The group Larsen consists of four Italian musicians on standard rock tools with some additional homey instrumentation: harmonium, xylophone, accordion. Their recent Play album, on Important Records, adds some guests, in the form of a cellist, a keyboardist, a violinist and a synthesizer player. Wondering, at this point, what Larsen has to do with the Disquiet Downstream section, beyond the fact that Play shares a record-label home with Jack Dangers (of the industrial band Meat Beat Manifesto), not to mention art-noisemakers Fe-Mail and Merzbow, and late ambient figure Muslimgauze? Well, according to Important, Larsen preceded the Play recording sessions with a particular exercise: “improvising around some of their favorite melodies from Autechre albums,” Autechre’s groundbreaking glitch having about as much to do, on the surface, with accordion rock as, well, fill in your favorite cultural-divide simile here. As it turns out, the Autechre factor infused Larsen’s recordings with a deep post-rock vibe. The Pitchfork online magazine’s MP3 page, pitchforkmedia.com/mp3, features a nearly eight-minute Larsen piece, “C,” which slowly makes its way from stasis to just short of ecstasy, building and building like some folksy ritual. And over at the Important site, at importantrecords.com, are two more tracks (on the Play album’s page). One, clocking in at two minutes, appears to be an edit of the Pitchfork track. The other, at three minutes, is an edit of an even more drone-like recording, the accordion bringing to mind, immediately, the protean work of Pauline Oliveros. Aside from this latter track’s clipped close, it’s heavenly.