That's a good point. When I saw the robotic symphony, I thought it was pretty ridiculous, because you don't need separate speakers to play the sounds of differ

That's a good point. When I saw the robotic symphony, I thought it was pretty ridiculous, because you don't need separate speakers to play the sounds of different instruments. But a normal person in 1900 wouldn't have understood this from a picture, and if they saw a picture of a normal rock concert today, they wouldn't know what it was or how anyone could hear the instruments (though they'd recognize the drums and guitars as such).