The Flaming Lips are no strangers to strangeness. But before the vinyl pressed with blood, before the flash drives encased in gummy skulls, before the flash drives encased in gummy fetuses, before the six-hour song, and before the 24-hour song, there was Zaireeka. Consisting of four different CDs that have to be played simultaneously on four different CD players to make up one musical whole, the Flaming Lips’ 1997 album is, depending on whom you ask, either the most groundbreaking experimental masterpiece released on a major label since Lou Reed’s Metal Machine Music or the biggest troll job released on a major label since Metal Machine Music. Either way, when it first came out 20 years ago tomorrow, it had to come with a warning label to keep the squares away:

WARNING: This is a unique recording. These eight compositions are to be played using as many as four compact disc players, and have synchronized start times. This recording also contains frequencies not normally heard on commercial recordings and on rare occasion has caused the listener to become disoriented.

In 1996, coming off of the relative commercial failure of Clouds Taste Metallic, the Flaming Lips were disoriented. They had ridden the unexpected success of “She Don’t Use Jelly” straight to alt-rock semi-stardom and a baffling appearance on 90210, but despite its considerable artistic merit and the equally considerable momentum behind them, Clouds Taste Metallic failed to connect with a buying audience. Then guitarist Ronald Jones left the group, depriving the band of the primary weapon in their psych-rock arsenal. They were forced to regroup. And for Wayne Coyne and company, “regrouping” meant diving headlong into madness.

The first bout of insanity came to be known as the Parking Lot Experiments. In the summer of 1996, Coyne and Steven Drozd, fascinated by the alien, brutalist space of parking garages, dreamed up a grand symphony of parked cars. They distributed 40 cassette tapes, comprising one sprawling original composition, to 40 volunteers, who synchronized their car stereos on command. The second bout of insanity was turning the concept behind that wild performance art spectacle into an actual album. After their manager convinced the label that it would make a good PR stunt and would soon be followed by another, more traditional album, Warner Bros., then beset by companywide turmoil in the wake of a series of firings, agreed to give the band $200,000 for their next two albums and leave them alone. And with that $200,000, the band made both Zaireeka, the album born of the Parking Lot Experiments, and their true masterpiece, 1999’s The Soft Bulletin.

Unlike The Soft Bulletin, which is welcoming in its sheer, shining melodicism, Zaireeka is a willfully difficult album. When most people hear the phrase “difficult album,” they think dissonance, noise, and atonality, and Zaireeka has all that, sure. But Zaireeka is difficult in another way, too: logistically. Not only do you have to have four CD players to listen to it, but you have to have four hands to start them at the same time. And because every CD player runs at a slightly different speed, the music becomes progressively more out of sync over the course of one playthrough. Back when Pitchfork still gave albums a 0.0, they gave Zaireeka a 0.0. Here’s a sample line from their infamous review: “Do I wanna buy three more CD players with which to enjoy Zaireeka or, say, eat?”

The Lips saw these seemingly insurmountable issues as features, not bugs. The album’s supposed to be difficult. It’s supposed to not quite sync up. It’s supposed to sound different every time. And, perhaps most importantly, it’s not supposed to be one guy with four CD players. The listening experience, as Coyne envisioned it, was communal, social, collective. It was friends getting together, hauling their stereos around, and sitting breathlessly in a room, letting the music wash over them in an overwhelming wave. It was the Zaireeka party. It was an event.

This is the part where I admit that I’ve never listened to Zaireeka the way it’s supposed to be listened to. I was four years old when the album came out. I got into the Flaming Lips in middle school because my cool older cousin gave me a copy of The Soft Bulletin on CD. I didn’t have any friends who listened to the Flaming Lips to have a listening party with. But when I learned about Zaireeka, I had to hear it. I was that kind of kid. So I spent a whole afternoon plotting, coming up with ways to turn that communal experience into a solitary one.

First I downloaded the MP3s. Then I downloaded three different media players in addition to iTunes and tried to play all four at once on one computer. But that wasn’t right — for the authentic experience, the music had to be coming from four different places, so it would sound different depending on where in the room you were sitting. I tried again. I burned the MP3s onto four different CDs, rounded up all the CD players I could find — laptop computers, desktop computers, stereos — and ran around the room hitting play on all of them as fast as I could. It wasn’t the platonic ideal of the Zaireeka party, but I still felt a little rush as I heard the staggered announcement at the beginning fall into place: “This is track number one, this is CD number one…number two…number three…and number four.” And then the music came in, a cloud of keening synths and crashing drums and textures bouncing across the room.

Because of the Flaming Lips’ reputation as gimmick artists, I think Zaireeka is often seen as either a total lark or an exercise in unnecessary pretentiousness. And it is those things, kind of. But the fact is, Wayne Coyne was dealing with some genuine art-school shit. Playing one piece of audio on several different devices and hearing it get progressively more and more out of sync is straight out of Steve Reich’s playbook. Exploring the relationship between space, sound, and the acoustic properties of a room is very Alvin Lucier. If you squint, a Zaireeka party might look a little like a Fluxus happening. But Coyne approached all of it with the same sense of childlike wonder that marks all of the Flaming Lips’ output, more dorm room philosophy than grad school dissertation. Somehow, despite all of its inaccessibility, it felt accessible. It was the magic of the Flaming Lips.

The bigger shame is that the perception of Zaireeka as a conceptual art stunt overshadows its status as a piece of actual recorded music. Granted, the concept was a big part of the appeal, and because the music itself was so hard to actually listen to, the concept was all that many people experienced. But speaking solely in terms of genuine musical merit, Zaireeka is a good album. It was the Lips’ first album after the departure of Jones, and in some sense, it was the end of their time as a rock band and the beginning of their time as a space-traveling psychedelic pop orchestra. It was, in other words, the beginning of the band that made The Soft Bulletin.

Although Zaireeka wasn’t the Flaming Lips’ first album with producer Dave Fridmann, it was the first album recorded at his new Tarbox Road Studios in upstate New York, and his hand is definitely visible in the record’s sweeping vistas of neon sound. But the real revelation was the increased role of Drozd, long the Lips’ secret weapon. Initially, he was just their drummer, but with Jones gone, he decided to fill the void left by the loss of a lead guitarist by becoming the band’s multi-instrumentalist and arranger, shading in the blown-out soundscapes with keyboards and strings and horns and synths. It was a whole new sound for them — still weird, but less scuzzily psychedelic and more grandly symphonic.

It was also dark. Although Zaireeka still has the Lips’ goofy sense of humor and some of their sweetly earnest melodic sensibilities — see the big sing-along that closes “The Big Ol’ Bug Is The New Baby Now,” or “How Will We Know (Futuristic Crashendos),” extremely high and low frequencies notwithstanding, or the beginning and ending passages of “A Machine In India” — it’s also, for the most part, obsessed with death and madness and paranoia and existential despair. Although the lyrics are often inscrutably surrealistic, the music bears this out, splattering the melody with synths and screams and distant transmissions of alien noise. Drozd, the musical genius behind it, was in the throes of a serious heroin addiction at the time, and if you want to hear it that way, you can find some of that darkness in the album’s demented splendor. Maybe you’ll hear that once and then hear something completely different the next time you listen. That’s how it works.

Twenty years on, Zaireeka’s legacy is a little hard to parse. It can’t really be called influential, because there hasn’t been anything like it since. And besides actual bootlegs and unreleased material, it’s hard to think of any other relatively well-known album by a relatively well-known band that so few people have actually heard. For a band so concerned with populist spectacle — see any Flaming Lips concert from the last two decades, rococo affairs full of glitter and confetti and giant hamster balls — there’s something almost perverse about obscuring songs this good behind the off-putting and difficult presentation. But at the same time, the songs can’t be separated from their context. That difficulty is Zaireeka.

Whatever else it did, Zaireeka raised questions about why we consume music, when we consume music, how we consume music, and what we expect from our music. In the age of the iPod, which ushered in a new era of personal, private, portable listening not too long after Zaireeka came out, Zaireeka felt intentionally archaic. Now, it’s downright obsolete. No one plays CDs anymore. No one has CD players anymore. New laptops don’t even come with disc drives. The album has since come out on vinyl, and you can find fan-edited one-disc mixdowns online. Even in these secondary formats, it’s still very much worth hearing. But that warning label — “These eight compositions are to be played using as many as four compact disc players” — is for a world that doesn’t exist anymore.