I can only speak for the FB4, but the fans arent that loud. If nobody is playing music, you will hear your fan very faintly. If they are scraping the violins at the time, you won'thear your fans..
I did some patching to FB4 at home yesterday and felt that fan at the back of console is quite noisy. After Hog 3 it was disturbingly loud. I would not take FB4 to audience in classical music concert, there is always some parts that are totally silent. Of cource I do not know how Roadhog 4 is like but would go to listen it first.
