Xenakios has released PaulXStretch, a freeware time-stretching VST and AU plugin based on the PaulStretch extreme time-stretching algorithm.
PaulStretch is the most popular third-party freeware tool for audio time-stretching, capable of delivering extreme changes in sample speed/tempo without affecting the pitch. Of course, some amount of time-stretching distortion is always present, but this is often used as a creative effect. The software’s single drawback is the fact that it can’t be used within a digital audio workstation because it isn’t available as a VST or Audio Unit plugin. As a result, the users need to take the offline workflow route which defaults to applying the time-stretching algorithm in a separate app (Paul’s Extreme Time Stretch) and then importing the processed audio file back into the DAW. This all changes now with the release of PaulXStretch.
The VST/AU plugin version of PaulStretch loads like any other virtual effect and provides instant results. The workflow is quite simple. Load it as an insert effect on an audio channel, press the Capture button to record a portion of the audio into PaulXStretch’s internal buffer, and make sure to turn off Capture mode when you’re done. From there, you can isolate any part of the recorded audio with the sample length slider and proceed with the actual time-stretching of the content. The control scheme is the same as in the standalone version of PaulStretch and allows the user to go quite a bit into detail with audio processing. Whereas some of the advanced functionality is not for the faint of heart, the most important actions like time-stretching and pitch shifting are easy to pull off with just a couple of clicks.
Performance-wise, PaulXStretch does a pretty good job even in this relatively early phase of development. The author is releasing new versions on a regular basis, fixing bugs and improving the overall user experience. As far as freeware time-stretching VST plugins go, PaulXStretch is easily the best one you can download right now. It currently works in 64-bit plugin hosts on Windows and macOS, with a Linux version expected for release later on. Support for 32-bit digital audio workstations is not planned.
PaulXStretch is available for free download via Xenakios (2.8 MB download size, ZIP archive, 64-bit VST & AU plugin formats for Windows & macOS).