Instructions
Wired Headset
Locate the “Mute” button on your Xbox 360 headset's cable connector. The connector is at the bottom of your headset's cord (it plugs into the controller).
Press the “Mute” button.
Unmute your headset by pressing the “Mute” button once more.
Wireless Headset
Locate the “Power/Mute” button on the center of your Xbox 360 wireless headset.
Press the “Power/Mute” button. Two beeps will sound inside the headset, indicating that it is temporarily muted.
Unmute your wireless headset by pressing the “Power/Mute” button again. Two beeps will sound again to indicate that the headset is no longer muted.