The Music Box music is directly from Phantom Manor in Disneyland Paris. They have a gazebo just to the side, on your left, in the queue line and the music is playing from there. It is very cool and spooky and really sets the mood.
Wow. Thank you everyone!! You brought back wonderful memories that I've had with my family. I cannot say how grateful I am. Reminds me of being with my family in the evening outside of the Mansion. Thanks again everyone for taking the time to post!