A mixer strip in Ardour is a vertical view of the track, from a mixing point of view. This view is convenient to deal with I/O, effects, panning/muting, gain, etc… It has a general "top to bottom" flow.
The mixer strips breaks down into:
At the top of the window, is the group tabs (here, recm…). This allows to group tracks together for common controls.
Bellow are 3 buttons:
Right clicking on the color bar will bring up a context menu, which is exactly the same as clicking on the Track name button.
Clicking the Track name button will bring up a menu:
The dropdown button shows the current input port(s), i.e. what's plugged to the "in" of the track. By default, each audio track is connected to the system inputs, ready for recording, as shown by the number(s). Clicking the dropdown Inputs button will allow to change the inputs, through a menu:
The Routing Grid can also be shown by right clicking the dropdown Inputs button. It allows to make the connections through a matrix, and connect things that are not listed in the menu above, or connect to multiple sources at once, reduce the number of inputs, etc…
On audio tracks, is a Trim knob, as on traditional consoles. It set the base input level for the track, avoiding any clipping. Notice that it trims both any input, but (when playing back), also the level of the playlist as displayed in the Editor. It makes sense as while playing, the input of the track is the playlist, on which the mixer strip acts.
On midi tracks, it is replaced by a MIDI Input button, that allows/disallows MIDI input on the track.
On audio tracks only, the Polarity button(s), 1 per input, allow to reverse the signal, i.e. a negative value will be positive and vice-versa. This can help deal with phasing issues.
The processor box is where the effects are added. By default, one effect is always present: the Fader (see below). The effects can be added pre-fader and appear in brown, or post-fader, where they will appear in dark green. The signal flow is represented by lines, red for the MIDI and green for the audio.
It is also where the Sends come from, wether external or auxiliary.
To learn more about the processor box, see The Processor Box.
The Panner visually displays how the sound will be distributed between the different outputs. They'll look and behave differently if the track is mono, stereo, or has multiple channels.
Right clicking the Panner will show a menu:
See Panning to learn more about how to control the panner, and what kind of panners are available inside Ardour.
The most noticeable button here is the Record Enable one, with a red circle. When enabled, next time the Global record will be armed and playback started, everything that comes from the input of the track will be recorded. Right clicking a disabled record button allows to enable Rec-Safe, thus protecting the track against accidental recording.
The buttons on the right, In and Disk, show what the user is listening to by lighting up, between the Input and the actual content of the playlist on Disk.
They also allow to override the automatic switching by pressing them to lock one source or the other to be what the user is hearing.
These buttons allow to Mute (or silence) the track, or Solo them, shutting down the gain of the other tracks (totally by default, can be set to partially in the options). See Muting and Soloing for more information.
Notice that by default, Solo overrides Mute, i.e. if a track is both Soloed and Muted, it will play. That can be changed in the preferences.
The two led button above are related to solo:
On the right of this part is a Meter, displaying the level of the track's output after the fader. In can be set to display the signal at any point, see below Metering Point. Right clicking this meter shows a menu allowing to switch the meter type.
The big Gain slider on the left allows to change the gain of the track. Its default O dB value is reminded with a white horizontal line, and its precise value is shown in a text field above it, that doubles as a way to type in a numeric value.
The text field above the meter shows the "Peak", i.e. the mawimum value that has been reached during playback. To avoid distortion, the value should stay below O dB, and if it goes above this value, the text field will turn red. Clicking on this field will reset the Peak value (for a new measurement or a new part of the track).
Notice that if any gain automation has been set and the automation state is set on "Play" (see below), then the Gain fader is driven by the automation, and not by the user. The Gain fader will turn grey to show it's inactive.
If at least one control master exists, this button will show up, allowing the user to link this track to any control master.
Clicking the button lists all the available control masters, and a menu option to Unassign all. Notice that a track can have be a slave to as many control masters as they are in the session, hence multiplying the number of C.M. buttons. The displayed number is the number of the Control Master, not the count of C.M. linked to the track. A track with no control master assigned will show a unique button with a "-vca-" label instead of this number.
This button allows to choose the mode used regarding automation:
This button displays the mix group information as does the tab in the header (see above). It is convenient though, as it allows to quickly switch the track from one group to another with a drop down menu, also allowing to affect the track to a non-adjascent group (which the tab won't easily allow).
The metering displayed in the meter is by default is 'Post', i.e. Post fader. It can be changed with this button to Any point of the signal flow:
This button is exactly the same as the Input button, but applies to the output of the track.
This buttons open up a little text editor, that can be used to add some written notes to the track, as e.g. a particular setting. The button's caption is replaced by the beginning of the text, so it can be used as a "sub" name for the track.