Problem: volume mutes itself, pops, staggers video

[DukeOliver]

Recently I've had a problem on my fall 2008 unibody macbook that occurs when I listen to itunes or watch a video online. Every once in a while the sound and video will stop, the volume icon on my menu bar will flicker to 'mute,' and I can hear a small popping sound.

Restarting and deleting the soundpreferences plist hasn't helped the situation. Any thoughts?

 

[Makosuke]

Sounds like there's either something wrong with the sound hardware--when it cuts out the volume disables (no hardware to play sound seen) and you hear funny noises--or with the headphone port.

Question: If you plug in headphones, are they muted? (The OS remembers volume levels for headphones and speakers separately.) If so, try turning the volume up to a level different from the speakers and see what happens when it cuts out--if, instead of going to mute, it's going to whatever the set headphone volume is, the problem is with the port, with the computer detecting headphones being plugged in when there are none. This can happen if there's a bit of dirt or something conductive stuck in the headphone port that's causing contact where there should be none, and can often be fixed by carefully digging it out with a toothpick or something similar.

If it's cutting out completely, unrelated to the headphone jack, then I'd have to think sound hardware.