PT 12 ADC Help


Hello from New Orleans everyone!  I’m really happy this board is back.

I have a technical question with pro tools that I cannot seem to quite figure out. These are problems with large “God” Mix sessions.  +400 Voices on an HDX system.

A large portion of this question I copied from my Avid Forum post.

I am having some trouble with PT12 and using delay compensation when mixing and printing(destructive punch) all within the same session.

Searches on the avid DUC presented solutions to some of the problems. All of my record tracks I have disabled the low latency monitoring. (Ctrl-Command-click the track compensation indicator in the mix window) This allowed my stems to hit my 5.1 printmaster correctly, all looked good.

Now that I printed and am QCing things I am seeing a new problem.

My units bus and route to various stems. Those stems bus to a 5.1 Printmaster and are double bussed to 5.1 > 2.0 fold downs using dolby surcode. This gives us our stereo dialog, music, and fx stems.

The 2.0 crash downs are bussed to an output.

The 5.1 Printmaster is routed to our monitor system and also double bussed to a 5.1>2.0 fold down.

All of the stems delay compensate correctly and match the units.
The 5.1 print master compensates correctly, matching stems and units.
The 2.0 print master compensates correctly and matches.

The FX Crashdown, which is comprised of FX(5.1), Foley(LCR), and group(5.0) all crash down and compensate correctly – matching up to the stems and units.

The MX Crashdown, which is comprised of only the 5.1 Music folded down compensates correctly.

The Dialog Crashdown, which is comprised of 3 mono dialog stems and a 5.0 dialog stem, is where funky things are happening and not correctly compensating.

The entire DX crash down does not properly compensate. I can quickly tell by where my head and tail pops are. Easy fix if it was a global difference, but even within it, the DX A, B, C and D stems are not hitting the crash at the correct time. So if I slip it to match my DX A stem, it matches my B stem but does not match my C or D stem.

What is odd, is that they are hitting the 5.1 print master correctly, but not the 2nd bus that they are being sent to, which is where that fold down happens.


I have tried using a send instead of double bussing.  Same problem.  Anyone know how/where adc is calculated and may know how to best optimize for this.

It was recommended that I modify pick off points and where I am monitoring from but I need to be able to monitor from my 5.1 printmaster record track.  We use a Colin broad/PEC-Direct here and need that to remain as part of the setup.


How are the mono and 5.0 stems being patched into the crashdown? Are the mono stems being sent directly into the 5.0 bus and panned center, or are they hard-patched into the Center of the 5.0 bus using subpaths? If it’s the second, Pro Tools can sometimes have issues compensating delays between the subpaths of busses, which would lead to the mono stems not lining up correctly with the 5.0 or even each other. Try routing the mono stems the 5.0 DX Crashdown bus panned to the center and see if this helps.


I was reading a lot about adc problems recently and something that apparently causes major adc problems is using dummy busses. All busses need to go to a physical output to avoid adc loopback issues which will cause adc to incorrectly compensate. I’ve since stopped using a dummy bus and instead use a digital out that goes nowhere as my ‘null’ output.

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