I love the music box. One serious issue with the box is that it does not mute game music so the background music plays over the music box. The background music is at least twice as loudas the music boxes music is.
The music box uses the Effects volume slider and the normal music is the Music slider. Seems like you will have to adjust them to your liking. Also, there are other Effects in houses - fires and fountains that may be hard to hear the music over...
I the music box. However there does seem to be an issue. Notice at :30 in the video, when the music gets quiet/silent the game music seems louder and as a result when the music box plays again.. There is a horrible music clashing sound.
I am not sure if the game music is being suppressed a little when the sound is going (as a lot of games do) and it gets louder right before the music box sounds again.