I wore that 8 track tape out (Triology). I've always been a hardcore fan of ELP. Actually got some albums of "Nice", the band K. Emerson was in before ELP. Never seen a better keybord/synthesizer player. Rick Wakeman (Yes) was top notch but didn't have nothing on K. Emerson.
I liked the above post about the quad system much less 8-tracks.
I still have a quad stereo system with a quad 8 track player and wore out or repaired many of those cartridges. Never had a 4 channel ELP tape though.
Not sure if I saw ELP at philla or hershey in the early 80's but it was a cool show.
Roger Waters had a quad set up that was pretty cool.
I think Another brick in the wall starts with the helicopter.
People were looking in the sky thinking a heli was going to land in the audience.