I was flying around exploring all of the new biomes in 1.7.2 when the background music began playing a different track, This would be fine, except the track that was currently playing never stopped. This created some very uncomfortable dissonance in the sound. *What I expected to happen was....: The first track would fade out as the second track began.

*What actually happened was...: The first track never stopped playing and the 2 tracks were playing simultaneously.
Steps to Reproduce:*
1. Make sure music is on
2. Eventually the background music will play 2 songs at once.