Home Theater Projectors :
You're finally making the jump to the holy grail of home theater video displays; the front projection system. There's nothing else that delivers that really big, impressive video image like a front projection system. It's how you get that real cinema experience in your home theater. Home theater projector prices have plummeted in recent years, and the size of the units have shrunk right along with the prices. No more do have to live with a coffin sized box on your ceiling. As sizes have decreased, the image quality and brightness have actually improved dramatically. You'll notice image quality and brightness are two separate issues.
How do choose the correct home theater projector for your application from the myriad of projectors on the market today? There are so many different units, each with their strengths and weaknesses. First of all, there are two main projection technology categories, analog and digital. Analog projectors are based on CRTs, a mature technology that's been around for decades. Those are the projectors with the separate red, green and blue picture tubes and three lenses on the front. The other projectors use one of the newer digital technologies. These projectors have a single lens on the front. There are three major types of digital projectors on the market today; LCD (Liquid Crystal Display), DLP (Digital Light Processing) and LCOS (Liquid Crystal On Silicon). Each type of digital projector has it's advantages too.
You need to evaluate your specific requirements in order to make the proper decision. First of all, look at the room. Is it a dedicated home theater or a multi use room? Do you have complete control of the light? What aesthetic concerns are you dealing with? What is your projector budget? How large of an image do you want? Do you watch primarily DVD movies, TV movies, sports, or other TV programming? What specific source components will you be using with your projector now or in the future? Is picture quality the most important thing, or are other concerns, such as noise, size or brightness more important? Are you installing the projector yourself, or are you hiring a custom installer to do the installation for you? Where must the projector be placed? Can you get the required video and control cables to that location? These questions must be answered to ensure you get the proper projector for your home theater. If you are using a custom installer, they will take into account these factors and specify the appropriate unit for you.
Dramatic improvements in the picture quality of digital projectors notwithstanding, CRT projectors still deliver the most film like image. They have no pixel structure and deliver rich, deep blacks. Properly set up and calibrated, with a good video processor, and with the proper size screen, a CRT projector will deliver simply stunning picture quality. You'll need to use a good quality projection screen, typically with 1.3 – 2.5 gain depending upon the size, viewing angel and ambient light in the room. Prices on really great CRT projectors have fallen like a rock in the last year or two. You can get a 9” CRT projector that used to cost $35,000 to $50,000, for less than a third of that figure now. Many firms no longer make CRT projectors due to the decreased demand for projectors using this technology. In addition, the required video processors have decreased dramatically as well. Ten years ago a great video processor used to cost $10,000 to $20,000. Now you can get one for well under $5,000 and as little as $2,000, brand new. They also easily last 8,000 – 10,000 hours when properly set up.
If they are so fantastic, why doesn't everybody still use CRT projectors? Well, there are many detriments to a CRT projector as well. The best ones, with the 9” tubes, are simply huge. It's like hanging an upside down bathtub on your ceiling. If you want to put one under a coffee table, it'll be one large table. They are also very heavy, around 150 – 200lbs, so you need the proper structure to support them. CRT projectors also require precise placement. They must be perfectly square with the screen, at the correct elevation for good picture quality. In addition, while many digital projectors have zoom lenses, allowing the projector to be placed at a range of distance from the screen, CRT projectors must be at a very precise distance for a specific screen size. These factors severely limit placement options. While the larger CRT projectors put out more light than their smaller counterparts, they have pretty dim images compared to even the least expensive digital projectors. Finally, CRT projectors require specialized setup in order to get a watchable, much less an optimum image. Every 6 months to a year, they must be re-calibrated to ensure you are still getting optimum picture quality.
There are some very good reasons why most people are using digital projectors in their home theaters today. Many are small and light, require minimal setup and calibration (compared to a CRT), are quiet and have a bright, sharp image. But, there are many different digital projectors, ranging in price from around $700.00 to over $100,000.00. Which one is the best for your specific application? Thankfully, the situation is changing, but many of the digital projectors marketed for home theater use are really just re-badged presentation units. Presentation projectors sacrifice good video quality for brightness. Brightness is much more important when giving a Powerpoint presentation in a lit room than the correct color palate or the black level. The red on the pie chart looks great, no matter what, as long as you can see it from the back row.
You want to choose one of the newer units that has been truly designed for home theater applications. The actual technology used for the imaging chip is not all that important, there are great examples using all three of the digital technologies. Companies such as Sony, Runco, InFocus, Vidikron, Marantz, Benq, Panasonic, Sharp, Optima and Sanyo and some others all make great home theater projectors. The projector will have great black levels, to accurately reproduce detail in the darker areas of the picture and give great contrast. Absolute brightness is not extremely important, unless you have a multi-use room without complete light control or you have a lot of people over for sporting events. If you are entertaining many people for sports, it's nice to have some light on in the room, so a brighter projector is advantageous.
Projectors come in a number of different resolutions. The lower the resolution, the smaller the screen you can use before you can see pixel structure. Also, the lower resolutions will not support true HDTV. Most will display HD, but at a decreased resolution. The lowest end projectors typically have resolutions of 800 x 600. The Texas Instruments Matterhorn chip is popular on budget priced wide screen projectors, and has a resolution of 1024 x 576. Anything over a resolution of 720 will allow for true HDTV. The TI series of HD-2 DLP chips has a resolution of 1280 x 720. In April of 2005, TI announced new DLP chips with 1920 x 1080 was ready for production, allowing for true 1080p resolutions. Projectors with this chip will begin shipping in Q1 of 2006. Blu-Ray Disc has stated they will support 1080p, so by late 2006 there will be commercially available 1080p content besides Microsoft's WMHD discs.
Another very important aspect of home theater projectors is the internal video processing. This is one of the primary differences between good home theater projectors and presentation projectors. Digital projectors must display progressive scan images at the native resolution of the chip, so any interlaced signal, such as 1080i HDTV, must be de-interlaced and then scaled to the native chip resolution. Poor quality video processors, weather in the projector or external units, cause all sorts of video artifacts that can get in the way of a satisfying video presentation. This subject alone is too in depth for this article, as entire texts have been written on the subject. However, one common video artifact is “jaggies” where diagonal lines are jagged instead of straight. Another annoying artifact caused by poor video processing is moire'. This is a pattern seen as alternating light and dark lines that change position as the image moves.
You'll want to be sure your projector supports the HDMI or DVI with HDCP copy protection to allow you to connect a HD-DVD, scaling DVD player or Blu-Ray Disc player. These devices will only allow maximum resolution on a display that has a digital video input with HDCP copy protection. In the future, cable TV and satellite providers may restrict the maximum resolution to their digital outputs too.
When choosing your new home theater projectors, make sure it has the video quality, brightness, size, auditory and budget characteristics that you need. Projectors are a large investment, choose carefully and you will be rewarded with years of thrilling video in your home theater.
