Eric Clapton concert in the late 70s, it was ear bleeding loud that many left the concert to stand in the outer entrance hall area, and after Cocaine 1/2 of the 20,000 left the show which I thought odd, they stayed to hear that song I guess. Even earplugs sounded loud. My ears rang for 2 days after the concert. That back even then was not at all an enjoyable concert. Muddy Waters Opened for him, so that was cool and the highlight.