In the beginning, it was all greasy riffage, lean beats and an unerring, angst-ridden crunch. Everything The Black Keys did reeked of sweaty adolescents getting off to Zeppelin in between frozen pizza rolls and Pabsts in a basement in Akron, Ohio. On the likes of Rubber Factory and Magic Potion, purists of roots, blues and ’70s-ish garage rock alike found their ambassador to the throngs of modern- and indie-rock.

Since, the duo has teamed with producer Danger Mouse, collaborated on hip-hop side projects, gone solo and, on their latest, found themselves at the famed Muscle Shoals Sound Studios. Yep, it’s been something of a zigzag road toward adulthood and, maybe, the mainstream.

Most here sounds of a piece, with sinewy keys, a rambunctious, rubbery bass sound (overcompensation for the instrument’s absence on early outings?), a new polish on guitarist Dan Auerbach’s voice and a general vibe of loose R&B-ish rock. Sure the Keys can still cook: “Unknown Brother” stews nicely, “Next Girl” burns, “She’s Long Gone” is pure Southern deep-fry. But the more ingredients they seem to add (Danger Mouse again, that overdone bass!), the less there is differentiating the band from, say, The Strokes.

There are reminders that the boys haven’t quite grown up. “Sinister Kid” sounds like an overproduced nugget from an earlier album. But in comparison to those salad days, this effort feels like the pair throwing on some button-downs for a little laptop job search at the corner Starbucks.