Prime 4+ - Ableton Link desync issue

Engine DJ Hardware Standalone Controllers
1

Hey all,

I have encountered a bug regarding the Ableton Link feature. I have captured the issue (twice) in a YouTube video: https://www.youtube.com/watch?v=rQPPws2tj3c

I have several clients in an Ableton Link session:

  • Ableton Live 12 Suite
  • Denon DJ Prime 4+
  • “Link to MIDI” app running on an iPad 7th gen, connected to this lighting to USB adapter - USB cable to my livelooper, a BOSS RC-505 MK2
  • Pangolin Quickshow (lasershow management, following the beat)
  • Custom Python script joining the Link session

The only way I can sync my Denon DJ is by using the Sync button. For one track, this works fine. I cannot reproduce the bug with just one track.

However, when I have 2 synced tracks playing at the same time, both synced, and I change the tempo of the latest track I synced, there is a big chance that the BPM will be slightly different on all clients, except the Denon DJ.

In the video footage you can see that after changing the tempo, the Denon DJ things the Ableton Link BPM is 153.64, while the rest of the devices thing it’s 153.53. Because I was moving the tempo fader upwards, it seems Denon DJ is not sending all the data towards the network but thinks it did. Here are the noticable timestamps from the YouTube video, for convenience:

  • 00:00 Synced to 120 BPM
  • 00:08 Moving 1 of the tempo sliders upwards (not the main track)
  • 00:10 Desynced (153.65 vs 153.53)
  • 00:20 Moving tempo slider again, synced again (121.34 BPM)
  • 00:33 Moving the tempo slider downwards causing a desync (99.80 vs 100.10)

So in this video I was able to reproduce it almost immediately, twice in a row. The second time I was going down tempo, and again, you see that the Denon thinks it had sent everything, because itself is in a lower tempo than the rest of the Ableton Link session.

I had a Denon DJ SC Live 4 before, running 4.3.2. I had the same experience with Ableton Link going out of sync, but wasn’t able to isolate the problem. Now that I have a Prime 4+, I am able to. My Prime 4+ is currently running firmware 4.2.0.

I already filed a support ticket @ Denon support, but just wanted to mention this to y’all. I found one topic similar to this issue, which might nave the same root cause: Prime 4 Ableton Link - tempo drift without beatgrid snapping?

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I found that the Ableton Link ‘methodology’ doesn’t match well with DJ’ing. What I mean is that instead of the Prime 4+ being able to maintain “Master” status, or the Prime 4+ itself holding some priority, the Prime 4+ doesn’t establish itself as the ‘first’ or ‘longest’ client in the Ableton Link network, and instead each track being played is handled separately.

So while you can turn on Sync and mix Deck 2 into Deck 1, and then Deck 1 into Deck 2, and the first/longest running track will be the ‘master’ track, when you add Ableton Link, you may be able to mix Deck 2 into Deck 1, but when you load a new track into Deck 1, your laptop or other device then becomes the lead for Ableton Link.

While the goal of Ableton Link is to have all devices be able to govern BPM, and changes in tempo, this idea is faulty when you include a DJ controller, as you likely want to keep it as the lead.

It can be confusing because you can find documentation about Ableton Link that clearly says there is a ‘master’ device, while there are other documents suggesting Ableton Link is more ‘democratic’. It seems as though both of these are true, depending if you have “Full” or “Passive” mode enabled on devices.

I believe the solution (though I haven’t figured out how to accomplish this…) is to have the Prime 4+ in “Full” mode, while having any other device, including your Ableton Live on your Laptop, run in “Passive” mode.

That being said, when I use Ableton Link on the Prime 4+, I touch the BPM of the track to manually set it as “master” track. This solves a lot of the odd behavior. I believe that Denon should re-evaluate their approach and do what they can to preserve the normal “Longest track is master” that is used for normal Sync, and have an option to carry over that behavior when using Ableton Link.

Until then, it’s too finicky for me.

Edit: I see that Ableton Live has “Tempo Follower” setting for Ableton Link. I’d prefer the controller to just state the BPM and for Ableton Live to follow, but it seems like a workaround.

You might encounter situations where a Link connection or MIDI Clock are not available. Or, sometimes you might prefer not to use a rigid, computer-generated clock. For example, you might like Live’s tempo to follow the natural push and pull of a drummer in your band, or you might be trying to synchronize to a set of turntables during a DJ performance. This is where Tempo Follower comes in. Tempo Follower analyzes an incoming audio signal in real-time and interprets its tempo, allowing Live to follow along and keep in time.

To set an external audio input as a source for Tempo Follower, first open Live’s Link, Tempo & MIDI Settings. In the Tempo Follower section, set the Input Channel (Ext. In) to the input on your audio interface that is connected to the source you wish to follow. For a drum kit, this might be a dedicated overhead microphone. For turntables, you might choose to use a record output or effects loop from a DJ mixer. Note that while Tempo Follower’s algorithm is optimized for use with audio signals that have a clear rhythm, you can also be creative and experiment with different sources.

ref: Synchronizing with Link, Tempo Follower, and MIDI — Ableton Reference Manual Version 12 | Ableton

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@meLon_Cucumis thanks for your extensive reply!

My workaround is to set up Ableton Link before even playing the first track. From that point everything stays in sync. As long as the BPM is turned green, I know it will change the Ableton Link sync when I touch the tempo fader.

It’s funny you mention the master/slave situation. Because I think I may have figured out the root cause of my initial bug report and it had to do with that.

One of the Ableton Link clients I have is QuickShow. This laser controller application has “In” and “Out” configurables on Ableton Link:

image
image242×551 11.1 KB

When I hover the “Out” button it states “In and Out may cause feedback”.

So I suspect it was my own fault. Looking back I am pretty sure I got both In & Out enabled.

So I did a few sessions with just “In” enabled and Ableton Link stayed in sync perfectly!

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