Choosing a Video-Display Technology: What kind of HDTV set is right for you?

The Perfect Vision reviews a lot of video gear—and video displays especially. We cover as much ground in our reviews as we can and offer as many comparisons among technologies as we can, but we also keep our word counts tight and move fast so we can cover as many products for you as possible. So every once in a while it’s nice to stretch our legs a little bit, get outside of the review process, and comment on what’s happening in the ever-changing, quickly evolving world of display technology.

In this article I’m going to offer an overview of the knowledge we’ve gleaned from our experiences living with currently available display technologies, focusing on movie-enthusiast- level performance. I’m going to talk about where we are now and where we are headed in the near future.

CRT: The Prehistoric Monster

I ripped off that line from Randy Tomlinson’s review of Sony’s stunning KV-34XBR960 in Issue 63, which is an excellent place to start. Sony’s ultra-high-resolution Super Fine Pitch tube has practically reinvented the CRT at a time when it’s about to go away. This is a broadcast-quality picture, now selling at retail for $1899! We reviewed this 34" direct-view set, as well as three 30" direct-view CRTs from major manufacturers, and found that with the exception of form factor, size (both the screen and the box), and light output, the CRT direct-view, allegedly in its last days as a viable technology, dominates its flat-panel counterparts in virtually every aspect of image quality. In particular, CRTs have practically infinite contrast ratio as a result of their ability to do blacks that are, in the words of Spinal Tap’s immortal Derek Smalls, “none more black.” What’s more, CRTs do colors that are strikingly more vibrant and far more natural-looking than their digital competitors.

Both of these attributes have earned the CRT direct-view ardent support from movie lovers. Fans of this technology also admire its striking clarity and depth, which is enhanced in some ways by its forgiving nature with the artifacts that plague many broadcast signals. CRT beam spots are tightly focused in the center and gently fade out at the edges. Pixels are digital in every respect, crisp and uniform from edge to edge with no soft fade to hide the warts. Ruthless, in a word.

But the reasons the CRT is being shown the door are still there. Although the images are sumptuous, CRT screen sizes aren’t big enough for most dedicated-theater environments— 16:9 direct-view CRTs top out at a den-sized 34" diagonal. Worse, in spite of their diminutive screen sizes, CRTs have big, deep room footprints and often tip the scales at a backspraining 200 pounds or more.

CRTs are a hard bargain, but if you can get around these issues, your eyes will feast on breathtaking, natural images other technologies can’t equal. And the category is at its zenith with respect to quality. CRTs are better than ever, but it may be now or never for buying one.

Flat Panel: The “It” Girl

TV hanging on their wall and those who want to have a cool flat-panel TV hanging on their wall. Flat panels are the CE industry’s “It” girl, and all sales projections indicate spectacular growth in this category in the next few years. As you’ve gathered from what I wrote above, flat panels solve some of the CRT’s problems, but fall down by comparison in other ways. Let’s look at the two currently prevalent flavors of flat panel: plasma and LCD.

A funny thing happened a couple of years ago when the plasma panel was poised to take over the Earth. The LCD flat panel roared onto the scene out of nowhere, with the help of some very aggressive marketing. I’ll leave it to the marketing guys to convince you which of these panels has a longer life-span. I’m more interested in performance, and I think you should be more interested in which technology’s set of tradeoffs works best for you.

Plasmas are available in smaller sizes, but 42" is where the action starts, and, while we’re seeing some prototypes of larger models, 60" diagonal is roughly where it ends. The 42" models represent a sweet spot in manufacturing efficiency and it’s showing at retail. These things are getting cheaper every day, with attractive, HD-pixel-count models starting at $2000.

In addition to hanging a larger image on the wall with a 4" profile, plasma light output typically outshines CRT and is eclipsed only by LCD flat panels. But that prodigious light output comes at a price. While plasma’s combination of light output and high resolution is dazzling with bright, video-based material like HD sporting events, it has always struggled to make the convincing blacks and shadow details that draw movie lovers to CRTs. This has prevented us in the past from recommending plasmas as a primary display for a theater environment, relegating them to use as bedroom or secondary displays. In the last year or so, however, we’ve seen the first plasma panels with the black-level/contrast-ratio chops to make them worthy of recommendation to movie nuts. We obviously hope to see this trend continue.

High-resolution pixel counts and even higher light output than plasmas, but, as you might guess, they pay the price for that light output in washed-out blacks and poor contrast. In brightly lit rooms LCD flat panels will actually hold their contrast better than plasmas, due to differences in the screen materials and reflectivity. On a showroom floor LCD’s sharper-than-life resolution, blazing light output, and on-axis immunity to ambient light draw people’s attention away from the plasma sitting next to it. But when these folks get home and dim the lights for movie night, the LCD’s weaknesses with blacks become apparent. Currently plasmas are a better choice for people who value watching movies with the lights down; LCD is a better choice for smaller screen sizes in brightly lit rooms, when movies aren’t a paramount consideration. Another spec that LCD manufacturers cite over and over again is response time. Images unequivocally linger on LCD panels longer than with plasma. Early models showed distinct trails with moving objects on screen. New models are better and, indeed, boast improved response times, but it’s important to know that specified response times can be based how long it takes the driving electronics to switch the pixels to “off,” which is not a true indicator of how long the images actually take to decay on screen. Some people will be bothered by this phenomenon more than others, but the fact is plasmas don’t have lagging response time.

All of LCD’s issues seem to be exacerbated at larger screen sizes. (These bigger sets are also more expensive than comparably sized plasmas.) Some manufacturers apparently realize this and are selling plasmas in screen sizes of 37"-and-above, and LCDs in the smaller sizes, where they are priced more attractively.

The wild card in flat panel is Toshiba’s SED (Self-Emitting Diode) technology, a hybrid of plasma and CRT in both technology and performance. Toshiba claims SED will yield full 1080p pixel counts with better light output and vastly better blacks than plasma. Early demos have looked promising, but we won’t know more until we see production units in 2006.

RPTVs: Big Screens in Transition

Like the direct-view category, RPTVs are rapidly transitioning to fixed-pixel microdisplay technologies with mixed results in terms of performance. CRT RTPVs are still available, and last we checked were offering excellent performance at bargain prices.

There are two kinds of people in the world: those who have a cool flat-panel Outside of typically minor geometry and convergence errors, CRT RPTVs potentially offer few performance compromises. Resolution and colors are excellent, and thanks to deep blacks, contrast is phenomenal and currently unmatched by fixed-pixel RPTVs. While some microdisplays may offer higher light output, CRT RTPVs are plenty bright and capable of making terrific pictures even in fairly brightly-lit rooms.

Microdisplays mostly eliminate convergence and geometry issues and offer a bright image that’s very crisp due to the nature of discrete pixels. Most casual observers will subjectively find a fixed-pixel display “sharper” to the eye than a CRT that actually has higher resolution. But the big thing microdisplays offer is that they’re much smaller and lighter than the CRT big screens. And that’s not even counting the 7" deep models that can hang on the wall!

DLP has made enormous inroads in RPTVs just as it has in front projection. DLP RPTVs are available only in single- chip configurations, which means a color wheel and its concomitant problems are front and center. Viewer fatigue and color separation rainbow artifacts have been diminished greatly in recent-generation DLPs but are nevertheless a fact of DLP life.

Further, DLPs are now showing up with lower pixel counts, using “Smooth Picture” pixel-shifting technology to generate 1280x720 on-screen pixels from 640x720 chips; soon, this same technique will be used to create1920x1080 pixel images from 960x1080 DLP chips. Our initial observations suggest that this technique is not entirely seamless, but we need to see more examples to be sure.

DLP’s chief advantage over other projection technologies is in its rich, dark, ever-improving blacks. Interestingly this advantage doesn’t seem to hold up in rear-projection applications. Perhaps having the lamp always on, in conjunction with the mirrors and other light-path components of RPTVs, makes that impossible. But what this also means is that the rapidly expanding three-chip technologies we’re seeing in RPTV have an advantage over DLP. Why live with a color wheel if you don’t have to?