Someone mentioned a Clapton show from the Journeyman show. Saw one of those at the Hartford CC and while not loudest I've heard, the sound was extremely harsh and I had to leave well before the end.
Had 3rd row far left seats at the Beacon Theater for an Allman Bros. show in the 90's. We were right in front of a speaker stack on the stage and I couldn't hear a thing when the show ended. Good sound but really really loud.
I've been to over 100 Grateful Dead and Garcia Band shows and the sound was great at most of them. Sometimes it would take the sound guys a few songs to get things just exactly perfect but once they did it didn't get much better. Often extremely loud but the sound was so clean it rarely felt uncomfortable. And when Lesh's bass was dialed in it was heaven.
I've had pretty severe tinnitus for at least 40 years, mostly due to having a lot of ear infections and other issues when I was a kid. All the concerts probably haven't helped but I don't think they've made it much worse either. The brain is usually pretty good at blocking it out most of the time.