The Black Keys. (Danny Clinch/Danny Clinch)

Who doesn’t like the Black Keys?

Until recently, probably the same people who didn’t like Jennifer Lawrence — outliers, purists, grumps. They were the one rock band most everyone could agree on: hipsters and classic rock fans, frat boys and dad rockers. They were the rare mainstream band that made you feel cooler for listening to them.

The Black Keys started off in an Akron, Ohio, basement, armed with a dedication to classic ’60s blues-rock thump that bordered on the archival. They didn’t get arena-famous until the release of their 2010 album, “Brothers,” almost a decade into their careers. They outsold and outlasted their rivals by being a little better and a lot more anonymous. There wasn’t always more to love about the Black Keys, but just as important for longevity’s sake, there was less to dislike.

But the backlash comes for everyone, and, on the eve of the release of the Black Keys’ eighth studio album, “Turn Blue,” the duo seems on the verge of a public reckoning. Their recent and atypical high visibility hasn’t helped: There were two messy divorces, and a one-sided feud with Jack White. Drummer Patrick Carney complained about Justin Bieber to a TMZ camera crew outside the Chateau Marmont last year, which is simultaneously the most and least rock-and-roll thing a musician can do. He then Twitter-beefed with an army of teen Beliebers, a feud he revived just in time for the release of “Turn Blue.” Singer-guitarist Dan Auerbach worked with Lana Del Rey. Signs of a backlash snowballed so quickly that even the Black Keys worried about it. “I don’t view us as underdogs anymore,” Carney recently told Mojo magazine. “In fact, I view us as more of a target now.”

In a musical sense, at least, the Black Keys have reacted to fame with the same diffidence with which they regarded not-fame. Over the years, the band has gradually evolved from garage rock primitivists to expert usurpers of just about every conceivable (mostly) American musical form of the late ’60s and early-to-mid ’70s, from glam rock to power pop to bubblegum, with everything bolted to a sturdy blues-rock chassis.

“Turn Blue” is a rangy, psychedelia-obsessed R&B album that removes some of the duo’s signature visceral thwack, replacing it with pleasures that aren’t as direct. It’s the sound of a band backing away, if only by inches, from the sound that made them famous. Auerbach and Carney have always been musical shape-shifters, but “Turn Blue” is the first album where the change doesn’t feel incremental. In a sense, it is: It’s easy to trace some of the sounds here to their earliest work, and, given their reputation as musical magpies, it’s easy to see these rambling psych soul tracks, with their echoes of country and even gospel, not as departures but simply as examples of sub-genres they hadn’t previously gotten around to.

“Turn Blue” is probably the Black Keys’ most confident album, and certainly the most fastidiously made. But with the exception of the remarkable opening and closing tracks, it’s a bit of a slog. It robs Auerbach and Carney of some of the things they’re best at — simple, reductivist, stripped-down garage-blues — in favor of songs that are dark and expansive, those plentiful hooks buried underneath sometimes impenetrable layers of fuzz and sprawling melodies.

Opener “Weight of Love” works a deep funk groove, with an extended guitar solo (previously unthinkable) and a wall of female backing vocals. Clocking in at almost seven minutes, it’s the longest song the band has ever done, and it’s quite a thing. The DNA of the entire album is contained within. The title track, with its emphasis on organs and on Auerbach’s wavery falsetto, is an exercise in mid-’60s Sunset Strip nostalgia; “Bullet in the Brain” is great, galloping, synth-y rock.

Many of the album’s songs seem to refer to Auerbach’s recent, very public divorce, but other than a few stray blog-baiting couplets (“The house it burned/But nothing there was mine,” from the nervy “In Our Prime,” is probably a reference to that time Auerbach’s ex is alleged to have set fire to his house), don’t expect much in the way of romantic insight. “I searched far and wide, hoping I was wrong/But baby, all the good women are gone,” Auerbach sings on “Gotta Get Away,” the disc’s only full-tilt boogie.

“Turn Blue” is otherwise as leisurely as its predecessor, the hook-a-minute street racer “El Camino,” was fast. For the first time, though, the Black Keys fully inhabit these songs, instead of regarding them from the outside in, as if they were fully realized rock stars at last, and not just strangers, passing through.

Stewart is a freelance writer.