Video Display Screens
The second wave in windows of worship
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South Barrington, Illinois' Willow Creek Community Church employs two huge LED panels that normally flank the stage, but are rigged to allow the screens to be moved, even onto the stage floor to form an extra-wide center screen. Until recently, LED panels for video were used solely in the realm of sports stadiums and other outdoor venues. (Photo courtesy of Steve Hall -- Hedrich Blessing.) |
The addition of video displays to church services was akin to breaking the sound barrier in aviation. The first wave of new video came to the larger sanctuaries in the form of increasingly prominent front and rear projection displays. These have been followed by a second wave of self-contained LCD, LED, and plasma display panels (PDPs) appearing in the services of smaller churches and expanding the role of video beyond main sanctuary projection to other tasks around the building. These new display devices offer any house of worship a perfectly tailored installation, but to craft this custom viewing experience, several factors must be carefully considered.
Many size and placement options help give video display a power ranging from punctuation to domination. The screen's degree of prominence in the sanctuary is an expression of the collective personality of the pastor and the congregation. In this choice, the factors of content, size, and position set the course for all of the remaining elements.
Display Options
While the primary content of flat screens will usually not be image magnification (IMAG) of those on the platform provided by one or more video cameras, these displays can be used to augment IMAG in areas with line-of-sight challenges. For this solution, the size issue narrows the choice among self-contained devices to either a plasma or LED display. LCD (liquid crystal) displays are based on transistors and capacitors and while still growing, their size tops out below the maximum for plasma, but they are closing the size gap. For a premium but falling price, plasma screens make excellent video displays for reaching other areas of the church because they combine high resolution (the number of dots or "pixels" making the image) and a generally wider viewing angle than rear screen projection provides. On rear screen projection displays, the image brightness drops rapidly as the viewer moves from a position directly in front of the screen. Plasma display panels will give a viewing angle comparable to a conventional TV set. Plasma displays handle ambient light very well, deliver reasonably good contrast ratio, and their slim form allows a wide range of mounting options as long as the considerable weight is supported. They are available in sizes over 100 diagonal inches, but above 50 inches, the price rises rapidly. Currently, a 100-inch model will cost about $70,000 and will use 675 watts of power. On power consumption, LED panels hold a decided edge over both projection and plasma.
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At New Hope Baptist Church, the pastor at the podium has a plasma video monitor mounted straight ahead. The 50-inch plasma display is next to the clock on the balcony so that the pastor can get his timing and video cues while looking straight out into the congregation. |
One increasingly popular use for in-sanctuary plasma displays is as monitor for the pastor or presenter; sometimes called a confidence monitor. Putting the panel in a wedge-shaped box on the front lip of the stage is a popular mounting option-so it looks like an audio floor monitor. Monitors can also be mounted on the balcony wall or rear wall of the room facing the chancel so that the pastor can see what the big projection displays behind or beside him are showing without the need to turn and look. New Hope Baptist Church in Fayetteville, Georgia has found a benefit in this. Here, a 50-inch plasma display is mounted next to the clock on the balcony so that the pastor can get his timing and video cues when looking straight out into the congregation.
The new big boys of electronic video display are the LED (light emitting diode) panels. These provide maximum size, brightness, contrast, and viewing angle, but those benefits come at a high price, though the price is coming down. Willow Creek Community Church in South Barrington, Illinois has two huge LED panels flanking the performance area in its massive auditorium. Until recently, LED panels for video were used solely in the realm of sports stadiums and other large venues, but as some churches have built enormous worship centers, the LED display with increasing resolution specs has begun a crossover into the mega-church A/V market.
Instead of one or two monster panels, a similar effect may be found in a number of smaller screens arranged in a video wall. The Victory Church in Oklahoma City, Oklahoma has a wall of 50-inch plasma screens onstage, fed by a DVI video amplifier.
The Grace Church in Peoria, Illinois has a video wall at the rear of the chancel composed of sixteen 52-inch internal CRT projection video screens in a four-by-four configuration for a total diagonal picture area of 160 inches. John Spuler, director of communications, set up the sources.
"I added a digital A/V mixer to the signal path," he explains. "The mixer is used by a volunteer to route the appropriate signals to the wall. He is able to select from a computer running MediaShout for lyrics, Bible verses, sermon illustrations, and text, a live feed from our TV studio, a signal from a DVD/VHS combo deck, and a signal from a Sony Beta SP playback deck."
If only text and logos will be shown, CRT or LCD panels may be the best choice. LCDs use the same principle as the displays on laptop computers and they will work best for the types of images normally associated with computers, provided the images shown are sized and formatted for those screens. LCD viewing angles have improved with active matrix displays. LCD panels are just as thin as plasmas, but their lighter weight affords more mounting options. LCDs still exhibit a little image smear on fast moving video images however, so for this application, plasma still has the edge.
Video Everywhere
At the same time video displays began appearing in the main sanctuary for services, they also spread to other areas of the church and now see substantial use in video conferencing, electronic signage, and worship service video to cry rooms and other buildings. The less-demanding screen size in these roles brings more options.
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The Victory Church in Oklahoma City, Oklahoma has a wall of 50-inch plasma screens onstage. |
Among the applications for video display elsewhere in the church, another technology worth considering is DLP, or digital light processing. Technically, this can be considered a projection method, but the since the entire process with all its components can be housed in one physical unit, we will consider this technology along with the other self-contained video display methods. DLP works by using a vast array of tiny mirrors on a semiconductor chip and moving these little mirrors rapidly while shining a powerful light on them through a rotating color wheel. Self-contained DLP rear projection units provide an excellent picture with good black levels, which are important to a clear image. They need very little maintenance but they are also quite expensive for the size of the image provided, and the viewing angle is fairly limited. If high-budget picture clarity in a relatively small area is the guiding factor, DLP is worth a look.
CRTs - Still Alive and Kicking
Far from banishing good old CRT TV monitors from the church, the acceptance of video display in the house of worship has actually spurred the population of CRTs. New Hope Baptist Church in Fayetteville, Georgia is a prime example, where they augment the large projection and plasma panels.
"We have 27 CRT monitors on the campus," says Bill Entrekin, New Hope's technical coordinator. "We have them in the sanctuary, the balcony, the lobby, and the administrative offices in other buildings. These are all tied together on a network so that any source including electronic signage, text notices, cable TV channels, and video with sound from the sanctuary services can be selected locally." In New Hope's TV control room, CRT and LCD monitors share the racks.
Burn-In - The Gift that Keeps on Giving
One factor to consider with long-term display of static images and text is possible burn-in, and this is one of the advantages of the maturity of CRT technology where burn-in has been substantially reduced. The display tends to retain the image after long exposure to a static picture. Many digital signage applications, particularly large outdoor signs, use LED displays and with these, the term "burn-in" refers to the initial period of use during which the display will rapidly lose a percentage of its brightness before leveling out at a much slower rate of loss. Plasma displays do suffer burn-in when a static image is shown for a considerable time, so if the church logo is to be displayed as a default image, a plasma panel may not be the tool for the job. On the latest models, burn-in has been reduced and the half life of modern plasma displays-the time before the unit reaches half its original brightness?has increased to around 60,000 hours.
Plasma and LCD displays will have an edge over DLP in thickness and mounting options, but if a recessed wall location is planned, even a big, conventional CRT TV set can work as long as adequate ventilation is provided. Large rear projection CRT TVs can also be used in such locations, but they tend to suffer with occasional convergence problems where a colored fringe appears around elements in the projected images. Non-warranty repairs for this can be expensive.
Outdoor signage must withstand high ambient light levels and very wide viewing angles. The smaller, relatively tough LED displays have the advantage on these factors, and there is a wide choice among these specifically for signage applications. Plasma and LCD units should not be considered for any outdoor application due to their relatively delicate nature and the fact that they do not work well in ambient temperature extremes.
HDTV
The present 4:3 format, or aspect ratio, is rapidly disappearing, and with the coming of HDTV, 16:9 or "sixteen by nine" will quite literally be the shape of things to come. This will affect graphics formatting and the appearance of video images. Pictures from 3:4 video cameras will appear somewhat horizontally stretched on 16:9 display panels.
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Sixteen 52-inch internal CRT projection video screens make up this video wall at Grace Presbyterian Church in Peoria, Illinois. |
The next consideration for HDTV is the resolution that the screen can show. HDTV comes in two basic flavors known as 1080i and 720p. In 1080i, the picture is composed of 1,920 pixels or dots horizontally and 1,080 vertically with interlaced scanning. Each video frame is composed of two scanned fields where the first field shows the odd horizontal lines and the second shows the even lines. This is the traditional TV scanning method.
The more common HDTV format is 720p, painting a picture that is 1,280 by 720 pixels in resolution, with each frame a complete scan of all 720 lines. Even with less scanning lines, it is virtually indistinguishable from 1080i to the average viewer. This type of scanning typically makes crisper images, particularly where the content involves rapid motion or camera panning.
Now that video displays have entered the house of worship environment, there will be no going back. So it is wise to learn the ups and downs of each display type.
