Some does not contribute to the construction of the narrative but functions instead as an “additive,” music that adds to the fi lm but not to the narrative.
I think that the same piece of music could be both narrative and additive at different points of the story. For example, at the start of the Harry Potter franchise (this is all hypothetical I can't really remember the right details), the famous Hogwarts theme starts playing as they enter the school and it sounds spooky and exciting, but even without the music the thought of entering a magic school is still spooky and exciting, so it is additive. But when this music plays at the very end of the series as the main characters send their kids off to the school from the train station, it adds a sense of nostalgia to us, the viewer, who will be hearing the music for the "last" time in the movies, like hearing the school song as you graduate. While this sense of goodbye doesn't necessarily exist in the film because the characters have already graduated for a long time and are instead just sending their kids off. So in a sense, it's narrative.