTV, LCoS, DTI, DVI-and a swirling vortex of new terminology-plasma, screen burn-in, liquid crystal, 16:9-also contribute to the mayhem that even audio/video professionals have a hard time keeping up with.
Most of us have televisions that display a picture on a cathode-ray tube (CRT), the standard for televisions since the commercialization of the medium more than 50 years ago. At the back of that tube is an electron gun that fires a vertical beam of electrons scanning onto the front of the tube-the screen-which is coated with a layer of tiny phosphor dots that glow red, green or blue when excited by the electrons. The picture we see, at least in standard sets, consists of these tiny scan lines, 480 of them to be exact, flashing on the screen 60 times per second. But this relatively small number of scan lines does not allow for very fine resolution. Look closely at the picture on your standard set and you will see the lines are coarse-comparable to the coarse dots in the photos in your morning paper.
The desire to achieve finer definition is the driving force behind the development of high-definition television, HDTV, in which the scan lines are set at a minimum of 720 and up to 1080. With nearly twice or more the number of lines, you can imagine that the amount of detail allowed comes far closer to the resolution we are used to when viewing a 35mm film in a theater.
The trick is that you must have an HD-capable or HD-ready television to view these greatly enhanced broadcasts. Now the confusion begins. All HD televisions are digital sets, but not the other way around, and the FCC-mandated switch, at least for now, only states that broadcasters convert to digital by 2007, and that does not necessarily mean HDTV.
As you might already have guessed, the catalyst behind this changeover is not altruistic-it boils down to money.
“The real motivation for the government to make this switch,” says Wood, who, for several years was a writer for Home Theater magazine before taking the helm of Digital TV, “has less to do with giving people better TV pictures and more to do with the FCC selling the bandwidth [the broadcast frequency spectrum] for channels two through 13 to wireless companies so they can sell more cell phones.”
“Broadcast TV will be entirely UHF and it will all be digital,” says Randy Tomlinson, an Atlanta-based certified television calibration tech and a regular contributor to The Perfect Vision magazine. “That way you can pack a lot more information into a very small amount of that bandwidth. Instead of channels two, three or four, you’ll have something like 19-1, 19-2, 19-3 and so on. That’s because the bandwidth for the old channel 19 can accommodate five or six digital broadcasts simultaneously. However, HD broadcasts take up more bandwidth, which limits the number of programs that could be broadcast at any one time.”
“There will be more and more HD content available,” adds Wood, “but cable and satellite systems have a vested interest in having 500 channels available, so you will not see a total conversion to HD because that would effectively reduce the total number of channels available to maybe 100 and that just won’t happen, even though the FCC has also mandated that at some point, all TVs sold must have an HD tuner.
“Be that as it may, I think buying an HD set is the way to go today,” Wood says, “because there is already a lot of broadcast content out there and since HD sets can take advantage of progressive scan DVD content. The improved playback of films and concerts on progressive scan DVD players is alone worth the slightly extra expense of the HD set.”
Another dilemma facing TV buyers is screen shape. Our trusty old CRT sets are roughly square shaped with a measured horizontal-to-vertical ratio of four units by three units (4:3). But most films are widescreen and, to be viewed properly, need a wider rectangle than this. If you rent letterbox-formatted DVDs, you’ve seen this shape, even on a 4:3 set, which displays black bars top and bottom to fill out the square. This wider screen size is measured at 16 units by nine units (16:9). “Usually I’d suggest getting a 16:9 screen,” Wood says, “but some screens suffer from screen burn. If you watch a lot of 4:3 material with plasma screens and rear-projection CRT sets, you will burn-in the phosphors in the middle of the screen, and when you watch 16:9 material you will really notice that dimmer area in the middle.”
Today’s sets break into two main groups: the direct-view sets such as the standard CRT and flat-panel screen LCDs and plasmas; and projection sets, which come in rear- and front-projection varieties.
Far and away the most prevalent technology is the CRT, which offers familiarity among its many advantages, but it also has downsides. “CRTs do dark colors and blacks like nothing else if adjusted properly,” claims Tomlinson. “And they can show resolution and detail in dark areas other screens can’t touch. Plus color fidelity is usually slightly better than plasmas or LCDs. The potential for a great picture is very, very high. Unfortunately you have to deal with a box that weighs 200 pounds and takes up a lot of space. Besides, you can’t make a picture tube with very high resolution and still get a high level of light out of the picture.”
The Norah Jones of the video-display world is plasma, the pet home-entertainment device of people who are “looking for something really cool,” as Wood sees the increasingly popular format. “I don’t think plasma is a technology that will be around much longer. I think they will come up with something different because plasmas are so delicate. But they make a nice picture. If you have the money to go super thin and you’re OK with plasma’s downsides, then by all means, go nuts.”
Wood describes the workings of a plasma screen as “something like an egg crate” in which each cell of the crate represents one pixel, and each of those has three subpixels consisting of a red, a green and a blue phosphor. “The computer processor creates a grid of the image and, according to what the image is, lights up the appropriate phosphor with the help of a plasma of neon and xenon gas. If it’s supposed to be red, the red phosphor lights up; if yellow, the red and green light up; if white all three phosphors light up and so on.”
So what are those downsides then, and what about the good stuff plasma is capable of?
Tomlinson says, “Plasmas are incredibly detailed and bright. For watching in a brightly lit room, there is probably nothing better. They are light and thin and can be mounted on the wall. With a plasma you can get a very large picture and you can put it about anywhere. You can also achieve very high HD resolution which you can’t get with a direct-view CRT.”
On the other hand, “Most plasmas don’t have perfectly accurate colors,” Wood says. “The red shifts a little orange and the green is often a lime green. Plasmas also suffer severely from burn-in, meaning that any static image that stays on the screen too long, like the ticker tape scroll on CNN or other news channels, can exert additional wear on that part of the screen and the image can burn into the screen permanently.
“One thing to remember,” Wood advises, “is that most of the $3,000 plasmas, like the ones you get at Costco or Best Buy, are not HD, but EDTVs-that is, Extended Definition TVs. That is great for DVD, but HDTV signals will be scaled down, resolution-wise, and you will lose some definition. In higher priced plasmas you get into higher resolution screens, anywhere from 720 to 1080.”
The other flat-panel display, the LCD, is familiar to anyone with a laptop computer, where this technology is the screen of choice. Tomlinson says, “The LCD is a sandwich composed of a liquid-crystal material between two glass plates with a fluorescent backlight used to illuminate the crystals.” Wood picks up here: “Each individual pixel contains a red, blue and green element, and the video processor directs each of these to become opaque or translucent, or something in between, allowing the backlight to shine through in the proper amount, according to what is needed to compose the picture. And because we are dealing with a strong backlight, LCDs can be very bright. Conversely, because of this, LCDs do not do blacks very well. Dark areas usually seem to be washed out, a bit flat. Plus, the pixels are relatively far apart, so it often appears that you are looking at the picture through a screen door.”
But LCD does have some advantages. According to Tomlinson, the LCD image is “sharp as a tack, every bit as sharp as plasma.” Wood adds, “LCDs don’t burn-in like plasmas. You can watch CNN or the Bloomberg channel all day long and it won’t affect the screen.”
Projection sets, the second major category of displays, break down into a couple of subgroups: the far more common rear-projection sets and the often very expensive front projection sets. And they each comprise three major technologies.
The first and most prevalent of the rear-projectors is the CRT rear-projection set. These, Wood says, “consist of three small CRTs, one each for red, green and blue, built into a cabinet, and each with a lens to project an image onto the screen in the front. You have all the advantages and disadvantages of the direct-view CRT except that the rear-projection set is capable of higher resolution because you are no longer putting all three colors onto one screen of phosphors. Instead you have one tube dedicated to each individual color, and that allows higher resolution.” On the downside, “you have to converge three colors into a single image on the screen. That’s largely a maintenance issue, but most people don’t realize that over time, those three CRTs will drift in different directions and that they can do something about it. To get the picture spot-on again, it is usually just a matter of reconverging the three images, something done fairly simply by the consumer.”
Tomlinson gives these sets a rave review. “The rear-projection CRT is probably the most bang for the buck of all HD sets out there. You can get one for well below $2,000 and even the really, really good ones are not much more than that. For watching movies, it’s hard to beat them.”
The DLP (digital light processor) rear-projection set is a technology apparently poised to give the CRT a run for its money. It is based on a thumbnail-size chip developed by Texas Instruments that, according to Wood, “contains millions of microscopic mirrors which flip ridiculously fast, reflecting light from a bright bulb onto or away from the screen. A color filter wheel spins in front of the chip to add color to the image. You get all the advantages of a fixed pixel screen like a plasma, but no convergence or burn-in problems as with other sets. Plus, the cabinet is far smaller than the CRT rear-projection set, only about 16 inches deep. All are HD-capable, plus you can get bigger and brighter images and very good, saturated colors.” Tomlinson adds, “DLP is the most advanced of the rear-projection sets and the most likely technology to overturn the CRT. Every year they just get better.”
There is also an LCD version of rear-projection display. “But for that,” Wood says, “you can just copy your notes for the LCD direct-view set.”
As for front-projection sets, you can choose from a CRT version, a DLP version or an LCD version. Similarly, Wood says that these have the same advantages as their other configurations with the exception that CRT front-projection sets will “produce the best image you’ll see anywhere, but the maintenance is ridiculous, the cost is ridiculous and the projectors are just huge.”
When it comes to selecting the best television for your particular needs, Tomlinson’s advice is to “balance the way you’re going to use the TV with cost and each TV’s strengths and weaknesses. In our magazine, we try to drill into people that there is no perfect technology. You have to weigh all the advantages and disadvantages to come up with the ideal choice. That often comes down to which set can handle dark and black images the best. It’s difficult to go into a dealer’s showroom and pick out the best set.
You never know how their sets are adjusted. Ideally, when a set goes to a darker scene you should see anywhere from black to dark gray. You shouldn’t see an overall color tint of red or green to the picture. If you see a black and white picture, there should be no color tint at all. Take some of your favorite DVDs to demo, particularly movies with dark scenes. The dealer will have a fit because his sets might look really bad with dark content, particularly if you compare plasma with a rear-projection CRT-you’ll see the inability for that new technology to do blacks compared to the old technology of the CRT.”
Wood has some additional tips. “In dark or bright areas, make sure you still see some detail. On a dark suit, make sure you can see the lapels and on white objects like clouds or tablecloths, make sure they don’t become just a white mass. Also, colors should look reasonably natural. If flesh tones seem natural, make sure you can still see vibrant blues and greens. You should not see any ringing or ghosting around images. If text comes up, it shouldn’t have lots of little black and white lines around it. Plus, assess your own viewing environment. If you always watch TV with the lights on, make sure the lights are on in the store.”
The last thing to consider is setup. Let your dealer install the set and then give your TV a careful fine-tuning. The ISF (Imaging Science Foundation) trains and certifies technicians who can come into your home and make critical color and picture adjustments for somewhere between $300 and $500. If you can’t afford that, you can buy a test disc like Digital Video Essentials (available at videoessentials.com), which offers not only a myriad of test patterns to properly adjust your screen via its front panel controls, but it also includes audio tracks to ensure proper levels and placement of speakers for your surround-sound system. If you are assembling, or already have, a multichannel home-theater setup, this disc will, if followed carefully, work wonders, assisting you in getting the most out of your system. I monkeyed around with my four-year-old Trinitron using the disc and was surprised at how much better the color was, even with the most basic of adjustments.
“Any set can benefit from calibration,” Tomlinson says. “If you spend a lot on a TV, you probably want it to look its best. Many sets look terrible right out of the box but can be drastically improved with calibration.”Originally Published