The major addition to the 2005 game is the "Top 25 Toughest Places to Play," compiled by EA Sports.
These rankings are based on home winning percentage, average attendance, and "atmosphere" (i.e., fan rowdiness and noise).
Players with the home field advantage on defense can increase the crowd's volume before the snap by repeatedly pressing a certain button on the controller, depending on the system.
Likewise, the player with the home field advantage on offense can quiet the crowd with one press of the same button.
If the noise is sufficient, when the quarterback tries to call an audible, one of his teammates will come down to him and gesture that he can't understand him.