Music certainly has elements of magic in it. Who would've thought a couple of sound waves could bring people together from vastly different backgrounds? Some sound design techniques are a bit more mysterious than others. When we think about music perception and creating an auditory illusion, we can't help but talk about the Shepard tone.
You might not have heard of the term, but chances are you've experienced the Shepard tone in a small way. Below, we'll decode everything you need to know about the mysterious Shepard tone and showcase some sonic examples to solidify your musical understanding.
What is a Shepard Tone?
As the name suggests, the Shepard tone was developed by cognitive scientist Roger Shepard. It's commonly referred to as the "sonic barber pole" for its tendency to produce a continuously ascending or descending sound, much akin to the always rising stripes of a barber pole.
Conversely, you can hear the Shepard tone using descending notes on the Falling Falling site.
The sound is created by layering two sine waves, separated by octaves moving in a scale-like manner while adjusting the loudness of each individual tone to create the desired effect. This scale is referred to as "the Shepard scale".
Understanding the Shepard Scale
The Shepard scale creates an eerie, tense feeling that seems as though it is continuously ascending or descending. This is because the octave separation and subtle changes in amplitude help the rising or falling pitch loop seamlessly, creating the same illusion perpetually.
Shepard scales can be made by programming sine wave MIDI in your DAW and following the parameters of the musical scale, which has many similarities to the basic chromatic scale. Several VSTs and Plugins may have sounds with Shepard tones built-in like the Valhalla Space Modulator or iZotope Mobius.
Why Would You Create a Shepard Tone?
The Shepard tone is interesting in itself by way of being an audio illusion. However, the layering of sine waves for Shepard tones can also be used more deliberately in music production, composing, and sound design.
If there is one thing the Shepard tone embodies to the human ear, it's the sound of tension. You can hear the tension created by a perpetual rising Shepard tone in James Tenny's For Ann :
This tension can be used to build up to an impactful moment in a movie scene, for instance. It could also be used to create impact before the chorus of a song, or as an interesting introduction or outro to a composition as showcased below.
It's important to note that there are plenty of ways to frame these overlapping notes to create an audio illusion. Other specific variations of Shepard tones include the Shepard-risset glissando (created by the French composer Jean-Claude Risset), the perpetual melody, and the tritone paradox:
7 Examples of the Shepard Tone in Music
Perhaps the best way to understand the Shepard tone is to hear it. Here are some of the most popular uses of the Shepard tone illusion in film scores and music:
Sad Beautiful Tragic by Taylor Swift
The intro of Sad Beautiful Tragic has a sad wine that uses the Shepard tone to build a sense of longing, one going further and further into the night:
I Am The Walrus by The Beatles
This mystical song by The Beatles features an ascending Shepard tone at the very end of the track:
The Batpod in The Dark Knight
In The Dark Knight and The Dark Knight Rises , the sound effect of the Batpod was created by using a Shepard tone:
Always Ascending by Franz Ferdinand
Franz Ferdinand created the song Always Ascending with, you guessed it, ascending Shepard tones:
Super Mario 64
Old-school Nintendo gamers know the Shepard tone all too well. In the classic Super Mario 64, a player will hear a modified Shepard scale whenever they climb the neverending staircase in Peach's castle.
Lose Control by Missy Elliott
The classic Lose Control by Missy Elliott has a prominent sample that uses a Shepard tone to create tension throughout the beat's instrumental:
Oil Blast Scene in Dunkirk by Hans Zimmer
In the film score of Dunkirk directed by Christopher Nolan, Hans Zimmer can be heard using a Shepard tone in the oil blast scene. You will feel the sense of everlasting ascension:
Shepard Tone FAQ
Intrigued by this notable illusion? Here are some commonly asked questions and answers to help you expand your understanding of the Shepard tone:
What does Shepard's tone do?
The Shepard tone or Shepard scale sounds as though tones are perpetually rising or falling, without any particular sonic destination. Sound designers and producers can use this unique effect to build tension in music and sound effects.
What is an Auditory Illusion?
Auditory illusions are sounds and sound design practices meant to trick your ears into hearing something that isn't there or create a specific sonic sensation. The Shepard scale, ascending or descending, is just one of these auditory illusions.
Does the Shepard tone actually work?
The shepard tone does actually work in the sense that it does sound like something perpetually rising or falling with no particular destination. The Shepard tone definition is essentially a group of sine waves separated by octaves which creates sonic tension.
What is the Shepard tone symptoms?
The Shepard tone is an auditory illusion that creates the sonic feeling of never-ending rising (ascending Shepard tone) or falling (descending Shepard tone). It may make a listener feel uneasy or help build tension toward the climax of a song.
The Shepard tone is just one of many mysterious auditory illusions we can utilize to evoke different feelings in our sound design. Have fun layering sine waves to build suspenseful music and expand your sound design skills.