CHULA VISTA, CA--More than one hundred of the world’s best BMX racers met in California for this year’s BMX Supercross World Cup, and thousands of spectators heard every squeal of the tires, thanks to a creative use of a Shure PSM 700 personal in-ear monitoring system.
The action took place at the U.S. Olympic Training Center (OTC) race course in southern San Diego County. The track was modeled after the course at the Beijing Olympics, but the three-acre site created some challenges as far as audio was concerned. With leased audio systems costing close to $30,000 per event, OTC officials decided the World Cup was the perfect opportunity to install a permanent sonic infrastructure that could be expanded as needs arose.
The OTC enlisted the help of Quiet Voice Audio of Fallbrook to design and build the system. “The rental systems previously used at the OTC were mainly generic in their approach,” explained Quiet Voice founder and Principal Jon Bart. “As a result, obtaining full coverage and the volume needed for these high-energy special events often fell short.”
Bart began by inspecting the race course and adjacent areas, only to discover the absence of conduits needed for loudspeaker cable runs and balanced audio feed lines. Electrical outlets were also minimal at best—three to be exact—over the entire coverage area.
“There was, however, a tower located on the east side of the track that could serve as a vantage point for mixing and as a main system control center,” Bart said. “The question remaining was how to get our audio signals from there to all points of coverage. With seating on all four sides, the track needed a lot more than the single point source arrays that had been used by many of the rental sound companies in the past.”
With little to no hope of developing a totally hard-wired distributed system plan, given the lack of conduits and power, Bart decided wireless was the solution. “It was only logical,” Bart said. “Why not use UHF-FM to get our signals across some of the distances involved, and never mind the need for loudspeaker lines? We wanted to see how far we could push the envelope distance-wise with full quieting.”
With a total of 14 self-powered loudspeakers distributed around the track, Quiet Voice decided to take a trailblazing step and use a Shure PSM® 700 personal in-ear monitoring system in a unique way. Made safe by mounting inside of a weatherproof Pelican box outfitted with a Lemo connector for an antenna connection, a TRS 3.5mm connector to manage audio output, and a Shure PS9US 9V battery eliminator with a female 9V terminal clip added, the PSM ®700 receiver was attached to the side of one of the self-powered loudspeakers distributed on the opposite side of the track facing the control tower. Using Shure paddle antennas at the receiver and transmitter end in the tower, Quiet Voice took the wireless signal received at the single loudspeaker location on the other side of the track and fed it to 8 of the 14 loudspeakers via standard balanced lines. The remaining six loudspeakers near the control tower were wired with conventional cabling.
“Shure’s PSM 700 system was a natural choice, due to its size, wide frequency response, smooth compression, quiet operation, and rugged construction,” Bart remarked. “It also allowed us to get clean, full-quieting signals from point-to-point using off-the-shelf directional antennas. Now we have plenty of room for future growth throughout the OTC, since we can easily cover larger areas by simply adding more receivers at additional points across the complex.”
The unorthodox wireless design proved to be a success on race day, when the emcees used Shure ULX Beta 58 wireless microphones, and, according to Bart, “cut through the night like a laser above the DJ track. If you’re a sound person, you know that feeling when everything is working. The race introduction rolled into the Pledge of Allegiance and National Anthem. Then the Navy SEAL Leap Frogs parachuted onto the track trailed by colored smoke and an American flag. The crowd went nuts, but you could still clearly hear the voices of the emcees above it all. We live for that, and the OTC staff and sponsors were pleased as well.”
Like everyone else, Bart likes a story with a happy ending. The BMX Supercross World Cup was a win-win proposition in terms of audio, with Bart and his crew getting an opportunity to think creatively and use high quality Shure components in ways not normally envisioned.