SEQ541 is a MIDI pattern sequencer for OS X. The program is extremely flexible, all it requires is that you have an external MIDI device generating a clock and it will output notes in time to a pattern sequence you specify. Why is SEQ541 for you?

  • I wrote this program because I wanted a way to control my Roland SH-32 synthesizer (which does not have a built-in sequencer) in time with my Korg ER-1 Rhythm synthesizer (which does have a built-in sequencer). It works pretty damn well for this purpose, especially live, where I would rather be playing pre-programmed melodies and basslines and tweak the knobs in real-time.
  • If a full-blown sequencer is too much software for your music, then pattern based music programming might be the way to go. My musical background all started with MOD files, so I've never really let go of the pattern paradigm for music composition. SEQ541 is a great tool for doing pattern based composition with your MIDI gear.
  • If you have a MIDI synth with a built-in sequencer, you can use SEQ541 to visually edit sequences for the device, then play then back into the device while it's recording. I use SEQ541 to do this with my Korg EA-1.
  • If you're a software synth person, SEQ541 works really well for controlling software synths like Native Instruments Absynth or Waldorf A-1 in time with your external MIDI hardware.
If you have a hardware (or software) synth that you wish you could control using patterns, this is your program!

If enough interest (read: cash) is generated for this program there are a lot more features I would like to add, but for now, it does everything I need for my music. :-)

features (limitations?)

  • you can't record patterns, only input them via mouse
  • 128-note polyphony
  • you can run as many pattern sequencers simultaneously as your CPU can handle
  • you can store as many patterns as you want per sequencer
  • while playing, transitions to the next pattern don't occur until the current pattern is done playing
  • variable pattern length: 16, 32, 48 and 64 notes
  • variable note length: 16th note through whole note in 16th note steps
  • fixed note-on velocity 0x64
  • play/stop must be driven from an external MIDI source
  • MIDI clock must be from an external MIDI source
  • can drive any hardware or software MIDI device
  • can echo MIDI clock to the external MIDI device (for arpegio or whatever)


SEQ541 1.0 is now free software under GPL!

You can download SEQ541 here.

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