Avicii made his reverse Dylan-goes-electric move at the EDM-centric Ultra Fest, inviting bluegrass musicians onstage during his set. The crowd was baffled, but the Swede's debut album picks up on this Mumford & Synths sound for a set of folk, soul and addictive house beats. Dan Tyminski of Union Station sings the grand Appalachian stomper "Hey Brother," and Imagine Dragons penned "Heart Upon My Sleeve." True saves room for two funky disco jams featuring banging diva vocals from Audra Mae and Adam Lambert.Rollingstone