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QTractor MIDI setup issues

I currently have QTractor set up via JACK to take input from my MIDI controller keyboard, record it and pass it to QSynth (which generates appropriate noises). However, when QSynth receives the MIDI notes, it seems to use them only very minimalistically: there is no volume change on note velocity, no recognition that the note is being held down (at least on the instruments I have checked, though that could just be their decay), and the reverb and chorus settings in QSynth don't seem to affect the sound. QTractor displays variation in note velocity in any MIDI tracks I record onto, but these variations don't seem to be acted upon by QSynth.

I have alternatively tried setting an instrument on the MIDI track in QTractor (using the same VS2 files that I used with QSynth), and although the level bars go up and down in the mixer when I enable monitoring and hit keys, no sound is actually generated by QTractor unless I hook up QSynth (which has the aforementioned drawbacks). QSynth doesn't take any notice of the instrument set in QTractor, which makes sense

Are there extra things I need to set up to get this working? I feel like I must be missing something.

rncbc's picture

Hi, you're welcome.

I think you have it a bit confused or at least you got me confused :)...

First, you have to know that Qtractor does not generate any sound per se. You need to drive (via MIDI) some instrument plugin or an external soft-synth like Qsynth, right?

Second, Qsynth is a front-end to FluidSynth which in turn is a SoundFont2 (SF2) sampler: all to say that the issues you are experiencing are probably specific to the SF2 you have loaded and not quite of Qtractor's fault: again, it doesn't generate any sound, it just transmits the MIDI messages to Qsynth/fluidsynth if properly connected to it--it is Qsynth (in fact, it is the FluidSynth engine) that produces the audio output that is driven by the MIDI on its input.

Third, I fail to recall what a VS2 file is. Did you mean SF2 ?


x6herbius's picture

Ah, I did write this quite late on in the evening, I did mean SF2. :P

I think I understand what you're saying, but what's the point of allowing an instrument to be selected on a MIDI track in QTractor if it doesn't actually use that instrument? Is is just a label?

rncbc's picture

Not just a label but a property to the MIDI track, relating to its assigned MIDI channel and to a Bank and Program selection.

Remember that are at least three (3) major modes of MIDI instruments all of those can be driven by a Qtractor MIDI track/channel:

  1. external outboard hardware instruments (being the original targets from day one); connected/wired via the physical MIDI interface and cables;
  2. external software instruments (eg. Qsynth/fluidsynth, etc.); connected via ALSA MIDI; this is the mode you're having as far as I can tell;
  3. internal software instrument plugins (eg. DSSI, VSTi or LV2); these maybe inserted in MIDI tracks or MIDI output buses; all signal flow runs internally; sound is rendered through a designated audio output bus (Master out is the default);

Only the later (ie. plugins) makes Qtractor produce audio or sound in its own (via JACK audio output ports that you connect at will).


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