Cnet.com
By: David Katzmaier
October 23, 2009

We're willing to bet that when Vizio announced the VF551XVT back in January, plenty of savvy HDTV bargain hunters marked down "June" as the time they'd buy this 55-inch LED-based LCD. Then the company pushed its release back to September. Then it announced that the "Via" VF552XVT--basically the same as this model with one of the most compelling feature packages we've ever seen, including a Bluetooth remote and Wi-Fi connectivity to complement a robust suite of interactive services--would be shipping in November for the same price. Suddenly the much-anticipated VF551XVT seemed a bit less impressive.

For the sub-$2,000 price, however, this Vizio still delivers impressive picture quality to big-screen shoppers who can't wait for its successor or don't care about interactive doodads (and no, there's no way to upgrade a 551 to get Via functionality). Its black levels are among the deepest we've tested this year, and while the fluctuating backlight may give videophiles pause, it's not a deal-breaker. The VF551XVT also succeeds on most other performance fronts, although we can't say the same about its styling. Like all big-screen LCDs the Vizio's main competition comes from similar-size plasmas that cost even less, but if you have your heart set on LCD, the Vizio VF551XVT is currently the over-50-inch bargain of the year.

Design
[Editors' note: Many of the Design and Features elements are identical between the VF551XVT and the VF550XVT we reviewed earlier, so readers of the earlier review may experience some déjà vu when reading the same sections below.]

Vizio's big-screen LCD looks unassuming for the most part, with the standard glossy black frame surrounding the picture area. But the nondetachable speaker bar along the bottom, with its silver coloring, reflective supports, bulbous shape and see-through panel exposing the wall behind the TV, assumes a bit too much, and we predict you'll either love it or hate it. We fall into the latter camp. The only external difference between the VF551XVT and the VF550XVT is the former's addition of an illuminated row of "tech logos" on the left-hand side. There's a menu item that promises to disable the illumination, but it didn't work on our review sample.

The 55-inch VF551XVT measures 51.5 inches wide by 36 inches tall by 13.5 inches deep and weighs a svelte 90.2 pounds with stand attached. Remove the nonswiveling stand and its dimensions become 51.5 by 33.9 by 5 inches and its weight 78 pounds.

We liked Vizio's large remote, with its oversize chrome-colored cursor pad surrounded by well-spaced, easily differentiated, yellow-backlit keys. Highlights include a section that offers direct access to different input types, "A, B, C, and D" keys for other devices, such as cable boxes, that double as picture-in-picture controls, and the capability to command three other devices. Many of the keys double-up, but the remote handles these well--we appreciate that the oft-used key to control aspect ratio shares the bright red "record" key, for example.

The menu system for the XVT models squeezes onto the left side of the screen, and it's hard to mistake the bare-bones graphics for a Samsung or Sony menu. We found ourselves annoyed at the fact that you can only see one parameter at a time and that too much scrolling is required to access all of the settings. On the plus side we liked the text explanations of various menu items.

Features
LED backlighting with local dimming highlights the Vizio's feature set. Local dimming, which Vizio calls Smart Dimming, means the array of LED zones behind the screen can be individually dimmed or brightened according to program content, which allows the TV to produce deeper black levels than would otherwise be possible.

Vizio also claims a 240Hz refresh rate, which is designed to combat blurring in motion. There are two species of 240Hz and Vizio employs the "scanning backlight" variety, which augments the usual 120Hz technique of doubling the standard 60-frame signal with a backlight that flashes very rapidly on and off (much faster than humans can perceive) to help reduce motion blur. In our tests the other 240Hz technique, which actually quadruples the standard signal and is used by Sony and Samsung, produced better results than Vizio's method, which is also employed by Toshiba and LG. See performance for details.

Vizio's implementation of dejudder processing is similar to past 120Hz and 240Hz displays, which force you to engage the smoothing effect if you want to enjoy the benefits of reduced blurring. 2009 models from Samsung and Toshiba, on the other hand, allow you to separate the two functions, an option we really prefer to have. The VF551XVT has offers three strengths of dejudder and also offers a separate "Real Cinema" function, although the latter had no effect we could discern.

A good selection of picture adjustments is on-hand, including a whopping nine fully adjustable picture modes. Four of these modes, Golf, Baseball, Basketball, and Football, serve to perpetuate the mistaken notion that picture settings can be optimized for particular sports. In case you're wondering, we detected no discernable benefit to watching a Football game in said mode as opposed to, say, Golf mode, but it's nice to have the extra adjustability afforded by four additional picture modes, regardless of their names. Unfortunately, none of the picture modes are independent per input.

Vizio SV470XVT
The extra-tweaky viewer can adjust Red, Green, and Blue gain and offset for each of the four color temperature modes.

We liked that Vizio included adjustments for all four of the color temperature presets, allowing you to tweak them to your liking. There's also a range of options that should mostly be left off for high-quality sources. There are three strengths each of two varieties of noise reduction, four Color Enhancement modes, and an Advanced Adaptive Luma setting that adjusts the picture according to program content.

Aspect ratio control on the VF551XVT is about average, with only three options available for HD sources and four for standard-def. In Vizio's favor the default HD mode, labeled "Wide," does not scale 1080i and 1080p sources or introduce overscan, but we wish there was another mode at least that provided some overscan, for those channels with interference along the extreme edges of the image.

Regarding other features we did appreciate the inclusion of a versatile picture-in-picture option, which goes missing on many HDTVs these days. The USB input on the side allows the TV to display videos, photos and music on the big screen. On the other hand the Vizio is missing a dedicated power-saving mode.

Vizio VF551XVT
With four HDMI inputs and a PC input, Vizio's the colorful-coded rear connection bay packs plenty of ports.

A whopping five total HDMI inputs highlight the excellent connectivity of the Vizio VF551XT. The company located four on the back panel and placed a fifth on the side, for as many HDMI inputs as we've seen on any HDTV. The side panel also sports one of the two component-video inputs, along with an AV input with composite video and the USB port. The back gets the second component input, a PC input (1,920x1,080 maximum resolution), an AV input with composite and S-Video, an RF input for antenna and cable, an optical digital audio output and an analog stereo output.

Vizio VF551XVT
The side panel is likewise packed with connections, including a fifth HDMI and a second component-video jack.

Performance
The Vizio VF550XVT's picture competes well against the better LCDs and plasmas we've reviewed this year, enough to score an "8" in this category. Deep blacks are its strong suit, and while they come at the expense of some contrast and a variable backlight, the tradeoffs are not too severe for most viewers. Meanwhile the set gets most of the other picture quality categories right, aside from that constant LCD bugaboo: viewing angle. That said, it still can't beat the better Panasonic plasmas we've reviewed this year, such as the similar-size Panasonic TC-P54G10.

TV settings: Vizio VF551XVT

Setting up the Vizio VF551XVT for optimal picture quality meant starting in Movie mode, which had default light output of 50ftl, a slightly dark gamma, and a default color temperature that was also uneven. Unfortunately, adjusting the available user menu controls didn't help much. We dialed in our nominal 40ftl light output, but the resulting gamma was even darker (2.6 versus the 2.2 ideal), and we were unable to smooth out the grayscale much--this set could really use a selection of gamma presets and a more linear grayscale. The lack of a color management system also prevented us from correcting the slightly off primary color of green.

Geek Box:

TEST                                                           RESULT                      SCORE
Before color temp (20/80)                      6800/6244                  Good
After color temp                                    6512/6499                  Good
Before grayscale variation                      187                            Good
After grayscale variation                        276                            Average
Color of red (x/y)                                0.646/0.326                Good
Color of green                                     0.286/0.642                Average
Color of blue                                        0.151/0.056                Good
Overscan                                            0.0%                          Good
Defeatable edge enhancement               Y                               Good
480i 2:3 pull-down, 24 fps                     Pass                           Good
1080i video resolution                           Pass                          Good
1080i film resolution                             Pass                           Good
 
Power consumption: Thanks to its aggressive backlight variation and LED technology, the Vizio VF551XVT is one of the most efficient HDTVs we've ever tested. Its post-calibration number surpassed that of the Samsung UN55B8500 handily, although its default picture setting consumed about 30 watts more. In either case it's a power sipper of the highest order.

For our comparison lined up some of the best flat panels we've tested this year. They included the Samsung UNB8500, the Sony KDL-55XBR8, the LG 47LH90 and the Toshiba 46SV670U from the local dimming LED camp, as well as the Samsung LN52B750, the Panasonic TC-P50V10 and the Pioneer PRO-111FD to represent the best of the standard-backlit LCD and plasma camps, respectively. We reverted to an old favorite for our principal image quality tests--"Watchmen" on Blu-ray.

Black level: In dark scenes the Vizio is capable of producing a deeper shade of black than any LCD display we've tested this year aside from the Samsung 8500. Scenes like Chapter 3, when Rorschach investigates The Comedian's apartment, had that realistic, inky quality in black areas, shadows and the letterbox bars, lending a level of realism that only deep blacks can. In the very darkest scenes, such as the 19:24 mark when Dreiberg enters his darkened apartment, the Vizio went darker than even the Panasonic V10 plasma; it equaled the XBR8 in this scene and surpassed the other displays (aside form the 8500 and the Pioneer plasma). In brighter scenes we noticed much less of a difference, however, and in such scenes the Vizio's letterbox bars in particular got lighter than many of the other sets'.

Adjusting the Vizio for those dark blacks meant sacrificing some contrast and shadow detail, however. In Dreiberg's apartment, for example, the sliver of light in his doorway appeared noticeably dimmer on the Vizio than on any of the other sets. The same goes for bright parts of other dark scenes, like the windows in the bright cityscape at the 12:24 mark. It appears that to achieve its deep black levels, the Vizio dims its entre backlight, which has the effect of reducing contrast. We could have increased the backlight control to compensate, but that would have brightened the Vizio's superb black levels.

We definitely prefer deep blacks and dimmer highlights to bright blacks and bright highlights, but the V10 and the XBR8 seen next to the Vizio looked slightly punchier overall in mixed dark-and-bright scenes, which comprise a large number of moments in the often noirish "Watchmen." That said, the Vizio still looked superb in these scenes.

The Vizio's shadow detail also didn't match that of the other HDTVs in our comparison. When the camera flies from the dark street and up the side of the building at the beginning of Chapter 3, for example, we couldn't discern the sewer grate or the same level of detail in the bloodstain as we could on the other sets. The same went for details in Dreiberg's workshop at the 21:00 mark, before he flips on the lights. If the Vizio allowed a higher gamma setting it could probably alleviate some of these issues; increasing the brightness control did reveal a few more details, but compromised black levels too much for our tastes.

One positive effect of dimming bright areas on the Vizio is an apparent reduction in blooming. In scenes with adjacent black-and-white material, such as the light from Rorschach's flashlight in Chapter 3 when it hits the border of the bottom letterbox bar, the Vizio was nearly as good as the Samsung 8500 at preventing the light from spilling into the bar. We still saw blooming when we looked, especially in the bars or around the white text on a black background (like the menu of our PS3 when we stopped playback), but we never found the effect distracting during program material. The effect did increase when we brightened the backlight, however, and afterward was about on-par with the LG and worse than the XBR8, although still better than the Toshiba.

We did find the Vizio's backlight fluctuations distracting in some scenes. The opening credits, which fade up in and out over comic book tableaus, provided the best example. The entire backlight would dim and fade to black, then abruptly turn back on when the image brightened. We saw the same abrupt change around the 1:27:00 mark after Laurie Jupiter KOs the agent. The abrupt changes only occurred during extended fades to black, however, and they weren't as annoying as we saw on the Samsung B7000, for example.

Color accuracy: The Vizio's color acquitted itself well for the most part, with solid primary and secondary colors and a grayscale that wasn't too far off. But in midbright areas, as we mentioned, the scale turned bluish to a noticeable degree, which led to less accurate skin tones. In the restaurant scene in Chapter 8, for example, the zoom in to Laurie Jupiter's face as she sees Dreiberg revealed a slightly paler, cooler tone to her face and bare shoulders, as opposed to the warmer, redder tone seen on our reference displays and the other TVs in the room.

Perhaps due to the somewhat dimmer highlights, saturation in that and other midbright scenes suffered a bit in side-by-side comparisons, although it improved as the image brightened. We also appreciated that darker areas of the picture remained relatively neutral. Yes, blacks and shadows were somewhat redder than we saw on the plasmas and the 8500, but they lacked the green tinge of the XBR8 and looked truer than most of the other sets.

Video processing: First off we checked out the Vizio's motion resolution and were surprised that it didn't score as well as other 240Hz displays. On our test pattern we counted between 600-700 lines of resolution, just a bit more than we'd expect from a 120Hz model, as opposed to the 900-1000 lines we've seen on other 240Hz models with scanning backlights (namely, the LG and the Toshiba). Turning off dejudder dropped the Vizio down to between 300-400 lines, which is standard for any LCD. As usual, however, it was impossible for us to discern any blurring or other visible effect of this difference in program material, as opposed to test patterns. The Vizio also correctly deinterlaced both film- and video-based material.

The dejudder processing used by Vizio, found under the Smooth Motion Effect menu, performed relatively well, with fewer artifacts than many such modes we've seen in the past, and better performance than we saw on the VF550XVT. Low was the most acceptable setting to our eyes, while in Medium and High modes the incidence of artifacts increased. In Laurie's interrogation in Chapter 22, for example, we noticed some breakup and interference in the birch tree wallpaper during the initial zoom toward the room, and some breakup of the shaking heads of the scientist and subsequently Nixon a bit later, but such effects were rare in Low mode. As usual our biggest objection to such modes was the artificial, videolike look they all imposed on the film, smoothing out motion too much. Notably, we couldn't see much difference when we engaged either of the Real Cinema settings.

We much preferred leaving dejudder turned off and allowing the Vizio to handle 1080p/24 sources without too much smoothing, something it did well. We checked out our favorite test, the helicopter shot over the deck of the aircraft carrier from "I Am Legend," and saw the proper cadence of film, without any of the hitching stutter of 2:3 pulldown. Again that's an improvement over the VF550XVT.

Uniformity: The Vizio exhibited the same poor off-angle performance we've seen on other LED-based LCDs--its excellent black levels washed out to a large extent when seen from seats other than the sweet spot directly in front of the screen. Moving one seat cushion in either direction on the couch caused the opposite edge of the screen to lighten noticeably, and of course moving further off-angle worsened the picture. The effect was as pronounced or more so than we saw on any of the other LED sets in our test, and we suspect the Vizio's off-angle washout appeared more evident because it had more depth of black to lose than most of the other displays. The non-LED Samsung B750 fared better, and of course the plasmas were basically perfect from off-angle.

The Vizio's screen delivered commendably even brightness across its surface, equaling the XBR8 and the plasmas in this arena. It didn't show the slightly brighter sides we saw on the Samsung LCDs, and the corners were basically as bright as the middle on our review sample.

Bright lighting: Under bright lights the matte screen of the VF551XVT strutted its stuff, attenuating reflections better than the glossy-screened Samsung and Toshiba LCDs as well as the plasmas. As usual there was a tradeoff in black-level performance under bright lights, where the glossy screens came out ahead, but it was minimal in our opinion. The VF551XVT still showed lots of contrast under lights, and handily outperformed the plasmas in this regard.

Standard-definition: With lower-resolution standard-def sources, the VF551XVT performed quite well. It delivered every line of the DVD format, and on our test disc's bridge and grass the details looked as sharp as we'd expect. The set was as good as the LG and the Samsung at squelching jaggies in moving diagonal lines and a waving American flag, and better than the Panasonic and the Sony. Noise reduction functioned well, and the Strong setting should please people who simply want the cleanest look possible with lower-quality sources--it knocked out motes and noise almost completely, without sacrificing too much sharpness. Finally the Vizio handled 2:3 pulldown detection with no problems, eliminating moire from the grandstands behind the test disc's racing car.

PC: As with most Vizios we've tested in the past, the VF551XVT made a superb big-screen PC monitor. When connected with either HDMI or VGA it displayed the full resolution of 1920x1080 sources with no overscan and crisp text. The only flaw was visible edge enhancement via VGA that we couldn't remove using the standard controls.