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Qtractor 0.9.3 - The End of Autumn'18 Release


Qtractor 0.9.3 (end-of-autumn'18 beta) is out!

All the changes that were simply decrastinated for this season are as follows:

  • Auto-backward now skips the end-of-session location.
  • Audio clip time-stretching and pitch-shifting limits are now 10-fold in either direction.
  • Custom color (palette) theme editor introduced; color (palette) theme changes are now effective immediately, except on default.
  • Old deprecated Qt4 build support is no more.
  • Recover audio and MIDI dedicated port connections when changing any of the Metronome, Player and/or Control option settings.
  • Fix MIDI track (and bus) bank/program reset to none.
  • Anti-glitch micro-fade-in is disabled on audio clips with zero offset.
  • Audio and MIDI file players also stopped on Transport / Panic command.
  • LV2 plug-in UI GTK2 and X11 in Qt5 host native support are now disabled on default configure.
  • Get rid of symlink duplicates on the default plugin search paths.
  • According to Debian policy and guidelines, the out-of process plugin scanner (qtractor_plugin_scan) is now installed to $LIBDIR/qtractor.


Qtractor is an audio/MIDI multi-track sequencer application written in C++ with the Qt framework. Target platform is Linux, where the Jack Audio Connection Kit (JACK) for audio and the Advanced Linux Sound Architecture (ALSA) for MIDI are the main infrastructures to evolve as a fairly-featured Linux desktop audio workstation GUI, specially dedicated to the personal home-studio.


Project page:


Git repos:

Wiki (help wanted!):


Qtractor is free, open-source Linux Audio software, distributed under the terms of the GNU General Public License (GPL) version 2 or later.

Enjoy && Keep the fun.

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Thanks as ever for your work on the Q stuff. I'm just about to update the wiki but would like to check the below first whenever you have time.

Audio clip time-stretching and pitch-shifting limits are now 10-fold in either direction

It seems the maximum you can input is 1000% (10-fold) so that looks fine, but for the minimum you can input down to 1% (100-fold), so this looks incorrect. Should the input be restricted to 10% minimum? However, even if you input 1% the file still sounds the same as 10%, so this looks like a minor bug.

FYI, inputting less than 1% has produced some weird effects, e.g.

- 0.9%: sometimes snaps to 100% (which I assume is correct?), but sometimes snaps to 90%, 10% or 1% (which I assume is wrong)
- 0.1%: sometimes snaps to 100% (correct?), sometimes 1% (wrong?)

I have no idea why the figures change. Perhaps it's the result of a series of operations or something? In any case, if the input is restricted to 10% minimum I suppose it won't matter.

The limits seem to be +/- 40 semitones. Just to check - is this the desired range? If so, I'll include this info in the wiki as I think semitones will be a useful reference.

rncbc's picture

thanks yuba

re. Time-stretching
as you might know audio clip time-stretching is given in percentage, being 100% (x1.0) for the original non-stretched signal; the actual minimum value now is 10% (x0.1) and the maximum is 1000% (x10) thus the "10-fold" saying in the change-log.

however you're of course right, the minimum input value on the audio clip properties dialog is indeed 1% (x0.01) and not the actual 10% (x0.1). So yes, this is a bug in the input spin-box minimum value on the dialog box: all values entered below 9.9% will be clamped to 10% internally even though the spin-box widget display says otherwise--yes, it's a UI bug, but the 10-fold rule prevails, nevertheless.

re. Pitch-shifting
yes, -/+40 semitones is the new range: it's an approximation to a 10-fold change which would be like -/+39.8 if you consider the 12-tone/octave logarithmic scale.


ps. fixed on git head master already (>=

Thanks for the confirmation and fix. It looks fine this end now. Will update the wiki with this new info.

Hi Rui, quickly mentionning that as of now, Qtractor has been updated to 0.9.3 in LibraZiK-2 (including the updated pdf), with your help on github's issue tracker.

Thank you !

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