ardour-tutorial/content/recording-audio/understanding-routing/index.en.md

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title = "Understanding routing"
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weight = 6
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Routing an audio signal is sending it from somewhere to somewhere else.

In addition to getting audio signals to and from Ardour, routing plays
an important part inside Ardour itself. Examples of using routing inside
Ardour include routing audio from Tracks to the Master Bus or to other
Busses, creating 'sends', routing the outputs from Busses to the Master
Bus, etc. (see chapter on **Creating a Track** for an explanation of
Tracks and Busses). All routing, both internal and external to Ardour,
is handled by JACK.

### Routing in Ardour

The standard routing of inputs, tracks and busses in Ardour is
determined when a new Session is created in the Advanced Options of the
New Session dialog box (see **Starting a Session** chapter). By default,
the routing is as follows:

- The audio device inputs are routed to the Track inputs.
- All outputs from Tracks and Busses are routed to the master bus
  inputs.
- The Master Bus outputs are routed to the audio device outputs.

Note that when a new Bus is created, nothing is routed to its input.

This routing setup makes sense for sessions containing only Tracks, but
to make use of any Busses (other than the Master Bus) or to get creative
with the paths of the audio signals inside Ardour, we need to be able to
change the routing. 

The Audio Connection Manager window (also known as the patchbay) is the
main way to make connections to, from ,and within Ardour's mixer. You
can open this window with the shortcut "*Alt*" + "*N*", or through the
menu *Window > Audio Connections*.

![Audio Connection Manager](en/Ardour4_Audio_Connection_Manager_Menu.png) 

The patchbay presents two groups of ports; one set of sources, and one
of destinations. Sources and destinations are organized by tabs. The
available sources are displayed vertically on the left side, and the
destinations are displayed horizontally at the bottom.

In the screenshot below, notice that the "*Hardware*" tab is selected on
the top left (that's a source), and the "*Ardour Tracks*" is selected as
a destination in the bottom. This means that the matrix you see displays
connections from available hardware sound sources (for example, a
microphone), into existing Ardour tracks.  

![ACM 1](en/Ardour4_Audio_Connection_Manager_1.png) 

The green dots represent a connection. The screenshot above tells us
that incoming sounds from "*system: capture\_1*" (the first input source
of your soundcard, or the built-in microphone of your laptop) are going
into Ardour track named "*Audio 1*", and also that incoming sounds from
"*system: capture\_1*" and "*system: capture\_2*" are respectively going
into the Left and Right inputs of Ardour track named "*Audio 2.*" 

Notice we can see that "*Audio 1*" is a Mono track because it only has
one connection slot, while track "*Audio 2*" is Stereo since it has two
slots (Left and Right).

The next screenshot shows the signal path from Ardour Tracks (selected
vertical tab) into Ardour Busses (selected horizontal tab). As mentioned
earlier, the default setting for all Ardour Tracks is that their sound
goes to the Master Bus.

![ACM 2](en/Ardour4_Audio_Connection_Manager_2.png) 

Note: remember that "*Audio 1*" is a Mono track? We saw it in the
earlier screenshot that "*Audio 1*" only has one input slot. But now on
the screenshot above you see that "Audio 1" has two outputs (Left and
Right). This is normal: we define whether a track is Mono or Stereo by
its *number of inputs*, not outputs. Mono tracks will hold a single
channel of audio, but you can still choose to place the sound on the
left or the right speaker (or anywhere in between). More on this in the
chapter **Panning**.

Finally, let's explore a couple more tabs in the Audio Connection
Manager to see the sound going from the Master Bus to the actual
hardware outputs (your loudspeakers or headphones):

![ACM 3](en/Ardour4_Audio_Connection_Manager_3.png) 

As you can see, the selected source tab is now "*Ardour Busses*", and
the destination tab is "*Hardware*". This session happens to have only
one bus, the default "master out". The green dots show that all sounds
coming out of the Master Bus are going to system playback 1 and 2, which
are the outputs of your soundcard. 

### How to connect and disconnect?

To make a connection, click on the desired empty square in the matrix; a
green dot will appear to indicate the connection is made.

To undo a connection, simply click on an existing green dot and it will
disappear.

### Practical example of routing to a bus 

In the following example session, there are two guitar Tracks and one
unused Bus called Guitar Bus, all Stereo.

![ACM 4](en/Ardour4_Ardour_Connection_Manager_4.png) 

Suppose you want to send the output from the two guitar Tracks to the
Guitar Bus instead of the Master Bus. This can be useful to control the
volume of both guitars with just one Fader (in this case the Guitar Bus
fader). Then the output of the Guitar Bus, which is the sum of the two
guitars, goes directly to the Master Bus.

Here is how to edit the patchbay to get the desired routing. Select
"Ardour Tracks" tab from Sources (vertical tabs), and "Ardour Busses"
from destinations (horizontal bottom tabs). Undo existing connections
from both Tracks to Master. Then create connections from both Tracks to
Guitar Bus. The final result would look like this: 

![ACM 5](en/Ardour4_Audio_Connection_Manager_5.png) 

Now both guitar tracks are routed to the Guitar Bus, and no longer
directly connected to the Master Bus. We then make sure that the Guitar
Bus is, by its turn, routed to the Master Bus (the output routing of a
Bus is edited in the same way as for a Track), so that we can still hear
the sound from both guitar Tracks. Now we can control the volume of both
guitar Tracks together by changing the Fader of the Guitar Bus. What's
more, we can now add Plugins to the Guitar Bus to process the sound of
both guitar Tracks together.

### Track- or Bus-specific views of the Patchbay

The Audio Connection Manager (Patchbay) that you open with **Alt + P** shows you 
the complete matrix of every single source and every single destination
available in Ardour. Sometimes this is too much: you just want to quickly change 
the routing of a single track input or output, for example. Ardour allows you to 
access a relevant subset of Patchbay connections when you click directly on the 
Inputs or Outputs button of a Track or Bus in the Mixer Strip.

The Inputs button is at the top, and the Outputs button is on the bottom of the 
strip. Clicking on either one will show you a menu of connection options. In the 
screenshot below, for example, you would click on the "1/2" button right under
the track name "Guitar-1" in order to access this menu:

![Editor Mixer In Out](en/Ardour4_Editor_Mixer_In_Out.png)

You may select a connection right there from the menu, or choose "Routing Grid" 
to see a simpler version of the Audio Connection Manager with only the Inputs 
or Outputs of the selected Track or Bus. 

### All Ardour connections are JACK connections

It is important to realize that any routings that you make or disconnect
from within Ardour are in fact JACK routings, which you can see from
other applications like Qjackctl, Catia, or JackPilot, depending on your
Operating System. Below is an example of a Catia window (Linux only)
displaying the same JACK connections discussed above:

![Catia](en/Ardour4_Catia_Example.png) 

Continuing
----------

In this chapter, we covered how to manage Routing inside Ardour, or
between Ardour and the sound card. However, one of the strengths of
using the JACK system is that it can also manage connections between
applications on the same computer. To gain a better understanding of how
this works, please continue to the chapter **Routing Between
Applications**. If you would prefer to work only with Ardour, then skip
ahead to the section on **Arranging Tracks**.

Next: [ROUTING BETWEEN APPLICATIONS](../routing-between-applications) or [ARRANGING TRACKS](../arranging-tracks)