All of Phil Elverum's Mount Eerie albums are massive and mysterious, but none more so than Sauna. His first new music since 2012's diptych of Ocean Roar and Clear Moon, Elverum trades the former's powerful tides, the latter's delicate reflections, and the alien vulnerability of the companion piece Pre-Human Ideas for a more holistic approach. Possibly even more meditative than its predecessors, on Sauna Elverum explores the transformation of fire, wood, water, and the self, literally and figuratively. Everything is insular: he shrouds his introspection in misty guitars and percussion and has internal conversations with his other selves (voiced by Allyson Foster and Ashley Eriksson). Even the loudest moments here, such as "Turmoil" and "Boat" -- which fuse his love of shoegaze and black metal -- feel gentler than some of the outbursts on his previous album, as though they were tempered by heat. Vast yet intimate, in some ways Sauna is the most like the Microphones album that gave Mount Eerie its name in the first place.