Linux MIDI: A Brief Survey, Part 2

In part two of this ever-expanding MIDI series, a look at various sequencers, from Rosegarden to seq24.

In its fundamental aspects, MusE resembles Rosegarden and many other audio/MIDI sequencers. However, Werner Schweer, MusE's chief designer, has decided to remove the program's music notation interface, branching those facilities off into his MuseScore music notation program. MusE will continue to improve its audio and MIDI support, but from at least version 0.7 on there is no music notation interface in MusE. Thus, if notation is unnecessary for your work, MusE should suit your needs perfectly.

Basic operations are similar to working with Rosegarden. However, MusE plays a little more nicely with ALSA and JACK, allowing external utilities to be used for managing device connections (Figure 3). MusE also is well designed for synchronization possibilities, supporting MMC and performance synchronization by MIDI clock, MTC and the JACK transport control interface. MusE can be configured as either the master transport controller or a slave to incoming control signals in any of its supported formats.

Figure 3. MusE 0.6.3 in Full Array

MusE's audio capabilities include support for LADSPA plugins as well as a native softsynth plugin interface--MESS, the MusE Experimental Soft Synth. Although the MESS API has not been used beyond MusE itself, it is a promising interface. You can see an example in Figure 4, a screenshot showing off Alin Weiller's DeicsOnze, a DX11/TX81Z emulator running as a native MusE softsynth.

Figure 4. MusE 0.7 with DX/TX Softsynth Running on Linux/PPC (screenshot courtesy of Robert Jonsson)


Seq24 is unique. It is a MIDI-only sequencer with no audio support, and its design philosophy resembles that of popular hardware sequencers such as the Kawai Q80 and the Alesis MMT8. A key feature of seq24 is its intended aim as a performance-oriented composition tool, with special attention given to its loop recording and playback capabilities.

You can loop record in real time from a MIDI keyboard, a virtual keyboard (see Figure 5) or the mouse drawing tool. Autoquantization can be applied to start-time and duration, so your efforts can sound better than your technique. Many editing operations are usable in real time, such as cut/copy/paste and pattern relocation, and a variety of keyboard controls are available for combining patterns in interesting ways during playback.

In some ways, seq24 also reminds me of the venerable Dr. T's KCS, a keyboard-controlled sequencer for the Commodore C64 that packed an amazing amount of power into 64 kilobytes of memory space. The KCS performance controls made the most of the machine's limited resources by triggering sequences from the computer or MIDI keyboard as needed, rather than keeping them in memory as an arrangement of linear tracks. seq24's performance controls similarly are the key to using the program to its fullest, letting the user combine and recombine sequence loops in imaginative ways.

seq24 is lean software, focused on doing a few tasks and doing them well. Programmer Rob Buse refers to seq24 as a simple program, and it is, but you still need to take a few minutes to study the SEQ24 text in the source package to acquaint yourself with the program's keyboard controls. seq24's simplicity conceals an excellent pattern-based real-time MIDI sequencer that's powerful live performance software and just plain great fun.

Figure 5. seq24 0.5.3 at Play with vkbd, a Virtual Keyboard


Jazz++ has an interesting history. It originally was developed as cross-platform commercial software for Windows and Linux, with a GUI based on what then was known as wxWindows. At some point, its developers decided to open the Jazz++ source code and distribute the program under the GPL.

Jazz++ was the first Linux audio/MIDI sequencer. It also was designed with various experimental features, a consideration I find musically thoughtful in software design. The wxWindows graphics were used well in interfaces for randomizing pitches, velocities and controller curves, but alas, interest in Gtk and Qt proved to be powerful competition.

Nevertheless, wxWidgets (as wxWindows now is known) has evolved into an attractive and powerful graphics toolkit, and a new group of programmers has taken up the evolution of JazzPlusPlus, updating the program's interface to the more modern toolkit. Binaries are not available yet, and the source code currently is available only in CVS.


Similis sum folio de quo ludunt venti.


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vkeybd not vkbd

Anonymous's picture

"Figure 5. seq24 0.5.3 at Play with vkbd, a Virtual Keyboard" After extensive googling, I could not find vkbd. However, the app in the screenshot appears to be vkeybd (


Alain's picture

There is another excellent piece of software that's worth mentioning. Noteedit, a score editor and midi player.


StartCom MultiMedia Edition

StartCom's picture

May I suggest a quite complete Linux OS, with many applications mentioned in this article, build-in? StartCom Linux offers a Addon CD for it's StartCom MultiMedia Edition with lots of applications which lets transform this Linux system into a productive Music Recording Studio. Installation Instructions are here and view also the related press release and screenshots.

Rosegarden authors etc

Chris Cannam's picture

A very nice article!

Just a quick note:

During the late 90s, Chris Cannam and Richard Bown decided to update Rosegarden drastically

Rosegarden has three main authors, and it's primarily the other one, Guillaume Laurent, who deserves the credit for kick-starting the drastic update.

Another couple of additions: Rosegarden also supports the JACK transport synchronisation mechanism (mentioned in connection with MusE in the article); and with the DSSI-VST bridge plugin, you can also use Windows VST effects and instruments as plugins in Rosegarden (mentioned in connection with SoftWerk in the article).

Author's reply

Anonymous's picture

Hi Chris !

Thanks for the additions, and please pass my apologies to Guillaume for my forgetfulness. RG is impressive major Linux software, you guys have all done fantastic work on it. Looking forward to 1.0 !



No problem :-)

Guillaume Laurent's picture

Can I submit a patch to the article ? :-)