Final mix stereo image skewed

[uncle dunc]

I've had this recurring issue for years now. I suspected it was my mixer, but it's not.

I had been using a Yamaha 01V96 digital mixer, running DP tracks into 16 individual mixer channels via ADAT lightpipe, with the 01V96 lightpipe routed back into the third bank of my 2408 for the final mix. (The 2408 has 3 banks of ADAT lightpipe.) Every now and then, a particular project would produce a skewed stereo image on the stereo mix file, even though it was fine through the speakers. The only solution was to change the stereo channel on the 2408 that was accepting the mix send from the 01V96, or to change the port on the PCI card. (The Motu PCI card has 4 ports for the cable going to the 2408 box.)

A couple of years ago, I replaced the 2408 system with a Behringer X32 compact, using the same technique - sending the digital signal back into the DP project for the final mix, but the skewed stereo image on the mix file has randomly returned.

On a recent 5-song band project, I set up a template file and then copied it for each song before the session. Tracking and overdubs went fine. Now, getting ready to send rough mixes to the client, I'm getting a skewed stereo image, but it's different on each song. On one, the vocal is pushed way over to the right, on another, the vocal is moved away from center, but not to the extent of the other song. That's when it occurred to me, it's unlikely that two different digital mixers would be having the same random issue.

Today I tried running one of the songs through a new mixer scene, but that didn't fix the stereo image. Then I tried opening a different DP project and running it through the same mixer scene as the skewed stereo mix and the mix was fine. That means my DP files are getting corrupted while I'm working on them, or maybe the template file was corrupt. Is this a known issue?

Granted, I need to upgrade my old Mac Pro from OS 10.12 to 10.14 (I'm wary of losing my old 32 bit plugins) and from DP 10 to DP 11, but I'm in the middle of several projects. Any suggestions? My workaround at the moment is to send an analog signal back into DP for the final mix, which works, but it's not an ideal solution.

[bayswater]

Very odd. I once used a 2408, an 828 and a Tascam DA tape deck all connected via ADAT. The signal path went in and out of DP via the 828. The only issue I remember is that there were sometimes timing errors on channel 7 of one of the ADAT connections that seemed to be happening with the 2408. It’s not obvious how that would lead to a change in the stereo image, but I guess it’s possible.

Can you reproduce this consistently? If so, perhaps it is possible to capture and monitor the audio at each stage of the signal path and find exactly where it happens.

[EMRR]

I’ve had this pop up randomly, and i currently have a tech whatever going with MOTU about it.

In my case it’s analog out through processing and back in, a bounce will always be correct.

No real answers yet, but bypassing all plugins in preferences solves it. Bypassing, even deleting, all plugs manually changes nothing.

i can change interface input pair when it happens and it goes away. But it acts and looks like a playback problem. It’s nonsensical and eludes simple answers. Other chunks in the same project with same routing will be fine. Swapping L/R doesn’t change the skew.
Mix out is always fine but captured mix is skewed.

I used to always think it was a cable or patchbay problem but have definitely dismissed that option. I’ve methodically been through the entire list of possibilities, and the answer seems to be some sort of chunk corruption. I’ve deleted and rebuilt the bus outs and the capture track to no avail.