May 8, 2020

Shepard's Tone

by Will, Ginger-Beard of Power

Have you ever heard of the auditory illusion called a Shepard's tone? You may not know its name, but you have definitely heard one. A Shepard's tone is an audio illusion formed by overlaying separate tones separated by octaves that each rise/fall and repeat independently of one another.  The sound seems to get higher or lower, but never really does. Google it for an example. 

Named after Robert Shepard, this auditory trick is used to build suspense. Think of a moment in a horror movie when someone is terrified, panting, waiting for the attack of the monster. The suspense builds. And builds. And builds. This ability to continually increase that sense of tension would not be possible without the use of Shepard's tones. 

The tone can also be used in other ways. In The Dark Knight, the Shepard's Tone was used for the Batpod to create the illusion that the motorcycle was continuously accelerating without the interruption of shifting. It is also often used in House music to create suspense before the beat drops. In SuperMario 6, it is used in an “endless” staircase to make you think you are continuously going upward when in reality you are blocked halfway up the stairs and not moving at all. You don’t figure it out until you try to turn around and go back down. 

The most interesting part about the Shepard's tone is the effect it can have on you emotionally. That buildup of suspense can pull your mind upward, create a sense of dread, increase your heart rate, and create actual physical stress. All this from an illusionary sound. For me, knowing about this has changed how I let things influence my emotions.