Arrowhead Stadium, the home of the Kansas City Chiefs, the N.F.L.’s defending champions, is a very loud place. During a 2014 game, a sound meter captured a decibel reading equivalent to a jet’s taking off, earning a Guinness World Record for “Loudest crowd roar at a sports stadium.” Around 11 a.m. on Thursday, Sept. 7, Brian Melillo, an audio engineer for NBC Sports’ flagship N.F.L. telecast, “Sunday Night Football,” arrived at Arrowhead to prepare for that evening’s game against the Detroit Lions. It was a big occasion: the annual season opener, the N.F.L. Kickoff game, traditionally hosted by the winner of last season’s Super Bowl. There would be speeches, fireworks, a military flyover, the unfurling of a championship banner. A crowd of more than 73,000 was expected. “Arrowhead is a pretty rowdy setting,” Melillo said. “It can present some problems.” Broadcasting a football game on live television is one of the most complex technical and logistical challenges in entertainment. ...