Is this a dance record? Industrial rock? And where is that majestic and moody material that made them a household name with “The Joshua Tree?” Only three years earlier that LP sold millions, landed the Band on the cover of Rolling Stone, scored a Grammy for Album of the Year and immediately became one of the definitive rock albums of its time.

Hansa is where David Bowie recorded “Heroes” with Brian Eno, the art rock visionary who is now U2’s producer. Edge and Bono are working on a demo called “Sick Puppy” that features an infectious bass line from Clayton. It’s promising, but still just a meandering jam with nonsense lyrics.

Mullen has some questions about what exactly the band is trying to accomplish. The drummer is the one who has always taken it upon himself to ask the difficult questions. He understands U2 and he doesn’t understand how he’s supposed to fit in with the drum loops they’re experimenting with.

“It was getting really tense,” says Mark “Flood” Ellis, the band’s engineer at the time. “Nothing was coming and there was a lot of doom and gloom.”

But as they keep jamming on “Sick Puppy,” a single chord change emerges. It might be an overstatement to say that single chord change set U2 on the path from being rock stars to global icons. But it might not be.

Daniel Lanois, Eno’s production partner, hears it first, a simple yet seductive A minor to G sequence. He gets it on tape and plays it for the band. It’s delicious and Bono, as he does before there are words, begins to scat over it. They move into the big studio, somebody calls out chords, and before long U2 has written “One,” the emotional centerpiece of 1991’s “Achtung Baby.” The album would become a triumph. The song would become U2’s savior.

“In the end, it’s what we needed to hear more than our audience needed to hear it,” Bono said in a recent interview with The Post. “The song ended up being about our desire to stick together. ‘We are one, but not the same.’ And that is a thematic for our band.”

The Sex Pistols lasted about three years. The Beatles a little less than eight. The Rolling Stones and the Who soldier on, but at this point their respective singer and guitarist are the only original members left.

When U2 arrives in the District this weekend to receive the Kennedy Center Honors, the four people accepting the award will be the same four who first convened as teenagers in Dublin in 1976. As they approach a staggering 50 years together, the foursome has remained intact and, more compellingly, an active, creative unit.

Staying together hasn’t always been easy nor has it been dumb luck.

“We come close to breaking up much more often than you’d think,” says Bono. “Usually after the really good albums, because they cost you in personal relationships because you’re pushing each other and get really at your elastic limit.”

Forty-six years ago, Mullen, then just 14, scribbled “Drummer seeks musicians to form band” on a piece of paper and posted it on the bulletin board at the Mount Temple Comprehensive School in Dublin. Since that first Saturday gathering in his kitchen, U2 has followed a communal plan that’s rooted in both the contractual and the emotional. Paul McGuinness, their manager from 1978 until 2013, drew up the blueprint when they were still teenagers. There won’t be any money for a while, he told them. But what there is, you should split up evenly.

With bank accounts connected to creative destinies, they had the structure to weather the inevitable conflicts that emerge when members of a high school gang grow into wealthy men with families, frailties and differing opinions.

“It’s a band, so there have been arguments, hard arguments, not talking to each other arguments, of course there are,” says Bob Geldof, the Boomtown Rats frontman, activist and longtime friend. “But for them, they realized that the band is worth more than any individual idea.”

They started by calling themselves Feedback, then the Hype, and finally, by the spring of 1978, they became U2. The musical planet they arrived on was something of a wasteland. Punk was dying as quickly as it was born. Synth pop and its accompanying poofy haircuts were becoming all the rage. And if you played loud guitar rock, you tended to do it one way — with shredding guitars, revolving drum sets and bassists who thumped out blistering rhythms.

U2 took a different approach. Using only the common elements of a rock band — guitar, bass, drums, vocals — the band landed on a signature sound that has been present since “Out of Control,” the A side of their debut EP in 1979. On that song, Edge plays a series of notes that float into a jagged harmony, Mullen smashes the snare with military precision and Bono sings with the pleading urgency that would drive first wave hits like “Sunday Bloody Sunday” and “Pride (In the Name of Love)” to soaring heights. Though the sonic canvas would expand, the philosophy pushing it would not.

“It’s like that old adage, the whole is greater than the sum of its parts,” says Steve Lillywhite, who produced U2’s first three albums and has continued to work with them. “In fact, part of their art is to make it be good with limitations. Make it with what you have. A lot of music now suffers from the ability to use anything you want. You’ve got the world at your fingertips. Well, what do you want?”

Paul Hewson, renamed Bono Vox by his friends after the name of a local hearing aid shop, led with a buttery bullhorn of a voice. He was never afraid to reach or overreach, whether leaping into a crowd at Live Aid, approaching world leaders for causes or making an ill-fated deal to plant a new album on your cellphone. He’s got a voice like no other. And he doesn’t let you forget it.

“I’ve done karaoke with him,” says Geldof, “and I picked Hank Williams and frankly, anyone could sing it. He picks a song by Love. He immediately gives a profound Bono, this indrawn breath. The eyes close and he sings it better than them. For f—’s sake. Shut up. Do karaoke properly, you’re meant to be s—.”

Dave “Edge” Evans was the soft-spoken son of an engineer who rejected the traditional guitar hero. Forget Jimmy Page, Eric Clapton or Jeff Beck; he loved Television’s Tom Verlaine, PiL’s Keith Levene and John McKay of Siouxsie and the Banshees.

“They were all playing the instrument in a fresh way,” he says. “I took that as a bit of a throwdown, saying, if they can do something that’s never been done before, so can I. So it just became kind of a fundamental rule. If it sounds like white rock and a bluesy rock from the mid-’70s it’s like, no.” He bought an Electro-Harmonix Memory Man delay pedal, which allowed him to create the distinctive layers of echo that thickened and textured the sound. His playing wasn’t flashy but it was instantly recognizable.

Adam Clayton, in the earliest days, served as the de facto rock star, the guy Bono called “our posh Sid Vicious.” He had glorious hair, dated (and got engaged to) supermodel Naomi Campbell and eventually became the lone member who ended up in rehab. These days, he is married to Mariana Teixeira De Carvalho, a father and surrounded by the art collection that populates his home, Danesmoate, the 18th-century mansion in which U2 recorded much of “The Joshua Tree.”

“I’m the least virtuoso of everyone,” Clayton says about his playing, and yet imagine “New Year’s Day” or “Bullet the Blue Sky” without his bass lines.

Then there is Mullen. “The bulls— detector,” says Clayton. He is largely self-trained as a drummer, a powerhouse who now struggles with the physical toll of a lifetime of pounding. He’s the least public of the group’s four members, by far. The interview he gave for this story was, he said, his first in seven years. He’s blunt — he says if the band plays live in 2023 it will likely be without him, as he needs surgery to continue playing — and admits the dynamics in the band are not the same as they were decades ago. As the ’80s wore on and U2’s stature grew, band decisions would be made by what they called the “Politburo,” named after the policymaking committees in most communist systems. In Mullen’s view, the system that served the band well for so long has now become more of a benevolent dictatorship.

“You only do this if you’re having the best time,” Mullen says. “And not everyone is going to make it because the price is so high. So I think the challenge is for more generosity. More openness to the process. I am autonomous and I value my autonomy. I don’t sing from the same hymn sheet. I don’t play to the same version of God. So everyone has their limits. And you only do this if it is a great time you’re having, you know?”

Making something special usually requires taking risks. And U2 has never shied away from them.

They were on an upward trajectory after releasing “War” in 1983 but instead of bringing back Lillywhite as producer, they recruited Eno. His work with Talking Heads had impressed the band; his catalogue of ambient music concerned their record label.

No matter. U2 hired him to helm “The Unforgettable Fire” and he arrived in Ireland with Daniel Lanois, his producing partner. They formed a perfect team: Eno experimented with sounds while Lanois, a guitarist and master of rhythmic music, scoured the tapes for special moments.

Eno and Lanois helped them build “Bad” from a short, echoing riff into a sprawling centerpiece about a friend’s heroin addiction. They produced U2’s first U.S. Top-40 single, “Pride (In the Name of Love),” a tribute to the Rev. Martin Luther King Jr. Lanois still remembers urging the prayer-like ballad, “MLK,” out of Bono to wrap the album.

“I think what we did on that record was more ethereal,” says Lanois. “I had this beautiful, Sony C500 microphone and he sang on the couch — ‘Sleep, sleep tonight’ — and it’s a tremendous tenderness that shows up on that record that may not have been there previous.”

“The Unforgettable Fire” took three months. “The Joshua Tree,” a full year.

There were moments of tension that escalated to confrontation. As they struggled with the album opener, “Where the Streets Have No Name,” Eno at one point tried to erase all recorded tracks of the song, convinced that the band needed a fresh start. Flood says that engineer Pat McCarthy forcefully stopped him, tackling the producer. (Eno declined to comment and McCarthy, in an interview, only volunteered that Edge made him promise to protect the tapes.)

On “The Joshua Tree,” Eno and Lanois were given the freedom to pursue new ideas with the purpose of reinventing what U2 could be. But eventually, McGuinness called in Lillywhite, who understood the band’s more traditional rock side. He came in largely to work on singles, which became a regular routine.

“Brian Eno’s job is to destroy U2,” says Lillywhite. “That’s why they want him. Because Brian hates guitars and drums. He will take the track and take out the guitar and drums and put on his blippity, blippity and it doesn’t sound like a record but it has something nice about it. So then I’ll take it and try to make sense of everything and sometimes get it right.”

“When Steve came in, everyone thought he was killing their favorite child,” says Clayton. “You’re going to ruffle a few feathers. But really, without Steve coming in, we’d still be mixing all those records. They’d never have been released.”

So how do you chop down a Joshua Tree? Or perhaps the better question is why?

That subject drove Davis Guggenheim’s 2011 feature-length documentary, “From the Sky Down.” The short answer is that the enormous growth of U2’s audience after “The Joshua Tree” briefly left the group struggling with direction. That became clear with “Rattle and Hum,” a project that started small — an indie documentary and album exploring American roots music — and ended with a Hollywood premiere and a major theatrical release. It was too much.

“Five studios, four musicians, a movie … I stopped producing recordings because ‘Rattle and Hum’ almost put me in a box,” says Jimmy Iovine, who produced Bruce Springsteen, Patti Smith and Tom Petty before “Rattle and Hum.”

The problem with “Rattle and Hum” wasn’t the music. It was the sense that U2 was overexposed and overreaching and it was the first time that people asked, “Just who do these guys think they are?”

“It’s a tad early for the band to be lobbying for admission to the pantheon,” The Washington Post wrote at the time.

“’Rattle and Hum’ is the sound of four men who still haven’t found what they’re looking for,” added Rolling Stone.

“I mean, obviously, we take our work seriously and it’s not to us, a kind of trivial throwaway thing,” says Edge today. “But by the same token, not everything could be made as if your life depends on it. That stuff gets tiresome as well. I think we realized that was part of the caricature that we had created around ourselves, and that again felt like going for creative freedom was to dismantle that, which was ‘Achtung Baby.’”

It was the Zoo TV Tour, launched with “Achtung Baby,” that really signaled the next era of the band. The previous time they played live, they were the stone-faced sincere rockers decked out in cowboy cosplay. This time, they were the strobe-lit entertainers, the stars of a show meant to embrace and mock fame.

Bono arrived as the leather-clad “Fly” and later transformed into a devilish character, “MacPhisto,” complete with a golden jacket. The band installed hundreds of television screens, which broadcast slogans and interviews and even, at times, closed circuit conversations from other countries. Trabants, the tiny obsolete, East German automobiles, were wired and hung for lighting. It was a meta-spectacle poking fun at the ridiculousness of spectacle itself.

“For me, that was the pivot and a brilliant one,” says R.E.M.’s Michael Stipe, frontman of another band that grew from critically acclaimed in the ’80s to worldwide force in the ’90s. “The idea of calling the White House from the stage and having someone actually pick up and you realize it isn’t a trick, that’s happening in real time. They were absolutely prescient to recognize the coming wave of the digital revolution and what it meant.”

This fall, Bono embarked on a short tour to support his 576-page memoir, “Surrender: 40 Songs, One Story.” Working with Gavin Friday, his childhood friend and U2’s longtime creative director, the goal was to craft a stage show worthy of a Broadway run.

He first told Friday he wanted to perform only a few U2 songs for the presentation and hoped Edge could accompany him. “Don’t go out with Edge,” Friday told him. “It is braver and would show the work better if you don’t make it a U2 show.”

So the two-hour performance featured Bono acting out the book, doing impressions of central characters, and singing 14 U2 songs while backed by producer and keyboardist Jacknife Lee, harpist Gemma Doherty and cellist Kate Ellis. The sold-out shows were attended by some of his pals like President Bill Clinton, Sean Penn and Colin Farrell.

But writing a book has not changed how Bono feels about U2. There are no plans to do a solo album. For “Surrender,” U2 recorded 40 stripped-down versions of the songs featured in the memoir, with the collection set to be released next year. They also have a nearly finished album of new original songs called “Songs of Ascent.” But Bono and Edge aren’t sure when to release it. They aren’t sure about a lot.

They entered the millennium as relevant as ever. Bono, the nudgy statesman, boldly crossing political lines to raise billions for developing countries and push for debt relief. Even then, U2 was never out of mind.

“He could talk about the fact that they were trying to still make music and travel and tour,” says Condoleezza Rice, the former secretary of state who worked with Bono and also attended a U2 concert that left her in awe. “And yet he was always running off to talk to some government about AIDS.”

“Beautiful Day,” released late in 2000, became an inspiring, post-9/11 anthem. “Vertigo,” four years later, blasted across TV screens in an iPod commercial as U2 proved it was both a great band and on the technology vanguard.

And then came their next deal with Apple, which planted their 2014 album, “Songs of Experience,” automatically into users’ iTunes accounts. Instead of discussing the merits of “The Miracle (of Joey Ramone)” or Bono’s heart-twisting tribute to his late mother, “Iris (Hold Me Close),” critics shamed U2 as exhibit A in the insidious intrusion of tech spam.

Which leads to 2022. While U2 continues to make compelling, new music — just cue up the catchy twofer of “Get Out of Your Own Way” and “American Soul” on 2017′s “Songs of Innocence,” bridged by a guest spot from Kendrick Lamar — the lure of nostalgia is hard to deny. Their two “Joshua Tree” anniversary tours, in 2017 and 2019, grossed almost $400 million worldwide.

But Bono and Edge don’t want to give in that easily. During the pandemic, Edge wrote furiously. Bono loves the idea of adding those new songs to their live sets, of building up programs that allow U2 to do what it does best.

“We’re our own festival when we go out,” says Bono. “And that’s untouchable.”

The new album, he says, will move away from the band’s recent work, which has been softer. He wants Edge’s guitar to drive the music, to turn the volume up. He does not sound tired or ready for the oldies circuit. He sounds hopeful, thinking that there could be no better time for his beloved rock band.

“The country’s changed for a group like U2,” Bono says. “But I have a feeling that we have something. That if we can distill it on these next sessions, this unreasonable guitar record that we all want to make actually, I just feel there’s a moment … I don’t know if you can capture people for a whole album. But what if it was just an EP or just one song that could burst through? We don’t need it on the pop charts. We don’t. But we need people to pass it around. I think we do want that.”

The Kennedy Center Honors will be broadcast Dec. 28 at 8 p.m. on CBS.