Podcast #418: Front Projector Technologies

We have to admit, we got a little giddy when we got an email from Jason asking us to go over the various technology options available for front projector home theaters.  With rear projection television fading into the sunset, we don't often get the opportunity to talk about the various merits of LCD, DLP, and LCoS projection technologies anymore.  It'll be like the good old days.

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Today's Show:

News:

• Analog HD from Blu-ray isn't going anywhere
• HD Netflix Streaming on PC Coming This Year?
• Blockbuster On Demand coming to Connected Samsung HDTVs...
• LED-Backlit Models to See Major Growth, Reaching 20% of LCD TVs This Year

Other:

• Zarban.com, The House of Commentaries
• Lanyardlab.com - Custom lanyards made in 4-7 days
• Sound&Vision 2009 Editors Choice Awards

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• Audioengine 5 (A5) Premium Powered Bookshelf Speakers.
• INSTEON Home Theater Lighting Control Kit
• The RedEye Remote Control System
• Aperion Home Audio Link™ System
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Front Projector Technologies

We have to admit, we got a little giddy when we got an email from Jason asking us to go over the various technology options available for front projector home theaters. With rear projection television fading into the sunset, we don't often get the opportunity to talk about the various merits of LCD, DLP, and LCoS projection technologies anymore.  It'll be like the good old days.

We've seen many technologies come and go since Episode 1 of the podcast. We've had a great time over the years explaining and analyzing the pros and cons of CRT displays, LCD projection, DLP TVs and even a brief love affair with LCoS technology.  Anyone remember Brillian? Although it seems everything is flat panel these days, many of these technologies live on as front projectors.

LCD

The earliest digital projectors were based on Liquid Crystal Display (LCD) technology. We have podcast episodes in the archives all about it, but most of them were lost in the transition to our new website.  Bottom line, LCD is a tried and true technology. It typically has very vibrant color and provide a very sharp, crisp picture.

On the downside, LCD's vibrant color and crisp picture tends to produce video that doesn't looks quite as real or lifelike as other technologies.  Many describe it as looking more digital. It also doesn't have the contrast capabilities of the other technologies, which is critical to home theater applications.  For the office, LCD is great, for the home theater, it hasn't quite won the hearts and minds of the masses.

DLP

Digital Light Projection (DLP) is a Texas Instruments invention that uses millions of tiny mirrors to reflect the light your see onscreen. Historically, it has been one of the more controversial and debated technologies on the show.  When you're feeling nostalgic, go ahead and do a Google search for wobulation. ; That'll bring back some memories.

On the upside, DLP produces better contrast and black levels than LCD.  This makes it ideal for home theater applications. On the downside, it isn't quite as sharp as LCD and has suffered from all sorts of crazy screen artifacts like rainbows, silk screen effect and others. Ara has two DLP rear projection sets that he is quite fond of.

LCoS

Liquid Crystal on Silicon (LCoS) comes in several variants.  JVC markets it as D-ILA; Sony markets it as SXRD.  LCoS uses liquid crystals like LCD, but they are reflective (almost like mirrors) instead of transmissive.  At a really high level, the technology almost feels like the perfect marriage of the other two.

Of the projectors we've seen and used, the LCoS models tend to come out on top.  They produce a great, vivid picture and excellent contrast ratios. We were big fans of SXRD and D-ILA rear projection TVs (Braden owns a JVC) when they were out, and have always been impressed with their front projector variants as well. Early on DLP had an edge in contrast ratios, but that no longer holds true.

Of course, LCoS doesn't come without a price.  The Sony and JVC projectors tend to be more expensive than their DLP or LCD competition, with JVC edging Sony slightly in the bang for your buck department.

Conclusion

Bottom line, LCD projectors are bright, vivid and inexpensive.  DLP projectors are darker, provide better contrast and don't cost as much.  LCoS projectors probably give the best picture, but they cost a lot.  You have to weigh the pros and cons for yourself and see what your budget will allow.  In the end, though, no matter what you choose, there's no denying that a 120" screen is pretty darn cool.

Download Episode #418

Comments

[Andrew]

I wanted to make some corrections to what you talked about on the show.

First on HDMI version and 3D. One of the biggest things you need for 3D is more bandwidth on the cable for the extra frames. HDMI 1.3 only guarantees enough for 1080i 3D. However, HDMI 1.3 high speed has more than enough bandwidth to send 3D in 1080p. The highest 1080p 3D is 1080p/48, and since HDMI 1.3 high speed can already do 1080p/60; you don't really need HDMI 1.4 to get 3D. HDMI 1.4 does contain other features (audio return channel, ethernet, and 4k resolution) that can't be added through firmware. However, as long as the device can be updated with software to put the 3D video in a HDMI 1.4 approved container (frame packing 3D format at either 720p/50 and 1080p/24 or 720p/60 and 1080p/24, side-by-side horizontal at either 1080i/50 or 1080i/60, and top-and-bottom at either 720p/50 and 1080p/24 or 720p/60 and 1080p/24) it doesn't matter whether or not you are 1.4 or 1.3 at the source. Of course, Sony is the only one bothering to add that functionality to older devices. Other manufacturers are just telling you to buy a new player.

Second, you said the image constraint token would turn off the analog outputs on your blu-ray player. This is not true! It will constrain the image, not block it. What this means is that your analog output will be limited to 540p instead of the maximum of 1080p. Since very few TV's that only have analog in accept 1080p over component (they are limited to 1080i, 720p, or 540p), I don't think the image constraint token affects more than a handful of people.

[HT Guys]

Hi Andrew,

Thanks for the clarifying post and catching our errors!

Ara

[Paul W]

I was confused about the 3D over HDMI 1.3 thing as well, but this interview at the Home Theater Geeks podcast was rather informative.

[Kent]

Surprised you guys didn’t discuss illumination technologies. Like the different between light bulbs and the newer LED chips that are coming out in projectors.

[Scott Fosseen]

I am on a committee that twice a year evaluates over 60 business use data projectors. We setup 6 projectors at a time, all provided with the same input material. I have been involved since the days of putting a LCD plate on top of an Overhead projector so I have seen technology change quite a bit.

The primary technology is "3 LCD" or DLP on the projectors we look at. On side-by-side comparisons it is possible to pick out the technologies, but still the images are really close. If looking at one projector at a time I expect 95% or more viewers would not be able to tell the difference in image quality based on the projector display technology.

When comparing the business type of projectors to Home Theater projectors the higher contrast ratios are detectable in dark scenes. I would preface that with under controlled lighting conditions. Ambient lighting on the screen will negate the benefit of ultra-high contrast ratios.

Other technology topics to consider:

From the business projectors, DLP technology does not require filters, LCD technology does. If your projector is mounted where it is difficult to access, cleaning a filter every 500 hours of use could be tiresome. Not cleaning the filter can lead to projector failure do to heat issues.

Lens throw ratio would also be something to be aware of. The lens throw ratio will determine where the projector needs to be mounted relative to the screen. The wrong throw ratio will prevent you from mounting the projector where you may want it mounted.

The projection screen or surface will also make a difference on how the projector will perform.

Projector Mounting position can also play a role in picture quality. Lower cost projectors use a technology called "Keystone Correction" to square up the picture if the projector is mounted higher or lower in relation to the screen than it was designed for. Once keystone correction has been enabled the image is processed through a video processor, even if the image is of a native resolution (1080p signal to a 1080p projector). Does this make a noticeable difference in the image? Probably not that most people would be able to see. The way around this and other mounting issues is to purchase a projector with "Lens Shift".

With Lens Shift the projector mounting position is less critical. Lens shift is the equalivant of an Optical zoom on a camera, where Keystone Correction is similar to Digital Zoom.