Linux MIDI: A Brief Survey, Part 2

Two months ago, I began what I thought
would be a two-part summary of MIDI software for Linux. That plan has
changed somewhat, and this installment actually is Part 2 of what will
be at least a four-part series. This month, I'm your guide to the
world of Linux MIDI sequencers. Next month, I'll
introduce some helpful MIDI utilities. Then, in the final installment,
I'll look at some of the interesting MIDI languages and experimental
environments available to Linux MIDI musicians.

First, a brief review of what a sequencer is and does. Old-school
MIDI musicians would define a sequencer as software or hardware that
records MIDI data entered by way of a performance on a MIDI-enabled
instrument--keyboard, guitar, wind controller--and provides some means for editing
and arranging the recorded data. Remember, MIDI data is not audio data,
and MIDI messages simply give commands to a connected device (hardware or
software) that then should respond according to the particular message.
For example, a MIDI note-on message tells an instrument to play a
specified note, while a stream of pitch bend message tells the instrument to perform a pitch
bend to the specified degree. The range of MIDI message commands is
impressive, and a sequencer can be used to automate a variety of studio
equipment, such as mixers, effects processors and multitrack recorders,
whether tape or digital.

New-school MIDI musicians are more software-based, using softsynths
and plugins in place of racks of external gear. Modern sequencers
also are expected to support audio tracks that can be synchronized with MIDI
tracks. The audio/MIDI sequencer is now the rule: MIDI-only sequencers
still are available, but they have become the exception.

User interfaces for sequencers can take various forms, the most
popular of which include the "piano-roll" coordinate grid system, the
event list and standard music notation. Data may be entered directly
from a MIDI-capable instrument or from the computer keyboard. Once the
data is entered, it may be represented and edited by any or all of the
available user interfaces. Track displays help the musician see the data
in a familiar model adopted from the tape-recording paradigm.

Sequencers also are designed for synchronization with other equipment and
software. MIDI clock and MIDI time code (MTC) messages provide a means
for accurately synchronizing time-critical operations, and MIDI machine
control (MMC) messages can operate the transports and other controls
available on MMC-aware equipment.

Before we go further, I must remind readers that I am not providing
tutorials in these articles. If you want to know more about the programs
presented here, please visit their Web homes and give the software a spin
yourself. Okay, with all that out of the way, let's now look at some of
the available Linux MIDI sequencers.
Rosegarden
Rosegarden is the most mature Linux sequencer, with a development
history extending back to 1993. During the late 90s, Chris Cannam and
Richard Bown decided to update Rosegarden drastically, replacing the aged
Xaw/Motif-like toolkit with the more modern Qt graphics and substantially
upgrading every aspect of the program. The current version of Rosegarden
is a fully modern audio/MIDI sequencer with editor interfaces in all
the expected modes (Figure 1). It offers full sets of the usual MIDI
editing tools, such as various cut/copy/paste functions, data filtering and
substitution routines, block operations and so forth. The program's audio
editing capabilities necessarily are more limited, but you can configure
Rosegarden to summon your favorite soundfile editor for detailed work
on your audio data without leaving the garden.
Figure 1. Rosegarden 0.9.9 in Glory
Rosegarden supports the LADSPA plugin API for its audio processing, and
the most recent versions have incorporated support for the Disposable
Soft Synth Interface (DSSI), an audio programming interface designed
for instrument plugins. DSSI expands Rosegarden's support for software
synthesizers, but its potential as a "LADSPA for instruments" plugin
interface hopefully will appeal to other Linux audio application
developers.

Under the Composition/Studio menu item, you can find Rosegarden's MIDI and
audio device managers. Rosegarden polls your system for available
devices, real and virtual, and maintains its own accounts of their activities
(Figure 2). The program supports ALSA and JACK, but it prefers to set
its connections internally. That is, the user is advised not to use an
external utility such as qjackctl for managing those connections.
Figure 2. The Rosegarden MIDI Device Manager
Once your connections are made, you can proceed to arm a track for
recording by clicking on the small button to the left of the track
name. When you're ready to record, click on the big red record button, and
Rosegarden starts recording whatever comes in through the selected MIDI
input device. After recording, you can edit your performance to perfection
in any of Rosegarden's editors.

Rosegarden has too many features to enumerate or show off here, so you'll
have to visit the Rosegarden Web site to get the full low-down. One of
my favorite aspects of Rosegarden is its ability to export data to the
Csound score format, essentially functioning as a MIDI- or notation-based
front end to that most awesome music and sound programming/processing
environment. Other Linux music and sound applications that support
output to the Csound score format include the Denemo notation-based interface,
the Ceres/Ceres3 spectral domain editors and the Common Music music
programming environment. All these programs are listed on the
Linux soundapps pages.

By the way, Rosegarden's standard music notation capabilities are
excellent, with particularly impressive methods for finessing notation
created from imported MIDI files. Printed output is quite good, and for
users who want the ultimate in printed music output, Rosegarden can export
your work in the
LilyPond music typesetter file format.
MusE
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
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
KeyboardJazz++/JazzPlusPlus
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.
SoftWerk
Paul Davis is well known for his Ardour and JACK projects, and he also
has made significant contributions to ALSA development. Thus, it should be
no surprise to learn that Paul also created one of the coolest Linux
MIDI sequencers, called SoftWerk.

SoftWerk's design has been inspired by the Schaltwerk, a hardware analog
sequencer built by the Doepfer company. The inspiration is evident
if you compare this
image with the screenshot in Figure 6. However, SoftWerk can do
things quite beyond the capabilities of its hardware ancestor.

In its default configuration, SoftWerk opens with eight sequence tracks,
each with 16 steps. Steps can be toggled on or off, the sequence
length may be lengthened or shortened at will and additional tracks can
be added. No provision for saving performances is supplied, but you
can record your SoftWerk's output with the ALSA sequencer interface, or
you can capture the audio output from your SoftWerk-driven synths.

Some interesting controls have been added to SoftWerk, including some
handy randomization controls. MIDI note numbers may be entered into step
positions manually, by way of a MIDI keyboard, or you can have SoftWerk
enter random MIDI note values. Sequences can be played forward, backward,
end to end or in random order.

Figure 6 demonstrates SoftWerk at work with the Crystal VSTi plugin
running under the libfst system. This is another gift from Paul Davis and Torben
Hohn that enables the use of VST/VSTi plugins under Linux.
Figure 6. SoftWerk, qjackctl and the Crystal VSTi
Synthesizer
SoftWerk essentially is a performance-oriented sequencer, and I must
say that I whiled away many hours playing around with it. You can have
incredible fun with it, but remember that SoftWerk also is a capable
instrument and a welcome addition to any Linux MIDI-based studio.
TiSM
TiSM is Samuel Dufour-Kowalski's Temporal Information Sequencing
Machine, a real-time MIDI sequencing environment based on the Tcl
programming language. TiSM differs greatly from the other sequencers
presented here, requiring the user to learn how to compose scripts in
Tcl (an easy language for beginners) that control the sound production
of a MIDI system.

Figure 7 shows off TiSM's various GUI helper panels. Despite these nice
graphic displays, program operation absolutely depends on user-supplied
Tcl scripts. Fortunately, some example scripts are available from the
TiSM Web site (see Resources), along with a PDF document describing the basic use of
the program; this document also is readable on-line.
Figure 7. TiSM 0.2.4
TiSM has by far the highest geek appeal of the sequencers presented in
this article. The user needs to comprehend TiSM's design structure
and the Tcl language, as well as the composition and significance of MIDI
data messages. Although these demands may not be amenable to the casual
MIDI musician, for those of us who want total control over the
MIDI stream, TiSM is a good way to get it.
Next Time
Next time, I'll present some synthesizer editor/librarians and some other
useful MIDI utilities. Until then, you can download and try out
some of these sequencers. Let me know if you make any music with them,
I'll be glad to point people to your efforts. And don't forget to let
the developers of this software know what you like about their work and
what you'd like to see in future versions. It all works better that way.
Resources
Rosegarden

MusE

seq24

JazzPlusPlus

SoftWerk

TiSM

Many other MIDI applications for Linux are listed
here.

Dave Phillips is a musician, teacher and writer living in Findlay,
Ohio. He has been an active member of the Linux audio community since
his first contact with Linux in 1995. He is the author of The Book of
Linux Music & Sound, as well as numerous articles in
Linux Journal.