I have Ubuntu Studio 14, and I had to go into the sound settings and change the USB sound to "Set as Fallback" then all the volume buttons on the keyboard, the ones on my USB headset and the ones in the notification panel all changed the USB volume level.
I have Ubuntu Studio 14, and I had to go into the sound settings and change the USB sound to "Set as Fallback" then all the volume buttons on the keyboard, the ones on my USB headset and the ones in the notification panel all changed the USB volume level.