I get beeping noises if i don't play any music or sounds from my external speaker via audio out from the mba. Then when i do play something say like a song, the speakers will make a loud pop noise and play the song. After i stop the song the speakers are quiet but after a minute, the speakers will make a loud pop noise again and make beeping noises. Its as if the audio hardware would shut off when no song or sound is produce and the beeping sounds would come on.