It's not perfect, but the sound manager gets the job done.  It's capable of stopping sounds early, as well as telling clients to stop playing sounds from Femtocraft when the user switches dimensions (but not when they log out, by the time the event is called the player has already disconnected, and for some god forsaken reason I can't find out when a player exits, clientside.  This means that I can't use the looping functionality of the sound player because players who quit to the main menu will hear these sounds for the rest of their life.)