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Revision as of 05:27, 23 June 2010 by Crantila (talk | contribs) (added some)

Address: User:Crantila/FSC/Sequencers/Qtractor

Features and Strengths

This is what Qtractor is good for. It seems to me that Qtractor wants to meld Ardour and Rosegarden.

When to Use Qtractor


When to Avoid Qtractor


Requirements and Installation

Is this available from RPM Fusion and Planet CCRMA? Hmm... I wonder which to use

Software Requirements

  • libvorbis
  • libmad
  • jack-audio-connection-kit
  • slv2
  • rubberband
  • libogg
  • liblo
  • libsndfile
  • libsamplerate

There are no large dependencies. If you have not yet installed QjackCtl for JACK (jack-audio-connection-kit), then it is recommended that you do so at this time. See the JACK portion of this guide for more information.


  • In PackageKit or KPackage kit, install qtractor, or run su -c 'yum install qtractor'


This probably isn't necessary, but it's nice to know.

Go to 'View > Options' to see the configuration window.

"Audio" Tab:

  • Capture/Export:
    • You can choose the file type, and sample format or quality, for exportation of audio.
    • The default choice is OGG Vorbis at "4" quality.
    • Standard ".wav" format is called "WAV Microsoft"
    • Standard ".aiff" format is called "AIFF Apple-SGI"
    • Many options are available, but I recommend FLAC, which is FLOSS, lossless, and compressed.
    • A higher number for sample format will yield greater quality:
      • CD Audio has 16-bit samples,
      • Most audio is recorded, and hardware supports, 24-bit samples,
      • Sample sizes larger than "Signed 24-Bit" are only practically useful if your hardware supports those sample sizes.
  • Playback:
    • Sample-rate converter type:
      • Sinc (Best Quality)
      • Sinc (Medium Quality)
      • Sinc (Fastest)
      • Zero Order Hold
      • Linear
    • Transport mode:
      • Full
      • Master
      • Slave
      • None
    • Automatic time-stretching
    • WSOLA time-stretching
    • WSOLA quick seek
    • Dedicated audition/pre-listening player outputs (provided in JACK; Ardour does this by default; it's useful for this)
  • Metronome
    • Enable audio metronome
      • File (bar)
      • File (beat)
    • Dedicated audio metronome outputs (also like Ardour... right?)

"MIDI" Tab:

  • Capture/Export
    • File format:
      • SMF Format 1
      • SMF Format 0
    • Quantize: aligns events to beats as closely as specified.
      • None
      • Beat
      • Beat/2
      • Beat/etc.
  • Playback
    • Queue timer (resolution):
      • (default)
      • system timer (1000Hz)
      • PCM playback-0-0-0 (slave), etc. ???
  • Control
    • MMC:
      • None
      • Input
      • Output
      • Duplex
    • Device: "(Any)" or 0-127
    • SPP: None, Input, Output, Duplex
    • Dedicated MIDI control input/output (like Rosegarden)
  • Metronome
    • Enable MIDI metronome
    • Channel: (default 10)
    • Note (bar): choose percussion instrument, velocity, duration
    • Note (beat): choose percussion instrument, velocity, duration
    • Dedicated MIDI metronome output

"Display" Tab: Pretty much self-explanatory

"Plugins" Tab: Allows you to choose directories for LADSPA, LV2, and DSSI plugins, adding multiple directories of each kind. Also,

  • Instruments
    • Dedicated audio outputs (check-box): ????

Configuring MIDI Channel Names

So that Qtractor knows your "instruments" and patch names and stuff, you'll need to import your SoundFont (if you're using Qsynth) !!

  1. Go to 'View > Instruments'
  2. Click "Import"
  3. Navigate to /usr/share/soundfonts
  4. Import whichever SoundFonts you would like to use (like the default FluidR3 GM).
  5. This is all tha Qtractor needs for general configuration.
  6. For each MIDI track that you have, either at creation or later by accessing the "Track Properties" window (for example, by right-clicking on the track's info-box in the left column and then "Track Properties")
    1. If it says "(No instrument)" then choose a SoundFont and change to that.
    2. The "Bank Select Method" can normally be left alone.
    3. Choose a bank (they all have different programs/sounds).
    4. Choose a program (this is the actual sound).
    5. Click "OK" to accept the new settings.

Using Qtractor


Qtractor is very similar to Rosegarden and Ardour. To understand the basics of all three DAWs (Digital Audio Workstations), use the Ardour tutorial's _whatever_ section. It mostly applies to this.

Using JACK with Qtractor

Qtractor includes the important part of QjackCtl's interface, so it is not necessary to run both programs together. However, you may wish to use other features of QjackCtl, like its ability to save a "patch bay." Mention that they're programmed by the same person/people, I think.

To get Qtractor's implementation of QjackCtl's "Connections" window, you'll have to click on the "Connections" button on the toolbar, or 'View > Connections' or F8. Qtractor's "MIDI" tab is equivalent to QjackCtl's "ALSA" tab.

When you start Qtractor, it automatically starts JACK, unless it is already started.

=== Miscellaneous ===\ !! When creating a MIDI track, the "omni" check-box determines whether that track will accept input from any MIDI channel, or just the one to which it's assigned !!

!! To move the transport to a particular point, shift-click in the measure number !!

!! You can change whether you want to follow the transport by auto-scrolling, with the button on the toolbar !!

!! In the matrix editor and the main screen, when you want to scroll left-right, hold control and use the mouse's scroll wheel !!

!! In matrix editor, "Tools" to adjust velocity is "Resize" and you can set it absolutely !!

Exporting MIDI and Audio Together

To export MIDI tracks with audio in Qtractor:

Play through the file in Qtractor, while routing the MIDI output into a track that's being recorded in Qtractor... effectively converting the MIDI to audio so that when you export the audio, it will all be done together. Also explain why you have to do this. Also, it's probably better to re-record the audio AND the MIDI, because then you will have the proper balance applied in a single audio track.

  1. Create a new, empty audio track in Qtractor.
  2. Check the the following is connected to Qtractor's master bus:
    • All of Qtractor's audio output that you want in the final recording.
    • All of your MIDI synthesizer's output ("all of Qsynth's output") that you want in the final recording.
    • Nothing else.
  3. Move Qtractor's transport to the start of the session.
  4. Arm the new track onto which you intend to record.
  5. Un-arm all other tracks.
  6. Arm Qtractor's transport.
  7. Press "Play" on the transport, and wait as the session plays through.
  8. Unfortunately, for this part, there is no way to go faster than real-time.
  9. Qtractor will not automatically stop the transport upon reaching the end of the previously-recorded material.
  10. When Qtractor reaches the end of the previously-recorded material, stop the transport, un-arm the new track, and create a saved copy of the Qtractor file... or export it immediately, I'm not sure...

Using the Blue Place-Markers

Here are some things you can do with the blue place-markers:

  • Mark one particular place:
    1. Move the cursor to the place you want to mark.
    2. Left-click and hold on the location
    3. Drag the cursor to the right just a little bit.
    4. Two blue markers will appear.
    5. Instead of leaving them separate, move the second blue marker over top the first one.
    6. Release the mouse button.
    7. The arrows should be converged.
  • Mark a range:
    1. Move the cursor to the place where you want the left-most marker.
    2. Left-click and hold.
    3. Drag the cursor to the location where you want the right-most marker.
    4. Release the button.
    5. The blue markers should mark the particular range.
  • Move one of the markers:
    1. ja
    2. aj
  • Something else?

Use-Case Demonstration

I've created a demonstration of what a first-time user might try as their first project with Qtractor. The following sequences demonstrate the decision-making, and the various features that could be learned. This does not attempt to show a generic method for creation, but rather the specific way that I created a new composition with the inspiration stated below.


The goal of this demonstration is to illustrate Qtractor's ultimate strength: combining audio and MIDI tracks. I decided to start with a portion of one of my favourite compositions, and to composer a MIDI "alter-ego" to go along with it. The piece is listed below in "Requirements."

Since that particular movement is a "theme and variations" movement, it starts with a theme, then continues with varied versions of that theme. The theme is in two parts, each of which is repeated once. Beethoven uses several compositional techniques that are typical of his time period, and achieves a consistently similar, but consistently new, movement.

We are no longer bound by the aesthetic rules of Beethoven's time. Something about the notation editor also being different.


  • The recording of the sonata that I used, or else your times will be off a little.
  • Qsynth.

Getting Qtractor Ready

  1. Open QjackCtl, and start JACK.
  2. Open Qsynth, and configure it with one instance, using the default FluidR3 SoundFont.
  3. Open Qtractor
  4. Configure the MIDI tracks to cooperate with the default FluidR3 SoundFont.
  5. Switch to QjackCtl and ensure the proper connections:
    • Qtractor's MIDI out (on "ALSA" page) is connected to Qsynth's MIDI in
    • Qsynth's audio out is connected to system in (the speakers)
    • Qtractor's audio out is conencted to system in (the speakers)
    • No other connections are necessary.

Import the Audio File

  1. Create a new audio track.
  2. Right-click on the audio track, and go to "Clip" (a "Clip" in Qtractor is equivalent to a "Region" in Ardour) then "Import"
  3. Locate the audio file that you want to import (in this case, I imported a recording of the second movement of beethoven's Op.57 piano sonata, "Appassionata."
  4. If the clip doesn't start at the beginning of the track, then click and drag it to the beginning.

Marking the First Formal Area

In addition to the transport, Qtractor has two blue place-markers, which sometimes merge into one. The best way to learn the behaviour of the blue place-markers is by using them. They are intended to mark a range in the work area ("main screen").

  1. We're keeping the standard tempo of 120 beats per minute, and the metre is 4/4
  2. Start from the beginning, and listen until the end of the first formal section, which I've decided is about the fourth beat of measure 12 (use the ruler to see).
  3. Mark that point with the blue arrow.
  4. Mark the beginning of the formal area by left-clicking at the beginning of the session. If the transport is at the beginning, then it will hide a blue marker placed at the beginning.
  5. Create a new clip, by clicking 'Edit > Clip > New'
  6. The clip editor will appear.

Creating the Initial Impetus

I want something simple, to balance the simple-sounding chorale at the beginning that is the theme of this movement. What could be simpler than a moment of sound, followed by some moments of silence?