These youthful Chicago favorites ostensibly explore “the intersection between country and blues” on their fifth album, but it’s kinda funny how often it comes out feeling like swamp blues. Sometimes, that’s clearly intentional, as on the Slim Harpo homage “That’s My Gal,” with Joel Patterson’s tingly guitar. But even on ostensibly more raucous, Chicago-style romps like “Fraulein on Paulina,” with Patterson’s piercing guitar playing off Joe Nosek’s dense harp, the band manages a sort of equivalent to the relaxed, deliberate groove of swamp blues — and that is no easy feat. This is a band; these guys play together effortlessly and intimately. In addition to credible originals, they turn in faithful but personal interpretations of everything from Lightnin’ Hopkins’s “Katie Mae,” Muddy Waters’ “Feel like Going Home,” the Rolling Stones’ “Off the Hook” and Ray Sharpe’s “Oh My Baby’s Gone” to Hank Williams Sr.’s “The Blues Come Around,” then go out on the catchy instrumental “Tribute to the Black Lone Ranger.” The CBKs are assimilationists with a strong yet mellow late-night feel, and they give themselves lots of room to grow.