I installed Minecraft yesterday. I can't remember if the sound issue was here when I first played to, maybe I didn't mind at the start.
-The walking/running/jumping sounds on grass and rocks are so low or absent
Note that the walking/running/jumping sound on gravel are present
-The sound occurring when an item breaks is absent
-Some sounds, as the "click" occurring when the in game menu is closed is far too loud.
Linked issues
Comments 2
First issue: Sound too low is not a bug.
Second issue: Maybe a broken sound file. Stop Minecraft, delete .minecraft/assets/ and restart.
Third issue: Duplicate of MC-36502.
Besides that, your OS is outdated. Please download the free update for OS X from the Mac App Store
Maybe you should go to the sound menu...