I have a track recorded in reaper which I want to variably speed up and slow down as an effect behind my other tracks. Is this an option? Do I need a plugin?
Your best bet with achieving this effect solely with Reaper is to use multiple (background) projects.
Move the audio track to a separate tab. Make sure that you have following options ticked:
Then in the new (background) project you can apply playrate automation. First make sure that master track can be seen (
You may probably want to select "Preserve pitch in audio items when changing master playrate" by right clicking on the
Manipulating MIDI tracks would be easier, as tempo changes should do the job, though you may still need to resort to background projects.
I'm not really familiar with Reaper, but just tried it out with a short clip and it seems to work. This is not a real automatic way, and if you need to do this often this might not be suitable. Instructions are for the Mac, but PC function naming should be similar.
You could try using the