EverTones Auditory Illusion App Released for iPhone and iPod Touch

Feb. 18, 2009 - PRLog -- ShiftingBlue.com announces the immediate availability of EverTones, an auditory illusion application for iPhone and iPod Touch.

EverTones lets you play either a single tone or series of notes that endlessly increase or decrease in pitch but never ultimately end up any higher or lower, no matter how long you listen.

This illusion is sometimes referred to as an audio barber pole since the sonic effect is similar to the behavior of  the white and red spiral stripes that seem to keep climbing upward as a barber pole spins. People have also referred to it as the audio equivalent of M. C. Escher's lithograph "Ascending and Descending" which depicts a never ending staircase.

The effect was described by Bell Labs psychologist Roger Shepard in a 1964 paper entitled "Circularity in Judgements of Relative Pitch" which was published in the Journal of the Acoustical Society of America.

A version of the effect has been identified in numerous musical works including Pink Floyd's Echoes, Queen's A Day at the Races, Robert Wyatt's Rock Bottom, Bach's Fantasy and Fugue in G minor for organ, and Chopin's Etude no. 3, op. 10 as well as in the sound of the Bat-Pod in the most recently released Batman film, The Dark Knight.

Lots of fun and a great conversation piece!

EverTones is available immediately for $0.99 via the iTunes App Store at http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSof...