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Pro Tools bus/bed automation sync issues

Hey all, I've posted this on the Avid DUC also - I suspect this is a Pro Tools issue, not a DAPS issue, but posting here also to reach out to others who might be having the same problems.

I found a cracker this week - tracks that are assigned to a bus AND a Dolby Object appear to have a problem with the synchronization of automation. Look closely at the attached screen shot.

The first 3 tracks contain the exact same clips & volume automation (with a recurring 10dB drop in volume automation displayed on screen) - however the panning position and bus/object assignments are different.

The first track (FX D 1) is panned hard left and is a dual bus/object track; assigned to the bus.

The second track (FX D 2) is panned centre and is dual bus/object track; assigned to an object

The third track (FX D 11) is panned hard right and is ONLY assigned to a bus

The following 3 tracks (FX D 19, 20 & 21) are a recording from the Dolby Atmos Production Suite, that has been imported back into the session. You can clearly see that the timing of the volume automation is a long way out of sync, even though the audio itself is in sync - it is 6 frames early (24fps).

I've only just noticed this problem recently - but I'm pretty sure it didn't exist in the previous release of Pro Tools (2019.10). I'd also guess that the problem is with Pro Tools, as it exhibits itself before audio reaches the renderer.

Setup details as follows:

2019.12 Ultimate (Native)
Dolby Atmos Production Suite 3.4
Dolby Audio Bridge from PT to DAPS
Non Avid (Metric Halo 2882) audio interface from DAPS to monitoring
MacOS 10.13.6
iMac 17,1 (late 2015), 4.2GHz i7, 40GB RAM

Anybody having similar issues?

Hi James,

Interesting.   We're taking a look to see if we can reproduce this.  As resources are spread thin around people working from home this might take a bit but I'll get back to you as soon as I hear something definitive and try to test myself as well.



Thanks Adam - I certainly understand that resources are thin at the moment.

My 'workaround' has been to disable/remove the object assignment in the session - definitely not ideal. Interestingly there hasn't been any replies on the Avid forum...

Looking forward to hearing more

Hi James, 

Our QA guys haven't been able to replicate this issue thus far.   Can you reply and attach the Pro Tools session in question.   You should have separately received an invitation to a box folder if you are willing to upload the session folder including audio.   



Hi Adam, thanks for your collective efforts thus far. The session is quite large, and also for a large commercial project - not sure it's practical nor ethical for me to upload it to you. BUT, I will try and replicate it myself in a dummy session, and assuming that the problem persists I will most certainly send it your way. I'm not in the studio tomorrow, so it'll come at some point on Thursday.

Thanks again...

Hi James,  Yes of course I should have added if you had permission to upload it for testing purposes.   I didn't mean to imply otherwise.    Cool.  If you can replicate with another session we'd like to take a look later in the week.   Best,  Adam

Hi there Adam - had to pop into the studio for something else so made up the dummy session for you. I have uploaded it to the box folder for you. The session is the same session I've been working with, but with no media (clips are still on the timeline) except for the pink noise that I've used to demonstrate the problem at 00:45:00:00

An interesting development: as mentioned, my workaround was to remove the object assignments and work simply 'in-the-box'. In order to demonstrate this problem however I had to re-assign tracks to objects. Pro Tools kept bringing up a message in the I/O window when trying to assign objects to outputs that an assignment was already made and that I couldn't proceed (can't remember the specific wording, sorry), so I deleted all of the assigned outputs in the I/O page and re assigned from scratch. After doing this, the problem went away.

However, I then opened an older saved version of the project to test, and the problem came back again. This is the session that I've uploaded to you.

So, I guess I've demonstrated that a) there is a problem, b) there is a solution/fix & c) that the problem re-curs and is somehow persistent with a session, not system wide

I'd be very interested to learn if you find anything further



Hi James, 

Can you confirm for me that the session (with the problem) had automation (toggle track from object to bed) written in it. And/or if you were writing the fader automation whilst recording the master?

Thank you


Thank you for your reply Fin.

yes - automation toggle from object to bed - quite a lot of it

no - never writing automation whilst a master was recorded.

It's important to point out that I could hear this sync issue on playback whilst the renderer was set to 'input'. It was not limited to a specific track, status of the renderer, nor the automation write/read mode. Always, if a track had a dual assignment (object + bed) then the automation would be out of sync when the track was assigned to the bed. The automation went back in sync when the track was toggled to an object

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