Ardour does most of its internal signal routing via JACK:
all track and bus inputs and outputs are JACK ports, as are sends and
inserts, which means they can be tapped into by other JACK clients.
Only the signal flow inside a track or bus (i.e. from processor to processor) is
handled internally.
By default, Ardour will automatically create the following connections:
Track inputs are optionally auto-connected to hardware inputs,
in the round-robin order. In the example below where an audio interface
only has two inputs and 8 new tracks have been created, Ardour connects
the first input to the first track, then the second input to the second
track, then the first input to the third track, and repeats it until all
tracks have an input assigned for them. The exact configuration will
depend on how many channels have been chosen for each new track in the
Session > New Session dialog.
Bus inputs are left disconnected.
The number of track and bus outputs are equal to the number
of inputs of the master bus.
Track and bus outputs are always auto-connected to the master bus inputs.
Master bus outputs are connected to hardware outputs.
This configuration is sufficient to do basic tracking and playback of many
sessions without any adjustment by the user. Changing these connections
is generally not necessary and often leads to problems.
However, for many workflows during mixing, more complicated signal routing
is required. Ardour offers many possibilities for connecting things to fit any
particular workflow.