I wanted to put this in a broader category so it would get discussed more, and I am genuinely curious, but it is a bug, so I'll put it here.
A multitude of abilities and other things, like turret acquisitions, are playing incredibly loud sounds, no matter what volume I have SFX at in the Sound settings. The most reproducible instance of it is with the nexus explosion, and in fact this is probably the loudest instance as well. I know there were sound changes this patch, and my guess is the new system just isn't using my settings under SFX for everything considered SFX. I keep the master volume at one-hundred and crank up the Voice setting so that I can hear champions, since that is my favorite part, and that seems unaffected by the changes, as does the Announcer's voice. The issue is with everything classified as SFX, which I typically set at 50%. I tried moving that down to 25% and it turned down the volume of some stuff, but did nothing to negate the loudest sounds, like the nexus explosion. I have only started experiencing this bug on this patch, but I am fairly certain I encountered it on the PBE as well, although my settings on there are different so I didn't notice it as much. The bug never happened to SFX for my own champion's spells or abilities, but did for ally and enemy spells and abilities. I ran a Full Repair to see if my files were somehow corrupted and that did nothing for the issue. I also submitted a bug report with the link on the client, which gives a few more details.
Am I alone in this?