CITYPARK, the new home of St. Louis CITY SC, the city’s MLS franchise, was designed with maximizing crowd noise in mind. Each of its two tiers is within 120 feet of the pitch, the closest of any stadium in the league, creating a clamorous bowl that seats a total of 22,500. Officially opened on November 16, the new $457-million venue also has a 3,000-plus safe-standing supporter section where the most ardent fans will generate even more noise. Furthermore, the venue’s roof structure, designed to pay homage to the city’s trademark shimmering Gateway Arch, is made from perforated aluminum, contoured to keep that noise inside the stadium while even amplifying it in the bowl.
However, that roof also presented a challenge for hanging the venue’s PA system, which had to thread—literally—many needles imposed by the architectural design. It needed what only the L-Acoustics A15i loudspeaker could bring to the project: flexibility, directional control, and high-quality sound. Coupled with that was a unique and precise mounting process developed by the project’s rigging specialist, Cignal—the installation division of integrator Logic Systems—which worked closely with TSI.
“This was an incredible challenge,” said Chip Self, owner of Logic Systems, who also sold the venue a DiGiCo SD12 as its FOH audio console. “There’s a soffit underside of the roof, which is quarter-inch-thick aluminum and powder-coated, and the steel we had to hang from was almost 3 feet above that. Usually, we’d hang off the steel, and that would be that. But here, we had to create our own rigging infrastructure that would attach to the venue’s superstructure, then drop the five-eighth-inch speaker support rods down through three-quarter-inch holes in the perforated roof with extreme precision. And those rods could not touch any part of the roof, including the sides of the holes. We had to create a web of diagonal bracing cables to keep this new rigging infrastructure from moving. We had never faced anything like this before.”
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What helped enable this was the choice of the L-Acoustics A15i. Its lighter weight and high performance made this unique sound system approach possible, said Self, for what would become L-Acoustics’ first newly built MLS stadium in the US. “In addition to all of the structural hoops we had to jump through to fly the PA, we also had to be conscious of the aesthetic for the venue—they didn’t want to see any hardware, cables, et cetera below the roof,” he explained. “The A15i is light enough and powerful enough to let us put over 100 of them, along with more than 50 KS21i subs, in just the right places without overstraining the rigging solution. And the A15i also has more than two dozen possible mounting-attachment locations on the boxes, so we could invert them and hang them in any angle, attitude, or configuration and still get the performance we needed from each speaker.
“In some cases, we deployed the system to hang as a line array and in others as a point-source system. No matter how we positioned them, though, they sounded exactly the same, and very few speakers in the world can do that. Moreover, the A15i’s waveguide options let us position them close to other parts of the structure but direct the sound away from hard surfaces, which let us achieve a high level of intelligibility.”
Cignal has already applied versions of this novel system-rigging design developed for CITYPARK Stadium on other projects, including SLU’s Chaifetz basketball arena and the University of South Carolina’s Williams-Brice football stadium. They plan to use the design for an upcoming venue project at Baylor University in Waco, TX.
“CITYPARK’s sound system design revolved around the need for not only premium performance but also high value, and the A15i system hit that sweet spot head-on,” said Brennan Wilkins, senior associate at ME Engineers, the acoustics design and systems consultant to the project’s undertaking.
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He pointed out that A15i offered the output needed to make the bowl a loud and exciting environment, one that worked in synergy with the architectural roof design. “The A15i doesn’t so much compete with the crowd noise as keep up with it, which is what you want the PA system to do,” he said. “And because it’s L-Acoustics, it does so with musicality and excellent tonality, all within the allocated budget.”
Wilkins also notes the consistency of coverage achieved by the design. “Wherever you are in the venue, the sound will be there, too,” he said. “There’s not a bad seat in the entire house. This system is a real winner.”
