S1, E4: Dave Grohl chats with Terry Lickona, executive producer of TV's 'Austin City Limits.' Dave delves into the roots of the Austin music scene: from the blues of Jimmie Vaughan, to the psychedelic rock pioneered by Roky Erickson's 13th Floor Elevators, to punk bands Scratch Acid and the Big Boys. He also discusses the impact of commercialization with guitarist Gary Clark, Jr.