Digidesign Pro Tools LE 7.4: Do loop-based, time-stretched music with Pro Tools

OBJECTIVE: Use loops of varying tempos within a single Pro Tools project, at a consistent (or changing) tempo. BACKGROUND: Pro Tools 7.4 introduces “elastic audio” capabilities to provide sophisticated stretching options for loop-based music. This example shows a very basic application that integrates loops of varying tempos within a Pro Tools project.


  1. With a Pro Tools project open, go Window > Workspace.
  2. Navigate to the loop you want to use in the project (AIF, WAV, RX2 . . . it doesn’t matter). If needed, click on a folder’s + sign to expand it.
  3. Click on the Preview button (the speaker icon, either the one toward the top of the window, or under the “Waveform” column) to audition the loop at its native tempo.
  4. Click the “Conform to Tempo” button to hear the loop at the current project tempo.
  5. Drag the file into the Track List. A track appears in the Edit and Mix windows that contains the loop.
  6. Right-click on the loop, choose Loop, and you can specify the number of loop iterations. (This isn’t necessary to conform the loop to tempo, but an optional step if you want multiple loop iterations.)
  7. If you change the tempo, the loop will conform to the selected tempo.


  • Elastic audio can do far more than just simple time-stretching. This example shows automatic warping, but you can obtain even more detailed control with manual warping using the Warp Track view.
  • If there are no tracks in the session, and the file is tick-based, a dialog box will appear asking if you want to import the file’s tempo. If you answer “Don’t Import,” the session will use the existing session tempo.
  • Elastic audio analysis is based on finding transients. If these are ambiguous (e.g., a string pad), an Analysis view allows adding or removing transient markers to optimize the stretching process.