1939 Ensemble, Beats & Saints (Jealous Butcher)

[JAZZ APOCALYPTICA] 1939 Ensemble are often labeled as "post-rock," which is usually crit-speak for "we don't really know how to classify this." Certainly, they haven't made it easy. Starting out as an instrumental drums-and-vibes duo, the band has gradually expanded into a four-piece, shading their groove-based arrangements in trumpet, synth and guitar textures and winding up somewhere in the vicinity of "apocalyptic lounge music." On this six-song EP—also featuring difficult-to-discern contributions from Red Hot Chili Peppers guitarist Josh Klinghoffer and the late saxophonist Ralph Carney—the group helps suss out their reference points, pairing four covers with two originals. Though new songs "Bullseye" and "Illinois Lead Shot" swing with the band's signature mix of jazz-loft swank and ambient dread, the reworkings offer varying shifts in style. "Pluto," the aggro outlier on Bjork's otherwise placid 1997 classic Homogenic, gets an almost Detroit techno treatment, while Charles Mingus' "II B.S." is blown up to damn-near Zeppelin-size. The take on Stereolab's whirlpooling "Percolator" replicates the original's rhythmic angst. "Off You," by founding member Jose Medeles' other band, the Breeders, is the tender highlight, trembling softly against a night sky of twinkling vibes, brushed drums and buzzing keyboards. In the end, it's no easier to pigeonhole 1939 Ensemble—but if there's any cocktail party you want to be at when the bomb drops, it's theirs.

SEE IT: 1939 Ensemble plays Mississippi Studios, 3939 N Mississippi Ave., with Golden Retriever, on Friday, Jan. 12. 9 pm. $8 advance, $10 day of show. 21+. Get tickets here.