The Shepard tone: a rise that never ends
How does it work?
The sound is made of several components an octave apart. Their levels follow a bell-shaped window that is loudest in the middle frequencies: components in the middle of the window are clear, those at the edges almost silent.
All components rise together. When the top one reaches the edge of the window it falls silent, and at the same time a new component quietly appears at the bottom. The ear hears the note name (pitch class) but cannot quite tell which octave it is in, so the rise seems never to end.
History and use
The psychologist Roger Shepard described the illusion in 1964 as a stepped sequence; the composer Jean-Claude Risset developed a continuously gliding version. Today it is used in film and games to convey rising tension; the score of Christopher Nolan's Dunkirk is an often-cited example.
In Frekans Studio
The Endless Rise session plays the illusion on its own; the Gentle Wake-Up session combines it with a slow drone. On the Stage you can set the Shepard layer's centre frequency, number of octaves, direction and the time it takes to glide one octave. Because the cycle is locked to the session's period, the sound repeats without a seam.
Frequently asked questions
- Why do some people find it unsettling?
- A rise that never resolves gives the ear a sense that "something is about to happen"; that is why film uses it. If it feels unsettling, turn it down or stop listening.
- Is there a falling version?
- Yes. The same illusion can run in the other direction; on the Stage, just set the layer's direction to "down".
Listen and try
Last updated: 3 October 2026 · This article is for information only; it is not medical advice.