Change Pitch



Use Change Pitch to change the pitch of a track without changing its tempo (speed).
 * Accessed by: Effect > Change Pitch...
 * [[image:ChangePitch.png|Change Pitch dialog]]

Change Pitch works by applying an up or down percentage change to the existing pitch of a selection. As well as choosing the percent change directly you can define it as:
 * a change from one pitch to another
 * a change in semitones
 * a change from one frequency to another.

Pitch
If you know both the key the original recording is in and the key you want to change it to, change both the Pitch "from" and "to" values.
 * Estimated Start Pitch: Attempts to detect the pitch of the most meaningful note at the start of the selection. The letter (with sharp "#" / flat "b" suffix as required) indicates the musical note and the number indicates the octave position of the note. The frequency of the detected pitch is given in parentheses. For example, if you have a very short, quiet note on A3 followed by a longer, louder note on C4 Audacity will probably detect C4 but if the second note is the same volume then Audacity will probably detect A3.
 * "from" and "to" controls: The "from" and "to" controls each have a drop-down menu for selecting the musical note, then to right of that menu, a text box for selecting the octave of that note.
 * Semitones (half-steps): If you don't know the key the original recording is in but you know how many semitones it needs to be changed, enter that value here. For example you could duplicate a vocal track and then apply Change Pitch with a value of +7 semitones (a major fifth) to create a harmony vocal.

Frequency (Hz)
The "from" input box initializes to the first meaningful detected pitch in the selection and does not update if the other controls are changed. However if you know the original frequency and the frequency you want to change to, you can enter these in the "from" and "to" boxes. Detection of a steady sine tone will often be very accurate (with the upper frequency limitation noted below) in which case you may only need to change the "to" input box to the desired frequency for the tone.
 * Percent Change: If you would like to change the pitch by a given percent, enter a value in this input box or use the slider.

Limitations
Change Pitch is a time-stretching effect, because it defies the normal expectation that to lower the pitch of the audio it is necessary to reduce its speed (and thus its length) and vice-versa. As with any time-stretching effect, some audible distortions will be expected, particularly at more extreme settings.

Change Pitch does not keep the length exactly as before. This makes Change Pitch unsuitable for changing the pitch of individual very short notes. To avoid this problem, you can use Effect > Sliding Time Scale / Pitch Shift... instead, setting initial and final pitch change to the same amount.

The highest reliable detection frequency is about 1/8th of the sample rate. So for a sample rate of 2000 Hz, pitch detection will not be accurate much above 250 Hz and for the default project rate of 44100 Hz, detection will not be accurate much above 5500 Hz.

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