The Belonging Co., Nashville, TN. Photo by Ashley Mae Wright
It wasn’t so long ago that LED video walls seemed like Maseratis — cool, desirable, and too expensive. But in a very short time, LED wall components, from the LED tiles themselves to ancillary equipment like processors and scalers, have dropped in price dramatically. As a result, LED video walls have soared in popularity in house of worship applications, largely because they can overcome ambient light in sanctuaries and other worship spaces because they emit light rather than reflect it, as video projection does.
But there are a host of other considerations to take into account first. For instance, a typical 9-foot by 16-foot LED wall will weigh over a thousand pounds, far more than a drop-down projection screen. Thus, structural engineering input is necessary before everything else, says Nick Kofahl, chief vision officer at AV integrator Summit Integrated Systems of Lafayette, Colorado. “If you’re ground-stacking the wall tiles, no problem. But if you’re going to hang them on a wall or from the ceiling, then yes, [churches] need to consult a structural engineer first."
“If you’re ground-stacking the wall tiles, no problem. But if you’re going to hang them on a wall or from the ceiling ... [churches] need to consult a structural engineer first." Nick Kofahl, Chief Vision Officer, Summit Integrated System, Lafayette, CO
In addition, LED walls will have power requirements based on the amount of current they draw, which will be a function of both the size of the wall and the tightness of the LED pixel pitch. Deron Yevoli, Summit Integrated Systems' director of projects, estimates that that a 9-foot by 16-foot LED video wall will need between 4-8 208V circuits to operate properly. “That’s the dirty little secret of LED video walls,” he says. “Yes, they’re much more efficient than projection overall, but you still have to power every pixel.”
Keep your distance
There are a few rough formulas that are useful for choosing a resolution value, which increases with pixel pitch: depending upon the manufacturer (there’s that phrase again), experts recommend between five and eight feet per pixel distance from the wall to the first row of seating. For instance, a wall with 4-mm pitch will need at least 20 feet between the first row and the video wall so that the viewer can achieve visual convergence – that is, see the image rather than any individual pixels. Measuring that initial distance will help determine the best positioning and pixel density for each church’s LED wall. (Or vice versa if you’re building ground up.)
... a wall with 4-mm pitch will need at least 20 feet between the first row and the video wall so that the viewer can achieve visual convergence – that is, see the image rather than any individual pixels.
Mike Jarnagin, sales estimator/designer at integrator Ford AV with offices in Tulsa, Oklahoma also recommends keeping the far edges of seating areas in mind, especially as wider fan-shaped audience seating designs become more popular. “Depending upon the manufacturer, seats too far off the left or right of the video wall might see only black dots on the screen,” he says.
In the case of extremely wide seating areas, Jarnagin suggests providing for secondary screens, such as large LCD displays, for those seats. LED walls have peripheral coherency up to around 140 or 150 degrees off center axis, he adds, not as much as the nearly 180 degrees a good projection system can offer, but still enough to address most conventional seating designs. “Just remember that that will vary from manufacturer to manufacturer,” he adds.
Yevoli points out that using a video wall behind a pastor on stage requires special attention. Because he or she will be moving in front of an image of that movement, any significant latency in the signal will interfere with how viewers’ visual perception of that movement is processed. If the latency is more than a few frames of latency, it can create what are known as “video echoes” that affect visual coherency, not unlike the disconcerting effect when you hear an echo of your own voice on a cellphone. The result is distraction that can undermine the delivery of the message. The way to avoid this is more powerful processing and avoiding the need to scale an image by choosing a processor that’s matched to the resolution of the wall, be it 720 or 1080 HD, which will mitigate any lag due to processing time.
If the latency is more than a few milliseconds, it can create what are known as “video echoes” that affect visual coherency, not unlike the disconcerting effect when you hear an echo of your own voice on a cellphone.
Beat the heat
Individual LEDs give off relatively little heat, but when assembled into large walls, they can significantly impact the HVAC calculations for the spaces they’re used in. Jarnigin reports that a large LED wall — for instance, one that uses several hundred individual tiles — can generate between 80,000 and 90,000 additional BTUs per hour. “And LED walls dissipate their heat out the front of the wall, so it will add considerably to a room’s HVAC tonnage,” he says. “Plan for that ahead of time.”
Finally, given the growing variety of makes and models in the LED display market, Yevoli and Kofahl recommend investing in visits to see candidate displays in person, before investing in the products themselves. “Take some pictures and see how they translate to your church [project],” says Kofahl. “The LED world is the Wild, Wild West right now. It’s a matter of good stewardship to take the time to make the right choices.”
