Though inspired by Seattle’s drone metal pioneers Earth, fellow Pacific Northwesterners sunn O))) long ago surpassed their mentors in artiness, theatricality, ambition, and, somehow, volume. After a series of fruitful collaborations and expansions, the band celebrates its 25th anniversary by returning to its core duo: guitarists Greg Anderson and Stephen O’Malley zero back in on the robed, befogged, and mesmerizing drone that’s always been the black heart of their distinctive sound. Former and future fellow travelers – singer/songwriter Jesse Sykes (the Sweet Hereafter), her guitarist Phil Wandscher (ex-Whiskeytown), and multi-instrumentalist Bill Herzog (ex-Citizen’s Utilities) – set the inscrutable scene first.