I'm running my Mac through a Tascam US-122 USB audio device, which connects to my studio monitors. I finally ditched my hardware mixer which I have always used to control volume. I figured it would be easy to control things via the volume control, however that doesn't work. If I move the volume slider in iTunes, that DOES control volume, but there isn't any easy keyboard command for that. I was hoping hitting the function keys for volume would let me easily move the master volume (sent to the USB device) up or down. There must be some way to make this easy! I would really appreciate any advice.