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"[The client was] pleased beyond any expectation. There was not one sound complaint from the over 5,000 attendees during the entire three-day event... [The event] benefited immeasurably from the ability to design a sound system using MAPP Online. The ability to design a system as homework not only saves time on the job-site, but also achieves the best possible results."
- George Relles,
George Relles Sound
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Cement floors. Cinderblock walls. A square floor plan. Put it all together and you've got the kind of acoustical conditions that can make precise control over sound reflection next to impossible. It's not a situation you want to face without some serious analysis to guide loudspeaker selection and configuration. So when George Relles of George Relles Sound in Eugene, Ore., was preparing for the 27th Annual USA/Canada Lions Leadership Forum in Portland's Convention Center, he turned to the Meyer Sound MAPP Online acoustical prediction program for help in planning his sound reinforcement strategy. The results, he says, were "quite astounding." The Leadership Forum consisted largely of talks and presentations, delivered either from a podium or walking around stage using a wireless lavaliere microphone. There were also opening and closing ceremonies, which incorporated both music playback from CD and on-stage vocal ensembles including a large choir. Relles says that he realized at first sight that the room was going to be a challenge. "It was 340 feet wide by 340 feet deep, with an uncarpeted cement floor and concrete block walls. The acoustic treatment was insignificant." In addition to acoustical considerations, the event involved some physical constraints that limited options for speaker placement. "The stage design included three video-projection screens that extended 120 feet across the back of the stage," Relles says. "That created sight-line issues, and the trim of the bottom speaker had to be above the outside video screens at 18 feet above the ground. Plus there was a lack of rigging options in the ceiling. So we had to go with a bridle that landed the rigging points approximately 8 feet upstage from the edge of the stage." Another factor was the average age of the attendees at the conference, which Relles puts at 67 years. As a result, he says, "voice articulation was the essential goal of the sound system design." To minimize the impact of reflections on intelligibility, Relles used MAPP Online to design left/right clusters of M2D compact curvilinear array loudspeakers. "My goal was to create a beam of sound that would not interact with the back wall," he says. "Fortunately the last row of seating was about 60 feet from the back wall and the front row of seats was 20 feet in front of the stage, which was 60 feet wide and 30 feet deep. So using MAPP Online in the vertical plane, I designed the M2D system to project most of its energy above 400 Hz into the seating area." Relles reports he ended up with "a fairly flat architecture. The angles of the 10 boxes were 0, 0, 0, 1, 1, 1, 1, 1, 2, 2 degrees, and the rigging frame was angled down at 8 degrees. The speakers were spread 120 feet apart and were approximately 8 feet upstage." Relles also used MAPP Online to assess coverage requirements in the horizontal plane. "I determined that a single UPA-1P compact wide coverage loudspeaker on each side of the stage would be sufficient for the center near-fill," he says. "This was surprising to me because of the distance between the M2Ds, but I've become very trusting of MAPP Online, having used it now for almost two years." Once the system was set up, Relles was amazed at how well the MAPP Online design worked in the hall. "The articulation was excellent," he says. "The slap-back echo that did exist was of low enough frequency content that it did not interfere with the intelligibility." Relles checked coverage using a calibrated B & K 2238 SPL meter. "The A-weighted SPL using pink noise did not vary more that 5 dbA throughout the entire seating area," he says. "But just as MAPP Online predicted, the high and midrange frequency-content dropped off significantly behind the last row of seating." The result, Relles says, was a client who was "pleased beyond any expectation. There was not one sound complaint from the over 5,000 attendees during the entire three-day event. Considering the age of the attendees, that was quite remarkable." Relles adds that the event "benefited immeasurably from the ability to design a sound system using MAPP Online. The ability to design a system as homework not only saves time on the job-site, but also achieves the best possible results."
December, 2003
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FEATURED PRODUCTS
M2D UPA-1P MAPP Online
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