The one limitation to local-dimming LED technology is that, because the number of LEDs used in the backlight is not a 1:1 ratio with the number of pixels, the lighting is imprecise, causing a glowing effect. This effect is most evident in stationary or slow-moving scenes where a few bright objects are surrounded by a completely black background. For instance, in an episode of Sunrise Earth on Discovery HD, when the moon hangs in a still-darkened sky, the 46SV670U's local-dimming function created noticeable glow around the moon. End credits featuring white text on a black background is another good example of a scene where the glow is readily apparent. In these specific cases, the 46SV670U exhibited more glowing effect than the LG 55LH90 and was on par with the older Samsung model. However, when I switched to scenes that had more movement and more juxtaposition between light and dark elements--even a dark sky filled with stars--the glowing effect wasn't as obvious. In dark scenes from The Bourne Supremacy (Universal Home Video), Casino Royale (Sony Pictures Home Entertainment), and The Pirates of the Caribbean: The Curse of the Black Pearl (Buena Vista Home Entertainment), the 46SV670U produced nice, deep blacks with no pronounced glow--and it did a very good rendering of fine black details. In these scenes, the Toshiba and LG's black-level performances were comparable. Each TV's processor seemed to interpret light levels differently, causing the local-dimming effect to react differently. Sometimes black areas looked darker on the Toshiba; sometimes they looked darker on the LG. Overall, I'd call it a draw--and both models certainly offer better black-level performance than you'll see from a traditional CCFL-backlight LCD.
One other note on black level: like Samsung's Ultra Clear Panel, the 46SV670U's CrystalCoat front panel is reflective, designed to reject ambient light to help blacks look darker in a well-lit room. This proved to be effective. In a brighter viewing environment, the Toshiba's blacks consistently looked deeper than those of the LG, which has a standard matte screen.
With the past few Toshiba TVs I've reviewed, color has been a concern. Previous models had a very green push and lacked direct access to white-balance controls to fully correct the problem. In this respect, the 46SV670U offers needed improvement. The picture looks more natural, no longer veering excessively green. That's not to say the color palette is entirely accurate. The default color temperature is slightly cool (or blue) with bright content and noticeably cool in darker scenes. Frankly, this color temperature will probably appeal to many consumers, as it gives whites more pop. However, for those people (like me) who prefer a warmer color temperature, I was able to use the RGB offset and gain controls to dial in a more neutral temperature across the board. As for color points, the 46SV670U serves up rich but natural-looking reds and blues, but green and yellow are somewhat off the mark. This was evident when watching football or golf: The grass had an unnatural, overly yellow hue. Once again, the menu includes ColorMaster controls to precisely tweak each color point, and I was able to adjust greens and yellows to more closely mimic my reference display. Overall, while the out-of-the-box color is pleasing, the calibrated image, combined with the TV's fantastic contrast, really elevated the 46SV670U's game and produced a gorgeous image.
The TV's level of detail is excellent with both HDTV and Blu-ray content. With standard-definition DVD, I experimented with the Resolution+ technology to see how it affected the upconversion process. Toshiba claims that Resolution+ provides more than just edge enhancement, but that's definitely part of the process. If you enable Resolution+ and turn up the level to 4 or 5, you can clearly see the edge enhancement, or artificial sharpening, around lines. However, I found that a setting of just 1 or 2 did a nice job making the picture seem more detailed without adding a distracting amount of edge enhancement. At these settings, the Toshiba's picture looked more detailed than either the LG or Samsung with standard-def content.
In other processing areas, the 46SV670U did a nice job deinterlacing 480i and 1080i content, as long as the Film Stabilization mode was enabled (it doesn't matter if it's set for Standard or Smooth). With SD signals, the 46SV670U did a below-average job with the deinterlacing tests on my HQV Benchmark DVD; however, when I switched to my real-world torture demos from Gladiator (DreamWorks Home Entertainment) and The Bourne Identity (Universal Home Video), it performed quite well, producing minimal jaggies and no blatant moiré. Real-world scenes trump test discs in my book, so I'm giving the Toshiba good marks here. With 1080i sources, the TV did a solid job, both with test patterns from the HD HQV Benchmark BD and real-world demos from Mission Impossible III (Paramount Home Video) and Ghost Rider (Sony Pictures Home Entertainment). The processor was just a little slow to pick up the 3:2 cadence, creating an instance of moiré at the opening of chapter nine in Mission Impossible III, but then it locked on and rendered the rest of the scene cleanly. The 46SV670U also served up a very clean image--even with the noise-reduction controls turned off, the picture had almost no digital noise in backgrounds and light-to-dark transitions.
The ClearScan 240 technology successfully reduced motion blur, both with test patterns from the FPD Software Group Blu-ray disc and with real-world football broadcasts. During quick camera pans, finer details held up better with the Toshiba than they did with the older Samsung, which doesn't have a higher refresh rate. I'm not sure that ClearScan 240 is any more effective than Toshiba's ClearFrame 120Hz anti-blur feature, but they both accomplish the desired task: to reduce blur in faster-moving scenes. I really appreciate that Toshiba lets you enable ClearScan 240 without enabling the Film Stabilization mode, particularly the Smooth mode. A number of LCD manufacturers combine the anti-blur and de-judder technologies into one feature, so you can't have one without the other. I'm not a fan of motion interpolation, as I find it gives film sources an unnatural quality that's more distracting than judder. I will say that Toshiba's Smooth mode is subtler than what you get from Sony, Samsung, and others; if you love that super-smooth look, you might consider this a drawback. However, I consider it a plus. This is one Smooth mode I could actually watch, and it does not introduce as many smearing and stuttering artifacts as I've seen from some motion-interpolation modes. Again, if you don't like the smoothing effect at all, you can just set the FS mode for Standard with film sources.
Local-dimming LED technology has elevated LCD's game to rival plasma as a theater-worthy display technology; however, there are still a couple of areas where plasma has the advantage. For one, because plasma pixels generate their own light, the best performers can offer exceptional blacks and contrast without creating the glowing effect that I described above. That said, the 46SV670U's glowing effect is only noticeable in a small number of scenes and was hardly a deal-breaker for me.
The other area where plasma still has the edge is in viewing angle. LED-based LCDs exhibit the same viewing-angle limitations as traditional CCFL LCDs. Image saturation drops off when you view the TV off-angle. In this case, the Toshiba's viewing angle wasn't as good as the LG's with bright content. Both models suffered from higher blacks and lost black detail with darker scenes. You should be mindful of where you position the 46SV670U in your room and may need to put the stand's swiveling mechanism into play at times.
The CrystalCoat panel offers the benefit of improved black levels in a brighter room, but its reflectivity can still be distracting. If you're trying to watch a darker scene in a really bright viewing environment, you'll notice room reflections off the screen, which both distracts and interferes with the ability to discern fine details.
Finally, the 46SV670U lacks the Web connectivity and a video-on-demand platform available with many other TVs on the market today at this price point.
I think you can tell that I'm a fan of full-array LED backlighting systems with local dimming. I've yet to review an LCD that employs this technology that I wouldn't be content to own, and the 46SV670U is no exception. Its picture quality is very good with minimal adjustment and can look excellent if you take the time--or hire a professional--to perform an advanced setup. Beyond a great-looking image, what gives the Toshiba an edge for me are some of its other features: I prefer the ClearScan 240/Film Stabilization combo to other anti-blur/de-judder technologies I've seen, and Dolby Volume is a real perk for those who plan to use the TV's sound system. Throw in its nice connection panel, attractive design, and more-than-competitive price with other full-array LED TVs, and the 46SV670U becomes an easy and glowing recommendation.