Renkus-Heinz Helps Prairie Meadows Cut to the Chase

	Renkus-Heinz TRX-121 two-way Complex Conic loudspeakers at Prarie Meadow Raceway in Altoona, Iowa.

In 1989, Prairie Meadows Raceway opened its doors with the goal of giving central Iowa residents a horse racing facility of their own. Twenty-five years later, Prairie Meadows has grown to include a 168-room hotel with state-of-the-art amenities, live and simulcast horse racing, a massive casino with table games and more than 2,000 slot machines, restaurants, lounges, and a busy concert venue.

Among the horse racing community, Prairie Meadows has gained considerable recognition as an exceptionally well-designed and well-run facility, drawing racing fans from across the state and the region. Among the Raceway's many amenities is a massive four-story glass pavilion that offers comfortable indoor seating on multiple levels. It's a treat for spectators but with all the makings of a sonic nightmare, explains Mike Pedersen, senior staff engineer at Marshalltown, Iowa-based Mechdyne, the audio video integrators behind this state-of-the-art project.

"It's a challenging venue," says Pedersen. "It was built in phases over 20-plus years, and has a mix of seating styles, with stadium seating on one level, grandstand seating on another, as well as a multi-tiered dining area with tables. The original sound system has been expanded in a piecemeal fashion throughout the years, and had become untenable -- coverage was inconsistent and intelligibility was next to nil. They were actually cranking up the volume on each individual TV monitor just so people could hear the race."

"They originally came to us with concerns about the quality and coverage of the tiered seating areas overlooking the racetrack," explains Mechdyne designer Tim Taylor. "But they were also in the process of mapping out an expansion of the entire casino, which was going to require an audio system too. At that point it made far more sense to suggest that they implement a larger system with networked distribution and processing."

"It made sense from a budgetary perspective, certainly," adds Pedersen. "There was very little by way of documentation on the existing system, so just identifying where things were would have been very time consuming. We were able to design them a networked system that would give them DSP control, monitoring, and expandability, as well as providing them with full documentation going forward."

The 70V distributed audio system is based around more than 40 Renkus-Heinz TRX-121 two-way Complex Conic loudspeakers, with DSP and amplification handled by Biamp Tesira and Vocia networks. As Pedersen explains, one of the objectives behind the complex signal processing is to increase intelligibility and directionalize the sound source.

"When things get exciting, when the announcers get excited, we want the spectators to be turning their heads toward the direction of the audio," he says. "The goal was to draw the ear, and the eye, toward the racing action. So even though the speakers are mounted where the glass and ceiling meet, we needed to create the sonic impression that the sound was coming from down on the track."

In the casino area, several dozen TRX81 loudspeakers are flown from the ceiling to provide music and paging coverage. "It's a very high, open, unfinished ceiling, which limited our choices of loudspeakers," says Taylor. "The TRX81 has a very tight, controlled dispersion pattern, and by mounting them in a grid pointing straight down, we were able to achieve seamless coverage across the entire open seating area, with no overlap or dead zones."