How do you add music?

[Psychotronic]

While you're editing a room, go into Room Options (Command-L or in the File menu). Enter a number from 1 to 4 in the box that says Music Index, and then hit Save. You won't be able to hear the music while you're in the editor. Quit the editor, start up the regular Midnight Mansion program, and play your mansion. When Jack gets to the room you put the music in, the music should start.

If you still can't hear the music, check your options in the main game. Maybe you turned the music off at some point.