Chances are, when you think about the cradle of authentic rap music, Minnesota isn’t the first locale that springs to mind. But that’s exactly where longtime friends and collaborators Sean Daley and Anthony Davis, better known as Slug and Ant, have been kicking it all these years. By now, a dozen birthdays into each other’s business, Atmosphere has come up with The Family Sign, a rough-and-ready homage to their hard-living and even harder-touring lifestyle.

At once prideful and playful, the big, boisterous power chords that announce the inaugural diatribe, “My Key,” set the tone for the dire consequences of “The Last to Say” with all its slam-poetry trappings and graffiti witticisms. Think The Streets without the accent.

Less than content to dwell on the haunting subject of domestic abuse, Slug and Ant soon heap their jarring hyper-reality on the life-loving smash-up “She’s Enough” and then take a soul-strut down main on “Just for Show,” which staggers under the weight of its “back-in-the-day” U.K. dub underpinnings. Fleshing out their laconic lyrics with the help of skilled keyboardist Erick Anderson and gracious guitarist Nate Collis, The Family Sign revels in high-minded piano forays and stringed flourishes that trickle over gritty urban guerrilla manifestos with a refreshing wildness.

Less a string of songs than a collection of storied journeys into the mind’s eye, The Family Sign’s major standout is the vividly painted “Became,” which miraculously morphs into a graphic novel for the ears. Fashioning their own definition of a male role model from raw clay and an effortless cache, Atmosphere doesn’t need to be sophisticated to be sultry, as Slug and Ant prove on the snake-charming “Bad Bad Daddy.” Running the town in their hydraulically enhanced R&B-rap-reggae hybrid, Atmosphere doesn’t wait for brighter days to put the top down. They generate their own heat.