The volume controls aren't working well. I'm using a M-Audio Firewire Audiophile external sound device. There seems to be a headphone level control on the left which sort of works (its continuous so you never know where you are in its range) and a "Level Controller" on the right which doesn't do anything to the sound yet it controls the sound bar in Sys Prefs/Sound. I downloaded the 10.4.11 driver from M-Audio.