written by: Shane Burley•edited by: Rhonda Callow•updated: 6/7/2010
Here is a look at the audio effect pitch shifting, and what it is used for.
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Audio Effects in Post-Production
Digital audio effects are an essential part of audio post-production. These audio effects are different than those that are done through foley work or recording of live events. These audio effects come from the manipulation of existing sounds through the audio post-production software. These audio effects take many different forms, often changing the original tones and speeds to give an overall different feel and sound texture. One of the more common audio effects that is used is pitch shifting, and it follows a standard process of audio manipulation.
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Pitch shifting is a telling name for this audio effect because it really is just a shift in the pitch of the sound. With the pitch shifting audio effect you simply change the sound so that it comes out during its playback as a lower pitch. Pitch shifting is usually accomplished by extending the length of the audio track, thus making it longer in association with how much lower you want the pitch to be. A .5 pitch shift will result in an audio clip becoming twice as long in its playback, and this equation can be applied to whatever clip you have in association with how much pitch shifting you are looking to apply.
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The use of the pitch shift is not a set standard for audio alteration, such as certain filters are. Instead, the pitch shift audio effect alters the track at a fundamental level and takes away its commonality. Here you will make the audio track sound different than it once did, which is why the audio pitch shift is often used to create sounds that are not found naturally but will make sense for the story space. For example, a lawn mower recorded and then put through a pitch shift may sound like the groan of a monster. The reality of using the pitch shift is then to try out different intensities on different sounds and see if you can end up getting something that fits your need clearly. You can do this to try and imitate actual sounds or simply layer different types of sounds, which is commonly done in digital music post-production.
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Usually pitch shifting will be somewhat different than pitch correction. Pitch correction will be used to correct the pitch of something recorded so that it sounds as it was intended to. Pitch shifting can be used for this purpose, but usually pitch shifting refers to an audio effect that will alter an audio track to make it sound different than it existed originally. Pitch correction has often been linked with the auto-tune correction that has become popular. None of these definitions are exclusionary and pitch shifting is a regular part of pitch correction, yet one does not necessarily indicate the other.