Logic Pro X: Use Varispeed to alter the speed and pitch of audio
Varispeed provides a way to speed up or slow down the entire project, similar to the original varispeed feature of tape machines. The most practical use for this option is checking how a project might sound at a faster or slower tempo, and for practicing or recording a performance at a lower speed.
In Logic Pro, you can speed up or slow down a project between −50 percent and +100 percent, which is between 50 percent and 200 percent of the original tempo.
Varispeed is only available when Show Advanced Tools is selected in the Advanced preferences pane.
Turn Varispeed on or off
Click the Varispeed button in the control bar.
Note: If you don’t see the Varispeed button in the control bar, Control-click the control bar, choose Customize Control Bar and Display from the shortcut menu, choose Custom from the LCD pop-up menu, then select the Varispeed checkbox.
Choose a Varispeed mode
Click the upper part of the Varispeed display in the control bar, then choose one of the following:
Speed Only: Use to pitch shift the master output signal to balance the pitch change caused by varispeed. Only the speed changes, not the pitch.
Varispeed (Speed and Pitch): Use to emulate classic tape varispeed, where the pitch changes to reflect the speed change.
Varispeed and MIDI: Use to emulate classic tape varispeed and simultaneously transpose non-drum MIDI tracks, quantized to semitones.
Change the unit of measurement and adjust the value
Click the unit of measurement (%, bpm, st, Hz) in the lower part of the Varispeed display in the control bar, then choose one of the following:
Percentage (%): Displays the unit of measurement according to percentage.
Resulting Tempo (bpm): Displays the resulting tempo, dependent on the current tempo, which changes along with any tempo changes in the project.
Note: The Tempo display in the control bar always shows the original tempo value.
Detune (st): Displays the unit of measurement according to pitch change.
Tuning Reference (Hz): Displays the unit of measurement according to tuning reference.
Drag vertically on the value to adjust it, or double-click and enter a new value.