Side Chain Delay Compensation doesn't work properly

[styrmir]

Hi,
I am setting up a template and I need to use the key input on few compressors.
I found out that they don't sound the same when they are compressing the input signal or the signal from the side chain, even though it's the same signal at the same level.

I've been doing some null tests and it's pretty obvious. The difference seems to be the delay compensation (it's not going over the limit), and it doesn't change anything when I toggle the "Compensate Side Chains" on and off in the preferences.

The compressors are on master faders (to compress before the aux return cause I need to print the auxes with the compressor on) I just read that there is something different with the master fader ADC but I don't get why/how it's different?
This is better (but does not null, I still have to find out what's different) when I put another aux in the middle to insert the compressor, but the signal flow will get ridiculous pretty quickly if I need to make a new bus just to insert a compressor. And there is still no audible difference when I toggle the Side Chain ADC.

Why doesn't it change anything? I've tried this both using Rosetta and Native, and with different playback engines, still can't figure out why it can't compensate properly, any ideas?

thanks,
Styrmir

[Darryl Ramm]

Master faders are not compensated, by design, that's where you can throw all the high-latency nonsense plugins and not have ADC waste it's efforts trying to compensate stuff.

(and 2023.3 broke behaviors here, I think it's all been put back to normal. Not at a computer where I can check that)

[styrmir]

I don't mind that the Master Fader Delay is not compensated for, that's not really the problem. The problem is that the Side Chain signal is not arriving at the same time as the input signal. Shouldn't that be possible even though the output isn't compensated?

[Darryl Ramm]

Do a quick test. If you see this only on master faders then you know the cause.

[styrmir]

It looks like you're right, the master fader is the cause.
But isn't it a bug? Would you say that this is supposed to be this way?

[Darryl Ramm]

It is this way, I would not say it is a bug. Many users would likely assume it will not work and/or just shy away from any plugins on master faders… except worse case high latency mastering plugins. In my case I could not check, so it was just a guess. And just changing this might break existing sessions where they manually compensate stuff here… as Avid had found in the past (OK they can disable side chain comp but you still might break some sessions with side chains used on other tracks with ADC and on master faders with manual compensation). And potentially subtly breaking delay comp things with folks who have carefully crafted things to work would not be good, which then leaves turning this behavior on as an option... but by then it's just all getting too complex.

There are unfortunately much more critical real bugs with delay compensation and latency/timing corrections in Pro Tools that need to be addressed by Avid.

[irispill]

Hello all, I have the same issue but not having anything to do with a master fader. As an example, I need to key the bass from the kick track using FabFilter Pro G. Depending on the session, monitoring the sidechain key input on the bass track you will hear quite obviously that the key input and the actual kick are not synced. Sometimes the siedchain is way ahead of the kick track and other times behind. Lookahead on the FF ProG maxes out at 10ms and is usually of no help in this situation. Any advice would be very helpful. Both tracks in these cases are running Virtual Instruments and otherwise generally behave as regards delay compensation.

7,1 2019 Mac Pro Running OS Ventura 13.6 / 16 Core 3.2G / 384G Ram, 2TB NVMe System, Session and Library drives. PT 2023.9 / HDX1 / HD i/o 8x8x8 / UAD Octo Card.

[Darryl Ramm]

Since your problem is nothing to do with using a master fader then its not really related to this thread at all. Which really ought to have been closed as solved. It would have probably been better if you had created a new thread for your problem, you are likely going to have to troubleshoot what is going on here, starting with describing what the ADC delay data is showing you, maybe tear down the session to as simple as reproducible and show the signal routing in screenshots or share share that session. Explain what you have tried, does the problem happen HDX, hybrid or full native (using the Mac's inbuilt I/O if necessary)? etc.