Tech Focus: Stadium Sound — AV Systems Are Increasingly Sophisticated

As coronavirus pandemic affects construction, ‘community noise’ and architecture continue to influence audio design

COVID-19 has changed a lot of things, but physics isn’t one of them. Key concerns regarding sound inside (and around) sports venues have occupied the top of the list for much of the past decade: notably, low-frequency distribution, speech intelligibility, and SPL management. But the solutions are becoming more sophisticated.

Stephen Siegel, president/co-founder, Fulcrum Acoustic, which has installed sound systems at the Baltimore Ravens’ M&T Bank Stadium and Baylor University’s McLane Stadium, says that, although every sport wants to hype the sonic low end, managing all that bass is becoming an issue.

“‘Community noise,’ as it’s called, has become a problem,” he explains, “as more stadiums get built in downtown neighborhoods, with more sound — especially low frequencies — escaping from the bowl.”

The broader solution has been to use cardioid configurations of the larger number of subwoofers that systems deploy to boost the low end, a technique that can improve the directional focus of low frequencies, whose propagation tends to be omnidirectional. However, says Siegel, active (that is, powered) control systems of cardioid configurations can be expensive. Fulcrum Acoustic markets its proprietary passive cardioid system to achieve that end at lower cost and in less space.

“Containment of noise is perhaps the biggest challenge we’ve been seeing in sports venues recently,” he says. “This is becoming an even bigger problem in Europe, where any new soccer stadium is by definition going to be close to where people live.”

Architecture Affects Audio
The rise of soccer in the U.S. is another factor influencing sound-system design, according to Dan Palmer, business development manager, sports facilities, USA and Canada, L-Acoustics.

L-Acoustics’ Dan Palmer notes the influence the growth of soccer on the stadium architecture and sound design.

“MLS stadiums are largely open-air stadia,” he explains, “which utilize canopy architecture over the audience seating area [as] the primary rigging point for sound. It works very well but is unique to MLS.” So too are the stadiums’ smaller capacities relative to MLB and NFL venues, which also affect system design.

Palmer cites MLS LA Galaxy’s Dignity Health Sports Park, where a lightweight KIVA II/SB18 system is distributed in 18 arrays across the two canopies and meets all structural, weatherization, and performance criteria.

In Europe, where soccer is the dominant sport, the venues’ AV systems haven’t traditionally been as highly upgraded as they have become in the U.S. However, that’s all changing, says Palmer, noting major L-Acoustics upgrades at 75,000-seat Allianz Arena in Munich and 67,000-seat Olympique de Marseille Orange Velodrome in France, with significant premium implications for sound-system design on both continents.

“MLS has studied the other major sports,” he says, “and are adapting their sound and video to be as exciting as their game already is but [to] require sound systems that can adapt to their venues’ architectural requirements.”

Another challenge area for sound is a competition with video for real estate in the venue. As centerhung and end-zone scoreboards increase in size, line of sight has become equally valuable for video- and sound-system design. Palmer cites TCU’s Amon G. Carter Stadium, where an end-zone scoreboard left no accommodation for side-mounted line-source arrays. Instead, they had to fit into a window along the top of the scoreboard yet still meet a throw-distance requirement in excess of 600 ft., which three hangs of an L-Acoustics K1 system and its WST technology did achieve, along with other performance and cost criteria.

“Getting size right for sightlines, SPL, distribution/coverage is critical and is now a driving factor in sports-venue sound design,” he says. “The trend is in providing a premium and immersive experience for all with an ROI to support it.”

(Non-Acoustical) Clouds on the Horizon
However, COVID-19 is having an impact on sports sound to some extent. Palmer says venue projects begun before the pandemic hit seem to be moving forward. Work on SoFi Stadium, the new home for the NFL’s Los Angeles Rams and Chargers, has continued, albeit under stricter construction-activity guidelines instituted by the state in March, and the MLB’s Dodgers have nearly completed a $100 million renovation, including new sound.

On the other hand, some venues may hold back on capital spending until the COVID-19 crisis is resolved.

“Sports venues are already looking to back off on incurring costs for new sound and video systems and for upgrades to existing systems,” observes Paul Murdick, GM, TSI Global, an AV-systems integrator. “It’s business 101: if there’s no game, there’s no one in the seats, no television or radio, and there’s no revenue coming in. There’s no incentive to spend on new systems.”

Tulsa, OK’s OKONE Field, home to Los Angeles Dodgers’ Drillers AA team, where TSI Global put in a new scoreboard and an updated broadcast system with new fiber and new cameras, sits unused, the work finished just weeks before what would have been the April 9 Opening Day, a mute monument to the virus’s impact.

Another way that COVID-19 may influence system design (and venue architecture) is how flexible venues and their systems have to become. Murdick points out that venues that host more than one sport or league, such as the MLS expansion teams using local football and other stadiums as that league’s infrastructure is being built out — for instance, Nashville SC is using the NFL Titans’ Nissan Stadium as it waits for its own stadium to be built — may be in the best shape overall: a centrally managed league can resume play relatively quickly, whereas, with a more disparate nature, music touring will likely take some time to get back up to speed.

“If you already have multiple sports being played in the arena or stadium,” he says, “they’ll have revenue coming back in faster than if they had to wait for concerts to recover.”

His long-term concern is that the hiatus lasts so long that venues lose the sense that they need to keep systems at the cutting edge.

“There may be a tipping point to this,” he explains, “after which many stadiums and arenas start to regress, in terms of the level of audio and video they feel they need to compete.”

Fulcrum’s Siegel, though, says there’s plenty to look at beyond the bowls. He points to increasingly high-end workout and training facilities being built at colleges and even high schools to attract athletes, using DJ-grade sound systems as a foundational element. At Purdue University’s Football Performance Complex, for instance, the weight room and locker room have speaker and sub arrays, designed by AV consultant Idibri and supplied by Fulcrum Acoustic, that many nightclubs would envy.

“The [COVID-19] situation might slow some things down here and there,” he says, “but, unless there’s a radical change in sports-venue geometries, the way sound is used in them won’t change much.”