The tritone, or the diminished fifth, in music has been associated with evil since the Gregorian Monks came upon it in the 9th Century. I talk about the tritone and so-called “Devil Music” in Episodes 10 and 11, and also in my book Screaming for Pleasure: How Horror Makes You Happy and Healthy.
Here are some examples of the tritone in music:
Tritone Example 1:
Tritone Example 2: