How Do I Slow Down an MP3 File With Audacity?

Using Audacity's effects menu, you can slow the tempo of an MP3 to turn an upbeat song into something a little more relaxed -- or pitch the singer down so you have Darth Vader on lead vocals. You can change the tempo and pitch independently of one another for more tightly focused effects control, or together for uniform tempo and pitch slow-down. Each of these effects have their own tool: "Change Tempo," "Change Pitch" -- and "Change Speed" for both pitch and tempo.

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Image courtesy of Audacity.

Tempo Only

Step

Select the section of the MP3 file you want to slow down. If you're changing the tempo for the whole file, you can skip this step.

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Image courtesy of Audacity.
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Image courtesy of Audacity.

Step

Click "Effect" and select "Change Tempo."

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Image courtesy of Audacity.

Step

Drag the slider in the Change Tempo dialog to the desired percentage. You can also change the percentage using the Percent Change text field, or change the beats per minute or length using the provided fields.

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Image courtesy of Audacity.

Step

Click "Preview" to test out how your slow-down effect will sound. Adjust the tempo change as necessary and click "OK" when you're satisfied with the result.

Pitch Only

Step

Click "Effect" and select "Change Pitch."

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Image courtesy of Audacity.
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Image courtesy of Audacity.

Step

Drag the slider in the Change Pitch dialog to the desired percentage. You can also change the percentage using the Percent Change text field, or change the pitch using the drop-down menus and semitones text field. Editing the ranges in the frequency text fields will also change the pitch.

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Image courtesy of Audacity.

Step

Click "Preview" to test the pitched-down clip. Adjust the pitch as necessary and click "OK" when finished.

Pitch and Tempo

Step

Click "Effect" and select "Change Speed."

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Image courtesy of Audacity.
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Image courtesy of Audacity.

Step

Drag the slider in the Change Speed dialog to the desired percentage. You can also change the percentage using the Percent Change text field, or use the drop-down menus to select an original speed and the lower speed, based on the standard revolutions per minute of a vinyl record.

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Image courtesy of Audacity.

Step

Click "Preview" to test the sped-down track and adjust the speed as necessary. Click "OK" when you're finished fine-tuning the clip.