As of Ardour 6.0, Ardour provides the possibility of linking two or more surface to work as one surface. This means that two surfaces, one with 8 strips and one with 6 strips would look like a single 14 strip surface. A /bank_up or down on either surface with bank the two so that they bank in 14 strip increments.

Ardour 5.0 to 5.12 can use two surfaces as shown in Example 3.

Surface Linking Concepts

A group of surfaces linked together are called a Link Set. A Link Set is called by a positive integer number.
There may be more than one Link Set at a time used with Ardour.
Each surface inside a Link Set has a Link Id.
The Link ID is a positive integer numbering consecutive surfaces starting from 1 for the left most and going up to the right. So if there are three surfaces in a Link Set, The left surface will have a Link Id of 1, the middle surface will have a Link Id of 2 and the right surface will have a Link Id of 3.
There may not be skipped Link Ids. If there are a surface 1 and 3, there must also be a surface 2. Surface 1 must always exist. If any surface is missing, the track names will indicate the Link Id of the first device missing.
In most things, surfaces are separate and can do things independently.
- Each surface can have a different Gain Mode
- Each surface has it's own Bank Size
- Each surface has it's own Feedback
- Each surface has it's own Expanded Strip
However, some things are shared by all surfaces in a Link Set:
- Banking is done as a unit and each surface bank start is determined by the Link Set. Any surface can Bank Up or Bank Down.
- All surfaces share the same strip types. Setting Strip Types in any one surface sets it for the whole Link Set.

Setting Up a Link Set

There are only two OSC commands needed to set up a Link Set:

`/link/set linkset linkid`	Where linkset is the Link Set this surface will be added to and linkid is the Link Id of this surface.
`/link/bank_size linkset banksize`	Where linkset is the Link Set this surface will be added to and banksize is the target bank size for this Link Set. This Link Set will not operate unless the total strip numbers is banksize.

It is also possible to send link set and ID values as part of a /set_surface command. /set_surface bank_size strip_types feedback fadermode send_page_size plugin_page_size port linkset linkid

The /link/bank_size command is optional. Ardour defaults to linking with auto sizing banks where the Link Set bank size is determined by adding the available surface bank sizes together. So long as the Link Ids are consecutive, the Link Set is considered ready. If the surface wants to make sure all surfaces are present before the Link Set is ready, the /link/bank_size command will not allow the Link Set to be ready until the surface bank sizes add up to the Link Set's bank size.

Setting up a linked set of surfaces is a simple as choosing a number for the Link Set, 1 will work fine if there is only one linked set of surfaces, and giving each surface a Link Id. This can be done with the same method as the /set_surface command is sent or by having each surface send the /link/set command. As with other commands, the first parameter (linkset) may be sent inline: /link/set/1 linkid for those surfaces unable to send multi parameter OSC messages.

Example Multi Device Surfaces

Example 1

Assuming two devices, the left device has 8 strips and very little else on it's main page or tab. It may have secondary pages or tabs or a physical control section to access the extra selected strip controls like send levels or plugin controls. The right device has only 6 strips because it also has Master and Monitor channel as well as transport controls. It also has a select section. As part of it's Global controls it has a Bank up and a bank down button. (there is nothing stopping the left surface from also having banking buttons) The left surface will be linkid 1 and the right surface will be linkid 2. For this example the linkset will be 1.

Device 1 will have a "Connect" button that will send: /set_surface iiiiiiiii 8 159 8323 0 0 0 0 1 1 and the second device will have two buttons. One will be a "Connect" button that sends: /set_surface iiii 6 159 8403 0 and the other will be a "Link" button that will send: /link/set ii 1 2. These devices use two different methods of setup both to illustrate their use and because this will allow them to be used unlinked. Device 1 even as a linked device will operate on it's own as a one device Link Set. However, device 2 would show an error condition if device 1 is not present so we have a separate "Link" button. This is an optional way of doing things and both could use just one "Connect" button or both could have a separate "Link" button. Device 2 could also have an "Unlink" button that sends: /link/set ii 0 0 if desired.

To use these two devices as one, the "Connect" button on both devices and the "Link" button on the second device are pressed in any order. The two surfaces will now act as one surface with 14 bankable strips.

Example 2

This example will be more complex and use a total of five devices. The first three devices will form Link Set 1 and have 8 strips each. They are similar to the left device above, but will only show "input" strips. The last two devices will form Link Set 2. Device 1 will be similar to the first three devices with 8 strips and the other will be similar to the 6 strip device in example 1 having Master and transport controls as well. The devices in Link Set 2 will be set up to only use bus and VCA strips and so don't need to include record enable buttons etc. It is expected that all devices have banking buttons, but at least one surface in each Link Set would have to have them.

Devices 1 to 3 (from left to right) would each have a "Connect" button that sends: /set_surface iiiiiiiii 8 3 8323 0 0 0 0 1 n where n is the position or Link Id of that surface from 1 to 3, left to right. Device 4 would use: /set_surface iiiiiiiii 8 156 8323 0 0 0 0 2 1 and device 5 would use: /set_surface iiiiiiiii 6 156 8403 0 0 0 0 2 2.

As before, the "Connect" on each surface is pressed in any order and the resulting surface would have 24 input strips where the banking buttons on any of the first three surfaces would bank those three surfaces 24 strips at a time through the input strips (assuming more than 24 input strips are available). The last two strips would form a master and bus section with 14 bus only strips that will bank through the bus strips (assuming more than 14 bus strips). This combined surface would have 38 strips (plus Master) all together.

Example 3

In this example there are two devices as in example 1. However, the goal is to have only input strips on the left device and only bus strips, Master and transport controls on the right device. In this case linking is not needed. The left device would use a "Connect" button that sent: /set_surface iiii 8 3 8323 0 and the right device would use a "Connect" button that sent: /set_surface iiii 6 156 8403 0. The banking buttons on the left surface would bank through the input channels and the banking buttons on the right surface would bank through the buses and VCAs. As this example does not use Ardours OSC linking commands, it will also work with Ardour versions 5.0 to 5.12.