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Shepard's Scale 

Like the endless staircase, these twelve musical notes go up or down forever. It's impossible!

Pass your mouse over the dots one at a time in both directions. Listen carefully. Do the notes get higher in one direction and lower in the other? Which note is highest? Lowest?

Each note is really a chord made up of six notes in six different octaves. Volume shifts and ambiguous octave positions make this audio illusion happen.

 

Java Applet: 2001 Tony Azevedo.
Stairs Artwork: ©2001 R. Ausbourne
Visit Acoustic illusions to find more information, written music, and audio files.

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