By George Tsintzouras

Engaging and inspiring today’s congregations is increasingly difficult in a world saturated with corporate and secular images. The solution for many churches is to make each service more creative and interactive — specifically, to use large-screen projection to support the message each week. Bright and colorful images large enough to be seen from every seat serve to capture and hold the congregation’s attention, allowing the essential messages to be easily delivered and understood.

However, a single projector and screen may not be sufficient to meet this goal, especially in larger buildings and auditoriums. There is a limit to how large a screen a single projector of reasonable size and cost can properly illuminate.

The preferred solution is a multi-projector system, with a large, main screen displaying one image/message and possibly one or more, smaller satellite images on physically separate screens. The large, main image can be constructed of smaller, blended images, one from each projector in an array, with the edges of each image blended into the overlapping edges of adjacent images to form one seamless, wide aspect, display.

When choosing a projector, there are several key considerations. One factor is built-in support for warping and blending of the projected image. This is critical for combining images in either a tiled or stacked configuration, since each projector will typically be aimed at the screen from a slightly different angle.

Tiled array problems

The next important consideration, particularly for a tiled array, is the projector’s illumination system. It may be tempting to use lower-cost, commodity projectors with a high-gain screen to compensate for their lower typical light output.

However, the tiled nature of the composite image will be immediately obvious to any viewer not directly in front of the screen’s center. Low-gain screens are necessary to avoid this, which requires projectors with higher light output.

Another valuable feature, which makes setting up and maintaining a multi-projector system easier, particularly if it is necessary to physically move it to a new location, is an automatic blending and stacking system. This option, available for certain projectors equipped with the aforementioned image warping and blending functionality, requires very little training to operate and can completely automate the process of stacking and edge blending, saving time and resources.

Don’t compromise the image

There is also the option to create the images in stacked configurations, with each projector displaying the same image on the same screen, each adding its light to the total or providing redundancy to ensure the service continues if a projector fails. As well, a multi-lamp projector provides additional built-in redundancy (if a lamp fails) and ensures that the show goes on and the overall presentation is not compromised.

In today’s tough economic times, cost of ownership is likely the most important factor in the purchase of a projection system. Here too, careful selection pays dividends. The optical efficiency of the projector is likely the largest contributor.

The cost of replacement lamps is also a factor; the small lamps used in multi-lamp projectors usually last longer, provide redundancy and cost less to replace than the larger lamps used in single-lamp projectors to achieve the same light output. Air filters, which typically must be replaced regularly, are another ongoing expense; a projector that can operate without them provides an obvious advantage.

An effective church projection system, regardless of its size, must be bright, flexible, reliable, meet the needs of the church leaders and congregation, and all fit within a defined budget.

George Tsintzouras is director of product management, business products for Christie Digital Systems USA Inc., Cypress, CA. [www.christiedigital.com]

By Dave Cannaday

With today’s technology there are many solutions for achieving  balanced sound coverage in a large worship center. The old days of hanging speakers in one cluster from the center of the room are gone. Today there are many options to choose from.

One of the first things to consider when selecting speakers is the size and shape of the room. The height and depth of the room will help determine if you want a cluster design or line arrays. In a cluster design the room is covered in a series of zones. In this style of speaker system there is usually a cluster of speakers at the front of the room which is then divided into a left, center and right cluster configuration. Delay speakers are then used in the back portion of room to provide coverage to back half of sanctuary.

In a cluster design the use of multiple amplifier channels to control sections of the room is used. Along with the amplifier channels, a DSP (digital signal processor) channel is also needed. This provides all equalization, delays, gates and compression on main speaker systems.

A balanced system

When a system is balanced and tuned correctly, it will ramp (rise of sound) as one whole room, front to back and left to right with balanced coverage. This configuration requires a lot of time at the beginning tuning and adjusting volume per section so the entire room is equal when final the sound is heard.

Sometimes a cluster design is chosen because it’s easier to hide aesthetically behind bulk head and ceiling grids. This is a great choice when aesthetics without AV components are essential in the sanctuary. The best option for optimal sound is to leave speakers uncovered because it will help with the reflection of sound that may get trapped when put behind drywall in a bulk head.

One of the most common configurations used today are line arrays for speaker systems. A line array system is a line of speakers hung beneath each other. The main purpose of this is to evenly cover a room and throw sound long distances.

Line arrays are most commonly used in today’s large churches. A true line array system is normally used in distances of more than 80 feet. Sometimes there will be sound gaps in certain spaces. For instance, if a worship center includes a balcony, speakers for under the balcony will be needed to fill the sound loss. However, the sound produced by a line array system can be a remarkable solution for a sanctuary.

One of the downfalls to line arrays is that they are harder to mount behind a bulk head. Generally these systems are prominently placed and very visible; for some churches this isn’t a problem but for others it conflicts with the design of the space and the desired aesthetic.

More powerful sound

There are two types of line array systems: powered or non-powered. This refers to whether the amplifier is mounted in the back of the speaker (powered) or if it’s mounted on the floor in an amplifier room on the main level (non-powered). For non-powered speakers running wire between an amplifier on the floor and the speaker in the air can take hundreds of feet of wire. In theory the shorter the distance between amplifier and speaker means more power being delivered to the speaker, which in turn will produce a cleaner and much more powerful sound.

Another problem with line arrays is weight consideration. Depending on the types of speakers used the weight of the line array can be a significant problem. When amplifiers are mounted in speakers the weight of speakers and the line array is much higher.

Sub bass speakers are also important components to system configuration. The main decision is suspend the speakers or to place the sub bass speakers on the floor of the worship center. If a church chooses to suspend them, it will take more speakers to do the job and they won’t able to equal the energy of a few boxes sitting on the floor.

Style of worship

The way to determine which is best depends on a church’s style of worship. If services are contemporary and feature bass, drums and heavy keyboards, floor placement is best. If this sound dynamic is not essential, then a church could probably hang the sub bass speakers with little impact. Low bass notes produced by sub speakers can add a fullness and richness to worship services adding to the experience.

The two main types of speaker systems used in large worship centers can have a significant impact on services, and each configuration offers advantages. Cluster systems can be adapted to fit the aesthetics of a worship center and offer balanced and finely tuned sound. Line array systems can provide powerful far-reaching sound and also provide controlled balanced coverage. Whichever system a church chooses to install, the decision will have a profound impact on how services are experienced.

Dave Cannaday is a project manager for Custom Sound Designs Inc., Woodburn, IN. [csdus.com]