No sound on Mac OS

The sound in Minecraft is not working at all. I've checked that the Mac OS sound works in other apps (i.e., YouTube), and that the sound is on in the Minecraft Music & Sounds options control panel. Sounds simply do not work.

I tried a fresh install of Minecraft, and I also reinstalled Java 8 (although I don't think Minecraft even uses this on Mac). I also tried the "Fn3 + T" option to reload the resource packs. I also tried to use a 3rd party resource pack with sounds. No of this worked.