Musicians and club owners quickly learned that acoustically live rooms could dramatically detract from a performance.
Musical venues were draped with curtains and padded seats in an effort to reduce the room reflections.
Of course, non-electric sources like the human voice and brass instruments required amplification to keep up with the amplified sources.
Thus, the sound reinforcement system was the natural solution to the problem.
Before long, everything was electronically amplified, and a band could play at virtually any sound level and for an audience of almost any size.
There were obvious commercial advantages to amplified music. A chamber orchestra can only play to a few hundred people, and the best concert halls could hold less than two thousand. A larger hall produced reflections that were too late to provide the proper support.
On the other hand, an electronically amplified band could play to packed stadiums of ticket buyers. After the show, the sound system could be loaded into a truck and moved to the next city on the tour.
The only way to get consistent sound quality was to make the production independent of the room acoustics - exactly the opposite objective of traditional music.
So it’s not surprising that both viewpoints have carried forward into modern assembly spaces. The formally trained musicians and musical directors see the space as an amplification system for the organ, choir, and acoustical instruments.
They want a live space with carefully sculpted reflection support, including an orchestra shell and reflecting clouds over the audience.
The contemporary music camp wants an acoustically dead space where the sole source of sound are the amplifiers and sound reinforcement system.
A sound system is in control of everything - for better for for worse.
The operator plays a role similar in ways to the orchestra conductor, with the musicians playing and the operator determining the relative balance between the instruments as they are amplified through the reinforcement loudspeakers.
Whereas classical musicians sit in close proximity to hear each other, a contemporary band uses foldback (stage monitoring) to hear what is going on, again under the control of a technician. (Some modern in-ear monitoring systems offer control to the musicians.)