Let’s Make Some Noise!
When Seattle Seahawks running back Marshawn Lynch ran 67 yards for a touchdown in a 2011 playoff game, the home crowd’s raucous celebration registered as a minor earthquake at a nearby seismic monitoring station. It’s long been a point of pride for Seahawks fans, who call themselves the “12th man” and the “12ers,” that CenturyLink Field is the loudest stadium in sports. Technically, however, it isn’t. During a September 2014 Chiefs-Patriots game in Kansas City, a Guinness World Records tester recorded a measurement of 142.2 decibels at Arrowhead Stadium, surpassing the 137.6-decibel mark set the previous season in Seattle.
The official Seahawks’ Twitter account congratulated the Chiefs’ fans on their achievement, but Seattle fans were less gracious, taking to internet message boards to point out that Arrowhead can accommodate about 10,000 more fans than CenturyLink. True enough, countered Chiefs fans, but Arrowhead is an open stadium, while CenturyLink’s partial roof bounces sound back toward the field.
Both sides have a point, according to Jack Wrightson, whose Dallas-based acoustics design firm has consulted for both teams. “Building design can only contribute 5 to 10 percent to the perception of the loudness,” he says. “That’s not a trivial amount, but it’s really the noise of the crowd that makes the difference.”
Although there are inherent advantages to having a loud stadium — CenturyLink saw the most visitor false-start penalties over a decade-long span — it’s not the primary concern of owners, says Paul Griesemer, one of the architects who helped design CenturyLink, which opened in 2002. “When you design a stadium or arena, you think of all its uses,” he says. “It’s not just sports. It’s concerts, convocations, and speaking events.”
Architects and acoustical consultants must strike compromises to best accommodate these many uses. While highly reflective surfaces, like metal and concrete, may help trap the din of a cheering crowd, they can also render the discrete notes of a guitar solo unintelligible. Wrightson’s staff spends long hours modeling the interactions of crowd noise, the house sound system, and concert speakers. “Whether we put more emphasis on one of those more than the other,” he says, “has to do with the architecture of the building and where the owner wants to take it.”
Seahawks owner Paul Allen wanted CenturyLink Field to induce the collegiate fervor he experienced attending games at the University of Washington’s Husky Stadium, Griesemer says. That translated into building a stadium with the NFL’s smallest footprint, with raked seating close to the field and a roof that covers 70 percent of the stands to shield fans from the city’s stubbornly rainy weather — design elements that also help trap sound.
With other NFL stadiums he’s worked on, Griesemer says, loudness wasn’t much of a consideration. When Lambeau Field was renovated for $295 million in 2003, the Green Bay Packers organization “was more interested in maintaining the intimacy of the seating bowl.”
There are less savory ways to add decibels without exciting fans or redesigning stadiums. During games in 2013 and 2014, the Atlanta Falcons pumped fake fan noise through the Georgia Dome’s speakers, which is against league rules and resulted in a $350,000 fine and the loss of a fifth-round draft pick. “Injecting prerecorded sound never works,” Wrightson says. “It’s so artificial sounding and obviously coming from the loudspeakers.”
More sophisticated systems that amplify existing sound haven’t proven popular, either, Wrightson says. He’s more impressed by the $2 million “acoustical cloud” suspended from the ceiling of the Moda Center, home of the Portland Trail Blazers, the NBA team that’s also owned by Paul Allen. The cloud consists of 160 rotating panels with reflective and absorbent sides that can be adjusted to suit the desired acoustics of a particular event. “As budgets allow, I think we’ll see more of these in arenas,” Wrightson says. “But I don’t see them coming anytime soon to dome stadiums, where the roofs are measured in acres. It’s too expensive.”
The tens of thousands of screams it takes to spook a visiting quarterback come with a cost — hearing damage. The National Institute for Occupational Safety and Health says that humans may experience permanent hearing loss after eight hours’ exposure to 85 decibels, and each 3-decibel rise halves the recommended exposure time. Football games average between 80 and 90 decibels and, as the Guinness records attest, can go much higher.
Acoustic designers recognize this and limit the decibel output of stadium sound systems. (The NBA also sets limits on speaker noise.) But it’s much more difficult to shush an inebriated San Francisco 49ers fan — let alone thousands of them. In 1989, the NFL introduced a disruptive-noise penalty, but it was rarely enforced and dropped years later. “Fans know they are going to a football game and not searching for a book in a library,” NFL spokesman Brian McCarthy said after Kansas City bested the Seahawks’ noise record.
Wrightson advises fans to protect their hearing, but, he points out, there’s no standard for measuring crowd noise. The Guinness testers don’t, for instance, set up their equipment in the exact middle of the field at a specific height, so readings are highly variable. The levels reported in the Seahawks-Chiefs decibel race “would cause permanent hearing damage for even the briefest moment,” Wrightson says. “From a strictly scientific standpoint, I’m not sure you should trust the levels. But it is fair to say the fans are very loud.”
