An auditory illusion is an illusion of hearing, the sound equivalent of an optical illusion: the listener hears either sounds which are not present in the stimulus, or "impossible" sounds. In short, audio illusions highlight areas where the human ear and brain, as organic, makeshift tools, differ from perfect audio receptors (for better or for worse). For other uses, see illusion (disambiguation). ... Hearing (or audition) is one of the traditional five senses, and refers to the ability to detect sound. ... This article is about audible acoustic waves. ...

Examples of auditory illusions:

• the Shepard tone or scale, and the Deutsch tritone paradox
• hearing a missing fundamental frequency, given other parts of the harmonic series
• Various psychoacoustic tricks of lossy Audio compression
• Octave illusion/Deutsch's High-Low Illusion
• Deutsch's scale illusion
• Glissando illusion
• Illusory continuity of tones
• McGurk Effect
• Rorschach Audio

Figure 1: Shepard tones forming a Shepard scale, illustrated in a sequencer A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. ... The Deutsch tritone paradox is an auditory illusion created by Diana Deutsch (creator of a number of auditory illusions) to test the Shepard scale if proximity information was removed. ... A missing fundamental is a missing fundamental frequency which higher frequencies refer to. ... Pitched musical instruments are usually based on a harmonic oscillator such as a string or a column of air. ... A lossy data compression method is one where compressing a file and then decompressing it retrieves a file that may well be different to the original, but is close enough to be useful in some way. ... Audio compression can mean two things: Audio data compression - in which the amount of data in a recorded waveform is reduced for transmission. ... Discovered by Diana Deutsch in 1973, the octave illusion is an auditory illusion produced by simultaneously playing two sequences of two notes, high to low, and low to high, in separate stereo channels over headphones. ... Discovered by Diana Deutsch, Deutschs scale illusion is an auditory illusion produced by simultaneous ascending and descending major scales beginning in separate stereo channels with each successive note being switched to the opposite channel. ... An auditory illusion, the glissando illusion is created when a sound with a fixed pitch, such as an oboe, played with a sine wave gliding up and down in pitch, are both switched back and forth between stereo channels. ... The illusory continuity of tones is the auditory illusion caused when a tone is interrupted for a short time (approximately 50ms or less), during which a narrow band of noise is played. ... The McGurk effect is a perceptual phenomenon which demonstrates an interaction between hearing and vision in speech perception. ...

See also

• Psychoacoustics
• Optical illusion
• Tinnitus
• Doppler effect - not an illusion, but real physical phenomenon

Psychoacoustics is the study of subjective human perception of sounds. ... An optical illusion. ... Tinnitus (pronounced or ,[1] from the Latin word for ringing[2]) is the perception of sound in the human ear in the absence of corresponding external sound(s). ... A source of waves moving to the left. ...

External links

• Auditory illusions of space in MP3 format. Headphones recommended
• Demonstrations of various auditory illusions at Kyushu Institute of Design
• Diana Deutsch's Web Page