LMMS generates MIDI output events only for MIDI channel 0 when Jack, FluidSynth and LMMS are configured to use ALSA's "seq" MIDI driver. Reproducible: Always Steps to Reproduce: 1. Set up jack (I included a2jmidid and aj2midi_bridge, not sure if that matters), qsynth/fluidsynth and system audio 2. Start LMMS-1.0.2 3. With QJackCtl or Patchage, cut LMMS's PCM outputs so all generated sound must be MIDI 4. For the pre-generated TripleOscillator track, click on the settings icon->MIDI->output->FluidSynth 5. Click on TripleOscillator track to summon the instrument settings window 6. Verify in the MIDI tab that the MIDI channel is tuned to anything other than zero 7. Play the piano in the instrument settings window (or in the track's Piano Roll) Actual Results: LMMS indicates it's playing the notes, but no MIDI events are generated. If one neglects to cut LMMS's PCM connections, the software synthesizer output can be heard, though. Expected Results: MIDI output. This bug has been reported upstream and is tracked here: https://github.com/LMMS/lmms/issues/807.
lmms-1.0.x is long gone from the tree...