I am reviving this feature request because the reason for closure was absolutely stupid.
I have been walking around and someone who added a firearm to world set the volume to ear-bleeding levels of noise, which some are okay with and others are not. At this point, I don't give a single flying f*** about immersion; I care about lowering sounds which are louder than people when I'm trying to listen!
So how do you do this? Just have a GLOBAL volume slider for any sounds played like you have the GLOBAL volume slider for people! Every other system in the known universe has a volume slider for sound effects, and somehow High Fidelity feels immersion is more important than realizing how people perceive sound is also different!