How to turn off chat voice in Cod Modern Warfare 2?

In the main menu or during the match, press either the Option Menu button, or F3.

Then select Audio from the list of options.

After selecting the audio option, scroll down a bit till you find Voice Chat.

Now toggle the Voice Chat setting to Off.

After that scroll down a bit.

Until you get the channels.

Now change the setting to Mute yourself while connected to On.