How Does the Shepard Tone Work?
The use of various effects, visual and auditory. To create the illusion of suspense, thrill, eternal events, or infinite happenings is common in filmmaking. In fact, one of the ways that illusions are produced in film is through the use of the Shepard Tone. Which represents a unique sound that creates the auditory illusion of a swelling sound. That is used to build up the suspense or tension that the audience feels in relation to the story. But exactly how does the Shepard Tone work? And what does it sound like?
At Beverly Boy Productions, we’re always interested in breaking down some of the most intricate and tough to understand concepts in filmmaking.
To make them more approachable and easy to understand for the average individual. As well as for someone with advanced filmmaking knowledge.
In this guide, we’re breaking down an answer to the common question among beginning filmmakers, “How does the Shepard Tone work?”
What is the Shepard Tone?
First, let’s answer the simplest element of the question, “What is the Shepard Tone?” The Shepard Tone is defined as an audio illusion that is used to produce the feeling of rising or failing in an consistent, never-ending situation or pattern.
The Shepard Tone is named after the Shepard Scale which represents the overlapping of sound notes that are each one octave higher or lower than the next.
Shepard Scale
The Shepard Scale, although flowing up or down a single octave from one to the next, produces the sound illusion of a never-ending sound which fades in and out in such a way that the listener cannot hear the beginning or the end of the scale in any indistinguishable scale.
The sound that is played, the Shepard Tone, produces the notion that the phenomenon sometimes referred to as the “Musical Barber Pole” (due to the close resemblance to an endless illusion).
Shepard Tone illusion is used to produce the illusion of rising or falling in a continuous motion. It can be achieved by carrying out musical scales, one octave up or down, simultaneously and at different volumes.
How Does the Shepard Tone Work?
When asking the common question, “How does the Shepard Tone work?” it’s important for one to first fully understand what the Shepard Tone is.
Next, it’s important to understand that the Shepard Tone is largely used in music and in sound design. It’s an endlessly rising or falling tone that seemingly has not stopping point.
In film, answering the question, “How does the Shepard Tone work?” isn’t quite this simple. That’s because the Shepard Tone represents an illusion used in film to produce sound effects.
Which help the audience to feel connected. And to sense that there is a never-ending element to the story.
Examples
The use of the Shepard tone in film scores is most notably connected to Christopher Nolan in 2006 film release, The Prestige.
In this example of a film score that is using the Shepard Tone. The primary theme of The Prestige represents magic tricks and has a level of suspense and underlying mysteriousness to it.
The music played within the film represents similar themes and effects. The use of the Shepard Tone produces the illusion of a swelling, continuous rising, or falling, that the audience feels deeply about.
The Science of it
Creating the Shepard Tone includes the use of multiple sound waves which are separated by the single octave. These sine waves are then layered on top of one another, in such a way that there is a noticeable change in the highest-pitched tone by the end.
It’s become silent or quiet, and the middle tone that had the most balanced pitch will stay as loud as it was. The lower pitch tone also becomes louder. Which causes the bran to block out the loop and believe that the tone that it can hear is infinitely ascending.
