Professional music production with Ardour

Modern Classic

© Lead Image © Karel Miragaya, 123RF.com

© Lead Image © Karel Miragaya, 123RF.com

Article from Issue 183/2016
Author(s):

Version 4.4 of the free Ardour digital audio workstation impresses with optimum stability and well-conceived, functional extensions.

The Ardour project introduced version 4 of its music production suite in April 2015. As is often the case with version jumps, the software experienced several inconsistencies and errors, as well as many new capabilities. Version 4.4 [1], which was released in mid-October 2015, has been tidied up; it features new developments (Figure 1) and is even leaner and more stable than its predecessor.

Figure 1: Ardour 4.4 comes with the clear-cut Meterbridge (top left), a fully equipped mixer, and the instrument tuner plugin created by Robin Gareus.

You can now complete many tasks more easily than before without having to forego tried and tested complex methods. For example, Ardour 4.4 is immediately ready for use on a system without a JACK audio server – it just uses ALSA as an interface. Of course, the performance of this combination is greatly inferior to a setup with JACK.

If you then install the JACK Audio Connection Kit and fire it up before starting Ardour, you'll get not only the full performance you're used to with Adour 3, you'll get even more. (See also the "Ardour Anywhere – Even Without JACK" box.)

Ardour Anywhere – Even Without JACK

Ardour was developed from the outset as a reference application for the JACK audio server. French developer Stephane Letz ported JACK to Apple's operating system to make it possible to run Ardour on Mac OS X. Soon enough, people wanted an Ardour port for Microsoft systems, and a JACK for Windows was created. However, these ported JACK servers didn't prove so popular in third-party operating system environments and didn't provide the same quality as JACK for Linux in terms of performance and stability.

Ardour 4 ended this era because it also works directly with the sound system of the underlying operating system. This also applies to Linux: For the first time, Ardour users can now select and configure ALSA as a sound system. Adour's internal capabilities don't suffer, and the complex signal flow in the mixer works as usual.

As long as the plugins you use are also available on all platforms, it is possible to exchange Ardour projects arbitrarily with Ardour variants from band colleagues who use other platforms. However, JACK-specific functions, such as the use of external JACK software as a recording source or synchronizing with the drive from another JACK program, will not work with ALSA.

Ardour's user interface has been almost completely rewritten, and multiple optimizations result in lower memory requirements and quicker response for almost all functions. The 80 percent lower memory requirements announced at the release of Ardour 4 prove to be accurate in practice. Any popular PC from the past five years should be happy with the software's minimal requirements. See "Installing Ardour 4.4" to get started.

Installing Ardour 4.4

Ardour is and will remain free software; you can clone the source code anonymously and for free from the Git version management system by entering:

$ git clone git://git.ardour.org/ ardour/ardour.git 4.0

In principal, it is possible for reasonably experienced users to do this themselves using waf [2], but it's also pretty time-consuming work. The git statements can also cause problems on occasion, because Ardour has seen some fairly major development.

Therefore, you might want to download a prepared installation package from Ardour.org after making a donation of at least $1 using PayPal. If you register on the site and pay $50, you get all the upgrades for the current and next generation at no extra cost. The same applies to subscribers who pay $10 each month. However, you need a regular credit card registered with PayPal; users of prepaid cards have reported that they couldn't get the subscription.

If you either don't want to use PayPal or don't like the idea of doing it yourself using the source code and its uncertainties, the only option left is to wait until the latest version appears in the repositories of the distribution you use. Experience shows that this only takes a few weeks on multimedia distros like KXStudio.

Less Is More

After launching Ardour 4.4 with an empty project, free -m displays an additional memory consumption of around 200MB because Ardour preloads several functions in the background. Consumption only increases by another 50MB when you're setting up a new MIDI track with three large plugins. The system load increases by about 50 percent if you start the required modules Calf Monosynth and Guitarix independently from Ardour. This behavior by the application indicates that Ardour's performance requirements are strongly dependent on what exactly you want to do in the application. A single MIDI track together with its plugins can be used normally on a low-powered system as long as you don't have a "fat" desktop" and a load of system services working in the background.

However, if you're aiming for a typical music production with 30 or more tracks and dozens of plugins, you'll need a correspondingly powerful computer; in fact, it might well need to be a superfast machine. In the test, Ardour 4 ran reliably and smoothly with 40 tracks and 120 plugins on a computer with Intel i5-2500 CPU (3.3GHz) and 8GB of RAM with a latency of only 5.3ms (Figure 2). However, I was using a very respectable sound card in the form of an MAudio 1014 PCI. The same project, but on a similar computer with a simple USB 2 sound card, only ran without interruptions with JACK settings for 10ms latency.

Figure 2: More than 40 audio/MIDI tracks, a lot of plugins, and still only 50 percent CPU load with 2.7ms input latency: Ardour 4 requires significantly less power than its predecessor.

Ardour supports virtually all common techniques for music production, including synchronizing videos. Sound can be recorded on audio tracks, which may have up to 12 discrete channels. Using these channels, you can implement various surround-sound techniques in addition to stereo, such as 7.1 sound for game soundtracks. Ardour 4 can also control systems for wave-field synthesis, which is another step into the future of surround sound.

MIDI tracks record notes from connected instruments and events from controllers, which can also be drawn and edited using pen tools. Ardour does not provide its own editor for this; as in Tracktion, the editing tools work directly in the MIDI region in the track of the Editor window. Robin Gareus has completely redesigned the way MIDI signals are passed through to Ardour 4 tracks so that the plugins that output MIDI signals themselves can also be connected.

The new version can handle large projects really well. In our lab, I was able to edit a three-hour recording without any noticeable delays and to extend it by an additional eight stereo tracks with other music recordings. Only a seven-minute project with 52 channels led to a slight decline in the response speed and jump-started the fan. See the "Optimizing Ardour Projects" box for ways to improve the efficiency of your work.

Optimizing Ardour Projects

Ardour leaves it to you to decide what system resources a project consumes. Each new track takes as much power as required by the functions in the track, above and beyond the basic need of around 200MB of RAM after startup. Ardour is less focused on economy and more on smooth, comfortable operation. The cache for large pulse code modulation (PCM) data in the audio tracks results in reduced disk access. For example, even big jumps in very long recordings happen surprisingly fast with relatively few tracks. As you increase the number of tracks, you will quickly reach the capacity of your RAM.

Various strategies help to utilize available system resources optimally. First, you can specifically adapt the settings for the cache (Figure 3). Large buffers on a few tracks allow big jumps without a noticeable delay, even in long recordings. However, if you load a shorter project with many identical buffer settings, Ardour could use up all the system memory, because it tries to preload a set period of time on the PCM data near the playback cursor. This involves significantly more data with shorter pieces and many tracks than with a long piece with just a few tracks.

Add-ons also devour system capacity. Because Ardour computes all operations in real time, the plugins in all tracks also need the corresponding CPU and RAM resources at the same time. For example, a really economical three-band equalizer, if it is active in every track by default, can mutate into a hungry monster given 40 tracks or more.

Like all modern professional digital audio workstations (DAWs), Ardour also provides different options for implementing a more efficient usage strategy and still not have to do without any functions. Regions on tracks can be calculated individually or as sections drawn with the range tool (Bounce). For this, Ardour applies all plugins to the data in the track and exchanges raw data for the result. If you then turn off all the plugins, you will get exactly the same sound from the track.

Ardour does this automatically if you explicitly request the whole track to be frozen. Ardour also provides the Freeze and Unfreeze options in the context menu of each track. Thaw restores the track to the state before freezing, activates all plugins again and disperses the audio data general view generated when freezing back into the original regions.

Additionally, you can calculate individual regions or sections in the track using the Bounce (with processing) function (Figure 4), that is, to apply a single effect to certain parts of a track and then disable it. Unlike frozen tracks, the track as a whole can still be operated on as normal afterward.

Figure 3: You can adjust audio material buffering for default project types with a single click or define a custom setting with sliders.
Figure 4: The two Bounce functions in the context menu for regions work like the New Region function for regions. The calculated region replaces the corresponding source region.

Tending Old Flames

At first glance, only the advanced wizard for starting or creating projects really stands out in Ardour 4. The interface also looks pretty much the same as in Ardour 3, although it is much easier to read. Whereas the background, graphics, and controls were still monochrome in Ardour 3, subtle gradients now grace Ardour 4. The display of small elements and fonts is sharper and better harmonized.

The switch to the Cairo 2D library, which also significantly lowered the system load for the basic application, is responsible for the visual improvements. Graphics cards with 2D hardware acceleration make the Ardour 4 graphical user interface quicker than the Gtk elements used by older versions. Thanks to Cairo, from Ardour 4.2 onward, it is possible to scale labels and control elements continuously like buttons and regulators.

If you take a closer look, you'll see new tools in familiar places. Some tools supplement what was already there and others replace old functions. However, Ardour 4 doesn't focus on reducing (sometimes lamented) functional diversity. No functions from Ardour 3 were dropped in Ardour 4. The greatly developed tool for project settings opens up customization options (Figure 5); you can use it to adjust many global settings specifically for each project.

Figure 5: You can now control the basic settings for MIDI and manage the involvement of regions for specific projects.

The editor provides a few new modes for cutting and transporting regions. When cutting in Ripple mode, all the regions to the right slide to the new end of the regions to the left. If you move a region, all those to the right of it move to compensate. Play loop range is now a regular playback mode.

Ardour has always provided comprehensive support for controller hardware, such as the popular drive controllers and mixer from Mackie and Behringer. All mixer and plugin functions can also be controlled using signals from MIDI keyboards and controllers. However, classical MIDI signals only have a resolution of 7 bits, which only allows 127 gradations for the velocity of played notes and controller settings. Ardour 4 now supports advanced MIDI devices that have 14-bit signals to provide 16,000 gradations. Ardour has supported the even more accurate and even more flexible Open Sound Control (OSC) for many years. OSC is a protocol for transmitting high-res signals with high sampling rates via network. The receiving software interprets these signals as parameter changes.

Various minor improvements are evident across the whole interface, such as a new scissors tool; splitting at the operating point by pressing S also is still functional. Mixer inputs now have sliders for the input level, and the Save as function now creates a complete copy of the project in a new folder. The old snapshot function still exists here, too.

Since Ardour 4.2, it has been possible to roll the regions during playback while the playback pointer remains fixed in the middle. All tools are familiar with a new Smart mode, in which they adapt to the respective usage scenario. The Smart switch for the default pointer tool can be used like the range tool if the mouse pointer is at the top of the track. The MIDI editing tool on the far right can also draw notes using Smart mode (Figure 6).

Figure 6: The tool bar in Ardour 4.4 offers new modes and a pair of scissors, with various new functions awaiting in the menus, as well.

Prime Time

Working with videos is pretty easy (Figure 7). No weaknesses or unusual system loads were apparent in the lab. The thumbnails for the video timeline let you navigate intuitively in the film. On request, Ardour can automatically import an existing original soundtrack from the movie, and I experienced no inconsistencies between sound and vision in testing.

Figure 7: Video post-processing works best with two monitors: Ardour's video window behaves with abandon in the foreground, while the plugin interface remains in the background.

Ardour as an Audio Editor

Ardour operates very differently as a real-time DAW than typical sound editing programs such as Audacity, but it still works excellently as an editor. The Bounce and Render functions in particular are the key to this. Ardour uses them in different ways to write audio material on tracks into new audio files.

The arrangement of loops with recurring musical patterns is a typical application for a sound editor. For example, musicians like to cut individual sounds from an improvised bass line and arrange them so that an optimal loop is created for the respective piece. Using the Split/Separate function, you can extract an appropriate section of a region that you can then edit easily and precisely as a new region. The note grid built into the background of the editor helps place the notes in meter positions that match the speed of the song.

You can set the Snap Mode in the top middle drop-down list to Grid or the less rigorous Magnetic, or you can disable it completely by choosing No Grid. If disabled, regions and sections can be cut and moved with pixel-level accuracy. This also allows you to build deliberately small variations in a loop. The resolution of the grid can be set to all common values between a bar and a 128th note (Beats/128) for the mode to the right of the drop-down list.

The result often includes dozens of sometimes subtly positioned individual regions that can complicate the arrangement. The Range tool can help: You can use it to drag a contiguous block across all the regions in the loop. In doing so you are best to set it to a rough value like a bar or half-note. Right-clicking the new area then unveils the various Range functions. If you've only cut and arranged, using the pre-mixer type is a good idea. It just recomposes the original material and otherwise leaves the PCM data unchanged.

The alternative post-mixer (Figure 8) also renders all settings and plugins for the mixer channel into the new file created in this way. This is useful, for example, if you also want to add adjustments or a special effect to the cut material. If you write this effect in the new region, you can then delete or deactivate it in the track to save performance.

Figure 8: A new area with signal processing also renders plugins in the new region, such as the sophisticated Calf Multi Chorus and the very useful SpiceX2. You can then remove them both from the project.

Ardour's ability to configure and balance tracks and masters with more than two stereo channels makes it possible to mix modern multichannel film sound. Ardour might not be able to export proprietary formats such as DTS or Dolby Digital directly, but the multichannel WAV files that it outputs can be processed in a corresponding encoder. A free tool in the form of Aften [4] is also available for Dolby Digital, and the commercial encoder software can also process Ardour's outputs.

The MIDI tracks appear mature and solid in Ardour 4. Everything works perfectly with normal operations, such as recordings from MIDI drum kits and keyboards, but I also didn't have any issues with more complex actions like editing recording during playback. Ardour 4 also provides a few new functions for MIDI composers.

If you to select a few notes and right-click, the context menu will Quantize or Legatize these notes only, for example. In the Transform dialog, you can make various idiosyncratic transformations as well as a steady crescendo. The tempo for the whole piece and for tempo change markers can be changed with the Tap tempo button.

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