I have been using Ubuntu MATE 14.04 for some time now and have only just noticed that all volume and sound controls have vanished!
The Volume control has gone from the Notification Area in the MATE Panel and there are no mixer or other sound controls available in the Applications or System menus.
The sound on my PC is still working, though the only volume controls I have left are in various apps and the master volume control on my speakers.
I tried to restore the Volume / Sound control to the Panel, but no Sound Control is present in the Notification Area or the Panel’s ‘Add’ menu.
All controls for my sound card are missing: lspci shows it correctly as “Creative Labs SB Live! EMU10k1 (rev 04)”
As I say, my PC sound system was all present, correct and working, but now the panel Volume control has gone and I have no access to the mixer or equaliser controls.