Ardour can be used in many different ways, from extremely simple to extremely complex. Many projects can be handled using the following kind of workflow:
The first step is to create a new session, or open an existing one. A session consists of a folder containing a session file that defines all the information about the session. All media files used by the session are usually stored within the session folder.
More details on sessions can be found in Sessions chapter.
Once a session has been created, it will be necessary to add some audio and/or MIDI material to it—which can be done in one of 3 ways:
MIDI recordings consist of performance data ("play note X at time T") rather than actual sound. As a result, they are more flexible than actual audio, since the precise sound that they will generate when played depends on where the MIDI data is sent to. Two different synthesizers may produce very different sounds in response to the same incoming MIDI data.
Audio recordings can be made from external instruments with electrical outputs (keyboards, guitars, etc.), or via microphones or other sound capturing equipment.
Ardour uses the JACK Audio Connection Kit for all audio and MIDI I/O, which means that recording audio/MIDI from other applications is fundamentally identical to recording audio/MIDI from audio/MIDI hardware.
Sanity check: is this true anymore? Does Ardour's ALSA backend make this statment not exactly true?
Once there is material within the session, it can be arranged in time. This is done in one of the two main windows of Ardour: the Editor window.
Audio/MIDI data appears in chunks called regions, which are arranged into horizontal lanes called tracks. Tracks are stacked vertically in the Editor window. Regions can be copied, shortened, moved, and deleted without changing the actual data stored in the session at all—Ardour is a non-destructive editor. (Almost) nothing done while editing will ever modify the files stored on disk (with the exception of the session file itself).
Many transformations can be done to the contents of regions, again without altering anything on disk. It is possible to alter, move, and delete MIDI notes, and remove silence from audio regions, for example.
Sanity check: deleting MIDI notes doesn't change them on disk? Isn't anything done to MIDI a destructive operation?
Once the arrangement of the session mostly complete, the next step is the mixing phase. Mixing is a broad term to cover the way the audio signals that the session generates during playback are processed and added together into a final result that is actually heard. It can involve altering the relative levels of various parts of the session, adding effects that improve or transform certain elements, and others that bring the sound of the whole session to a new level.
Ardour allows automation of changes to any mixing parameters (such as volume, panning, and effects controls)—it will record the changes made over time, using a mouse or keyboard or some external control device, and can play back those changes later. This is very useful because often the settings needed will vary in one part of a session compared to another—rather than using a single setting for the volume of a track, it may need increases followed by decreases (for example, to track the changing volume of a singer). Using automation can make all of this relatively easy.
Once the arrangement and mix of the session is finalized, a single audio file that contains a ready-to-listen to version of the work is usually desired. Ardour allows the exporting of audio files in a variety of formats (simultaneously in some cases). This exported file would typically be used in creating a CD, or be the basis for digital distribution of the work.
Of course it is sometimes desirable to export material that isn't finished yet—for example, to give a copy to another party to mix on their own system. Ardour allows exporting as much of a session as desired, at any time, in any supported format.