A Shepard’s Tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the Shepard scale. This creates the auditory illusion of a tone that continually ascends or descends in pitch, yet which ultimately seems to get no higher or lower.
In Dunkirk, composer Hans Zimmer crafted his soundtrack around one chilling effect — and it’s an auditory masterpiece.
This is an effect you can use on any of your sound effects or music to build tension just like Hans. Let me know in the comments how you use the Shepard’s Tone in the comments below.