At the Sounding Edge: Introducing seq24

This MIDI sequencer's simple interfaces and design put usability and functionality at the forefront.

In this month's column, we look at the seq24 MIDI sequencer to see how you can use it in a Linux-based MIDI music production system. Given working ALSA and JACK installations, this system is easy to set up and use, great fun and a valuable production tool. Feel free to follow along while I walk through some of the program's basic techniques and introduce some not-so-basic procedures before taking my leave.

On his seq24 Web site (see Resources), developer Rob Buse describes seq24 as:

a loop based MIDI sequencer...created to provide a very simple interface for editing and playing MIDI loops...that would provide the functionality needed for a live performance, such as the Akai MPC line, the Kawai Q80 sequencer, or the popular Alesis MMT-8...a very minimal sequencer that excludes the bloated features of the large software sequencers and includes a small subset of features that I have found usable in performing.

Like Rob's description, seq24 itself is small and sweet, providing simple interfaces for pattern and song creation. If you've worked with Old School MIDI gear, such as Roland's TR drum machines or the hardware sequencers mentioned above, you should feel right at home with the program. But, even if seq24's design is totally new to you, you soon will be comfortable with it.

Pattern loop sequencers assume a bottom-to-top workflow from the creation of individual patterns to their repetition and linkage to a larger form. seq24 calls this linking stage a Performance. Patterns and Performances can be recorded in real time or in step-time. Almost every aspect of seq24 is intended to function in real time, but it is equally serviceable to those of us who like sequencing note by note.

seq24 is available as a package for users of the AGNULA/Demudi and PlanetCCRMA systems. It also is available in Thac's RPMs for Mandrake and as a source code tarball on the seq24 Web site. I prefer to roll my own, so the version demonstrated here is built from the 0.6.3 tarball. I assume you already know how to install your package of choice, so let's speed along and dive into making some music with seq24.

The Pattern Editor

If seq24 is in one of your application menus, simply click on its name or icon to start the program. If you choose to launch seq24 from an xterm, you can run it with the --help option to view a list of other command-line options. Otherwise, enter seq24 at the xterm prompt to launch the program in its default state. When it starts you should see the screen shown in Figure 1.

Figure 1. Starting seq24

Each bracketed area is a sequence container. Right-click within a container and select New from the popup menu to invoke the pattern sequence editor seen in Figure 2.

Figure 2. The seq24 Pattern Editor

Let's look closely at the various parts of the pattern editor. The top strip includes an entry box for a sequence name, followed by drop-down selectors for meter and sequence length, displayed as bars. The next strip includes quantization settings for note start-time and duration, a zoom view control and settings for MIDI device target and output channels. The next strip contains the all-important Undo button, a toggle for the Tools menu, two controls for sequence key and scale type (major/minor) and a selector for a background sequence to be played while composing the current pattern.

In the event entry grid you can enter, delete and edit note events in a familiar piano-roll display, where the vertical axis represents pitch and the horizontal axis represents time. Notes can be selected individually or in groups, and the few edit procedures include some quantizing and transposition options. By the way, the Snap-to setting applies to edit groups as well as to individual notes.

The blank area under the grid is dedicated to controller and velocity editing. The strip beneath that area offers an event selector for the controller edit area and three buttons for defining the MIDI I/O for the pattern. Don't worry if you can't immediately recall all these features; seq24 provides informative tooltips for almost every aspect of its interface.

It's time to record something with seq24. After opening a new pattern, I select its MIDI output destination and click on the third MIDI I/O button in the lower right to record incoming MIDI data. I hit the Play button on the seq24 main screen, play some notes on my MIDI keyboard and behold, I've recorded a new pattern into seq24. Next, I perform a little quantization by selecting a group of notes and applying the quantization function from the Tools menu. I then do a little velocity editing by clicking right or left within the controller edit area and dragging an edit line to shape the displayed values. Figure 3 displays the results so far.

Figure 3. Recording a Pattern

I also like step-entering events into a sequencer using the mouse, the computer keyboard, a MIDI keyboard or a combination of these methods. seq24 has no problem with any of these methods, and of course, it supports real-time recording with any or all of those input devices.

Whether in real time or not, repeat the process to create more patterns. Use the copy command from the expanded popup menu in an occupied sequence container and then paste a copied sequence into any empty container to create a variant of the original. When you have enough patterns to link together into a song form, it's time to employ the seq24 Performance editor.


Similis sum folio de quo ludunt venti.


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rick's picture

Any advice on setting up a Behringer FCB1010 midi foot pedal with seq24?? My fcb1010 is easy to configure for sooperlooper, etc., but seq24 is tough to get going, even with the documentation :O(

Slackware en Seq24

marco van der grient's picture

Afther some serious work I have seq24 working on my (slackware 10.2) dekstop. I have done the kernel hack for jackstart, because of the realtime benefits in normal user mode. An easy job, by the way!
I realy liked this artikel and it is inspiring to see that you can do so much with this sequencer and compatible friends, and that this collection of programs, organizesed with Seq24, beats sequencers as Rosegarden or even Cubase. It is realy inspiring for your own music.

A great benefit for me is not to be forced to use Gnome of KDE, since I realy do not like theze desktops because of there extensive use of resources, and that is reducing the quility of music (and joy?).

I have made slackware packages of all the programs and needed lib's. And will put them on a "webspace left". Thanx Dave Philips for done this (writing) job! And thanx for Seq24!
Greetings, Marco (I am a bassplayer, but in need for more digital music).

more additions (author's comment)

Anonymous's picture

I failed to note that the main page holds 32 sequence containers in what Rob calls a set. At the bottom right corner there's a spin button that accesses 32 sets, equalling 1024 sequence containers. Should be plenty for most purposes. :)

JACK support is reported as working by some users. Alas, I'm still not getting it happening with RH9, ALSA 1.04, JACK 0.99. Bummer.

completely off-topic

mimo's picture

A word of warning to musicians inspired by this article. Don't try this at home! I have worked with Linux since the early days of ALSA and with audio programs longer than some people can think and I have never seen more self-complacency than with the jack people. It might well be that jack works fine for its developers but for the average user (and even the more proficient one) it's a no-go. You install your realtime-lsm module, launch jackstart and all you get is

cannot get realtime capabilities, current capabilities are:
=ep cap_setpcap-ep
probably running under a kernel with capabilities disabled,
a suitable kernel would have printed something like "=eip"

That is with commoncap and realtime modules present. Now you wonder what the FAQ says: nothing, zero, null, void. The problem does not exist.

What are you talking about?

mike's picture

What are you talking about? im a newbie and this linux audio stuff rocks! It has all totally inspired me. I LOVE IT!!!! Ubuntu Studio rocks to! Thanks for the Great Articles Dave!!! Your teaching me a lot! You Rule!

have you ever listened about

Anonymous's picture

have you ever listened about realtime preemption patch? do you know why linux is linux and not windows, because you can tune your system to what you need, try a multimedia linux distribution like planet ccrma or agnula demudi and you got a system tuned for realtime, but obviously, the main distro's developers can't enable some features like this in their projects because of security issues (something microsoft have never mentioned, but already present in their window$), if you are not afraid from security problems you can simply run jack as root and no problems at all for the realtime preemption. but don't speak about something you don't know

Don't try this at home!

Carlos Pino's picture

Don't try this at home!

It could be better to say:

Don't try this at YOUR (mimo) home

For me works absolutely well.


Clinton's picture

If you are using realtime-lsm then you can just run jackd. Jackstart is only for when you have the patched kernel and not realtime-lsm.

clinton@drizzlehell:~/html/music$ jackstart -d alsa
jackstart: cannot get realtime capabilities, current capabilities are:
=ep cap_setpcap-ep
probably running under a kernel with capabilities disabled,
a suitable kernel would have printed something like "=eip"

clinton@drizzlehell:~/html/music$ jackd --realtime -d alsa jackd 0.99.0
Copyright 2001-2003 Paul Davis and others.
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details

loading driver ..
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
control device hw:0
configuring for 48000Hz, period = 1024 frames, buffer = 2 periods
Couldn't open hw:0 for 32bit samples trying 24bit instead
Couldn't open hw:0 for 24bit samples trying 16bit instead
Couldn't open hw:0 for 32bit samples trying 24bit instead
Couldn't open hw:0 for 24bit samples trying 16bit instead

Ta da, it works (make sure you are in the group that can use realtime-lsm, in Debian this defaults to audio).

some corrections (Author's notes)

Anonymous's picture

A few corrections:

When recording to a pattern the MIDI I/O button used should be the first button (as seen in Figure 3), not the third button (as referenced in the text).

ZAddSubFX == ZynAddSubFX

The page at has been updated to include some more details regarding setup and recording from the system described in "Power seq24". The examples themselves are also being continually updated (as I learn how to get more out of this setup).

Best regards,

Dave Phillips

seq24 in Mandrake contrib

Buchan Milne's picture

It would appear that the seq24 packages in Mandrake contrib are more up-to-date than Thac's packages (at least for 10.1, and 10.2 for which there are no Thac packages at present).

Mandrake 10.1 contrib has 0.5.1, Mandriva 2005LE contrib has 0.6.1.

While contrib is not officially supported, contrib packages are in bugzilla and do receive updates in community (at the maintainers discretion).

Thus, when packages are available in contrib, it is usually recommended to use them over 3rd-party packages.

(which is as much of the "Thac vs the community maintainers" issue as I will get into)