In between their viral covers, they’ve released three albums of original material and today marks the release of their fourth, which is aptly titled IV. Hailed as their best yet, Matthew, Chester, Alex and Leland’s latest offering presents 11 tracks of eclectic material that give a lesson in mood, and features contributions from producer-of-the-moment Kaytranada, Future Island’s Sam Herring and avant-garde saxophonist Colin Stetson, among others. We caught up with BBNG backstage at Barcelona-based music and technology festival Sónar to talk chasing saxophonists around the globe, words of wisdom from Ghostface and why Canadian producer Frank Dukes is an amazing mentor.