Change Speed

From Audacity Development Manual
Revision as of 02:46, 22 October 2010 by Windinthew (talk | contribs) (slowing down with Change Speed reduces frequencies rather than removes them.)
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Use the Change Speed effect to change the speed of a track, affecting both pitch and tempo.

Change Speed works by resampling the audio, affecting its frequency content. For example, the more you slow down the audio, the more all its frequencies will be reduced, making the audio sound "duller".

To change the tempo of a track without affecting its pitch or the range of frequencies it can contain, use Effect > Change Tempo... or Effect > Sliding Time Scale / Pitch Shift....

Accessed by: Effect > Change Speed...
Change Speed dialog
The Percent Change input box, slider and Standard Vinyl RPM popup menus are all linked: changing one will change the others.

Percent Change

If you know how much you want to change the speed of the audio in percent, enter that value here. You can also drag the slider to choose a Percent Change - the input box will update as you drag the slider.

Standard Vinyl RPM

If you have a recording of a record that was played back at the wrong speed you can correct that using these two popup menus. In the from popup choose the speed the record was played back at; in the to popup choose the speed is should have been played back at.