There’s something special about live music. But when you’re brought into a musician’s preparation process prior to his or her show, it’s another level of extraordinary. It’s like you were personally invited and led by the hand to some intimate thing you weren’t supposed to be a part of. Here’s Wilco, Nick Lowe, and gospel singer Mavis Staples rehearsing “The Weight” (originally by The Band) in the make-up room back in December at the Civic Opera House in Chicago.