In most respects, the Vizio produced a 3D experience as compelling as any I’ve seen from 3D sets that use active glasses. In some respects, it was better. 3D images were noticeably brighter, and 3D crosstalk was a nonissue. The few times I did see it were on images that have shown it on all of the sets I’ve tested. This suggests that it might be in the source material, not the sets. But on a number of scenes that often exhibit crosstalk, such as those in A Christmas Carol (the early scenes in Scrooge’s office, and later when he approaches his house at night), the Vizio produced no crosstalk at all. You can also tilt your head while you watch 3D on the XVT3D650SV and not experience crosstalk, darkened pictures, or a loss of the 3D effect.

By its nature, 3DTV with passive glasses provides only half of HD’s 1080p vertical resolution to each eye (see “A Passive Approach” on page 16). Nevertheless, images from a good, full HD 3D source at an appropriate viewing distance didn’t look soft in any way. However, there’s another price to pay. If you sit too close to the screen, at a distance that might otherwise be perfectly satisfying with HD material viewed in 2D, you’ll notice that the image is broken up by thin black horizontal lines that separate the rows of pixels. Details also take on subtle but distinct saw-toothed edges, and the image as a whole looks slightly grainy. These lines may be inherent in passive 3D HDTV technology. We suspect that they are, but until we see other examples of the breed, we can’t say for certain.

When you move farther back, most of these anomalies gradually disappear. How far back you need to go will depend on you, and I presume on the screen size. For this 65-incher, I had to sit 10 to 12 feet from the screen before these issues ceased to be clearly visible. Vizio representatives warned me about this during an informational interview before I could even bring up my observations. They recommended that I sit at least 10 feet back from the set.

Still, a viewing distance of 10 feet or more will compromise how much of the available image resolution you can see. It will also limit your sense of immersion in the 3D image if you’re the type of viewer who normally likes to sit up close. On the upside, it will offer a wider usable seating area before the set’s off-axis shortcomings become obvious.

Other 3D artifacts included slightly choppy motion on some 3D images. This appeared inter-mittently and was pretty typical of what I’ve seen before in 3D presentations. There was also the same red smear that I noted with 2D. This smearing was visible mainly on fleshtones, and unfortunately, it appeared far more frequently in 3D than in 2D. Only one of the eight 3D discs I sampled, Avatar, didn’t exhibit it at all. With the other 3D material, the problem ranged from noticeable but inoffensive (Coraline, Cloudy with a Chance of Meatballs) to severe (A Christmas Carol, The Polar Express). None of these discs has shown this problem on the active 3D sets I’ve tested, although it remains a puzzle why Avatar was completely free of it. It obviously depends on the software, and as with the visible horizontal lines I mentioned, may be inherent in either all passive 3DTV technology, LG’s specific iteration of it, or Vizio’s execution here. Or it might have nothing to do with passive 3D at all. The main component in a passive 3D HDTV is the patterned retarder (see “A Passive Approach,” page 16), which would appear more likely to affect motion in the vertical direction. The red smear appeared most often on horizontal movement. We’ll know more when we’ve seen other passive sets.

Conclusions
The Vizio XVT3D650SV has a lot to offer as a 2D set. It’s bright and detailed, with good color, impressive black levels, and fine video processing. Its flaws—no set, after all, is perfect—are minor and easy to ignore.

The Vizio did have at least one troublesome 3D issue—that red lag—that wouldn’t logically seem to originate from the passive-glasses technique. But without other passive 3D sets on hand, it’s as yet impossible to say for certain. There were other 3D trade-offs as well. You can’t have it all. At this point, it looks as though the video purist must decide whether the compromises in 3D resolution and seating dis- tance are a worthwhile trade-off for the very real benefits of passive-glasses 3D. We’ll look forward to exploring these issues in future passive 3DTV reviews.