On my 22nd birthday, September 29, 1976 I gave myself the present of a 12 hour train ride to Boston to hear the the world premiere of Renga with Apartment House 1776.
I was backstage with Cage and he was beatific. He had a weaved wooden basket overflowing with mushrooms that he was passing out like a young girl passing out daisies. He asked if I wanted some, but my experience with mushrooms, up to that point, had been limited, and of the illegal variety, and I kindly thanked him and declined.
Cage The Mycologist
Musically, at 22, I loved Hendrix, Beethoven and Cage's music. But at the time, it was really only Beethoven's music, particularly his 3rd, 5th, 6th and 9th Symphonies that I had as a frame of reference for classical music repertoire.
Hendrix
What I heard coming from the stage was the most beautiful, obstreperous, cacophonous, most meaningful, completely out of control music I had ever heard. I had no idea that a symphony orchestra could sound that way. There were four singers singing very different songs simultaneously. There were different drummers drumming in different times, at the same time, and the whole orchestra, it so subtly appeared, seemed to be playing completely independent of each other (I couldn't help noticing that one of the double bass players had his car keys out and was 'playing' those.)
The audience reaction was strong and swift. People were leaving. Some were covering their ears. Some were booing, loudly. I literally stood up in my chair and applauded. A resplendent experience. A total musical triumph!