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Qtractor 0.5.8 - The India Romeo is out, singing a serenade...

Spring is nigh.

Qtractor 0.5.8 (india romeo) is out, singing a serenade...

Nothing but the change-log (see below:))

Enjoy && lots of fun.


Project page:


Weblog (upstream support):


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


  • Dropped old audio ramping spin-locks as its glitching reduction weren't that effective anymore.
  • Audio bus and track gain may now be set for amplification again, from +0dB up to +6dB, while using the Mixer strip sliders/faders (an old function found missing ever since pre-TYOQA).
  • Basic LV2 X11 UI support has been added through libSUIL but only really effective if plugins doesn't support the LV2 External UI extension in addition which takes precedence on any case.
  • Improved precision tolerance on the Tempo Map / Markers dialog.
  • Reinstated and fixed (old) warning and impending re-conversion on loading session files which the original sample-rate differs from current audio device engine (aka. JACK).
  • LV2 Plugin State/Preset name discrimination fix (after a ticket by Jiri Prochaszka aka. Anchakor, thanks:)
  • Linked/ref-counted audio clips must not overlap and now must have a buffer-size worth of a gap between each other.
  • Something fishy has been detected in the SSE (not so) optimized code from SoundTouch's-inspired WSOLA time-stretching.
  • Splitting clips apart is now easier than ever: a brand new entry enters the main menu scene: Edit/Split (Ctrl+Y) splits up clips according to current range/rectangular selection.
  • Audio clip offsets are now properly corrected when time-stretching is applied via Shift/Ctrl+dragging any of the clip edges.
  • One semi-colon typo was hiding proper descrimination of peak files used to draw distinct waveforms of time-stretched audio clips.
  • Track automation curves are now also affected by Edit/Insert/Range commands.
  • Finally, some visual feedback is shown while audio track export is running, in he form of a main status progress bar.
  • New user option: save backup versions of existing session files.
  • Default session directory now set to regular file's path on load.
  • A convenient minimum slack duration has been fixed for MIDI SysEx messages.
  • LV2 Time/position information is now asynchronously fed back into their parameter (control input) ports when designated.
  • LV2 State is now properly restored for plugins inserted on buses, probably solving the Calf Fluidsynth SoundFont information missing on buses ticket, reported by Albert Graef, thanks.
  • Fixed an immediate null pointer crash on creating a parentless new group while on the files organizer widget.
  • Preparations for future Qt5 migration.

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Hi, QTractor looks interesting. Are there any sample projects around that I could try out?

rncbc's picture

you'll have to try it for yourself, and i won't be sorry for that. trust me :) qtractor is a sequencer so that it plays or records whatever samples or performance you set it to.

look, this is not some another self-contained, monolyth, all-in-one sound or music application. qtractor is a general purpose sequencer.

it plays audio and midi clips you arrange it to on a time line. although it has plugins, audio fx and midi instruments it was and still is keen to drive and be driven by (old-school) midi outboard equipment. real keyboards, guitars, drums. the concept here is "real" music instrumentation, composition and arrangement.

sure i could share a qtractor project file, no doubt, but trust me, it wouldn't make much sense or justice on your setup. or maybe not.

though, i will post here shortly a video and the corresponding project file for you to judge for yourself. stay tuned. ;)


rncbc's picture

as promised

original project session file: Bring1t0n_2.1.qtz

nb. the above video also features myself (lousy as usual) playing on the lead synth track #4 (auto-monitor) through synthv1 lv2 instrument plugin. all while capturing the screencast.


Awesome! Thank you very much.

rncbc's picture

yet another one.

source session file: CM158_DnB_1.qtz (9MB)

as before, the screencast video features yours trully adding an synthv1 instance and some (lousy) playing on the fly (which only starts on 1:14). also this time i got it a little better re. video sync and... scnr. added some youtube-effects while i was at it :)


ps. i should add that the videos were first edited on kdenlive, by just dumping the raw video and audio footage in, add some fade to/from black, a title and kick render. then upload to yt. simple as that.

pps. as implied on the session title prefix (CM158), most audio samples included were grabbed from Computer Music magazine (spanish ed.) issue 158 cover dvd.

rncbc's picture

one more, now showing off some automation,

session file: Db_155_Arp1-3a.qtz (11MB)



So, they have Computer Music mag in Spanish? Excellent! :-)

But to our onions. Your project sounds like a great idea, combining MIDI and audio in one production environment, and the feature list is impressive. But the guys I show stuff to (at the Music SIG of MelbPC, the Melbourne PC User Group; see website) are mostly more used to Windows. Some of them, frankly, are scared of anything more technical than GUI software ... So is there any chance you might make a Windows port of Qtractor any time soon?

Keep up the great work!


rncbc's picture

i'm afraid not any soon. qtractor is a linux-only application. tbh. i am personally committed to keep it straight that way in my foreseeable future.

so sorry (for your friends ;)) besides, linux is not that a highly-technical-only (read green-terminal/command-line-UI) anymore. in fact, i do all my stuff under a GUI :)


many thanks for this great work.this is for me the only useable sequencer for linux.better then ardour3.
greetings from germany

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