Football fans of the Seattle Seahawks and the Kansas City Chiefs routinely compete at home games to set the Guinness World Record for the noisiest stadium. On October 1, 2014, the Chiefs hit the latest peak: 142.2 decibels (dB). That level is like the painful, blistering roar of a jet engine at 100 feet—a typical example that hearing experts give for a noise that is more than loud enough to cause hearing damage. After the game, the fans were ecstatic. They reveled in the experience, noting the ringing in their ears or the feeling that their eardrums were about to explode. What was happening inside their ears was far from wonderful, however.