Episode 01 · The Shepard tone
Where’s
the top?
It sounds like it keeps getting higher.
Give it a moment. Then look inside.
Ready when you are. Sound starts with a tap.
The front panel is open
The reset is still there.
We stack six tones an octave apart. As they rise, the high ones fade away and low ones fade in. Your ears can follow the climb without noticing the handoff.
Watch the middle lights. They’re loudest. The edges go quiet before each tone wraps around.
What you’re hearing
A climb that goes in circles.
The pitches stay in the same range. It’s the changing mix that can make them seem to rise forever. Try falling, or slow it down and watch the lights.
This smooth version is called a Shepard–Risset glissando. The effect varies with the listener and the speakers. The lights show the same trick with the sound off.
Based on Roger Shepard’s 1964 paper, Circularity in Judgments of Relative Pitch. Continuous version associated with Jean-Claude Risset. More about the effect ↗