John Butler Trio performs on the "What" stage at the Bonnaroo Music and Arts festival.
John Butler Trio performs on the "What" stage at the Bonnaroo Music and Arts festival. Shantel Mitchell
John Butler spent his early 20s learning how to play the guitar using so-called "open tuning," in which the strings are tuned in such a way that intricate fretting is unnecessary; it's a technique employed by many slide guitarists, among others. Once he'd mastered his sound, Butler abandoned his dreams of becoming an art teacher and embarked on a new life as a busker in western Australia. With the John Butler Trio, he's become a best-selling roots-rock musician; after shuffling the band's lineup, he recorded its new album, April Uprising. Here, the band performs live at the Bonnaroo Music Festival in Manchester, Tenn.