Still finding this issue unfortunately. Can't hear engine and tires well enough over the crowd, and it's really disturbing... Sounds just like the replay from video posted to YT on every lap. PC - Steam - V1.10 - Default audio settings (only turned off Jeff) - Driving the esports event at monza in example. Video: https://youtu.be/XgMm3DoCvp8
Edit: Quitting the game and turning it on again fixed the issue. Clearly a bug, but would still like to turn crowds completely off (or have a slider).