Line array systems came out when I was in my mid 20s. The first company that I know to introduce them was Executone. I worked for that company, installing these systems in large theaters and churches in Maryland, Virginia and DC. It was a dangerous job, mainly because the sound columns were primarily installed in the corners of the venue near the ceiling and they were arched so they would face slightly downward. And, in the center of the room, hanging from the ceiling, was a monster sub system that consisted of 4 25-inch subs in a heavy, wooden enclosure. Let me tell you, that was no picnic to hang that baby. I'm guessing the weight was pretty close to 200 pounds. And, we were often working, without safety lines, 50 to 60 feet above the floor. I was pretty young and dumb back then, but Carol wasn't. She made sure I had a big accidental death policy.
Back then, the early 1960s, I was very impressed with the overall sound quality that we enjoyed in the theaters. It was magnificent to say the least, and there was no band that could duplicate it. IMO, the big difference was the vertical array sound columns that made the difference.
Gary