I have a pair of headphones which came with my phone. They're the standard type that comes with a mobile phone - TRSS 3.5mm jack with an inline microphone.
I was listening to Spotify on my phone. I must have yanked the cable too hard one time and now I only get intermittent sound through the headphones, so I have to move the cable with my finger until I get sound again, so I guess there's a weak contact on one of the wires (as it affects both L and R, I'm guessing the ground)
One thing I'm curious about though - when the wire is in a 'bad' position, the sound doesn't cut out entirely. Instead, the MP3 sounds suddenly as if it is playing at a very low bitrate (horrible MP3 artifacting, barely discernible vocals in songs etc). How is it doing this? I was under the impression that if it's an analog signal, the sound will either play, or it won't, or it will crackle. Instead, it sounds as if something has been digitally adjusted to play at a lower bitrate. Is this something to do with MP3 encoding? And if so, how come I can't hear the low bitrate sounds when the headphones are working correctly?