We're struggling with this issue a bit, as we are in front of the trombones, and they are seated about a foot and a half higher than we are. Thus, their bells are aimed directly at our ears. It's not that they play too loud, but that when they play we literally cannot hear anything but them.
What was strange is that nothing happened until I joined and began complaining about it!
We moved the trombones back a bit farther, so there was more distance between their bells and our heads! Actually, my colleagues (including the trombonists) say they had complained some time ago, asking for us all to be in one row, but were rebuffed by management. Apparently managements concerns were with how it all looked from the audience.
Unfortunately, this all makes my complaints look like I'm just being a pain in the a$$ to the stage managers -(e.g. "No one's complained before, why are you all of the sudden?"). Oh well. I'd rather be a pain in the a$$ than be deaf!