We ran into virtualization issues when upgrading from FMOD 02.03.05 to 02.03.06 or 02.03.07 in Unreal Engine 5.5. I managed to isolate the problem in a separate project and linked the video below.
The problem:
In FMOD 02.03.06 or higher, voices are not de-virtualized when the output in an event isn’t routed through it’s master channel after the spatialized, but through return channels into the mixer hierarchy instead. We have specific use cases where we use similar routing setups. If the signal is routed directly through the master of the event, the voices in engine are properly de-virtualized.
In the video below I show the problem isolated in a test project. In the second part of the video I downgrade back to 02.03.05, re-import the associated integration files and rebuild the banks, and the problem doesn’t occur anymore.
We switched back to FMOD 02.03.05 to solve this issue, even though this version is officially still an early access version. It would be great if it can be addressed in future FMOD versions.
If there are more questions, please let me know.
Video showcasing the problem: https://youtu.be/GA7g8OrBFDI?si=TMDr9BpAEIMafai_
