Working with Ableton Link

As long as you are running Beat Link Trigger on one of the common operating systems and processor architectures that are supported by lib-carabiner, there is nothing else you need to install or run, and a built-in copy of Carabiner will be started when you need it. If you are on a different platform, you will need to build, install and run Carabiner on your own.

With either approach, Beat Link Trigger can tie into an Ableton Link session, so you can synchronize programs like Ableton Live, Traktor, and an increasing collection of others (as well as more and more hardware), to the tempo and beat grid established by the players being watched by your triggers.

To work with Carabiner and Link, bring up the Carabiner Connection window by choosing Ableton Link: Carabiner Connection in the Network menu:

This will open the Carabiner Connection window (the set of devices you see at the bottom will depend on what is actually on your network):

Set the Carabiner Port value to match the port on which your Carabiner daemon should listen (or, if you are running your own independent copy, the port on which you have that Carabiner configured to listen). The default value of 17000 will work unless you need to explicitly tell it to use a different port because some other program is using port 17000 on your system.

The Latency value is the number of milliseconds it takes from when a beat is actually playing on the players in your DJ Link Pro network to when the corresponding beat packet is received by Beat Link Trigger. The default value of 1 ms seems to work well, but if your Ableton Link session seems to be running audibly behind beats from your Pioneer gear, you can increase this value until things sound right. You can also use negative latency values if you are receiving beat packets before the beats themselves are heard.

Once your port value is correct, you can click the Connect check box to establish a connection with Carabiner:

Once connected, you can no longer adjust the port value, but you can tweak the latency at any time while listening to sound from your Pioneer gear and Link-enabled software or hardware.

The current tempo of the Link session is shown, as well as the number of other Link-enabled programs (Link Peers) visible on the network.

In order to allow triggers to influence the Link session, configure a trigger to send to Link by choosing Message  Link in the trigger itself:

Triggers that work with Link can align the beat grid with either individual beats, or entire bars of four beats (the default). If you want simple beat-level alignment, uncheck the trigger’s Align bars check box.

If the systems you are integrating with support version 3 of the Ableton Link protocol, you can also use its Transport Control feature to tell them to start playing when the trigger activates, and stop when it deactivates, by checking the trigger’s Start/Stop checkbox. Software and devices using older versions of the protocol will simply ignore these instructions even if you have this turned on.

Once a trigger like this activates, the tempo of its watched player will show up as the Target BPM within the Carabiner Connection window. That is not happening yet, though:

Starting with version 0.4.0 of Beat Link Trigger, Carabiner can sync without using triggers at all. If you still want to use it in that mode, you need to choose Sync Mode  Triggers in the Carabiner window. Once Carabiner is connected and set to Triggers as its Sync Mode, whenever a Link trigger is active, Beat Link Trigger will control the Link session tempo, and will align it to the beat (or bar) of the trigger’s watched player:

Sometimes you simply want to tie the Ableton Link session to whatever is playing on the CDJs, without having to set up a trigger to manage it. You can do that by choosing Sync Mode  Passive in the Carabiner window. As soon as you do that the Ableton Link section of the window becomes enabled:

This gives you a place to control the things that a trigger would normally set for you (whether the Link session is currently being synced, and if it should be aligned at the level of beats or entire four-beat bars). Since it starts out with Sync unchecked, when you are ready to tie the Link session to the Pioneer beat grid, simply check the Sync checkbox in the Ableton Link section:

At this point the Link session will follow the master Pioneer player, until you change the Carabiner settings.

If you want the Ableton Link session to be a full participant on the Pioneer network, and able to become Tempo Master, choose Sync Mode  Full in the Carabiner window.

Once you successfully activate Full Sync Mode, the entire Ableton Link section is enabled, and you can have the Link session become Tempo Master for the Pioneer players by clicking the Master radio button in that section:

When Link is tempo master, any Ableton Link enabled software or hardware can control the Link session tempo, and any Pioneer players that are in Sync mode will follow along, aligning to the beats (or bars, if you have that option checked) of the Link timeline.

In this Sync Mode, the Link BPM becomes editable in this window as well. You can click on the arrows to nudge it up or down by 0.01 BPM at a time, or you can type a new tempo in the field and press Return to jump immediately to that tempo. This will affect both the Link session itself, and any Pioneer players that are in Sync mode.

The bottom section of the window lets you see and control which players are in Sync mode, and which is the Tempo Master.

Simply check or uncheck the Sync checkbox to adjust each player’s Sync state, or click the Master radio button of the player that you want to become the Tempo Master.

Beat Link’s implementation of the sync control protocol works in both directions. If the DJ causes another player to become Tempo Master, the Link session will gracefully give up that role. The checkboxes and radio buttons will update to reflect any changes made on the players themselves. And if there is a DJM mixer on the network, it can tell Beat Link to turn its own Sync on or off, or become Tempo Master, and Beat Link will obey.

If you would like to automatically connect to Carabiner and set up sync when you bring Beat Link Trigger online (this is especially useful now that BLT can automatically run Carabiner for you when you connect, but you can also do it if you are running your own custom build of Carabiner and can guarantee it is running before BLT goes online), you can accomplish this using the Came Online Expression, and there is an example of how to do this in the description of that expression.

The example shown in the Came Online Expression illustrates that the Carabiner Connection window is designed for convenient use by your custom expression code. Here is a list of functions that you can call.

In very special situations, for example when you want to synchronize with a set of Ableton tracks that have not been properly tempo marked or warped, but are all pretending to be at 120 BPM, you can tell Beat Link Trigger to ignore the actual tempo of the track that is playing on a CDJ, and adjust your fixed tempo value based on the current playback pitch.

To do this, use the Global Setup Expression to assign a value to the :use-fixed-sync-bpm global, like so:

Once you have done that, Beat Link Trigger will pretend that whatever track is playing has a native tempo of 120 beats per minute (or whatever value you have chosen). If the DJ plays it at a pitch of +5%, Beat Link Trigger will sync the Link session (or MIDI clock, which also supports this setting) to 126 BPM (which is 5% more than 120), regardless of the actual tempo of the track.

Don’t forget you have done this, or you will wonder why your sync is not working properly when you are trying to sync with tracks and systems that are properly beat gridded and tempo analyzed! To get back to normal, either remove the above line from your Global Setup Expression and quit and restart Beat Link Trigger, or edit the expression and replace that line with the following one, which undoes the setting immediately: