Listening to audio in iTunes, after approximately 30 seconds, the audio will sort of crackle, then go out completely. The song will continue playing, without sound. If I press pause and play or switch to a different track the audio plays normally, again for about 30 seconds, and then fizzles out again.
Running iTunes 220.127.116.11 under OSX 10.11.6
UPDATE: Tested audio in gpodder, and same result, so it is not an iTunes only issue.