3D Projector Adapter Review
May 2, 2011
Ever since the release of inexpensive 3D-ready DLP projectors, the question has been--what can you watch on them? For a long time, these projectors were incompatible with Blu-ray 3D movies, broadcast and satellite 3D, and 3D games from an Xbox 360 or Playstation 3.
That has now changed thanks to the Optoma 3D-XL. The 3D-XL takes a 3D signal from a game console, set-top box, or Blu-ray disc player and converts it into a format that a DLP-Link 3D projector can understand. This conversion lets you use inexpensive DLP-Link 3D-ready projectors with HDMI 1.4-compatible 3D film and video devices like Blu-ray players and game consoles, either using active shutter or passive polarized 3D glasses. With a street price slightly below $400 including glasses, the 3D-XL makes 3D projection truly affordable.
The Technology In Brief
There are many different way to transmit 3D film or video from one device to another, but they can be divided into two general categories. In one category are the HDMI 1.4 compatible formats, such as frame packing and side-by-side. These formats are written into the HDMI 1.4 specification, and any 3D device that is HDMI 1.4 compatible can understand them.
In the second category are transmission formats like frame-sequential and checkerboard, which are not in the HDMI 1.4 list of acceptable formats. While HDMI 1.4-compatible 3D devices may support these formats, they are not required to, and many do not. Meanwhile, DLP-Link 3D Ready projectors are not typically HDMI 1.4 compatible, and therefore cannot understand any of the HDMI 1.4-compatible formats. These projectors can only understand frame-sequential format, so in order to use them with 3D Blu-ray discs and broadcast content, you need a way to convert the signal into a format your projector can understand. That is what the 3D-XL does.
For a more complete explanation of the various 3D formats and interoperability issues arising from them, read our article "What Does 3D Ready Mean?"
What It Is / How It Works
To use the Optoma 3D-XL, one connects a Blu-ray 3D player, 3D set-top box, or 3D game console to one of the 3D-XL's HDMI inputs, then connects a 720p DLP-Link 3D Ready projector to the sole HDMI output. When fed an HDMI 1.4 1080p 3D signal, the 3D-XL converts it into a 720p, 120Hz frame-sequential signal that the projector can understand. In other words, it turns one kind of 3D signal into another.
What's the big deal? Well, projectors that can interpret the HDMI 1.4 3D standards, such as the Mitsubishi HC9000D and Sharp XV-Z17000, are expensive--much more expensive than projectors that can interpret 120Hz frame-sequential. As an example, the JVC DLA-RS40 has an MSRP of $4495, and is one of the least expensive full-1080p 3D projectors available. On the other hand, the Optoma HD66 has an MSRP of $699, and several other DLP-Link 3D Ready projectors share this price point. As such, the 3D-XL can help you put together a full 3D video system for under $1500, or $3000 less than the least expensive HDMI 1.4 3D projector available today. That's nothing to sneeze at.
So what does this magical device look like? The 3D-XL is a simple black box, less than a foot long on its longest side and a little over an inch thick. It has three HDMI ports on its rear panel (two inputs, one output), three buttons on the front panel (used to switch between inputs, change from frame-packing to side-by-side mode, and cycle the power), and a few small LED indicating the presence of power and signal. A small switch on the rear panel is only used when changing between single-projector and dual-projector configuration. There's a port for an infrared emitter in case you want to use IR-triggered glasses, such as NVIDIA's 3D Vision glasses. Rounding out the panel are a 9-pin D-sub RS232 port and a USB port used for firmware updates. Aside from a power plug, there's not much more to it.
Blu-ray / broadcast / game console compatibility. More than a few people purchased DLP-Link 3D projectors in the hopes that they'd work with new Blu-ray 3D and broadcast 3D formats--the projectors came before the content, so this was not an unreasonable hope. This didn't happen, and owners of DLP 3D Ready projectors were stuck watching what they could put together via computer. The 3D-XL brings a whole new world of 3D content to owners of these projectors without forcing them to spend a lot of money or switch to using an HTPC with an internal Blu-ray drive.
Inexpensive and easy to use. A complete setup including a DLP-Link 3D Ready projector, an Optoma 3D-XL, and two pairs of glasses costs less than $1500. The 3D-XL is almost fool-proof with its clearly-labeled ports and one-button operation. In comparison, a 1080p 3D projector costs at least $4500, and the list price may or may not include the required IR emitter and glasses for 3D display. What's more, many of these full 1080p 3D projectors cannot display 120Hz frame-sequential content from a computer, so gamers are out of luck.
DLP-Link glasses. DLP-Link works by adding imperceptible white flashes to the video signal, which the glasses read via a small sensor and use to remain in synchronization. White pulses have some advantages over infrared, such as not requiring an external emitter and not interfering with the operation of a remote control, but they also raise black level significantly. DLP-Link glasses are available from several different vendors, and any glasses marked DLP-Link should work with the 3D-XL. The same is not true of active-shutter glasses for infrared sync, which can be highly brand-specific. Prices and quality can range. An older pair of DLP-Link glasses in our lab showed a marked green tint and a loss of contrast compared to Optoma's glasses. And whereas some 3D glasses can cost upwards of $150, Optoma's DLP-Link 3D glasses cost about $75 from most retailers. When you're trying to watch a movie with a family of four, affordable glasses are important.
Alternate application: passive polarized 3D. The 3D-XL doesn't just do active-shutter 3D. A small switch on the back of the box can change the 3D-XL's output from 720p 3D to 1080p 2D, selecting one channel of the 3D image and sending it along while ignoring the other. You might see where this is going. With two 3D-XLs, two projectors, two polarizing filters, a silver screen, and some cheap passive glasses, it's possible to set up a passive polarized 3D system at home. This has its advantages, among them the ability to use higher-end projectors built for home theater and the ability to accommodate very large audience sizes since passive glasses are dirt-cheap (less than $5 per pair in some places). It has its downsides, too: a silver screen is mandatory, projector alignment can be tricky, and (obviously) you need to own two projectors and two 3D-XLs to make it work, which can get expensive. The passive polarized route isn't for everyone, but the 3D-XL is a great device for those who choose that method.
HDMI switch. The 3D-XL has two HDMI inputs and a button to switch between them. Many DLP-Link 3D Ready projectors have only one HDMI port. So, in addition to 3D conversion, the 3D-XL also improves connectivity.
Adjustability. Many DLP-Link 3D projectors have a special 3D mode or 3D image setting that is automatically enabled when 3D content is shown. Usually, this setting is not adjustable, nor is it possible to use a different setting when watching 3D. As a result, what you see is what you get--there's no ability to fine-tune the image when watching 3D. You can still make adjustments to the 2D picture, and many of these projectors offer very good 2D performance for the money, but the adjustments you make will not carry over to 3D.
Image quality. With the huge price difference between a 3D-XL setup and a dedicated 3D 1080p projector comes a significant difference in image quality as well. Aside from the obvious resolution difference of 1080p versus 720p, 1080p 3D projectors are typically built specifically for home theater operation, while DLP-Link 3D Ready projectors are often built for multi-purpose use. These DLP-Link projectors have lower contrast and less accurate color reproduction than 1080p 3D projectors do. They typically do not include features like long zoom lenses, horizontal and vertical lens shift, or powered adjustments. Whether these features are worth the difference in price depends on the type of content you like to watch, your viewing environment, and your individual tastes.
Optoma's 3D-XL is a simple, straightforward product that solves a common problem in 3D projection. The 3D-XL allows the best content available on Blu-ray and broadcast/satellite to be used on the most inexpensive 3D projectors available, a feat which was previously impossible. By down-converting and re-formatting the 3D signal, the 3D-XL can make 3D projection surprisingly affordable. While full-1080p 3D projectors offer a more precise, higher-resolution experience, the 3D-XL is a great choice for gamers and those looking for a budget-friendly 3D option.