When HP's 58-inch md5880n DLP and Sony's 60-inch KDS-R60XBR1 SXRD rear projectors converged simultaneously on our lab, we knew we had the prime candidates for another installment in our series of display technology face-offs. We began by calibrating and reviewing each set independently (see pages 32 and 34) before putting the TVs alongside each other in our darkened lab and tuning their pictures to match the ideal settings for brightness and color. The sets were fed the same test patterns and program material through a Gefen HDMI splitter; test signals were native 1080i HDTV or standard-def DVD content upconverted to 1080i by our high-end Denon DVD player. Al Griffin and David Katzmaier were joined by our TV reviewer Phil Ryan to fill out our panel of experts.

DETAIL One debate we hoped to squelch with this test was whether DLP could match LCoS on image detail. Both sets are spec'd at the 1,920 x 1,080-pixel resolution that defines a 1080p display, but they deliver the image differently. LCoS TVs use microdisplay chips that have a discrete 1,920 x 1,080-pixel grid; all the pixels on the chip appear simultaneously on the screen. DLP currently achieves 1080p resolution using a technique called "wobulation": the pixels are split between two fields flashed up in rapid succession, each with half the total pixels.

As it turned out, the Sony was marginally better at resolving test patterns, but the HP actually scored a bit higher in the subjective apparent sharpness of the picture, demonstrated by its ability to resolve the fine brush strokes in the close-up of an old oil painting in an HDNet travel show on Madrid. We called it a draw: these stellar sets proved that wobulated DLP and LCoS can both deliver all the goods in today's 1080i signals.

COLOR The first thing we look at in evaluating a TV's color is its ability to accurately maintain an industry-standard tone of gray as the brightness of the image increases from black to full-on white. We call this "grayscale tracking," and the HP did it very well, delivering a perfect neutral gray image on black-and-white test patterns of varying brightness. The Sony, on the other hand, also closely tracked the same hue at different brightness levels — but instead of delivering perfect gray, it lent a slight pink cast to the picture. This was mostly evident in bright scenes, such as one from the DVD of The Lord of the Rings: The Fellowship of the Ring that takes place on a snowcapped mountain. Both snow and sky looked a bit rosy or purple next to the more natural white and blue reproduced by the HP, although the effect wasn't obvious on most scenes and difficult to detect absent the HP right beside it.

SCORECARD:	DLP (HP)	LCoS (Sony)
DETAIL	•••••	•••••
COLOR	••••½	••••
UNIFORMITY	••••	••••½
CONTRAST	••••	•••••

Color accuracy was very good with both TVs as measured by test patterns, but the Sony's colors were noticeably more saturated than the HP's. It was satisfying to see such rich colors, but they occasionally looked unnatural and hyped next to the HP, especially red. That helped explain why the HP had more accurate and natural skin tones in one of the brighter scenes we viewed from the DVD of The Matrix Reloaded.

Are these differences attributable to the display technologies? For what it's worth, the rosy cast on the SXRD was reminiscent of a similar effect David has observed in earlier LCoS TVs, while the Sony's better saturation seems tied to its ability to produce a near-perfect black — something that may or may not be technology-dependent (more about that later). Either way, all things considered, our panel scored the HP slightly better overall on color.

UNIFORMITY "Picture uniformity" refers to various criteria that define how well a TV delivers a consistent viewing experience across its entire screen. For example, does the screen have "hot spots" in the middle or corners when showing full frame test patterns that fill it with one color? Does the image bow or slant? Are there motion artifacts of any kind?

The Sony had one distinct advantage here in that, like all LCoS projectors, it uses a separate display chip for each of the red, green, and blue primary colors. The HP, like all DLP rear projectors, uses a single DLP chip and a multi-segment color wheel that can cause rainbow trails to be seen along the edges of objects when the viewer blinks or "strobes" his eyes at just the right moment. Many people never see rainbows, but the simple fact is that LCoS displays don't suffer this problem.

The HP also exhibited a nearly invisible motion artifact we noticed in the Madrid travel piece in which the horizontal mortar lines of a brick building seemed to twitter a bit as the camera panned. It was very subtle and wouldn't be a problem in everyday viewing, but we wondered if it wasn't somehow related to the DLP's wobulation.

On the plus side, the HP offered more uniform color across all areas of its screen, and it had an uncommonly wide viewing angle that the Sony didn't share. Viewing angle is directly affected by the the projection screen, which Sony may have engineered to optimize light output or another characteristic of its LCoS technology at the expense of wider viewing angle. But in the end, the Sony's immunity to rainbows was enough to give the LCoS the nod on picture uniformity.

CONTRAST We've saved contrast for last because it proved to be the category that really set the two TVs apart. Some background: Both sets boast a highly desirable feature — an automatic iris or aperture in the light path that can shut down some light from the projection lamp during dark scenes to allow the TV to achieve a deeper black, and therefore better contrast, more detail in shadows, and punchier-looking colors. Only the Sony's menu allows users some direct control over the iris. The HP's dynamic aperture is turned on for most picture modes, and its setting is optimized by the source material. However, in the Studio mode, which is what we used to achieve a color-temperature closest to the industry-standard gray, the aperture is fixed at a position representing the best compromise between black level and other characteristics.

That in part may have accounted for some of the difference we saw in contrast and black level between these TVs, though probably not all of it. Even with its iris settings adjusted to minimize its effects, the Sony was the clear winner in this area. The HP still offered the more natural and neutral gray and certainly had a bright, punchy picture with excellent blacks — better than that of most other microdisplay TVs we've seen. But the Sony's black was about the purest and deepest we've encountered in a rear projector. For example, a dark bar scene from the DVD of Ed Wood, a black-and-white film, showed gobs of detail in the deep background; distant wall hangings were more clearly visible than on the DLP. Details in dark areas of clothing, such as the weave in the close-up of a deep blue sweater worn in The Matrix Reloaded, were also more evident on the Sony.

BOTTOM LINE In the end, all three of our panelists picked the Sony as their favorite, largely on the strength of its blacks. But we can't say with certainty what that proves about DLP and LCoS. At $3,500, the HP costs fully $1,000 less than the Sony for a similarly-sized TV that competes or excels in virtually every other critical area of picture quality. Could HP (or another DLP maker) start from here and match the Sony's black levels if it had another $1,000 to play with, or just by making factory adjustments to aperture or picture modes? Who knows? But consider this: at this writing, Sound & Vision has tested seven 1080p rear projectors with a mechanical iris: three DLPs (from HP and Mitsubishi) and four LCoS models (from Sony and JVC). All the DLPs produced excellent black levels that were the best we've seen from DLP, but none could match the Sony SXRDs or JVC's 70-inch D-ILA set in this area. We'll leave it to the engineers to tell us why, but for now, this round goes to LCoS.

The Final Weigh In

Al Griffin Anyone looking to Score a bigscreen HDTV will find no two better examples of the state of the art than the HP DLP and Sony SXRD (LCoS) assembled here. Having already reviewed the HP, and knowing that it costs a grand less than the Sony, I was very curious to see how it compared with its lauded rival. Good, as it turned out — and in some ways, not so good. The DLP's incredibly crisp detail not only let it compete with the more expensive TV, but it actually seemed to exceed the LCoS's picture sharpness on certain programs. The DLP also turned out to have superior screen uniformity and more natural color rendition. The LCoS's rich blacks and fine shadow detail, on the other hand, made it look dramatically better than the DLP with most movies viewed in our side-by-side comparison. Add to this a punchier, brighter-looking picture and an absence of "rainbows" — an inherent side effect with DLP rear-projection TVs — and you've got me edging over to the LCoS camp for this one, despite the HP's staggeringly good price.

David Katzmaier While I knew from our measurements of the individual sets that the LCoS (SXRD) HDTV could reproduce a deeper black, the difference didn't really hit home until I saw it side-by-side with the DLP. There was no contest in terms of deep blacks; in every scene with dark material, the SXRD was clearly superior. Its better depth of black also contributed to deeper color saturation. In scenes like a football game in bright sunlight, however, the sets looked much more equal. On the other hand, in white or gray scenes such as the snow in LOTR and the walls in Ed Wood, the SXRD was tinged with a faint but obvious reddish-purple, while the DLP was very uniform and neutral. The DLP did exhibit rainbows, or brief flashes of color, such as one I noticed in The Matrix Reloaded at the edge of a bright bulkhead next to a dark shadow. I had to look very hard to spot other differences between these two sets — to my eye they were equally sharp, and differences like color accuracy have little to do with the technology.

Phil Ryan Both of these sets did a great job delivering DVD and HDTV sources. Forced to choose between the two, I'd have to side with the LCoS for its much deeper blacks and lack of rainbow effect. I have to admit that, while I rarely used to complain about DLP rainbows, I have become more sensitive to them recently and spotted a few on the HP. To its credit, the HP served up a very consistent color from dark to light material, while the Sony suffered from a magenta color cast that was most noticeable in highlights and brighter material. In a scene from The Lord of the Rings: The Fellowship of the Ring, a blanket of white snow took on a purplish tinge that was obviously not there on the HP. But a dimly lit bar scene from Ed Wood showed off the Sony's top notch-black level, with Johnny Depp's suit jacket (and even a scantly lit beam in the background) alive with tons of shadow detail. Likewise, the LCoS's deep blacks lent an authority and believability to the picture that really helped to draw me in.

If you liked this article, you might enjoy the following:

Sony KDS-R60XBR1 60-inch SXRD HDTV
HP md5880n 58-inch DLP HDTV
DLP vs. LCD
Plasma vs. LCD

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