Since doom metal has its share of moss-bearded dudes blasting minor-chord riffs through Orange amps, Black Math Horseman is a welcome change. Wyllt, the debut from the female-fronted Los Angeles quartet, journeys past the boundaries of textbook stoner-rock and into the sprawling poppy fields of ambient psychedelic sludge. Sera Timms’ ghostly voice both complements and contrasts the dynamics of the opening song, “Tyrant.” In the softer verses, her breathy coos hover over the quietly pulsing music like a wisp of smoke. But as the verses volcanically erupt, that same voice takes on the phantasmal character of a troubled spirit. Producer Scott Reeder of Kyuss is a perfect tour guide for taking listeners straight into the eye of the storm, as best exemplified during the disturbingly tranquil moments in “Torment of the Metals.” But at the drop of a hat, his studio wizardry transports us to the heart of sonic maelstroms—“Deerslayer” is easily the most turbulent tune here. Black Math Horseman closes out Wyllt with the 11-minute epic “Bird of All Faiths and None/Bell from Madrone.”