Projectors are interesting beasts. They combine a relatively low-tech element (a lamp) with one of a variety of competing imaging devices (based on LCD, DLP, or LCoS) and a computer-driven back end that employs sensors and fast-evolving software to handle tasks such as image processing, calibration, and even fan management. Meanwhile the resolutions of our computer and video sources expand, and we suddenly have new options in the realm of signal path. As such, the marketplace for projectors presents a matrix of difficult technological choices, enough to overwhelm even the savvy among us. It's also a moving target: Today's 10,000-lumen projector might cost the same as the 5,000-lumen model of five years ago. But at some point, if you want to project an image, you have to pull the trigger on a purchase. "The potential life of a projector is forever," says Chuck Collins, vice president of commercial A/V of Digital Projection Inc. (DPI), "but technology marches on."
To assess the state of that march, I spoke with representatives at five major projector manufacturers: Christie Digital, Barco, Sony, Panasonic, and DPI. While each company understandably favors a different mix of technology for projectors present and future, I found that they agreed more than not on the major issues. Participating were Collins of DPI; Sander Phipps, senior product manager for professional projectors, Sony; George Tsintzouras, director, product management for business products, Christie; Sharon Dagan, worldwide projection product line manager, Barco; Sam Malik, general manager of the presentation technologies group, Sanyo; and Scott Wellington, marketing manager, projector systems, Panasonic.
For this article we focused on larger projectors, the ones that best serve sanctuaries with capacities from roughly 400 to 2,000. The panel participants agreed that for these sizes of sanctuaries, projectors rated between about 5,000 and 12,000 ANSI lumens will be appropriate. But ambient light conditions and sanctuary shapes vary, of course. Ultimately, says Dagan, "It's all about the people in the back."
Light Engines
The element that gives any large projector its oomph is a close cousin to Edison's incandescent triumph. "Generally, screen size, throw distance and ambient lighting are the major elements that have an impact on making a projector selection," says Wellington of Panasonic. The power ofa projector's lamp is by and large what determines how long a distance the projector throws, how big an image it can successfully produce, and how much ambient light it can overcome. It's the major factor in a projector's brightness rating, typically measured in ANSI lumens. The lamp is also the point at which the projector's colorimetry begins: different lamps produce light of different colors.
Today's powerful light engines require a bulb. True, all the major manufacturers are paying close attention to laser technology, which in the long term probably will prove to be an excellent light source. And with their pure, unchanging colors, energy efficiency and long lives, light-emitting diodes (LEDs) present an intriguing option as each successive generation of the technology yields better brightness. But as of now LEDs are nowhere near bright enough even for small sanctuaries, and they won't be for quite some time. Mercury lamps, once popular at the high end, seem to be waning in prominence. So for the present and the near future, the options are xenon and UHP lamps.
Xenon lamps used to be the only choice for projector models designed to serve large venues. They're considered to be great at reproducing colors faithfully, and maintaining a pure white light throughout their lives, but they're notoriously expensive and relatively short-lived. UHP lamps are much more affordable, but colors drift over the course of a lamp's lifetime.
Typically, xenon lamps are paired with high-end, three-chip DLP projectors and Sony's SXRD line, the company's version of LCoS. More on those imaging devices later. UHP lamps are generally paired with single-chip DLP and three-chip LCD models, which represent the mainstream of the business and professional projector market.
How much light?
How much lamp is enough? What lumen count is your sanctuary going to require? The experts I talked with stressed that taking measurements is crucial. For this task, the best bet is to work with a qualified systems integrator to determine such factors as screen size, throw distance, and the amount of ambient light a projector will need to overcome. However, says Collins of DPI, "A church needs to be cautious. You can't just buy on specs." He warns that lamps undergo degradation over their lifetimes. "If you think 5,000 lumens is what you need, then you really have to take into account the lamp-life degradation curve." The generally accepted figure is that for the majority of a lamp's life, its output will be only 80% of its initial output. That means buying more lamp than you need at the outset.
Of course, sometimes high brightness causes its own problems. Many churches find a spot underneath a balcony to be ideal for the hanging of a projector. Phipps of Sony points out that the larger and more powerful a projector gets, the more likely it will generate excessive heat and noise-necessitating the building of a special housing for sound dampening. "A lot of churches don't want to or can't build a projector booth or some sort of enclosure," he says. This is one area in which a venerable technology is enjoying improvements: Phipps mentions that the Sony VPL-FW300 and FH300 peak at only 30 dB of fan noise. "It can be in the audience without overpowering the room," he says.
Heat is another problem. "Proper ventilation is necessary," says Collins. He recalls seeing a projector installed underneath a church balcony, in a soffit. "It's an excellent use of real estate," he says, "but they weren't exhausting the heat. It cooks the electronics." Again, a systems integrator should be able to address heat and noise issues, so be sure to mention these concerns in initial meetings.
For many sanctuaries, natural sunlight streaming through windows is a part of the ambiance. Such ambient light, as variable as the weather, will complicate a church's brightness needs. The obvious solution is to assume peak sunlight for Sunday services, and purchase accordingly. A less-obvious option is to consider a projector that will allow a church to save energy and lamp life by running the projector at reduced brightness at night or under overcast skies. Tsintzouras of Christie has seen this scenario in play in a church that used the 10,000-lumen version of the company's HD10KM model. "Between noon and 3 p.m., where light is shining directly through the back window, the projector is running at full power," he says. "Then at other times, it's running in low-power mode."
Consider the Maintenance
Projector lamp life (and how best to preserve it) is an important consideration for churches, especially those installing front projectors in difficult-to-access places. "You have to bear in mind the long-term maintenance costs," says Dagan of Barco. "You don't want to mess with a projector except to turn it on or off."
Dual-lamp models can help a church avoid projector maintenance, whether they run in parallel at a slightly reduced brightness, thereby conserving life, or run one at a time. Lamp redundancy carries another obvious advantage, and Panasonic cites its PT-DZ6700U, PT-DW63000US and PT-D6000US models for this feature. "The Dual-Lamp System helps ensure uninterrupted religious services and presentations even if a lamp suddenly burns out," says Wellington.
Many projectors also house filters that collect dust and require cleaning after a certain number of hours (typically in the thousands). Phipps recommends considering a projector whose filter cleanings can be spaced out as long as its lamp changes. Wellington touts a new feature, an Auto-Cleaning Filter, that extends the initial filter maintenance to 10,000 usage hours for models such as the PT-D6000U (DLP) and the PT-F300U (LCD). For its part, Sanyo has introduced the AMF (Active Maintenance Filter) system, which it cites as a significant improvement to its LCD line.
Colorimetry and Image Quality
For image magnification (IMAG), accurate colors are desirable, if not essential. You will find in your research enough debate about the relative merits of DLP, LCoS, and LCD imaging devices to make your head spin, but there's agreement on some of the facts. LCD is a transmissive technology; that is, it lets light pass through three liquid-crystal panels of red, green, and blue on a per-pixel basis. As such it's more brightness-efficient than DLP, a reflective technology that uses millions of tiny mirrors on a chip to reflect light that's passed through a color wheel. LCoS (liquid crystal on silicon) is somewhat of a hybrid of the other two, using tiny liquid crystals on chips.
A short decade ago, LCD technology was reserved for lower-end business projectors, and DLP was the choice for higher-end, expensive models. Since then, LCD image quality has improved and DLP prices have come down. Three-panel DLP models are still generally more expensive than LCD models, but single-panel DLP models are comparable in price to their three-LCD brethren. Each have their technological pitfalls, and different people view their projected images differently. For instance, a certain proportion of the population sees a "rainbow" effect generated by the color wheel of a DLP projector. Most people do not. With LCD technology, the spaces between the pixels can generate a "screen-door" effect that's more of a problem in some models than in others. DLP projectors often lack some of the crispness that LCD can offer, which can be a good or bad thing. On one hand, some softness is desirable in motion video-it beats visible pixels. On the other hand, text typically displays better when it's crisp.
If you're comparing one-chip DLP to three-chip DLP technology, the color differences become obvious, according to Dagan of Barco. "Of course there is a difference in terms of specific colors," she says. "For example, some logos, symbols, and images use a lot of red, orange, and green. Those colors [look substantially different] from one-chip to three-chip. For yellow, with a one-chip you'll see a mustard yellow. The same thing with red-you see maroon." Especially if your church is doing IMAG, you'll want to demo your models while paying close attention to the colors, as your congregation will have a chance to compare the projected image with reality. "Brighter isn't always better," says Collins of DPI, a company that makes DLP models exclusively. "My pet peeve is colorimetry. We're all about being able to adjust the colors in the projector."
Outside the Box
Your projector is nothing without the content that it will play. To match that content, it's best if the projector has the same native resolution as its source material. Barring that, it should at least share an aspect ratio. Today, most computer sources are 16:10, and high-definition video sources are 16:9. Many churches are still sending 4:3 signals through their video systems, but manufacturers have been moving away from that aspect ratio for quite some time. "The migration to WXGA format (widescreen) is growing now at a faster rate," says Malik of Sanyo. "Although, there are still many HOWs that would like to keep the 4:3 format and standard XGA resolutions to avoid additional expense of replacing their existing screens." Wellington of Panasonic concurs-standard XGA is still the most popular resolution. The question is, what kind of content is your church displaying now, and what will it be showing a few years down the road?
That same question applies as you consider your new projector's cabling options. Is your facility set to overhaul its video system completely, or is the system being updated in piecemeal fashion? HD-SDI is a high-end digital option for video transmission that carries the advantage of low latency throughout a video system, and the technology does long cable runs. The challenge is that your whole video system, from camera to switcher to projector, needs to be HD-SDI. "There's a bandwidth advantage to serial digital (HD-SDI) but it costs you on the back end," says Tsintzouras of Christie. Because of its digital nature, Collins of DPI recommends DVI over analog options such as RGBHV (component video). "You see the signal exactly as its creator meant it to be seen," he says.
