Few bands express the experimental in metal like Zeal & Ardor, the project started by Swiss American Manuel Gagneux in 2014. No other headbangers have dared to marry black metal and electronics with ritualistic chants inspired by African-American spirituals and the blues. The result is an emotional sound veering between haunted invocations lined with icy tremolo-picking (“Come on Down”) and meditations that pour gritty howls and muddy distortion over funeral-procession beats (“Gravedigger's Chant”). Zeal & Ardor may sound like the devil incarnate, but as the gospel-kissed “Built on Ashes” shows, they can also achieve an uplifting catharsis.