Basically, I just installed Mountain Lion again thinking the problem would go away and it did for a while.... but it just came back. Basically everything was working fine for a day.. but now suddenly.. the audio pops/crackles/distorts randomly every 30 sec or so when playing any kind of audio through the speakers (whether via video, itunes, etc..). I know it's not a hardware problem as the problem completely goes away when I disable 'Automatic Graphic Switching' in energy saver preferences (but I prefer not to disable this as battery drains faster..). For some reason the graphics switching is causing audio crackles and pops. Anyone else having this issue and found a better fix?