For years now, 3D projectors have been slowly making their way into home theaters around the world, and almost all of those projectors use active shutter glass technology. Active shutter glasses are advantageous in that they keep the cost of the projector low and do not require a special screen in order to function, making them a great out-of-the-box solution for the home consumer. If you purchase a 3D projector that uses active shutter glasses, there are no more pieces to buy -- you're done.

However, for various reasons, some folks don't enjoy active shutter glasses. The eyewear is heavier than the glasses used in commercial theaters. Different brands of eyewear are not compatible with one another. Since the glasses are powered, they either need to be recharged or have their batteries changed. And they're expensive, too, at around $100 per pair. If you want to bring some friends over and watch a movie in 3D, it can mean a significant cash outlay to pick up extra glasses.

Enter the Volfoni SmartCrystal Pro. Like many commercial theaters, the SmartCrystal Pro uses a switching polarized filter positioned in front of the projector. This allows it, with the help of a silver screen, to use inexpensive passive polarized 3D glasses instead of the expensive powered active shutter glasses. This way, you can accommodate as many people as your theater can hold, and additional pairs of glasses cost very little. The system, which costs $1500 and includes five pairs of glasses and all necessary connection cables, is currently only available direct from its manufacturer, Volfoni. At the moment, it also requires a DLP 3D projector that supports either VESA output or DLP Link. It is, however, the first polarized 3D solution we've seen that is both affordable and easy to use.

What It Is

The SmartCrystal Pro is a switching polarizer designed to work with 3D home theater projectors. In essence, it converts these 3D projectors from active-shutter to passive-polarized systems. It is rated to work with projectors up to 5,000 lumens in brightness.


The Volfoni SmartCrystal Pro in its box

The SmartCrystal Pro system consists of only a few parts. There is the polarizer itself, the connection cables, and the included glasses (the system comes with five pairs). The whole system fits in a small box. Setup consists of placing the polarizer in front of your projector and running one wire, either VESA sync or power (in the case of DLP Link).

How It Works

To use the SmartCrystal Pro, you'll need a few things that aren't included in the box:

  • DLP 3D Projector
  • Silver polarization retention screen
  • 3D source

In other words, you need an existing 3D setup, plus a silver screen. The reason for the DLP requirement is that some LCD and LCoS 3D projectors already emit polarized light, and that can cause some odd behavior when paired with another polarizer. Volfoni is working on another version of the SmartCrystal Pro that will function properly with LCD and LCoS models, and that version should be announced in the coming months.


The SmartCrystal Pro in use with the BenQ W7000

What the SmartCrystal Pro does is takes the synchronization signal normally meant for active shutter glasses -- the signal that tells the glasses to switch between left eye and right eye images -- and instead uses it to signal the switching polarizer to swap between left-hand and right-hand circular polarization. The polarized light bounces off of the screen and is selectively passed by the glasses to your eyes. That's why a silver screen is necessary; normal white screens do not maintain polarization. There are some non-silver screens that maintain polarization, but don't just assume your existing screen is one of them. Our testing setup used the BenQ W7000 1080p DLP home theater projector and a 92" SeVision 3D GX silver pop-up screen from Severtson in addition to the SmartCrystal Pro.

Key Features

3D image quality. The SmartCrystal Pro works very well. As the W7000 does not have a VESA sync port, we used the polarizer's DLP Link compatibility mode. Setup consisted of placing the polarizer in front of the lens such that the projected image filled the polarizer as completely as possible (this helps to prevent overheating), then running either sync or power. In this case, we used a power supply.

Once a 3D signal starts playing, the SmartCrystal Pro picks up synchronization within a couple of frames. Crosstalk was minimal, though still visible in certain high-contrast scenes. Even in content with lots of fast motion, there was not much in the way of flicker or judder. After a few minutes, it was easy to "tune out" the technology and just enjoy the movie, which is the goal of any projection system.

Easy to Use. While polarization is not a new technology, other implementations have either been very expensive or difficult to setup properly. The most popular implementation involves two projectors with static (non-switching) polarizing filters in front of each one. The problems are myriad -- not only do the two projectors need to be precisely aligned, but each polarizing filter requires its own mounting bracket. In addition, the two projectors need to be placed in such a way that they do not cause one other to overheat, which can lead to shorter lamp lifetimes.

Contrast this with the SmartCrystal Pro, which can be placed in front of your existing DLP projector and connected with a single wire. Yes, it still requires a silver screen, but this is true of any polarized system, not just the SmartCrystal Pro.

Inexpensive glasses. This is really the main reason to go with a passive polarized system. If you have a large family or a lot of friends, or plan to have a lot of children around, the benefit of cheap glasses cannot be overstated. The system comes with five pairs of glasses, which are durable and resistant to breakage. Extra pairs cost $4 from Volfoni. But the SmartCrystal Pro uses circularly-polarized glasses, meaning that glasses from RealD 3D theaters are also compatible.

No batteries. Nothing is quite as annoying as when you go to watch a 3D movie only to find that your 3D glasses are out of batteries. Passive glasses, like those used by the SmartCrystal Pro, require no batteries. And since the polarizer draws power from the projector, there's nothing to worry about there, either.

More sanitary. In commercial and educational environments, there are serious sanitary concerns about having multiple people wear the same pair of glasses, and active shutter glasses are too expensive to be disposable. For this reason, many commercial installations (including most movie theaters) opt for polarized systems. Polarized glasses are inexpensive, and since they have no electronic parts it is easier to clean them without causing damage. While this is less of a concern in a home theater environment, it is still worth thinking about.

No sync issues. Since synchronization occurs between the polarizer and the projector over a wired link, there's no chance of someone losing sync while sitting in your audience.

 

Limitations

DLP Only. There are plenty of great 3D projectors out there that use LCD or LCoS technology, and the SmartCrystal Pro lacks compatibility with many of these products. While a new version is in the works and slated for announcement later this year, this will no doubt disappoint fans of polarized 3D projection who bought LCD-based 3D projectors. Hang tight -- it's coming.

Light loss. The SmartCrystal Pro has comparable efficiency to some other projectors, but it is not the brightest system we've seen. As an example, the BenQ W7000 we used for testing normally has 28% transmission using its DLP Link glasses, which is quite good. Using the SmartCrystal Pro with the W7000 lowered overall light transmission to 22%. While anything over 20% is respectable, and certainly usable, you still need to pay attention to screen size and installation when putting in your system.

One thing to keep in mind is that a silver screen typically has a much higher gain than a white screen, so brightness loss will be less severe in the optimal viewing position. Make sure to setup your theater to take advantage of this fact.

Light loss in 2D. Here's something to remember: the SmartCrystal polarizer sits in front of your projector all the time, no matter what you're watching, and it blocks some of the projector's light from reaching the screen. We measured about 40% light loss just leaving the polarizer in front of the lens, inactive, while watching a 2D Blu-ray movie. The way to counter this is by using a motorized sled with either a remote control or a 12V trigger, but these add complexity and expense to your system.

DLP Link color cast. DLP Link functions by inserting a light pulse into the 3D signal for synchronization purposes. The SmartCrystal Pro works with DLP Link, but using it in this mode may cause color balance issues. As an example, the W7000 has a red tint in its sync pulses which is canceled when using the projector's DLP Link glasses. However, the cancellation done by the SmartCrystal Pro is not perfect, so the image will look slightly more red on average.

Silver screen. Silver screens have come a long way over the years. The Severtson SeVision we used did a fine job of maintaining polarization and making the image look bright and sharp. However, even the best silver screen is no match for the smooth, even illumination of a mild-gain white screen when it comes to 2D viewing. A silver screen will have a narrower viewing angle and more noticeable brightness drop-off towards the sides of the viewing area. If you're also going to watch 2D, like most folks, you may want to look into retractable or drop-down silver screens, which is what we used for testing during this review. That way, when you're not watching 3D, you can switch back to a white screen. This, of course, adds cost.

Cost. Many people find the idea of $100 3D glasses irritating, and are resistant to spending so much to procure a family-sized supply. These people naturally turn to polarized 3D in an effort to save money on glasses. While it is true that polarized glasses are much less expensive than active shutter glasses, they are not truly cost-effective until you buy a significant quantity.

Here's an example. The BenQ W7000 costs about $2400 and its 3D glasses cost $99, so a family of four would spend about $2800 to get started watching 3D. For a super bowl party with 10 friends, you'd spend an extra thousand to supply them all with glasses, for a total of $3800. If you instead opt for a polarized system, you'd spend $2400 for the projector, $1500 for the polarizer and five sets of glasses, at least $400 for a silver screen, and then another $36 for nine additional sets of glasses. The end cost is still about $4350 -- more than you'd spend for active shutter glasses.

This is not to say that there aren't legitimate reasons to opt for polarization. As mentioned before, the polarized glasses are cheap to replace and require no batteries -- imagine trying to find 10 free USB ports to charge all of your active shutter glasses! If someone's child snaps a pair in half, you can replace them for $4, not $100. Some people prefer the look of polarization over that of active shutter eyewear. Being able to give everyone a new pair of glasses is more sanitary. All of these reasons are valid. For large audiences such as lecture halls and classrooms, the cost issue is a no-brainer. At home, though, it's not as cut and dried. This is not to dissuade you from going with polarization, but don't think of it as the "cheap" option. That argument doesn't hold up at home.

Conclusion

Volfoni's SmartCrystal Pro is a smart, simple, and inexpensive way to add polarized 3D to your home theater. It is easy to set up and use, requires only a single projector, and benefits from cheap, semi-disposable glasses. It is not without limitations, of course. The system currently works best with DLP projectors, and like all polarized systems it requires a silver screen. It does a good job of controlling cross-talk, and light loss is no more severe than on many other home theater 3D systems.

The SmartCrystal Pro has a lot going for it: durability, simplicity, and expandability stand out as its core strengths. The 3D image it produces looks as good as many other 3D projectors, high in contrast and rich in color. At $1500 direct from the manufacturer, it is not for everyone. But if you have been waiting for an easy-to-use polarized 3D option for your home theater, the SmartCrystal Pro is about as good as it gets, and represents a strong value in today's market.

Comments (5) Post a Comment
abdullah Posted Jun 5, 2012 10:03 PM PST
Hi, What about ghosting and hot-spotting. Did you test these?
Bill Livolsi Posted Jun 6, 2012 11:20 AM PST
Abdullah,

We did not notice an abnormal amount of crosstalk, which I referenced in the article. The crosstalk is similar to that observed on some other 3D projectors we've seen recently. However, the DLP Link glasses meant to be used with the W7000 did have less crosstalk.

As for hot-spotting, this is a property of the screen, not the polarizer, and we didn't feel it appropriate to discuss the screen properties in a review of the polarizer. That said, we didn't see any appreciable hotspotting on the Severtson SeVision 3D GX, either. If I were to purchase one, though, I would consider a tab-tensioned electric model, because the pop-up model we used did have some small waves in the material.
Abdullah Posted Jun 17, 2012 7:00 AM PST
Hey, thanks for the info. cheers.
elifas Posted Nov 9, 2012 5:31 AM PST
sorry, how much?
Chuck Posted Nov 26, 2012 10:20 AM PST
$1500 is a pretty high pricepoint for a DIY'er modification. Just bought a passive 65" for about the same price with no additional cost of silver screen. Until they come down to $500-700, it's probably worth the hassle of aligning 2 DLPs with polarizing filters, given the light loss you get with the unit.

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