In 68 I went to see Iron Butterfly, I went really early as soon as the tickets went on sale and I had a 5th row seat right in front of the "Leslie" of the organist.
In those days they didn't even have auditorium sound systems or even PA systems with the speakers mounted to the sides of the stage and high up like they do now, instead, every instrument had to have enough sound to fill the entire auditorium coming right from it's own amps on stage.
So this leslie with several thousand watts was only about 15 feet right in front of me and the sound was peaking right about where I sat.
I had to cover my ears and put my head down every time he cranked up the sound. The concert was much more pain than pleasure.