By Emmylou Harris, Buddy Miller, Mavis Staples, Shawn Colvin, The Milk Carton Kids, Chris Hillman, Herb Pedersen, Holly Williams, Chris Coleman, Trampled by Turtles, Lucinda Williams, Rodney Crowell, Lee Ann Womack, John Starling, Daniel Lanois, Iron & Wine, Shovels & Rope, Mary Chapin Carpenter, Vince Gill, Patty Griffin, Conor Oberst, Martina McBride, Sheryl Crow, Kris Kristofferson, Alison Krauss, Steve Earle, Sara Watkins