Alliance Redwoods Conference Grounds Deploys One-Of-A-Kind Portable Audio System With HARMAN JBL VERTEC® Loudspeakers and Crown Amplifiers

NORTHRIDGE, California – Alliance Redwoods Conference Grounds is a Christian retreat, conference center and summer camp located in northern California’s Sonoma County. Since 1946 the organization has provided families, churches and schools with recreational camp and other activities. Alliance Redwoods Conference Grounds has recently undergone major renovations to its facilities, including the revamping of a gymnasium to double as a music venue with the installation of a unique, custom JBL VERTEC® line array system that can be quickly set up and removed as needed.

“In recent years Alliance Redwoods has been upgrading the camp’s technology and infrastructure to revitalize it almost beyond recognition,” said Greg Adams of systems integrator Sound Expressions in Santa Rosa, California. “A need had arisen to create a larger music venue, and management decided the existing gymnasium should be adapted to create a functional live music space.”

Nevertheless, the gymnasium presented some major hurdles. “First of all, it still had to function as a gym—we couldn’t just gut it and build a dedicated music venue,” noted Adams. “Also, most people think of gyms as spaces with bad acoustics, and this one absolutely fit the stereotype. It was an echo chamber, a 100-percent unusable space for music as it originally stood.”

Sound Expressions brought in Rocky Gianetta of Perform Acoustics, a Roseville, California-based acoustical consultant and manufacturer, to conduct an acoustical study that included creating a number of EASE (Enhanced Acoustic Simulator for Engineers) models of the space. “Based on the models and Perform Acoustics’ recommendations for using their room treatment products, we determined we could tame the echo and make the space work,” Adams said.

Sound Expressions then used the JBL VERTEC Line Array Calculator II speaker configuration and acoustic modeling software to determine what loudspeakers would work best, and where they should be placed. They specified two line array clusters, each containing four JBL VERTEC VT4886 subcompact line array elements, complemented by two SRX728S subwoofers and four JBL MRX512M stage monitors. However, after the design work was complete, the actual installation still required Adams to come up with a novel solution.

“Because of structural and spatial limitations and the fact that the room had to be dual-purpose, we needed to move all the A/V and lighting equipment out of the way when not in use—not just the VERTEC line arrays, but also the video projector and LED lighting towers,” Adams pointed out. “We could not permanently mount anything.”

Adams and his team designed a custom truss that moves up and down using motorized chain hoists. The VT4886 loudspeakers, LED lighting system and video projector are permanently mounted on the truss. When not in use, the truss disassembles into three 10-foot pieces that drop into rollaway carts for easier storage.

The cables to connect the speakers, lighting and projector are permanently installed along wooden trusses in the ceiling. The VT4886 line array loudspeakers and SRX728S subwoofers are powered by Crown I-T12000HD and I-T9000 amplifiers, respectively, and the MRX512M monitors are driven by Crown XTi 2000 amps.

“With the Crown I-Tech HD’s we got rock solid clean power and the most comprehensive DSP available in an amplifier. Crown is optimized to work with JBL VERTEC and when we tuned the PA all the equalization was correct. Also, since we have so many users on this system, the ability to electronically lock the amplifier settings turned out to be a very valuable feature,” added Adams.

The audio system also features a Soundcraft GB8 32-input mixing console at the front-of-house position, which is installed in a custom-built, wheeled mixing cart. The cart houses a multi-pair snake cable that runs from the mixer to a custom, quick-disconnect system at the stage, which leads to the amp rack and mic connections. “We had to cut a lot of concrete to make that work,” noted Adams, “but it was the only way we could make the system portable and removable, while accommodating all the connections for microphones, amps, contact closure, power sequencing, Eurostrips and punch down blocks.

“The Alliance Redwoods staff did most of the work, under our supervision. They placed and angled the speakers according to the JBL Line Array Calculator II results, and we ran our system calibrations using SMAART. The predictions of the Line Array Calculator II software turned out to be extremely accurate. We’re very pleased with how such an unconventional sound reinforcement installation has turned out so well.”

For more information about Sound Expressions, please contact

HARMAN ( designs, manufactures and markets a wide range of audio and infotainment solutions for the automotive, consumer and professional markets – supported by 15 leading brands including AKG®, Harman Kardon®, Infinity®, JBL®, Lexicon® and Mark Levinson®. The Company is admired by audiophiles across multiple generations and supports leading professional entertainers and the venues where they perform. More than 20 million automobiles on the road today are equipped with HARMAN audio and infotainment systems. HARMAN has a workforce of about 11,000 people across the Americas, Europe and Asia, and reported sales of $3.5 billion for the twelve months ended December 31, 2010. The Company’s shares are traded on the New York Stock Exchange under the symbol NYSE:HAR.