Say this about Sylvan Esso: The band knows how to make an entrance. Following 2014's eponymous debut-introducing "Hey Mami," the North Carolina duo returns on April's What Now (Loma Vista) with the simply, perfectly titled "Sound." A distorted tone, finger-painting a rudimentary, fainting-couch refrain, slowly fades out to the background as a female vocal emerges in the foreground, gradually taking its place in crystal-clear a cappella. That voice belongs to Amelia Meath, the former Mountain Man harmonizer who has preserved her way with precise, judicious melody but replaced that band's spare and sisterly campfire folk with gleamingly hypnotic pop. The reference points gesture in unison toward Sweden, a twin hotbed of death metal and dance music: Springboard "The Glow" recalls little-heard fever-dreamer Loney Dear; synth parfait "Die Young" plays a naked game of ping-pong with prime Little Dragon; and spastic centerpiece "Kick Jump Twist" is totally in control and everywhere at once like young Robyn. In July, Meath and partner Nick Sanborn expanded their ranks, inviting friends from familial outfits (Mountain Man, Megafaun, Mountain Goats, Hiss Golden Messenger) to reimagine What Now as a full-band visual EP. That "record," titled Echo Mountain Sessions after its studio birthplace, is even more arresting, thanks largely to Jenn Wasner, who floats from bass to keys as effortlessly as she did from her main band, Wye Oak, to her side-project, opening act Flock of Dimes. As the latter, Wasner has released an eclipsing debut, If You See Me, Say Yes (Partisan), and a split-single with Sylvan Esso covering Crowded House's "Don't Dream It's Over" — if we're lucky, the obvious choice for this show's encore. Tickets $22.