Hee hee, I thought this thread would be about "actual" live performances, and not recordings of them.
I had the opportunity years ago to see an Emerson Lake and Plamer Concert at the Ampitheather in Chicago. They had just come out with their Brain Salad Surgery Album.
The sound was in Quadraphonic Sound, with humungous stacks of JBL Monitors, and Sectional Horns in all four corners of the Ampitheather. Something like 2 Million dollars in speakers alone.
It was an awesome concert, and the large venue really was something with the sound shifting back, and forth, and going round, and round.
That was Karn Evil #9 in "real quad"! I remember coming home that evening, and played my "quad" system, which consisted of two Mac Amps, a Bose Quad Pre-Amp, and four JBL L-65 Speakers, for a short period. It was like listening to a little transistor radio. They're still on my top fav list of vintage rock groups. Mark