A popular album track from their second eponymous album, this song was written by Pete Doherty, who also sings the song.
The song uses music as an analogy for love. When you hear "I no longer hear the music", think "I am no longer in love with you." However, the song is much more than that. It is about the pain of loss, even if the loss is so right - but it doesn't ever erase the good times.
Still, it's one of those songs that make me tear up just a little bit, because we've all been there.