In Look, I Made a Hat, the second volume of his collected lyrics and attendant observations on theater, Stephen Sondheim writes:
What bothers me [about amplification] is the softening effect it has on the audience’s concentration. [S]itting in those ceiling-scraping seats, hearing an orchestra hundreds of feet away, and squinting at Mary Martin’s face, which was the size of a dime, we had to concentrate. Mary Martin had a small, coy voice, and in order to hear her, we had to lean vertiginously forward. None of the luxury of sitting back and letting the show come to us – we had to lean into it. The concentration required was so great that we had to shut out the real world, and in so doing we became participants in the experience, all of which made it easy to suspend disbelief and enter another world; and the more of that in the theater, the better. With the advent of amplification, ears became lazy and audiences now tend to visit rather than enter.
Sondheim nails it here. I long ago stopped enjoying the act of seeing musicals in the theater (though I still have a great love of the works themselves), and amplification was a big reason why. Even when the amplification is done well, it puts you at a remove from the performance, not much better than sitting back in your sofa and watching it on television.
I’ve experienced this in my performances with the Martha Graham Dance Company as well. When we perform with live music, we are often in halls which are larger than the ones the works were conceived for. Appalachian Spring, for example, was written for 13 instruments and was premiered in a hall which seats 500; we are now frequently asked to perform it with the same size orchestra in a hall 3–4 times as large. So we occasionally do a little judicious sound reinforcement, to make sure that the sound reaches the entire audience. I admit that I’ve come to accept this as a necessary evil when the size of the house requires it, and so long as the primary impression remains an acoustic one.
But I have sometimes been asked by dance personnel to goose the amplification higher than that (or sometimes just to have the orchestra play certain sections louder). That part is too soft, they say; it’s hard for the audience to hear. My response is that it’s soft because Copland (or Barber, or whoever) wrote it soft; it’s a feature, not a bug. These composers knew what they were doing and what effect their music would have, and Graham knew what the music sounded like when she choreographed to it. They wanted to draw the audience into the world of the piece, not just lean them back comfortably in their seats.