MIDI sync between 2 GPs on a network

I’m hoping someone can help me out with this MIDI sync issue I’m having. I have 2 Macs in my live setup, both running GP. On one Mac, GP runs the backing tracks, the other GP is my keyboard rig, which also has a MIDI player, as well as sequencers that need to be in sync with the tempo. The machines are connected via an ethernet network, and I am using the Mac’s MIDI network setup. I have Ableton Link enabled. I did a test where I turned the metronome on on both GPs and pushed play. The machines do not stay in sync at all. I have the time information set to the same BPM for each GP Rackspace. Naturally, each machine has its own audio interface hardware. I’m not really sure where to go from here.

I haven’t used this feature, but the GP instance on one of the Macs must be set to sync to the other. Double-click on a rackspace name in the rackspace list. Check sync with external clock. Other users can offer more advice.

Actually the option to “Sync with external clock” and “Set time information” should be unchecked for your situation @stansongman

If you enable “Link” and you actually see “Link [1]” when you run both instances - the tempo will be synched properly. If you want to sync Start/Stop in both instances - you will have to enable the option to “Sync Start/Stop With Ableton Link” under General Options.

Obviously - make sure that your firewall is NOT blocking the network traffic .

Did you enable “LINK”?

@stansongman - just to clarify… if your two GPs connected via link - your Link button on both will look like this

Screen Shot 2020-10-29 at 7.44.30 AM

If it kist says “Link” without the number - you are either not on the same network or there is a firewall blocking the connection between the two instances.

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Thanks folks! Yes, I am using Link and that works fine. I’m doing more experiments here to see what exactly is going on here. I was mistaken - the metronome from both GPs are in sync when I hit Play. But, the audio tracks from the file player are not in sync with the metronome. I know they are right though, because I created and bounced them out from Logic myself, they are fixed to a tempo and quantized. I do set time information for all the rackspaces, because I’m running a Midi player and sequencer plugins that have to be tempo-synced as well.

It’s weird to me that the metronomes would be in sync, but the file player is not. Maybe it is some network latency thing? I’m creating a couple of test scenarios right now, I’ll let you know what I learn.

We do not time-stretch audio which means that a minute change in tempo will really not work for you.
If you do “set time information” in rackspaces - when you switch to that rackspace - the tempo will change everywhere. Rackspaces ALWAYS use the tempo that’s displayed.

“Set time information” does not mean “USE time information” - it means “Override the current tempo with this tempo”

Only MIDI and /start/stop can be properly synced this way on two computers. You’d have to use something else that does audio time stretching to sync audio playback properly.