In an insightful essay for Vox, video editor Christophe Haubursin takes a pretty detailed looked at how director Chris Nolan and composer Hans Zimmer employ certain sounds to add an additional emotional layer to a scene. One such technique featured in the film Dunkirk, is the use of the Shepard Tone – a tri-tone auditory illusion of scales going on without end – which can create an overwhelming sense of anxiety, urgency and tension.
Christopher Nolan’s Dunkirk is a nerve-wracking movie. Three separate storylines tell the tale of the famed World War II evacuation in a intense two hours of film. A lot of that feeling has to do with how the film’s score uses Shepard tones — layered sound waves that simulate a constant ascent in tone — to create a sensation of building tension.