While much is made these days of large churches using high-end video cameras and broadcast-quality equipment to project live images of the pastor and worship team onto their video screens, the reality is that most churches don't need systems this extensive. In fact, most churches' video requirements don't go beyond the need to put up lyrics and sermon bullet points on projection screens, and perhaps play an occasional video clip from a computer or video disc. And with the spread of HD video, the options in how video is controlled and transmitted through a facility have changed over the past few years.
The best place to start is not with equipment—it's with the ministry and the people. “Meeting the needs of a worship community requires careful and diligent examination of the church's vision of the perfect worship experience or service,” states Glenn Peacock, senior design engineer at Level 3 Audio Visual in Mesa, Ariz. “You then carefully work your way from there, looking at the skill of the users and the history of the church's relationship with technology. It is very easy for a church to be oversold on solutions they will never use (or lack the skill to use). It is also easy for the church to be undersold because of the desire to save money.”
Chuck Collins, vice president of sales for Digital Projection Inc., agrees. “The user should provide a complete list of ‘care-abouts' to their integrator or consultant. The entire system component list should be considered and, at that point, decisions can be made as to where to be more budget-minded.”
So, think through not merely what you need your video system to do now, but about what you anticipate needing it to do in the future. And how far down the road is that future? Buying equipment now that you will need to replace a year from now may not be the wisest stewardship option.
THE EVALUATION STAGE
Once you know what your needs are, you can start evaluating components and infrastructure. Do you want to go with a standard definition (SD) system, or are you going high definition (HD)? Are you able and willing to perhaps buy higher-end components that all use the same signal type, or are you going to want to mix and match equipment types? Are you going to need to switch between various signal sources (such as a computer, DVD player, etc.), or are you typically going to only use one signal source with your system?
If your needs won't go beyond using a computer for the majority of your church's video source needs, this can simplify things greatly. As Don Gspann, owner at Concept Professional Systems Inc. in Farmingdale, N.J., states, “If the church is only using two inputs and one is the computer for Sunday services, and the other input is the DVD player for an occasional youth movie night, then I would tell them to just switch the input on the projector.”
This approach can be problematic if you need to switch inputs during your service, however. “Switching inputs on the projector will not be seamless,” explains Ben Cating, senior consultant with Acoustic Dimensions in Dallas. “You will always see a glitch. This is further problematic for sources that require HDCP (a form of content protection present in digital video signals) handshaking, as the process may take up to three seconds.” Gspann agrees, and suggests going a more sophisticated route in these situations.
The type of glitch to which Cating and Gspann refer can be anything from the output going black to the video flickering and rolling while the projector synchronizes with the new signal source.
If you need to switch between a variety of input sources during your services or events, you should consider adding a video switcher to the system. At its most fundamental level, a video switcher takes multiple input sources and allows you to select one to be sent to the main output. Many basic video switchers can handle numerous signal formats and input connection types, and can often scale the input signal to match the output signal of the projector.
“I would look for a basic video switcher that at least has the most common video inputs: composite, component, and VGA, and one that will at least scale the output to VGA,” suggests Gspann. “A step up from that would be a switcher that has ‘universal' inputs that can accept anything from composite to DVI-HD, and output it to VGA or DVI.”
In addition, the switcher may contain one or more frame synchronizers. A frame synchronizer delays the video signal slightly so that it aligns with the part of the image the projector is currently processing. It wouldn't do for the switcher to be outputting the first few pixels of an image when the projector is currently painting the middle of the output image—the input signal needs to be delayed until it is synchronized with the output signal. A switcher with one frame synchronizer needs to switch briefly to black before showing the new signal, to allow the frame synchronizer to start processing the new input. A system with two synchronizers can switch seamlessly between two signals, and the new “previewed” signal starts being processed by the second synchronizer before the switch takes place.
If you anticipate having several inputs and doing frequent switching between sources, there are some other options to consider. A very usable feature is called a multi-viewer—[with] the ability to tile all connected sources, preview, and program images on one monitor. This saves money and space and is a sensible, functional feature that adds to the ease-of-use goal. Remote panels and control options for control systems (such as AMX and Crestron) or working with DMX (lighting control signals) or even an iPad may have immediate benefits or be useful in the future.
EQUIPMENT FACTORS
When selecting equipment, it's important that you look closely at the cabling options and signal types that are supported, and ensure that it's actually possible to connect all your preferred selections together. For example, some switchers may only use HD-SDI connections for all inputs and outputs. You're not going to be able to connect a consumer DVD player to this switcher without having to purchase converter boxes. Likewise, if you buy projectors that operate at 720p (1,280 x 720 progressive) resolution, it wouldn't make a lot of sense to buy an SD switcher and not be able to use the full resolution of the switcher.
So, what should be considered when looking at signal transmission to your projection system?
Everyone concurs that digital is the way to go, and is certainly the best option for HD signals. For shorter runs, an appropriate quality DVI cable can get you about 50 feet. For longer runs, computer networking cable (often referred to as CAT5, CAT6 or UTP) can be quite effective for transmitting video signals. To use UTP cable, a balun (balanced/unbalanced converter) device is used to convert a video input signal into a format transmittable over UTP cable, and then another balun is used to convert the signal back to a standard video format at the receiving end. These video extenders can provide transmission distances of hundreds of feet.
For a more professional option, serial digital interface (SDI) signals transmit both HD and SD signals digitally over a single coax cable, and can also provide hundreds of feet of reach—but at a higher price tag. Fiber optic cabling can provide even longer cable runs for larger installations or sending a video signal to an overflow room at the other end of your facility. HDMI is also a possibility, but is really geared more to the home theater environment. “Most commercial projectors have both HDMI or DVI inputs, but DVI connectors typically fasten to the projector with more stability than an HDMI connector,” states Collins.
For connecting your input sources to your switcher, cable lengths generally aren't a concern. Decide what equipment will serve you best, and make sure that they have the connectors and resolution capabilities to be connected to each other. And if you ever have guest presenters, make sure you can handle their needs as well.
“Always be prepared for the person that walks in with an analog RGBHV (15-pin VGA) need,” advises Peacock. “For that matter, be prepared for the guy that shows up with a 35-mm slide tray and eight-track tape for the music,” he also quips. But his point is well considered—if you have a lot of guest speakers, you never know what they may show up with. Do you have guest speakers from Europe? Can you play the PAL-formatted DVD they may show up with? Having an inventory of cables and adapters to handle most options would be wise.
IS EDGE BLENDING FOR YOU?
One of the latest trends showing up in churches is the use of ultra-large screens and edge-blending projectors. Cary Church of God in Cary, N.C., (recently covered in CPM) uses four projectors edge-blended together to make one huge video backdrop (19 feet by 43 feet) for its platform. Edge blending is the process of aligning and overlapping multiple projectors and “feathering” the overlapping areas together to provide a seamless image. If your church puts on plays or other dramatic elements, edge-blended projectors can be a phenomenal way to do backdrops. However, setting up an edge-blending system can be tedious and complex.
“Depending on the content,” Cating adds, “edge-blending can be done by the average church tech guy. It's easier to overlook blending problems on busy graphical content; however, it's more critical if you're using it for a presentation that includes people's faces or fine text.”
Peacock stresses taking a professional installation approach. “This should be designed and installed professionally. It is really easy to mess this up,” he says. And mis-aligned projectors produce a very distracting image.
To wrap up, let's talk briefly about installation issues. Two common problems typically show up in projection systems. The first is the “rolling band” effect—a darker or lighter bar that slowly moves up through the screen.
“The bar traveling through your image is a ‘hum bar.' It's humming—you can't hear it, but you can see it,” states Gspann. This is the same sort of ground loop that causes the 60-Hz hum in your audio system. Like an audio system, all components of a video system should be powered from the same bus in your circuit breaker panel, and ideally from a dedicated isolated ground power system. Lacking that, you can install isolation devices to break the ground loop that's causing the hum bar. The wrong way to fix this problem is to use ground lifts, states Gspann.
Another issue that can appear is “ghosting”—when the image repeats itself a few pixels over from the original display of the image. Collins states that this is frequently caused by cable runs that are too long; signals that aren't amplified appropriately for the distance; or a video signal exceeding the bandwidth capabilities of the cable.
A basic video system can be reasonably easy for a church to purchase and set up themselves. However, there are risks involved. Rarely does a church have someone who fully understands the potential problems and all the options available, and you can waste more money through poor decisions than you'd spend on hiring an experienced consultant.
“Engage an established, well-referenced professional and avoid the liability of errors and having to learn the business for a one-time installation,” states Peacock. “Engage a vendor that will take responsibility for the design with a well-established track record. Avoid using the elder's brother-in-law who used to work at the car stereo place.”
Collins agrees: “Most everyone in AV agrees with the axiom ‘you get what you pay for.'” This goes for both equipment and your consultant.
