A lot of music used in scary films is composed using keys that change our mood and emotions. Using major keys will give a sense of happiness and positivity, that’s why a lot of composers turn to minor keys to build atmosphere in horror film. Minor keys tend to make us feel sad or concerned, to many people it can even give the feeling that the sound is off key, making us feel as though something is about to happen. The iconic Halloween (1978) theme song is a great example of this. Written in F# minor it creates an eerie and spooky atmosphere.
Using a Tritone, also known as the ‘Devil in Music’ is where composers simultaneously play two notes that are three tones apart. This effect creates an uneasy feeling of dissonance, where the music sounds unstable and unfinished. This is what gives us that feeling of being on edge and unsure of what’s around the corner – this is exactly where the composer wants us to be!