Instructions
Place a game disc in your Xbox 360 and power up the console.
Highlight "Options" or "Settings" from the game's main menu and press the "A" button.
Select "Audio" from the list of options and press the "A" button.
Press down on the directional pad or left control stick to highlight the audio setting you wish to change.
Press left on the stick or directional pad to lower the volume and right to raise the volume for that aspect of the audio. Repeat this process to adjust the remaining audio settings.
Press the "B" button repeatedly to back out from the audio settings and game option screens and return to the game's main menu.