I enjoy iTunes playing music tracks while I am working but need to mute when my 'phone rings, by keyboard instead of activating the app from minimised state each time to do so. I have downloaded Synergy also to try to do this but still cannot when I have another app open. I can use the volume keys ok but cannot mute at a single key stroke! Is there a simple way to do this or do I have to open and minimise every time I get a call?