Shepard Illusion

The Shepard scale is one of the most famous auditory illusions. It is made out of Shepard tones which are in fact a superposition of several sine tones that trick your ears so you can't decide which tone has the higher and whcih one the lower pitch. You can even use them to go infinitely up or down the major scale - seemingly!

The Shepard Illusion app lets you explore the fascinating universe of Shepard tones and the Shepard scale. It gives you a circular keyboard for a 10-voice polyphonic Shepard scale synthesizer and real time controls for some sound parameters.

This app is brought to you by Germany's science entertainer Felix Homann who has developed it for his "ShowLabor" science shows. Enjoy!