Pitch shifting is asound recording technique in which the originalpitch of a sound is raised or lowered.Effects units that raise or lower pitch by a pre-designatedmusical interval (transposition) are known aspitch shifters.
The simplest methods are used to increase pitch and reduce durations or, conversely, reduce pitch and increase duration. This can be done by replaying a sound waveform at a different speed than it was recorded. It could be accomplished on an earlyreel-to-reel tape recorder by changing the diameter of thecapstan or using a different motor. As for vinyl records, placing a finger on the turntable to give friction will slow it, while giving it a "spin" can advance it. As technologies improved, motor speed andpitch control could be achieved electronically byservo drive system circuits.[1]
Apitch shifter is a soundeffects unit that raises or lowers thepitch of anaudio signal by a presetinterval. For example, a pitch shifter set to increase the pitch by a fourth will raise each note threediatonic intervals above the notes actually played. Simple pitch shifters raise or lower the pitch by one or twooctaves, while more sophisticated devices offer a range of interval alterations. Pitch shifters are included in mostaudio processors today.
Aharmonizer is a type of pitch shifter that combines the pitch-shifted signal with the original to create a two or more note harmony. TheEventide H910 Harmonizer,[2] released in 1975, was one of the first commercially available pitch-shifters and digital multi-effects units. On November 10, 1976, Eventide filed a trademark registration for "Harmonizer" and continues to maintain its rights to the Harmonizer trademark today.[3]
Indigital recording, pitch shifting is accomplished through digitalsignal processing. Older digital processors could often shift pitch only inpost-production, whereas many modern devices using computer processing technology can change pitch values virtually in real time.[4]
Pitch correction is a form of pitch shifting and is found in software such asAuto-Tune andMelodyne to correct intonation inaccuracies in a recording or performance. Pitch shifting may raise or lower all sounds in a recording by the same amount, whereas in practice, pitch correction may make different changes from note to note.[5]
Numerous cartoons have used pitch shifters to produce distinctive animal voices.Alvin and the Chipmunks recordings with David Seville (akaRoss Bagdasarian) were created by recording vocal tracks at slow speeds, then playing them back at normal speeds.Voice artistMel Blanc used pitch shifting techniques to create the voices ofTweety andDaffy Duck.[6]
In the 1970s, reruns of shows likeI Love Lucy were sped up in order to run more advertisements during commercial breaks. The Eventide H910 Harmonizer was used to downward pitch-shift the characters' voices back to normal after the episode was sped up.[7]
South Park creatorsTrey Parker andMatt Stone have used pitch shifting for most of their characters throughout the show's run.[8]
One notable early practitioner of pitch shifting in music isChuck Berry, who used the technique to make his voice sound younger. Many of theBeatles' records from 1966 and 1967 were made by recording instrumental tracks a half-step higher and the vocals correspondingly low. Examples include "Rain", "I'm Only Sleeping", and "When I'm Sixty-Four".
Electronic musicianBurial is known for including pitch-shifted samples of vocal melodies in his songs.[9]
Goregrind and occasionallydeath metal use vocals that are often pitch-shifted to sound unnaturally low and guttural.
The famous bass intro to the song "Seven Nation Army" byThe White Stripes, is the result of guitaristJack White playing anelectric guitar through a pitch shifting effects pedal set to an octave below. The band was a duo, who lacked a bassist and had never previously used one in any of their music, choosing instead to mimic the sound of a bass guitar.[10]
From 1986 to 1988, American musicianPrince used pitch shifting to create his “Camille” vocals.
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