Non Diegetic Music

Another factor that influences how music effects an audience is whether the music is diegetic or non-diegetic. Diegetic music is actually a part of the movie; the audience can hear the music, but so can the characters. The music is actually playing inside the fictional world of the film, not just in the soundtrack. Non-diegetic music however, is completely divorced from the characters in the film. It is there only for the benefit of the audience, and while the music still interacts with the movie in crucial ways, it does so without the knowledge of the characters.
Surprisingly, whether the music is diegetic or not does actually influence what emotion the audience pulls from the film.
In Steven Spielberg’s film Minority Report there is a sequence
In the play, one of the characters plays piano, and his job entails creating music and jingles with that piano. This music is diegetic; all the characters can hear it, and one of them is even the source of it. However, later in the play the man’s son plays the piano, but it serves as transition music. The son can hear it, so it is diegetic, but the other characters cannot, so it is also non-diegetic. This creative method of using music within the story also fulfills Aaron Copland’s fourth use for music in film— to build continuity. The play yo-yos back and forth between two world fairs forty years apart, and it makes those transitions via the use of music. Whenever the play switched between the two time periods, the stage would go dark, a light would switch on to represent a star, and a voiceover would play, accompanied by booming, open, galactic underscoring. In these ways, The Light Years use of music draws direct influence from film
The underscoring was mostly transitional, but it occasionally ventured into the realm of underscoring the actor’s speech. However, for the most part, the use of music was confined to when C.S. Lewis was walking around the stage. Yet this was not out of necessity; that sort of transitional music is somewhat common in theater, but there was actually no need for Lewis to walk at all. The style of his monologue was such that the entire play could easily have been delivered from the chair in the middle of stage. Instead, his pacing the stage intertwined with the music showed an alternate purpose. Rather than merely cutting the awkwardness of transitions, the music served to punctuate Lewis’s thoughts. Not solely accidental, or even incidental, the music instead served as a focus point. After the most thoughtful of monologues, the music would kick in, allowing the audience to stew in the thoughts they just heard and guiding them towards the emotional undercurrent of those thoughts. For instance, after Lewis’ first monologue about his atheism, the music was slow and thoughtful. This contrasted against the audience’s expectations about the play. Most people know C.S. Lewis was a Christian, but not as many people know he was such a staunch atheist. Starting the play off on that note made sense, but at least some of the audience was