# AudioPitchShift

AudioPitchShift[audio,r]

applies pitch shifting to audio by the ratio r, shifting every frequency to .

# Details and Options

• AudioPitchShift shifts the pitch of the input audio signal without affecting the duration.
• The frequency ratio r can be given as a pitch interval, including:
•  Quantity[oct,"octaves"] correspond to Quantity[sem,"semitones"] correspond to
• The following options are supported:
•  Method Automatic the method to use PartitionGranularity Automatic control the partitioning used for the computation of the short-time Fourier transform
• By default, a phase vocoder algorithm is used. Use Method->"Speech" for pitch shifting speech signals. In this case, while the fundamental frequency is changed, the formants of the signal are not modified.

# Examples

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## Basic Examples(2)

Shift the audio pitch by a factor of two:

Shift the audio pitch by a semitone:

## Scope(3)

A shift by n octaves corresponds to a frequency ratio of 2n:

A shift by s semitones corresponds to a frequency ratio of 2s/12:

AudioPitchShift can be used to change the pitch of a harmonically complex sound without altering its timbre and timing:

The frequency ratio between the components of the audio signal is not changed:

## Options(4)

### Method(1)

Use Method->"Speech" for speech signals to shift the pitch while maintaining other voice characteristics:

Compare with the normal pitch shifting, which dramatically affects the timbre of the voice:

### PartitionGranularity(3)

Using a bigger partition size will improve the frequency response but will smear the transient components:

Using a small offset value will in general increase the quality of the result at the cost of more computation time:

If only the partition size is specified, the offset is calculated as 25% of the partition size.

Use a different window shape to change the quality of the result:

By default, HannWindow is used.

## Applications(1)

Shift the pitch of an audio object to match a target frequency:

Extract the mean frequency with AudioLocalMeasurements:

Shift the audio to reach the target frequency:

## Properties & Relations(2)

AudioPitchShift and AudioFrequencyShift modify the spectrum of the signal in different ways:

AudioPitchShift shifts each frequency f in the signal by an amount proportional to the frequency itself (f'=f×shift), thus preserving the timbre in the shifted signal:

AudioFrequencyShift shifts every frequency f by the same amount (f'=f+shift), changing dramatically the timbre in the shifted signal:

Change the pitch of a recording by using a different sample rate:

AudioPitchShift changes the pitch without altering the timing:

## Possible Issues(2)

The quality of the result degrades with large shift parameters:

Using Method->"Speech" for non-speech signals may not sound as expected:

Wolfram Research (2016), AudioPitchShift, Wolfram Language function, https://reference.wolfram.com/language/ref/AudioPitchShift.html (updated 2020).

#### Text

Wolfram Research (2016), AudioPitchShift, Wolfram Language function, https://reference.wolfram.com/language/ref/AudioPitchShift.html (updated 2020).

#### CMS

Wolfram Language. 2016. "AudioPitchShift." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/AudioPitchShift.html.

#### APA

Wolfram Language. (2016). AudioPitchShift. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AudioPitchShift.html

#### BibTeX

@misc{reference.wolfram_2024_audiopitchshift, author="Wolfram Research", title="{AudioPitchShift}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/AudioPitchShift.html}", note=[Accessed: 22-May-2024 ]}

#### BibLaTeX

@online{reference.wolfram_2024_audiopitchshift, organization={Wolfram Research}, title={AudioPitchShift}, year={2020}, url={https://reference.wolfram.com/language/ref/AudioPitchShift.html}, note=[Accessed: 22-May-2024 ]}