Back in the late '70s/early '80s I ran the entertainment department of a theme park. Sound reinforcement was only just beginning to become based on real science and engineering, and I had difficulty getting budget approval for the equipment we really needed.
Fortunately, I had a small team of part-time, passionate college students and recent grads who were both knowledgeable and also really enjoyed making the most of what we could get, which was often used gear.
Our main stage featured four A7s, and we had great success upgrading them with TAD TD-2001s and TD-4001s for the highs.  Those TADs were just amazing at the time...nothing else came close.
We also had a large indoor dance floor that featured either 8 or 10 A7s (I don't remember which), lined up along the left and right perimeter of the floor, facing inward towards the center. It was, uh, "immersive."
Many bands that came to play at either the outdoor stage or the dance hall were skeptical when they first saw the A7s. They quickly realized, however, that the fidelity of our systems far outweighed what they were used to.