In the spring and summer of 2014, the psychedelic deconstructionists Darkside embarked on a series of performances so spellbinding that the most logical response to witnessing one was to quit your job, invest in a tasteful all-black wardrobe and follow them across multiple continents like the new Grateful Dead.

It was sound as séance, Eleusinian hallucinations of watching Jerry Garcia back Pharoah Sanders, kicking stardust grooves snatched from primordial savanna rituals. Or Pink Floyd performing a Valyrian sacrifice, but far funkier. A 12-foot, double-sided, “Moon Mirror” towered center stage, created by a mysterious Dutch and Norwegian duo named the Children of the Light. This supernatural-looking glass refracted tricky golden beams, absorbing tesseracts of analogue and HD-video projections, dosing the audience with what felt like liquid LSD submerged in a blazing infinity pool.

Then, it all abruptly vanished. By the fall of 2014, Darkside had reached the precipice of whatever passes for contemporary mainstream success. With one more album and tour, they could’ve headlined festivals and sold out arenas. They were on the verge of making Tame Impala look like the opening act at an exploding Technicolor dream extravaganza in Perth. Instead, the band declared an indeterminate hiatus. No new music or shows. Temporarily abandoning the prospect of mass adulation and yacht-club wealth, the duo of Nicolas Jaar and Dave Harrington pursued intimate and personal solo endeavors.

Darkside’s new sophomore effort, “Spiral,” ends the seven-year sabbatical. Another towering achievement, it’s a cinematic portal that sounds vaguely like a lost jam among the mid-’70s Grateful Dead, Tuareg guitar sorcerers Tinariwen, Nick Drake and if the sculptor Constantin Brancusi made beats. But it’s quintessentially Darkside, full of bruising, demotic grooves and vaporous delicacy. A soundtrack to a disco buried beneath shifting sand, underneath the ruins of a demolished world.

“We had been so deep inside of it for [three years straight], and we just realized that we had taken this chapter to its end,” says Harrington, the experimental jazz multi-instrumentalist turned Darkside guitar Orpheus, who created a recondite solo body of electronic and jazz odysseys in the intervening years. “There were so many other things that we wanted to do. Consensus can come easy when it’s just the two of you; it can be just a conversation. We did what we set out to do, and neither of us felt compelled to push it any further.”

He’s speaking in late June from the patio of Club Tee Gee, a bar in northeast Los Angeles, where Harrington, 35, moved a little over a year ago from his native New York. His shoulder-length hair and strawberry-blond goatee gives him a passing resemblance to a young Robert Plant. In early July, Harrington’s partner in Darkside, Jaar, the Chilean electronic composer, echoes an identical sentiment via Zoom from his Berlin home.

“We each have sides to our music that the other isn’t as interested in. If Dave wasn’t making his solo projects or if I wasn’t making some more experimental things, I don’t think we could go on to do this record,” Jaar, 31, says, alluding to the seven revered solo albums released during the Darkside interregnum (two under his house-slanted Against All Logic alias). “We needed that outlet to be able to continue making this.”

Matador Records

“Spiral” finds Darkside reclaiming a crown they’d never actively seek: the world’s best psychedelic band. The duo manages to be innovators in a bland retro-fetishizing playlist landscape. In their telepathic communion and reconciliation of polarities, they summon memories of the “Aquemini’ yin-yang of Outkast. Jaar is the brooding and enigmatic son of internationally renowned artist Alfredo Jaar, raised in Santiago and Manhattan, a shape-shifter with an indelible sense of self. He croons velvet wraithvocals in Romance languages and crafts resistance symphonies of fuzz and static. Harrington is the affable and joyous Big Boi of the pair, who believes in fun as a noble pursuit, the son of two journalists, raised in Manhattan on the Allman Brothers and Keith Jarrett, whose jam band ardor and guitar heroics ground Jaar’s avant-garde levitations.

What’s so striking is the sense of alchemy. You can hear traces of Darkside in the other’s respective solo projects, but their fusion operates like a philosophers’ stone. Darkside is something entirely distinct, a surreal form of magic at war with the rational.

“It’s like A + B = grapefruit,” Harrington says, laughing.

Credit a constant need to improvise. Even the band itself came about serendipitously. Harrington met Jaar through friends and musical collaborators from their shared alma matter of Brown, and with the breakout success of Jaar’s 2011 debut, “Space Is Only Noise,” he joined the touring band. The principal problem was that Jaar and the other member of the trio, Will Epstein, were still pursuing their degrees. So the run stretched over two years, with gigs booked during university breaks. Darkside emerged from free-form jam sessions, but eventually coalesced during the 2012 summer that the pair spent in Paris.

Renting an apartment in a northern arrondissement, Harrington and Jaar borrowed a basement writing room studio, ate a bunch of delicious Chinese and Pakistani takeout, and wrote during the week while gigging on the weekend. The following year, they finished their first opus in New York and realized their respective musical vernaculars and gifts produced something starkly different when combined.

“If you’re on the same wavelength, where you’re speaking the same language but are from different places, then you find the things you love together. Working with Nico, it’s so much easier to go toward the things that I love in music than when I’m on my own,” Harrington says. “We met inside the music and built the spiral from the inside out. It’s not like we were 16 and decided to start a band. We already had ideas about music and those ideas started talking to each other.”

Darkside eschewed press and self-mythology, barely kept up a social media presence, and only released a slim (but staggering) body of work: a self-released eponymous 2011 EP, an unofficial, slyly joking-but-still-serious Daft Punk remix album, and a full-length entitled “Psychic.” Released on indie powerhouse Matador in the fall of 2013, the debut LP cracked the Top 10 on Billboard’s U.S. Dance Charts, but barely dented the overall rankings.

Ruthlessly opposed to the corporate machinery of a sponsored and branded world, Darkside reinvented the jam band as a conceptual art opus. Then there was the name, Darkside, an unsubtle allusion to that dorm room bong-rip totem, “Dark Side of the Moon.”

“At first the name Darkside was an absurd inside joke, and then it gave us this feeling of, ‘Can you really do that?’ ” Jaar says, laughing. “As you play shows in all these different parts of the world, it comes to have a very different meaning for everyone. It becomes this thing where it’s not a joke somehow, and the record comes out and people take the music seriously, and now we have a band called . . . Darkside.”

Delirious word-of-mouth and critical raves made them the must-see band on the 2014 festival circuit. That run reached its climax inside a sweltering, dangerously packed Los Angeles Sports Arena in late August when the band made the dozens of others playing FYF Fest irrelevant with a performance that practically suspended time. They were unlikely prophets locked in telepathic mind-meld, their images periodically warping on the surface of the mirror, a sonic parallel to the shifty dual-identity deceptions of Italo Calvino or Nabokov.

After a 56-minute shadowland odyssey, the machine drums reached a headbanging pitch; Harrington’s guitar squealed and ascended into gorgeous crescendo. Then it happened — Harrington, wreathed in Druidic smoke, hoisted his guitar above his head and pickaxed his instrument into the guts of the 12-foot mirror, shattering it into oblivion. The arena rock cliche of the smashed guitar subverted into something original, the mirror destroyed in a similar way that the band had dismantled psych-rock tropes, stripping them into elemental parts, adding “Bitches Brew” and West African desert guitar reveries, and resuscitating it into previously unreachable forms. Within a week, shards of the sacred glass were selling on eBay to the highest bidder.

Had Darkside never played another note together, the mirror destruction would’ve been their equivalent of Michael Jordan hitting the game-winner in Game 6 of the 1998 NBA Finals. But plans for their reunion covertly began in 2018 in rural New Jersey, when the pair rented a house for 10 days to gauge the viability of whether a sequel even made sense. Jamming, long conversations and a mutual exchange of music ensued. Harrington brought all of his gear from Brooklyn, where he was living at the time. They played the family piano in the living room.

In the years that followed Darkside’s break, Jaar decamped from the United States. Before moving to Berlin over the past year, he’d spent much of the last half decade living by a river in Turin, Italy. There were occasional breaks to tour and artist residencies near Amsterdam and in Bethlehem. In addition to the seven solo albums, he scored several films, co-produced much of the last FKA Twigs album, and engaged himself politically and philanthropically. He announced that all record sales and streaming proceeds from his label, Other Music, would go to social justice organizations. He conducted sound workshops with children from the Palestinian Aida and Dheisheh refugee camps. The Darkside record was an opportunity to attempt to shut off his brain and lose himself in the slipstream.

“In creating music, I love jamming and coming from a place of ‘unthinking.’ I love being really in the flow with someone. I love long conversations and really being present,” Jaar says. “With Dave, I get to make music with someone who I can really be in a space that is our space. It’s a very loving feeling, and that’s why I really get a lot out of it. We’d hang out in the house for four hours and at some point be like, ‘Okay, let’s get the guitar out.’ ”

For reference, Jaar cites an interview with Pharoah Sanders where the reporter asks him, “What did Coltrane tell you in all those sessions?” and Sanders replied, “We didn’t speak about music.”

The overarching conceptual ambition of the new record focuses on the spiral as a center of gravity, where a chorus of voices and perspectives descend into these fluxes of energy. The band found themselves asking the questions: How to enter those spirals in silence, without adding extra thought or confusion? How can you know that you’re inside without verbal enunciation? How can you discover an extra-lingual way to evoke an emotion and radiate connection?

Initially, the answers proved elusive. The first sessions were slow and funky. Despite the strut, the band considered the output a cheap replica of themselves. In response, they delved into abstruse complexity (alternate tunings, microtonality), which led them to a place of minimalist simplicity. Movement and emotional nuance were constantly kept in mind. For the first time as a band, Harrington sat with an acoustic guitar, Jaar sat with a notebook, and they’d alternate between riffs, conversation and the lyrics that they inspired. First take was often best take. The record button was on at all times. A 10-minute Harrington guitar solo could be reduced to 20 seconds and then sped up into a minute.

“We work at music with time being flat, from any angle, at any point you can always go back into this, you can change that, you can flip that . . . whatever,” Harrington explains.

Excursions in the Mojave Desert, Amsterdam and Brooklyn followed. Just Harrington and Jaar, no engineer. The result was “Spiral,” 52 minutes in the interzone, a cosmic axis where all points intersect, beholden to neither contemporary trends nor febrile nostalgia. No live shows are allegedly on the horizon, and the mirror is permanently smashed. Jaar says that if they ever tour again, they’ll need to figure out how to symbolically reconstruct it. For the moment, however temporarily, he is willing to invite the light.

“Visibility is very important for me now. In the past three years, the shows that I have done are hardly ever in the dark. I want them as bright as possible. I want things to not feel like a spectacle or artifice. I like it being what it is,” Jaar says, all too aware that “it” will be different tomorrow.

“If it can seem as if the whole thing is a fragile, ridiculous construction, then let everyone see it. Things are in flux, they are at all times. I let that take precedence,” Jaar adds. “I believe in flux and I’m more afraid of solidity than I’m afraid of flux.”