FabFilter

Hello,

We are a post studio who works with MB and L2 on multichannel folders and aux tracks (from 5.1 to 7.1.2).
We noticed a huge change in system delay when deactivating MB and L2 because it was very difficult to mix at 15k samples of system delay ; getting rid of (almost) all instances of MB and changing every L2 to Avid's Pro Limiter lowered the system delay to 4k samples. The session is not very huge (around 600 voices, MB and L2 were on +/-20 tracks each).

I then tested in an empty session with 60 mono audio tracks and 10 5.1 audio tracks :
- with a Q3 on every insert A of every track, the system delay is at 0 samples.
- same but with MB : 960 samples
- L2 : 3115 samples
The mono tracks alone don't generate delay, deactivating them doesn't change anything to the system delay. The problem seems to be with multichannel tracks (it doesn't change when the L2 is in multi-mono or multichannel mode).
All plugins are up to date from the last bundle. No oversampling. PT buffer size is at 1024 samples.

Mixing rig : Mac Studio M1 Ultra 128GB, Ventura 13.6.9, PT Ultimate 2024.6, HDX w/ Hybrid Engine (only HDX has the same problem)
Testing rig : Mac Mini 2018 3,2 GHz 6-Core Intel Core i7 64GB, Monterey 12.7.5, PT Ultimate 2024.6, native

Are we doing something wrong ? Is a fix possible ?

Thank you for your help,

Best regards,

Jeanne