Church Reaches Congregation With AV
The new AV system in Salinas Valley Community Church supports multiple worship formats and a growing congregation.
CHALLENGE: Equip an expanded auditorium with a versatile AV system capable of reaching all 800 seats and accommodating various worship styles.
SOLUTION: Design and install a flexible AV solution, including a redesigned sound system based on electronic acoustic enhancement to minimize natural reverberation and add artificial reflections.
SALINAS VALLEY Community Church in Salinas, CA, has grown from a small Bible-study group in 1984 to today's weekly attendance of more than 2,000. Two years ago, the church began a major expansion of its campus, going from 500 seats to 800 to better accommodate its growing congregation. Sunday services at Salinas Valley include everything from traditional congregation-sung hymns to contemporary praise songs with a full rhythm section. This wide range of worship styles and formats made unusual demands on its auditorium. Oklahoma City, OK-based AV integrator Spectrum Design Group was enlisted to design and install an AV system to complement the church's enlarged space.
Salinas Valley raised more than $2 million, $800,000 of which was devoted to the new AV system. With such a major financial commitment, the church wanted to be as “future-proof” as possible, so it opted for a cross-matrix left/center/right sound system that could deliver stereo imaging to 90 percent of its shoebox-shaped auditorium (see sidebar). Spectrum implemented the complex design, which requires 36 DSP outputs via a Biamp AudiaFlex system and CobraNet. However, the building's low roofline made it difficult to install left/center/right clusters without blocking sightlines to the video screens the church needed, so Spectrum went compact on the sides.
“We crammed for every 1/4 inch we could get, so we used a cluster of three Renkus-Heinz ST7s with PN121M down-fills in the center channel, which handles the voice, plus ST4s and PN81 down-fills left and right,” says Spectrum's President Tom Johnson. “The ST7 has the CDT-2 CoEntrant Transducer with a 10-inch midrange cone and 2-inch compression driver. The ST4, which has CDT-1 with an 8-inch cone and 1-inch compression driver, is a little brighter. Sometimes that's an advantage in a smaller venue. We have four PN212 subs in the center and Bag End 18-inch subs on the sides for the organ pedal tones. There are also four PN121M delays. We have a lot of headroom with these loudspeakers.”
EXPANDING THE SWEET SPOT
Providing intelligible speech and well-defined, high-impact music to a large audience area can be a daunting task. Simply hanging large, high-output speakers in a left/right stereo configuration won't make an auditorium sound anything like a larger version of a living room stereo system. The signal flow required to bring an involving audio experience to every seat is much more complex.
Balancing the trade-offs between interior aesthetics and optimal sound system design allows everyone in the auditorium to understand the spoken word and to hear all the instruments and singers. But spatial imaging is a large part of the musical experience as well. Creating an auditory “soundstage” is challenging enough when the target is a 4-square-foot “sweet spot,” equidistant between the left and right speakers, as in a home or studio system. Expand the target to include 90 percent of an 800-seat room where most of the audience is far off center as Salinas Valley Community Church did, and some imaginative solutions are required.
Because there's no way to bring listeners closer to the sound, cross-matrixing brings the sound to the listeners, using each main cluster as an extension of the others. Typical clusters contain three speakers with 40 degrees horizontal beam-width (sections wider than 45 degrees create too much overlap). Each speaker delivers its main program channel (left, center, or right), plus copies of the other two channels, which are synchronized with their main sources via digital delay. Voice as well as kick and snare drums are usually mixed to the center channel, while instruments and choir are mixed in stereo.
One of Spectrum's challenges stemmed from Salinas Valley's original building, which wasn't designed for modern worship. Cutting into the concrete slab was not an option with the church's budget, so any new wiring and cabling that couldn't fit inside the existing conduit runs would require new overhead conduit. To minimize the total system cost, Spectrum specified self-powered PN and ST Series loudspeakers from Renkus-Heinz with a CobraNet input option, which allows up to 64 channels of digital audio to be distributed using standard Ethernet cable, hubs, and routers.
“The idea of using digital audio and Cat5 cable instead of analog audio on 12-gauge copper wire was fairly new, so the church asked us to draw two systems,” Johnson says. One system uses self-powered, networked Renkus-Heinz loudspeakers, while the other uses the same speakers with separate amplification and analog signal distribution. “We let electricians bid both, and the self-powered system came back 22 percent lower overall. The major difference was the cost of conduit installation and pulling cable. Because we could run all the audio channels for the three-way left/center/right clusters as digital data on narrower Cat5 cables, we were able to fit all the audio signals and the AC for the powered speakers inside the existing conduit. The analog design required multiple runs of 12-gauge wire, which would have to be pulled through newly installed overhead conduit on separate runs from the AC wiring. AC current doesn't induce hum or noise into the digital signal, which can happen when analog audio cables are close to electrical power cables. The church was really pleased that we could allocate their budget to new sound, lighting, and video equipment, instead of building infrastructure.”
The church's range of worship formats posed another problem for Spectrum. Salinas Valley offers three Sunday services: a traditional liturgy in which the choir and congregation sing hymns together, a more contemporary service with a praise band and choir, and a full contemporary service with a rock band. Each format requires different room acoustics. The traditional liturgy was designed for cathedrals with long reverberation times. But a kick drum in a cathedral is a thunder roll, not an impulse. Because changing room acoustics with movable architectural features such as ceiling panels or large reverberant chambers would have exceeded the church's budget, Spectrum's solution was to effectively minimize the natural reverberation in the room and add artificial reflections.
Spectrum chose the VRAS (Virtual Room Acoustic System) from Level Control Systems for the project because it provides spatial panning and dramatic sound effects in addition to electronic reverberation. “This VRAS system uses 16 microphones, 24 DSP channels, and 32 Crown CTs8200-powered Tannoy V-series 8-inch and 12-inch coaxials,” Johnson says. “Some of the speakers are doubled up to give us better coverage and more space mapping options. The Crown amps deliver almost 400 W per speaker to the system. It's a very potent rig. We come out of the AudiaFlex into the LCS so we can take control of the front speakers when we need to. The VRAS gives us multiple settings for preaching and congregational participation, all the way out to an RT60 past 4.5 seconds. They have a single slider control for all eight zones where they can grab the system as a whole. They have presets that are steerable space maps, so via a patch bay they can select a subgroup out of the console, send that to the VRAS system, and then roll it around the room in time with the music.”
Because VRAS provides electronic reverberation, Spectrum had to eliminate natural reverberation with a combination of Auralex 2-inch absorptive panels and wedges ranging from 3.75 inches to 5.875 inches thick. EASE/EARS models of the room determined the size and location of the panels. Johnson says this combination of extensive acoustical treatment and a carefully designed sound system produced successful results. “Our acoustical measurements showed that the room has a reverberation time of 0.8 seconds plus or minus a tenth of a second from 125 Hz to 8 kHz — unbelievably flat,” he says.
FOR MORE INFORMATION
Level Control Systemswww.lcsaudio.com
With such a complex sound system, operator qualifications also became an issue. “We arranged the main speakers, subs, and delays in clusters on Renkus-Heinz' R-Control [a standards-based network solution] as the operator sees them,” Johnson says. That takes a lot of the mystery out. They're able to look at everything and it really makes them comfortable with the system.” R-Control has an Internet Protocol (IP) interface, which allows Spectrum or Renkus-Heinz to check the system remotely via modem, if necessary.
For the front end, Spectrum installed a Yamaha DM2000, supplemented with six Aphex 1788 eight-channel remote mic preamps and an Aphex master system controller. Rack mount processors include a Klark Teknik compressor DN-504PLUS and TC Electronic Finalizers and Harmonizers. The praise band tweaks its own monitor mixes with an Aviom A-16 system, while an Aviom A-Net digital snake connects the stage and the mix position via Cat5 cable.
For the church's lighting system, all of its 34 lighting fixtures are automated and controlled by a Grand MA console from MA Lighting. Scrim sets on the back walls pick up lighting effects from Martin Pro Mac 2000 Profile fixtures. However, the stage itself posed a unique problem. “The back corner of the stage box slopes inward toward the room and it's only 12 feet high,” Johnson explains. “It was very difficult to light that. It wound up taking 20 Mac 250s and Mac 300 Wash fixtures to get it spread properly.”
To add video support that would fit under the space's low ceiling, Spectrum installed Stewart Filmscreen 16x9 projection systems left and right of the stage. Sanyo 10,000-ANSI-lumen projectors display images on the flame-retardant, high-brightness/high-contrast Stewart Firehawk material. The video system includes Canon Series XL-2 cameras for IMAG and close-ups, while a Ross Synergy 100 switcher allows services to be broadcast.
“It's quite a rig,” Johnson says. “The church is still exploring everything they can accomplish with the technology they have and we expect that their services will continue to get more exciting and involving for a long time.”
Christian Doering is a marketing partner at Dynamic Market Systems, a marketing consultant firm with clients in the professional AV industry. He can be reached at firstname.lastname@example.org.