Hello Fregrin,
Do you have any software installed that might be affecting the sound at all?
Any software from the manufacturers or for streaming for example.
Ok, i managed to fix the issue! I tried to verify the game files but the issue persisted so i deleted my sounddata folder and verified the files again, this time uplay downloaded the files correctly and fixed the issue!
I did this also (delete and verify) and seems i was missing lots of sounds when i returned to the game after 3gb download, thanks for the info! Hopefully this is now fixed.