New Paulstretch OS X build

As software projects go, PaulStretch is rather a shadowy enigma. Since I did the initial Mac OS X port, I’ve had very, very sporadic communications with the author Nasca Octavian Paul about it.

Then there’s the issue of versioning. Paul started a github repository, but it hasn’t been updated since March. It’s currently at version 2.2.2, but the only difference between 2.2-2 and 2.2-1 is that the version number it reports has changed.

At any rate, today I did a new build which is 1) OS X 10.6 (forward compatible with Lion, but perhaps not backwards compatible to Leopard or Tiger) 2) Up to date build, incorporating all of Paul’s changes. I also spent some time playing with it to make sure it works properly.

You can download it here:

It also has the latest refinements of the build scripts used to build PaulStretch from source. I use CMake, which is Kitware’s cross-platform build tool. CMake keeps getting smarter, and my CMake recipe for PaulStretch will download all the prerequisite libraries, build them, and then download the PaulStretch source, build it, and generate an Apple App Bundle.

And CMake really is cross-platform — the same build recipe will work unmodified on Linux (which I have tested) and possibly on Windows (which I haven’t tried).

If you still have a PowerPC Mac, you can try using which a friend of mine built, but it isn’t the most recent version of PaulStretch.

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96 Responses to New Paulstretch OS X build

  1. monkeeknifefight says:

    Thank you for porting this. I plan on destroying “Get Lucky” for my radio show.

  2. Try stretching something other than pop music because most of it sounds the same to start with! I stretched some 1960’s electronic music and it was way cool!

  3. dubhdavidblack says:

    Very good true observation, Tony Zilincik. I’ve gotten really interesting results using all kinds of stuff, and feel that the least satisfying results (when trying to create sounds for my own use) come from stuff that is beat-heavy &/or heavily compressed. The (generally) more sparse, dynamic source files seem to result in stretched output files with loads more timbral contours & magical tones. A lot of those random, miraculous little tones that might pop up for a second can so often inspire a whole piece or song.

  4. How hard would it be to port Paul’s amazing soft synth zynaddsubfx to os x? I may have asked this already. I would be willing to help. I’m running os x mavericks w/ newest version of Xcode.

    • chaircrusher says:

      I haven’t looked at how hard zynaddsubfx would be. If he used the same cross-platform libraries, probably not too bad.

      I really wish the FLTK people would do a proper 64-bit port; PaulStretch is stuck in 32-bit land because FLTK uses a legacy Apple toolkit.

  5. Richie says:

    do you have it for OS X 10.9

    • chaircrusher says:

      Not specifically. It should work fine.

      • Alex says:

        It wouldn’t work for me, all i got was buzzing and static… :(

        • Arthur Pewty says:

          Check your source files.

          Firstly, some of the libraries used do not like WAV files that contain meta-data of any kind.

          Secondly, keep them 16bit. If you want headroom then resample to 96K and downsample afterwards.


  6. er says:


  7. Jonathan says:

    Thanks for this! Was bugging me that it didn’t have an icon so i made one quickly, if anyone else wants it you can grab it here: to change the icon just right click on > get info, then drag the paulstretch.icns file on top of the little missing icon symbol next to where it says

  8. I try using Paulstretch but it always adds this crazy static to my tracks…any ideas?

    • chaircrusher says:

      Other people have fixed the static by changing audio devices. I’ve never encountered it.

  9. Max says:

    Any chance this will be ported properly to Cocoa? I ask because the save dialogs are really annoying to work with.

    • chaircrusher says:

      Can’t be converted to 64-bit/Cocoa, as it uses FLTK 1.7, which can’t handle Cocoa. Sorry!

  10. elevatormusicmaker says:

    Hi guys. Has anyone encountered problems getting this version of Paulstretch to work with different audio devices. It for some reason will not pick up my Presonus audio interface, and will only play through the mac speakers. I’m using 10.6. Is there a hidden preference option somewhere where one can select the audio output for PaulStretch?

    Thanks lads!

  11. Angie Congo says:

    I’m getting the static (stuttering popping sound) when I preview, but it doesn’t end up in my final tracks. It’s happening with all my output devices. I’d seriously pay money to help this issue go away. Any plans to tackle this?

  12. Daniel Nielsen says:

    Why can I only export 43 seconds of the stretched audio file? Is it a bug or is it just me?

  13. Pingback: Secret weapons for experimental sound design: Paul’s Extreme Timestretch | jasefos

  14. Arthur Pewty says:

    For a slighter smoother sound…

    If you are not afraid of using the terminal then the python scripts are here:

    You will need to install the numpy and scipy libs, and preferably a newer python than the system python.

    You can use home-brew to do it easily enough:

    brew install python
    pip install numpy scipy
    python -s10 -w1 infile.wav outfile.wav

    WAV files cannot contain metadata, and need to be 16bit, sample rate can be >44.1k.


  15. Pingback: How to create an ambient pad with Paul’s Extreme Sound Stretch | Free Guitar Lessons Online Blog

  16. exporting 32 bit wavs and importing them on Logic or Ableton I get overly distorted corrupt files. While they play fine on audacity and VLC. any ideas?

  17. NJ says:

    Sorry to come off as a complete newbie, but can someone please explain how to install this. How exactly do I run

    I have recently started learning about the terminal, scripts and command line, but I am not beyond the basics yet. Thank you.

  18. Ben Sheppard says:

    Do you have the OSX build source up in a repository somewhere? Would love to try my hand at making this a 64 bit beast…

  19. Dale Garland says:

    Thanks for sorting this version out! I’m trying to think of a way to do batch processing with Paulstretch on Mac at the moment. I have a huge project I’m working on and would like to be able to process multiple files in one go without having to go in and out Paulstretch all the time.

    Unfortunately I’m not too clued up on the coding side of things and that sort of stuff. Do you have any suggestions for a way of making this build of Paulstretch work as an offline batch process? I’m thinking it might be possible to do this using Automator or terminal commands but I’m not sure where to start…

    • chaircrusher says:

      If you download the PaulStretch on, I believe it has a python scripting interface.

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