Grateful Dead Music Forum

greetings. i was poking around on archive and listened to some matrix recordings and it reminded me of dan healy of course. can anyone tell me what purpose the microphone mounted on the back of the foh board- it shuttled back and forth- left to right to left? anyone remember that?

I knew this. I think it had to do with the SIM (Source Independent Monitoring) system used to tune the Meyer system. I could be wrong.