Music playing while on 0 volume

I put the minecraft music volume to 0 and the music kept playing however it was very very softly

*What I expected to happen was the music to be muted

*What actually happened was the music was just very quiet

Steps to Reproduce:
1. Open a minecraft world
2. wait for some music to play
3. turn the music volume to 0
4. turn up your compuer volume to hear easier
5. the music should still play but it will be very quiet