Editors' note, updated 10-26-2009: The picture quality results noted below were obtained from the second of two review samples we tested. The first exhibited significantly worse image quality, characterized by flashing LED segments in dark scenes. Toshiba has released a firmware update, however, which cures the problem. See this blog post for more information.
Prior to messing with any of the SV670U's extensive picture controls, the Movie mode, as usual, proved best for critical viewing. Its default color temperature, preset 2, was quite blue, however, so we selected the preset 0, the best of the bunch (although it was still pretty blue), for our Geek Box "before" measurement. We also noticed that DynaLight was turned off, which according to the manual disables local dimming and according to our observations resulted in black levels that were as relatively light and unrealistic as your average non-LED-based LCD display.
Our first order of business in our calibration was to turn DynaLight on, because if you're not using local dimming you may as well get a cheaper TV. Next we set the TV's light output to our standard 40ftl, tweaked color temperature, and adjusted the remainder of the controls to optimal positions. Gamma ended up at a solid 2.18 versus the ideal of 2.2. We tried adjusting the Color Master color management system to improve the green primary color, and the cyan and magenta secondaries, and while our adjustments has some positive effect, we couldn't get those colors to approach the HDTV standard as closely as we'd like.
For comparison purposes we lined up a number of other high-end HDTVs next to the Toshiba, including the Sony KDL-55XBR8, Samsung LN46A950, and LG 47LH90--all LED-backlit with local dimming--the LED edge-lit Samsung UN46B7000, and the standard CCFL-backlit Samsung LN52B750. We also included a couple of plasmas, the Panasonic TC-P50V10 and the reference Pioneer PRO-111FD. We returned to the extremely dark (in more ways than one) "Watchmen" on Blu-ray for most of our image quality tests.
Black level: The upside is that the SV670U can deliver very deep black levels, to the point of shutting its backlight off completely during black screens and disappearing in our darkened lab. During dark scenes, such as the initial fight between the masked assailant and the Comedian in an unlit apartment at nighttime, shadows, darkened recesses, and the letterbox bars all remained generally deep, inky, and realistic, with that characteristic high-contrast punch we've come to expect from LED-based LCD displays, as well as the better plasmas. The Toshiba ranked about the same as the LG in overall black levels on most occasions--with blacks nearly indistinguishable during dark scenes from those of the Samsung B750, A950, and B7000 LCDs, and not quite as deep as those of the Sony XBR8, the Panasonic V10 and the Pioneer.
Blooming in dark areas on the Toshiba, conversely, was more noticeable than on the other local dimming LCDs we've tested. Bright elements in otherwise dark areas, such as the Comedian's chandelier and the glow of Rorschach's flashlight, spilled over onto the letterbox bars and the surrounding darkness. Onscreen graphics, such as the PS3 menus and icons, the disc menu, the progress bar during fast-forwards, and even the TV's own menu system, caused the most obvious instances. As usual, the blooming worsened considerably for people seated off-angle from the sweet spot directly in front of the screen.
We also noticed one instance when the backlights seemed to not dim enough, which again interrupted the darkness unnaturally. It came at 14:02, right before Rorschach finds the Comedian's newspaper clipping, when what looked like very faint brighter clouding flashed briefly in the shadows. We didn't notice the issue in any other scenes, however, although it was a much more severe problem with the first sample we reviewed (see the Editors' note above).
Black levels as a whole also varied depending on the overall brightness of the scene. In the opening credits, for example, when the comic book stills faded up from black and back down, the dark areas and letterbox bars would lighten and then darken again noticeably, instead of remaining a constant level of darkness as they should. The effect wasn't as abrupt as what we saw on the Samsung UN46B7000, but it was still more noticeable than on any of the other comparison sets.
The 670U's shadow detail was excellent. As Hollis sees Dreiberg out of his apartment, for example, the stairwell above and the shaded brick wall below appeared and well-defined--a bit better than the LG and on par with the best sets in our lineup.
Color accuracy: Color on Toshiba's LED-based LCD display deserves praise for the most part. After adjusting skin tones, such as the face, neck, and bosom of Laurie in her evening dress as she meets Dreiberg at the restaurant, appeared realistic and warm, albeit not quite as close to our reference as the LG. Colors appeared just a bit less saturated in many brighter scenes than on the other sets, perhaps because the Toshiba's black levels varied a bit, but they were still rich, and the difference would be hard to see beyond a side-by-side comparison. We appreciated that blacks and shadows remained neutral--without the subtle bluish tinge seen on the Samsungs and even truer than the LG, but not as good as the plasmas or the Sony XBR8.
The Toshiba's main color-related misstep had to do with its less accurate primary color of green and secondary cyan. We noticed in areas like the graveyard slightly more neon-looking grass during the Comedian's funeral and the more greenish color to Dr. Manhattan's aura, but the differences weren't too drastic.
Video processing: Overall, the SV670U series performed relatively well in this department. Like Samsung and unlike Sony and LG, Toshiba offers a couple of groups of settings to control the processing associated with its 240Hz refresh rate. The "ClearScan 240" setting seems to affect blurring only. Turning it on enabled the antiblurring effect, while leaving it turned off reduces motion resolution, increasing apparent blurring in our test.
According to our test, the 670U delivered comparable motion resolution to the other 240Hz models we've reviewed, coming in at between 900 and 1,000 lines, compared to standard 60Hz LCDs at around 300-400. It's worth noting that the Toshiba 670U outscored the company's 240Hz, non-LED-based 650U on this test, although both evinced the same sort of random interference in the highest-frequency areas. The interference was not visible in program material we watched.
As usual, we found it difficult to appreciate the extra resolution in any case. Comparing the Toshiba to the Samsung, for example, with the latter's antiblur effect turned off (thus delivering the same motion resolution as a 60Hz display), a fast-moving hockey game didn't seem appreciably sharper on the Toshiba. Some viewers are more sensitive to motion blur than we are, but for us 240Hz's antiblur properties don't seem worth it.
The other setting is called "Film Stabilization," and it has three choices: Off, Standard, and Smooth--all three deliver identical motion resolution numbers. The difference between Off and Standard will be difficult for most viewers to discern, since neither engages that obvious smoothing effect produced by, for example, the Standard setting on the Samsung and Low on the LG displays. On the Toshiba, Standard doesn't introduce dejudder; it simply allows the TV to preserve the proper cadence of 24-frame sources, namely Blu-rays with the player set to 1080p/24 output mode. In such a setup, the SV670U series' Standard setting worked well to keep the cadence intact, removing the hitching motion seen on standard 60Hz models, for example, as the camera flies over the deck of the Intrepid during "I Am Legend."
The only Toshiba setting that does introduce the smoothing dejudder action is, well, Smooth. As usual the smoothing effect made the film look more like video, but in the Toshiba's case there was some minor judder preserved, as well as fewer artifacts produced compared to the LG--which are both good things in our book. The SV670U series lacks an ultrasmooth, even more artificial-looking dejudder mode (e.g. High on the LG and Smooth on the Samsung), but we didn't miss it.
The Toshiba handles video- and film-based deinterlacing well. On the film-based deinterlacing tests, however, the only way we could get the SV670U to pass was to engage the Film stabilization mode to either Standard or Smooth. We recommend leaving the TV in Standard mode for most sources.
Uniformity: Toshiba's LED delivered relatively even brightness across the screen, as we've seen from most local-dimming displays, although in very dim scenes and the black letterbox bars we noticed that the corners appeared a bit lighter than the middle, similar to the effects we've seen on standard LCDs.
More of an issue, and again one common to LED-based LCDs in particular, was the 670U's poor off-angle performance. The image, when viewed from just one couch cushion to either side of the sweet spot in the middle, looked markedly more washed out and less impactful, especially on the far side of the image. Blooming and the relative brightness of the flashes also increased the further we moved from the sweet spot. The Toshiba ranked at the bottom of the LED-based displays in this arena, showing more washout and even some greenish discoloration from off-angle, although they were all pretty bad.
Bright lighting: Like the Samsung LCDs, the Toshiba 670U employs a glossy screen that has a tendency to reflect ambient light sources more strongly than the matte screens of the Sony and LG models. On the flipside it maintained black level performance under bright lights better than either of the two plasmas, albeit not as well as the Samsungs.
Standard-definition: Despite the SV670U's Resolution+ processing, touted as an aide to standard-def processing, the set didn't perform very well in this category. It did resolve every detail of the DVD format, although we did see some interference in the highest vertical resolution area of our test pattern. The grass and stone bridge provided a good test of Resolution+; turning up the seven-position "level" control seemed to add some sharpness to the image, improving definition in the bridge, for example, but it also introduced edge enhancement. We could achieve a functionally identical effect, to our eye, by increasing the Sharpness control on any TV.
The Toshiba failed to remove many jaggies from rotating diagonal lines, and the stripes on a waving American flag also evinced jagged edges; engaging the Resolution+ processing had no effect we could discern on those jaggies. Switching on the Toshiba's digital noise reduction worked well to remove motes and noise from difficult shots of skies and sunsets, but the Auto function didn't have as much of an effect. On the other hand the Toshiba is one of the first TVs we've tested in a while to fail the test for standard-def 2:3 pull-down. The best setting we could find for this test, Film Stabilization: Standard, removed the moire from the grandstands but only for a split-second.
PC: Via HDMI the Toshiba delivered excellent performance, as expected, displaying every line of a 1,920x1,080 source with no edge enhancement or overscan. Via VGA the best wide-screen resolution the set could hit was 1,360x768, and although the image looked as good as can be expected at that mode, many other LCDs have VGA inputs that can do better.
|Before color temp (20/80)||8512/7048||Poor|
|After color temp||6472/6513||Good|
|Before grayscale variation||1033||Poor|
|After grayscale variation||91||Good|
|Color of red (x/y)||0.644/0.322||Good|
|Color of green||0.272/0.65||Poor|
|Color of blue||0.153/0.048||Average|
|Defeatable edge enhancement||Y||Good|
|480i 2:3 pull-down, 24 fps||Fail||Poor|
|1080i video resolution||Pass||Good|
|1080i film resolution||Pass||Good|
Power consumption: We did not test the power consumption of the 55-inch Toshiba 55SV670U, but we did test the 46-inch model. For more information, refer to the review of the Toshiba 46SV670U.