Audio/MIDI multi-track sequencerhttp://qtractor.sourceforge.net/
Qtractor is an Audio/MIDI multi-track sequencer application written
in C++ around the Qt4 toolkit. The initial target platform will be 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.