Listening to my iPod

I'm listening to my iPod. The song has two lead synthesizer melodies alternately intertwining and and uncoupling in rhythm and melody, a breathy sine wave in the left ear and a sharp square wave in the right. The connection between the headphones and iPod is poor for the right channel, I'm trying to plug it in well. Instead of crackling, becoming silent or quieter, the lead synth line in the right channel descends in a portamento each time the connection is lost.