Syntax: 'earmuffs <level>' to turn on 'earmuffs 0' to turn off
If you set earmuffs to a certain level, you should not be able to hear via channels, poses, shouts, and tells. But if you are in the same room with someone you will hear what they say. To turn earmuffs off, all you do is type earmuffs 0 or earmuffs. If you set earmuffs to your level, you will not hear things told you from your level and down, but above your level you will still hear.
See also: lock