Hey everyone, I was just wondering if you could answer a question. Last night, the soundmen we were using did this thing while setting up in which they placed a microphone out on the floor (on a stand of course). For about 5 minutes, it sounded like a 747 was taking off through the mains. I think they were tuning something. It was neat, and I was just wondering what they were doing (forgot to ask them the purpose at the end of the night).