Quicksilver’s iTunes plugin comes with several excellent scripts, one of them is to mute iTunes.
The only problem is, that you can still hear all the system sounds. Pretty annoying if you are in a meeting or sitting in a class.
My workaround was to write an Apple Script to control the system volume:
|set curVol to (get (output volume of (get volume settings)))
if curVol > 0 then
set volume output volume 0
set volume output volume 50
This script will mute the system volume, or set it back to 50% if it’s already muted (the value for “set volume” is a percentage value from 0 to 100).
That’s it, I created a keyboard trigger to execute this script (I used Shift-Ctrl-Command + M) and I can mute my system without having to use the mouse or trackpad.