Desfonema Sequencer
A small tracker inspired midi sequencer written in python.
Features:
  • Pattern oriented design, with n tracks by pattern.
  • Convenient keyboard shortcuts and virtual keyboard.
  • Step and live editing.
  • MIDI Input (ALSA)
  • Text based file format (easy to manually edit or merge and better suited for version systems like subversion)
Demo song made with just 2 patterns: here using Yoshimi and Hydrogen and mixed with Ardour.
2011-08-06 - Version 0.3.2b - It's testing time.
  • Individual mute for each track instead of "solo" mode
  • Track expansion/shrinking
  • Variable lenght note in live recording
  • Step size in step editing mode
  • New shortcuts Alt+PgUp/Alt+PgDown for moving +1 octave/-1 octave
  • Fixed noise in synth/port change while playing
  • Many other changes
Download it here, try it and report bugs.

2011-06-22 - Version 0.3.1
  • Implemented nanosleep for better precision
  • MIDI Input configuration
  • Note paint in piano roll more readable
  • Scales helper
  • Volume change of selection with input volume selector
  • A lot of bugfixes and small improvements. See changelog for a complete list.
Download it here or read the docs.

Seq24
We used to mantain a custom version of the Seq24 sequencer with some extra features like:
  • Round robbin editing support: Notes can start at the end and the continue on the begin of the seq like if they where on a continuous piano roll
  • Quantimization on record, so you don't ever need to quantize your input
  • Fixed and Free record volume, a must have for your drum patterns
  • Remember last Save/Open path
  • Start/Stop Playing with Spacebar, from main window and from the Edit Piano Roll
  • New Quantize button on bar, for easy access to that godbless function
But finally those changes where merged into the main branch, so just grab the official version at http://launchpad.net/seq24.
Diseņo y Webmaster Desfonema - 2005