Most of the microphones used for the Grammys are wireless. Dave is in charge of assigning microphones, making sure that no two frequencies interact with each other, and preventing the use of unauthorized frequencies around the arena. It's no easy task. Last year, Bono walked on stage to accept an award with his Blackberry in his pocket, which wreaked havoc on the sound system. [Courtesy of The Recording Academy, Photograph by Alexandra Wyman/WireImage (c) 2007.]