Watching this video, I noticed that when the group sings harmony, J.D. moves to the center and sings/plays fills into Tony’s microphone; Tony moves and sings/plays into two otherwise unused microphones; and Doyle moves to sing into a microphone closer to the center, losing the microphone for the mandolin chop:
My question is: Why didn’t they just put a vocal mic in front of J.D. and move Doyle’s vocal mic in front of Doyle, thereby eliminating the need for movement (and allowing for the amplification of the mandolin chop during the chorus)? Can they really monitor their harmonies that much better by being a little closer together, or is it for some other reason?