Octave Ambiguity--Circularity in Pitch Judgement

Tones have clear pitches, but ambiguous octaves--i.e., they are of the same pitch class.

Ambiguous octave tones were used by Shepard and Risset to create illusions of endlessly ascending or descending pitches.

Risset's Continuous Scale:

• Click to listen
• Click to listen

Example uses:

• end of ``I am the Walrus'' (Beatles) Click to listen

• The Batpod sound effect: Click to listen