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Your keys to the kingdom

Use Jacker to create music from a cornucopia of free synthesizers and effects on GNU/Linux. Jacker uses the power of JACK MIDI to control external synthesizers, samplers and effects - with perfect timing. Connect your favorite instruments and exercise total control over every aspect of your song using the traditional tracker interface known from underground apps like "Impulse Tracker" or "Fasttracker 2". And of course, it's free and open, too.

All you need to get started is:

  • Your PC keyboard (chances are you are typing on it right now)
  • A JACK-compatible sampler app like QSynth, along with a few free instrument patches from HammerSound
  • A digital audio workstation like Ardour, if you want to mixdown and record your songs.
  • Some knowledge on how to build and install apps on Linux. Ask your friends!

Key Features

  • Powerful pattern editor with extensive PC keyboard support.
  • Professional sequencer allowing comfortable arrangement by keyboard and mouse.
  • Unlimited number of patterns with individual lane settings.
  • Written in C++ for convincing performance and strong realtime safety.
  • Supports up to 8 separate MIDI ports, with 16 channels each.
  • Supports CC controlling.
  • Support for different signatures and measures.
  • JSON based file format.
  • Preliminary JACK Transport support.


Jacker Sequencer

Showcase and Examples

Here are a few examples of tracks made using Jacker and QSynth only:


Jacker 2010.9.21 Latest source release. Changes:

  • Command-Line support. If a song name is passed to Jacker at startup, it will load it.
  • "install" command. You can now install Jacker globally.
  • New logo. Less glossy, more elegant.
  • Fixed a terrible timing error that introduced a jitter as big as the current latency.
  • Default number of tracks raised from 8 to 16.
  • Tracks can be renamed. Double-click track to pick a new name.
  • Mute buttons for each track. Not that reliable at the moment. Last played sound may hang. In this case, stop, then continue playing.
  • MIDI input to connect your keyboard, to test sounds before you track them. Click on a track label to route your keyboard to the particular output.
  • Initial JACK transport support. It's useful for synchronizing a recording to a DAW like Ardour. Can be switched on with the "Sync" button in the toolbar. Not too stable on start-up and loop borders. When in trouble, stop, seek, then start.

Jacker 2010.5.4 First release.