From the gloomy grit of Akron, Ohio, to the glitz of the Grammys, The Black Keys are one of the more unlikely success stories in rock. With a hard-driving, blues-drenched sound, the duo of guitarist-singer Dan Auerbach and drummer Patrick Carney, friends since childhood, broke through with their sixth album, 2010’s “Brothers,” and have been a top-level touring and recording phenomenon ever since.

In June, the Keys released “Let’s Rock,” their ninth record, and it’s in many ways a throwback to their earlier days: no keyboards, no outside producer (sorry, Danger Mouse).

“We hadn’t made an album just the two of us since ‘Brothers,’ and that was 10 years ago,” says Carney, on the phone with The Post during a break from tour rehearsal in Los Angeles. “So we wanted to get back in the studio, and we wanted to have fun making music.”

At 12 songs and less than 39 minutes long, “Let’s Rock” is a straightforward and catchy effort, with a touch of dark humor — the title comes from the last words of Tennessee murderer Edmund Zagorski before he was put to death in the electric chair last year, and the cover art is an image of said deadly furniture.

Carney chatted with us in advance of The Black Keys’ show next Tuesday at Barclays Center along with openers Modest Mouse and Jessy Wilson.

What was the transition like of going from clubs and theaters to arenas?

Well, our very first show we played to, like, 10 people, so we’ve played for audiences of 10 people to a couple hundred thousand at festivals and the Concert for Valor on the mall in DC. And you know there’s always an adjustment but ultimately for us, if we can stay close enough together on stage and feel the visceral energy of making music together, you can transcend the venue. The first time we ever played an arena was opening for Pearl Jam at Madison Square Garden, and two years later we were headlining there ourselves. I wasn’t nervous at all when we opened for Pearl Jam. I was very nervous when we played it ourselves, and I can’t explain why, because it’s the same gig and it’s better production. The hardest part of playing this gig is mentally accepting the fact that you achieved this position and that the pressure that you perceive is all generated by yourself. It’s important to remember that whoever’s paid the money and taken the effort to get to the show is there to have fun. I think the hardest part of a big gig is remembering that.

What kind of impact did that stress have on you guys?

I went through this stage fright thing that I hadn’t had for like eight years, and it hit me when we first started blowing up in 2010. It bummed me out a little bit. And then I talked to some friends who had experienced the same thing and they said the best way to cope with that is to deliberately stay positive about the experience rather than dread it. When I watch the Super Bowl [halftime show], even though it’s all, well, mostly fake, prerecorded s–t, I’m still like, “Man, that’s a lot to put yourself through.”

You’ve been touring with additional musicians for a while. Have you ever discussed expanding the core, recording band?

No. The band is Dan and I. All the business decisions are made by Dan and I. What label we want to be on, what booking agent, what tour. When we went on the road in 2010, we realized that we can’t perform all this s–t by ourselves, and you can’t strip the songs down to just a two-piece; a song like “Gold on the Ceiling,” you wouldn’t be able to have the main instrumental hook, so we started touring as a four-piece and now we tour as a five-piece. We just started taking people we really get along with and respect out with us. I guess it’s not that different from someone like Beck.

No matter how good the songs and the shows are, it seems an unlikely story that a band like The Black Keys would become this huge. Why do you think it happened?

I think that question in itself is probably why I experienced my spinout because I couldn’t explain it. It wasn’t something I had ever expected, and it wasn’t something that Dan and I ever imagined happening to us. When we made “Attack and Release” two years before “Brothers,” I think we had done one or two nights at the Electric Factory [in Philadelphia] and a couple nights at Terminal 5, and we felt that we were at the top of our game and we had reached the pinnacle and we were super proud of all that, and then to make another record and see how it went from there was amazing. I think if I could explain it I would be the most successful music manager in the business.

At first the band avoided licensing its songs to TV, movies and so on. What is your approach to that?

I think it’s something that started for us on the second album. We got offered a mayonnaise commercial in England, and they were going to pay us so much money. We couldn’t even fathom that type of cash. But our manager said we had to turn it down because it would make us not cool. And we were living in this $400 apartment in Akron, we’re not getting any radio play and we eventually said f–k it, we can’t even afford our f–king rent, so then we kept saying yes, except for a few things. We got a Hummer ad that we said no to at one point.

You announced your previous album, “Turn Blue,” via Mike Tyson’s Twitter account. Why?

It was absurd. Just like the whole reason the album is called “Let’s Rock” and has the electric chair on the cover. Dan and I appreciate the absurd side of this s–t, and I think it’s so hard to present yourself seriously, but you don’t want to be like a clown. I think it helps us with our own mental health to take the edge off to just try to have fun with this s–t and embrace that aspect of making music.