Auto-Tune is an audio processor created by Antares Audio Technologies, which uses a proprietary device to measure and alter pitch in vocal and instrumental music recording and performances through use of a phase vocoder.[not in citation given] It was originally intended to disguise or correct off-key inaccuracies, allowing vocal tracks to be perfectly tuned despite originally being slightly off-key.
The processor slightly bends pitches to the nearest true semitone (to the exact pitch of the nearest tone in traditional equal temperament). Auto-Tune can also be used as an effect to distort the human voice when pitch is raised or lowered significantly. The overall effect to the discerning ear can be described as hearing the voice leap from note to note stepwise, like a synthesizer.
Auto-Tune is available as a plug-in for professional audio multi-tracking suites used in a studio setting and as a stand-alone, rack-mounted unit for live performance processing. Auto-Tune has become standard equipment in professional recording studios.