It is well known that stadium noise can influence play on a football field, typically by interfering with the opposing team's ability to communicate with one another while setting up plays. Penn State personnel placed 11 sound meters in Beaver Stadium and found that the noise level could rise to 110 decibels (50X baseline) when the opposing team had the ball. Then, in an empty stadium, they used a loudspeaker to generate noise and measured the sound intensity on the field. This allowed them to map the locations at which the (loud) student body could be most effective.
To take advantage of this acoustic effect, Penn State plans to move the 20,000 seats in its student section squarely into the southern end zone when the entire stadium is reseated for the 2011 season. Barnard's computer model predicts that this relocation will quiet the east side of field slightly but increase the sound on the west side by almost 50 percent -- cutting the range of a quarterback's voice by another six inches and potentially causing more false starts and penalty opportunities.Link
, via Physics Buzz