Musicians have a growing number of options in the Linux ecosystem. Some well-established digital audio workstation (DAW) suites, such as Ardour or Qtractor – and several hundred effects and instruments – are available under a free license. However, proprietary software is also increasingly making its way into the market. One example is Tracktion  T6, a low-budget DAW. Version 6 of Tracktion has been officially available for Linux since the summer (Figure 1).

Figure 1: New tracks for automation, new step-sequencer clips, new MIDI functions, and improved system integration make Tracktion 6 an interesting product for musicians using Linux.

Just like Home

The Tracktion Software Company [1] has offered the program for Linux since 2013. The software was essentially designed as a Windows program, but uses Juce (see "The Juce Library" box) for its audio engine and interface. Juice author Julian Storer is active in the Linux audio scene and has published a wide range of plugins and tools for Linux musicians under free licenses.

Tracktion T6, like its predecessors, is available as a Debian package built in Ubuntu. However, the software doesn't explicitly require a specific version of Ubuntu and also works with other Debian derivatives. You can also convert the package into an RPM archive, which you can install in Fedora and openSUSE using Alien.

Soon after its initial launch, the software displays better integration with Linux than any of its predecessors: Both the interface and the internal functions easily mesh with the usual systems in Linux. Some small problems that arose in Tracktion 4 and 5 have been eliminated. For example, Tracktion  T6 connects to the Internet with no problem for downloading language files. Users can now also unlock registered licenses without any issues.

Searching for new plugins – which used to be quite tricky – is now easy. The application used to freeze with incompatible modules; it now just skips such files and displays them in a window as a reference at the end of the scan (Figure 2).

Figure 2: Some incompatible files in the plugin directory would have caused a crash in the past; however, scanning with the current version of Tracktion is a stress-free process.

Tracktion T6 cannot use LV2 plugins directly, however, the Linux VST version of the Carla plugin host can be used for this. Only the graphical interfaces for the modules loaded in Carla are problematic. Things work well if you use the tools that are installed generically in Carla for setting up plugins. This also applies to processing audio data, with which LV2 plugins integrated in Carla behave just as stably and flawlessly as other Linux VST effects or instruments (Figure 3).

Figure 3: You can load plugins in the LV2 and Windows VST formats, thanks to Carla VST.

Carla is able to load plugins in DLL format from Microsoft via a Wine bridge. Although this went well in the test, full functionality was not yet supported. For example, the basic slide controls for plugins installed in Carla (volume, mix), with curves for automation, were usable without any problem, but not the special parameters.

Integrating Tracktion T6 into the world of Jack and Alsa, including the MIDI functions, was much more successful. The MIDI keyboard connected to the PC via USB, and a drum set wired to the MIDI port for the MAudio sound card worked as well as expected with bona fide Linux software such as Ardour. You can combine plugins – if needed – using plugin racks. You can insert racks just like any other plugin by dragging and dropping from the preset list on the left or using the plus arrow at top right.

Tracktion T6 doesn't have any problems with any of these tasks, such as slight delays here or a pop there. Even if the program still announces Initializing Windows when launched in the terminal, it obviously feels at home on Linux, except for a few tiny details (see the "Problems and Solutions" box).

Tracktion provides a small, but excellent gift from the world of Windows to Linux. The time-stretch library élastique Pro from zplane [4] is used not only by Tracktion but also in other products, such as Abelton Live and some products from Avid. Stretching and compressing in élastique has made significant progress, regarding both quality and speed.

The Marketplace tab is the only new feature that I did not find in Version 6.1.10 (64-bit) for Linux. This tab lets you buy, download, and install extensions and plugins directly from the manufacturer's server and those of some other vendors. However, a look at the Marketplace in a browser [5] shows that nearly all the modules there still only support Mac OS X and Windows.

Musical Scriptorium

Tracktion sees itself as a sequencer: Using Tracktion, you can arrange musical events sequentially on multiple synchronized axes running in parallel and then play these events. The editor provides an array of tracks and a time frame. Although the grid is set to seconds, you can change it to the musical Bars/Beats in the Timecode menu at the bottom left. If Snap is activated at the bottom right, clips and notes in the editor skip to the next line in the grid. Unlike many other DAWs, the program takes the zoom factor into account: The greater the magnification, the finer the grid resolution. Although clips in a four-minute composition's overall view use full bars, they change to individual beats in a bar if you zoom in to just 10 seconds.

Notes in music actually follow strict mathematical rules regarding sequence and velocity. However, live music always deviates from this precision. Tracktion provides Groove Templates for its grid that emulate many shifts that are popular in practice. It is also possible to edit these templates in the Groove menus offered for MIDI and Step clips.

Most new functions for MIDI composers can be found in the Step sequencer clips (Figure 4). These are basically normal MIDI clips, but they specify the length of the notes and the loop and simplify the selection of the pitches.

Figure 4: You can map the velocity as a kind of curve in Step sequencers. Selecting the pattern and duration of each note is pretty flexible here.

A list in which an instrument is preset for each line appears on the left in a Step clip when you mouse over it. You can turn on an editor for velocity and duration of each note at the top, as needed. Using this approach, you can draw proper curves by holding the left mouse button or edit specific values for individual notes.

Clicking the name of the instrument opens a tool for setting a specific pitch at bottom center. Here you can choose one of the Groove Templates mentioned earlier, give it a new name, and draw common note sequences by clicking.

Besides setting the tone, the software also lets you select an individual tone generator in the new Set Destination menu. Here you can control different samplers and synthesizers simultaneously using a Step clip. This assumes that the different tone generators, which a Step clip will serve, are pooled in a rack plugin. The Set Destination menu displays a list of all the modules installed in a rack plugin that are able to receive MIDI notes.

Anyone wanting to play various instruments from a Step clip without using a rack plugin can use an old trick: Set the pitch on the keyboard below and one of the 10 MIDI channels for the instrument output in the Step clip. With instruments that also let you adjust these values, you can tailor them exactly to the instrument in the clip. Set the other sound generators so they don't output anything on that channel or the set pitch.

The developers have installed some wonderful innovations in the classic MIDI editor, which presents itself as a tool directly above the respective clip. Like Ardour, Tracktion T6 doesn't have a special editor in a separate window. If the appropriate zoom factor is set, this mode is good for direct editing and has the advantage that individual MIDI notes actually appear during composing in the position in the arrangement where the software plays them.

Tracktion recorded both the notes and the controller signals directly into the clip from the keyboard (Behringer UMX25) connected in the test. You can then edit them using a pen tool by clicking Controller or Type in the editor. You can draw the automation selected in the curve editor in Tracktion T6 for individual notes, as required (Figure 5). To do so, first select the note with a simple left-click, and then click Show Note Automation in the tool at the bottom in the middle.

Figure 5: You can draw curves for automating individual notes in the Tracktion 6 MIDI editor.

For all its interesting features for loop-oriented, electronic music, the program is still meant primarily for classical audio recordings.

Tape Machine

The software is consistently nondestructive when editing: All cut and loop operations only affect the behavior of clips that are visible in the editor; the file with the original recording remains unchanged. Some operations are inherently not specifically applicable to these clips, especially those that need the original material to be recalculated.

For example, the Loop Properties mode doesn't work at all with the material from the clip itself, but rather with the respective source file. The same applies to the functions in View Source Info (Figure 6).

Figure 6: The complete, six-minute-long source file is displayed on the Loop Properties tab for a clip that is only 20 seconds long.

To target these special functions to just one clip, you need a new audio file that contains only the material in the clip. To create one, export the clip using the Render Clip tool at bottom right in the audio clip tool. The program collects these files below Render in the project folder. The original recording remains completely unchanged.

Tracktion isn't familiar with special Punch markers, which automatically insert a recording from a specific point in a piece of music. Instead, Punch is controlled by the same I/O auxiliary lines that also mark the beginning and end of loops. When playing, you can set the marks on the cursor's position with the I and O keys.

The mode for retrospective recording is an exciting new function for projects with live musicians. You can set up a time frame that the software uses to record all input in the menu bottom left in Options | Retrospective Record. Those who had a great idea while warming up on their guitar or MIDI keyboard no longer need to fret that the recorder wasn't running yet.

Clicking the button with the clock at the top right adds the material at the cursor position to the currently active track. The program takes the last recording input for a specific track into account. If you set a five-minute buffer and record first MIDI notes and then audio data in this period, you will be left with the audio data only. The function discards MIDI clips as soon as material appears on the audio track, and vice versa.

The way recordings are played can be manipulated automatically. To do this, simply drag the A icon at the top right end of the track onto an adjuster that you want to automate. Tracktion immediately draws the curve with the parameter data on the track. This feature is nice and compact and similar to the actual material, and thus to the music being played. Things can become a little confusing with multiple curves, however, which is why the program now provides its own automation tracks (Figure 7).

Figure 7: Having the automation curves in their tracks helps provide a clearer overview in the software compared with several overlapping curves directly in the track.

Those who like recording multiple takes spontaneously for a passage will appreciate the new comp groups. If you record the same take successively on different tracks in the same comp group, the software allows you to set sections in each track, which the program then plays exclusively. This mode lets you put together a quick and intuitive take from the best sections of various attempts.