We have currently no mixer available in the default Xfce panel. See:
Bug 636227: medium, low, ---, kevin, NEW, RFE: No mixer applet on XFCE desktop (F14 Beta
In the past gnome-media was pulled in and we used the
gnome-volume-control applet (which starts by default).
Do we want to now pull that in again?
Or just put xfce4-mixer in there?
Or something else?