In his natural habitat as musical acolyte, he is both exuberant fan and erudite devotee on the artists he knows intimately. But after a decade as indie-rock outsider as frontman, songwriter and de facto autocrat for his Philly-based project, The War On Drugs, the spiralling success for his glimmering last record has seen him cast in a different role: as reluctant modern bannerman for the preservation of classic rock’s spirit.

It’s a spotlight that can be largely attributed to the global acclaim for that last record, Lost In The Dream, which inspired reams of critical acclaim (not least in these pages), massive shows the world over, a Brit nomination, and a gold certification for 250,000 record sales – of which a reportedly large percentage came from vinyl purchases – and hinting at the audience it awakened with the artists it was indebted to without sounding quite like any outright.

"You don’t want to have a career where to make the thing you need to make, you suffer for it."

The last time we spoke was the night before that masterstroke of a record was even announced when, deep in the throes of the personal and emotional turmoil inextricably linked with his making of it, Granduciel was far from in a position to deftly introduce it.

The enduring beauty of the album was the way emotional disconnection and intense isolation bled out through the very sonic texture of the songs, and the feeling of listening to them rather than just specific lyrical content. True to that, the real narrative of the record revealed itself to Granduciel not in an immediate lightbulb moment but as he got to know it also.

“The only way I really learned about the last one was when we started playing it, and I would sing it every night,” he explains. “There’s the surface of what things might be about, but what it’s truly about, or what I was truly experiencing, my own state of mind, only revealed itself more and more over time. You kind of start living it – it becomes your whole life. Everything that gets built around it, your tour and your band and your friends and your crew around this one thing you made.”

Did he have any anticipation of where those ten songs would take him?

“It was a beautiful thing, to have a moment like that, with something like that. But you don’t really hope for anything, you just do, you know? That’s how it is for me with music. I never felt compelled to ‘scream it’, it’s never felt like I had to be heard or I needed to get this out into the world. It’s what I do professionally, but I didn’t turn that record in thinking I had made something great. And it if didn’t get appreciated then I would be destined to live a life of…you know?”

It’s a thankfully more comfortable state of hindsight than what came across in the record’s contemporary situation. The mythology surrounding Lost In The Dream is now (in)famous, at least in some circles, with the extremity of the loneliness, anxiety and panic attacks that had begun to underpin Granduciel’s everyday, mixing with his dedication to total studio perfection and nearly destroying him in the process of its creation.

“I don’t worry about the anxiety so much...you just have to learn how to recognise it when it’s around...it’s just continuing to know what you need. For me, I just need to be busy, to be working".

Indeed, in that previous conversation, when I opened up about hearing the record – just one person rather than the swathes that were to come – you could hear him physically reel at the potential of such an immensely personal document being free in the world. In the words of his 10-year plus bandmate Dave Hartley: “Whatever has been said, whatever will be said, and whatever becomes, the mythology of the record is insufficient.”

His answer to how he was able to complete that record and begin to approach another was the same as it’s always been for Granduciel: work.

“I don’t worry about the anxiety so much,” he says. “One thing you learn is that it’s always there. You never get rid of it and it never just shows up, it just manifests itself in different ways. You just have to learn how to recognise it when it’s around, and how to maintain a level head. I’m not going to wish it away, or success it away – it’s just continuing to know what you need. For me, I just need to be busy, to be working, and not being sat on a couch waiting for something to happen, ‘cause that’s when it starts to spin.”

Granduciel takes the view of his craft as a profession seriously – hard-earned rather than a hobby – and his respect of that occupation extends to his ascetic lifestyle and involvement in all band matters, reportedly to the point of booking road crew and hotels for band members when in the studio.

So in 2015 he set about busying himself in work – and if perhaps in some state of relieved isolation both personally (he remains happily together with Krysten Ritter, star of Jessica Jones and Breaking Bad) and professionally off the back of Lost In The Dream – upped sticks to Los Angeles to create an artificial sense of it.

Grabbing “just one random box from [his] storage unit”, he tucked himself away with a first clutch of demos in the Sonora Recorders studio, with just the records in that box for company – Wilco’s A Ghost Is Born and Sky Blue Sky, Neil Young’s Silver & Gold – rather than his “whole collection of esoteric krautrock”.

After the toll that Lost In The Dream took on him personally, has he felt any pressure about being able to hit the same creative heights without going through the same emotional trauma? Was he concerned for his personal wellbeing?

“Yeah, I think so. I think the circumstances under which you are motivated to be creative, or to be open, or to be curious about your own psyche, is a tricky road,” he mulls after a long pause.

“Obviously for self-preservation you don’t want to have a career where to make the thing you need to make, you suffer for it. I think that record was a specific set of circumstances in my life where I was experiencing things for the first time. Where the record was necessarily ‘about’ that stuff, I’m not sure, but I was learning about that as I was writing that record, and writing it in the context of the rest of my life.”

“You’re so inside of every song from start to finish, and you remember a year’s worth of tracking and ideas and the bits that didn’t make it – but it takes a long time to get there."

Returning from the Lost In The Dream tour may have been a wholly different kind of return to the globetrot he embarked on for previous record Slave Ambient, but he remained insulated from his surroundings and by any distractions of success from both his work ethic and his commitment to its follow-up.

“I try not to let any of that stuff define what would come next or what would remain important to me about going to work every day in the studio. We came back from that tour and the only thing I was interested in doing was writing more music and trying to express whatever was on my mind.”

As for Granduciel, the process of making a record is absolutely all-consuming. A serial perfectionist and studio wizard, he talks at length about the painstaking process of creating the vivid internal worlds of his records where “you’re so inside of every song from start to finish, and you remember a year’s worth of tracking and ideas and the bits that didn’t make it – but it takes a long time to get there,” he explains excitedly. “It’s totally exhilarating to be at the point where it’s the only thing in the world that matters is these ten songs.”

Adam Granduciel

As the circus of American politics raged on, he kept his craft focused from the “fucking swamp hole of news” outside the studio door. “It was an intense time to make a record because there was so much going on and so many things that felt so much bigger than your record.

“But you have a job to do,” he continues. “It’s a slippery slope, you don’t wanna be overtly political for the sake of it. You write about your life and your experience, and how you live in the world. The context of an album is maybe even better – knowing that it was written in a certain amount of time is maybe better than it being written about a certain amount of time”.

The writing of a Drugs song is only the first piece in the puzzle before the mammoth task of realising in the studio the tones and sounds in Granduciel’s head. He tries to explain how he reaches the end state of a song he’s been working on for two and a half years. It gets to the point where he can “listen to the song, and I hear everything I wanna hear, but there’s nothing jumping out at me.

“I like things to sound natural," he says. "I want to hear all the little moments of inspiration but without anything being a hook or in your face. Thinking about songs in the context of a record to get, say, a consistent evolution of a drum sound…it takes a while to shape everything into its own self”.

The resulting ten tracks make up the massive A Deeper Understanding. It’s undoubtedly the most assured completion of that cohesive whole to date, in a sonic sense.

Where early albums saw Granduciel building up structures of sound before pulling rafters away to see what stuck, this record sounds finessed to perfection – surely breaking studio personal bests for number of channels utilised – as multiple layers of instruments tumble and glide around each other, panning and pulsing to build ever-swelling levels of dynamics and atmosphere around Granduciel’s voice, which aches closer to Bob Dylans' Time Out Of Mind than ever. His densely woven tapestries cite genre – heartland rock, widescreen Americana – but wriggle too much to be boxed into any. They echo through a “rock” band uninterested in playing anything as fixed as rock music.

A Deeper Understanding sounds alive with lucidity and scale. Tracks like “In Chains” pop with perfectly crafted snare shots, and the muscular grandiosity of “Strangest Thing” is unafraid to blow the bloody doors off. “Thinking Of A Place”, the 11-minute track first released for this year’s Record Store Day, engrosses hypnotically over its hazy runtime. “Holding On” throttles with the forward motion and zeal for new ground that’s already earned the band their credentials as road trip soundtrackers, and the strolling bass part that underpins “Clean Living” evokes as much melancholy alone as much else released this year. “You Don’t Have To Go” is an apt, slow-burning sign-off to the less urgent, more contemplative mood of the record with warm acquiescence – the second overwhelming album closer in a row.

Few records feel like tracks stick in your mind more for a sound than a chorus or hook, but the album feels so jam-packed with exquisite moments of sound within a single song – like an artist who knows the exact shade of a colour to fill a space – that to hum along to the record is more knowing when a Wurlitzer answers a guitar line than a chorus lyric. The attention to the detail of the moment, as much as the hook, timestamps any review – that guitar lick at X, that drum sound at Y.

He calls out Shawn Everett, the album’s engineer, as co-conspirator in the lushness of their final product. After all the “wormholes” they “understood each other a lot better than we did when we started, which is what you hope for...Shawn is a tweaker and I’m an enabler..." Granduciel says.

When Wilco released their 2004 classic A Ghost Is Born, a record often mentioned in articles about Granduciel, frontman Jeff Tweedy reflected the strained creative process and shifting nature of the band’s makeup by replacing the traditional hyphen between artist and album named with a “≤” symbol – much as how Lost In The Dream’s immense emotional rollercoaster transcended more than what the band represented to date.

A Deeper Understanding is the sound of Granduciel firmly taking back the farm, flipping the symbol back around with an oceanic, cohesive record that he feels at the emotional rudder of, rather than at the mercy of. If it doesn’t quite hit those affecting heights of Lost In The Dream, it conquers its sonic peaks.

That sense of control is clear from in the album’s press notes – a result of “collaboration, co-ordination and confidence on every level”, the antithetical comeback to the personal triptych Granduciel describes the last album as being borne from: “total loneliness, paranoia, and total isolation”. That level of assuredness allows the songwriting a greater degree of separation between subject and object, and therefore new sensory targets – nostalgia, regret, reformation – rather than the personal sucker punch that powered Lost In The Dream.

"We had by all accounts a ‘super successful’ couple of years with the record, but at the end of that road, what is that? I was in a new place, feeling incredibly isolated from the things that I felt got me there in the first place."

A classic reissued around the time Granduciel started the writing of the record encapsulated his state of mind.

“One of the records I was inspired by, purely by time, was The River [Bruce Springsteen's reissue], because it came out about the same time that I was wrapping up the tour," he explains.

"I was already thinking about the album, and the idea of entering adulthood. Even though I’ve been an adult for a long time, the looking at your life in the context of the rest of it, the context of your parents and your friends, and the changing landscape of growing older. And how do I fit into that? What’s the relationship to my music, and my past, and how I reconcile with regret or frustration. And feeling a little isolated – thinking how much how I really changed, how much have I really grown? When will I cross over into a different kind of life?”

His awareness of those other selves, and other people, comes across both in the album’s lyrical content – the endless search for “the real thing”, shadowboxing demons at the door, the clashing of light and dark.

It’s a tussle he speaks to: “It’s playing all those versions of yourself out. There’s the powerful ego of the self – the part of me that, after tour, where we had by all accounts a ‘super successful’ couple of years with the record, but at the end of that road, what is that? I was in a new place, feeling incredibly isolated from the things that I felt got me there in the first place. I was trying to reconnect, and was starting to make a record in a place where I’d never lived before, but also specifically not in a place where I’d made all my music in the past. Trying to connect with the creative part of me, and tap into the same intensity.”

The album’s title comes from a song by another serial perfectionist – Kate Bush, from her 1989 record The Sensual World. Walking around Philadelphia, towards the album’s completion, Granduciel got heavily into the (incredibly prescient) lament to surrendering real-life emotional connection for a computer screen, The title of the song made its way into first “Pain” and eventually the front cover.

“The title is me trying to get a little bit more to the heart of what’s important to me. I think it was my way of trying to figure out a little more about the root of the thing,” he explains. It’s in the same vein as his albums: getting more across with the way he says something than necessarily with the actual words he says.

“I’m trying to figure out a little bit more about my relationship with some of the things I’m writing about,” Granduciel continues. “It’s still pretty opaque writing – I could be much more disciplined. I’m consumed by sonics, but lyrics are still tough for me – I don’t have those notebooks of writing that I can peruse through. It’s difficult for me...there are times where I’m still trying to break through to the other side lyrically. For things that I may think I wanna be writing about, it’s tough”.

That opacity, bar the occasional stray into the odd trite moment, is why the emotional smog of these is so engulfing – there’s not one hidden meaning of the songs you can excavate with repeated listens, there’s only discovering increasingly what they mean to you.

Nevertheless, it’s a frankness that pervades the record from its very cover. Both as a reference to the “LA-recordness” that he saw about the album’s intent, and a stark answer to the nebulous profile shot in the old apartment that had housed both the development of the band and himself to that point, Granduciel peers out from the album’s sleeve.

“I felt compelled in some way to be real about the cover," he says, "but there was never any other photo that worked apart from that one. To me, it summed up the record – a little bit more exposed that the last one. This was obviously me, alone in my studio, which is my element, you know.”

The War On Drugs' Adam Granduciel

Its other digression is the band’s signing to Atlantic Records for a two-album deal, their first album outside of their history with independent Secretly Canadian.

“It was just one big ‘sure, why not – let’s give it a go!’ I knew the most important thing to me was that I had control of the record,” Granduciel explains of his one conditional contract point: full creative control. “We’d spent ten years building this sweet little thing, and as long as we could keep that intact, I was psyched”.

With an A&R rep, Steve Ralbovsky, who against the stereotypical major label template was reportedly aggrieved when “Thinking Of A Place” was trimmed from a luxuriant 14 minutes to a brief 11-plus, they found a new home for the band’s wish to extend their means – both in the studio, and their ambition outside it.

His Californian stint might be over but Granduciel “won’t shit talk LA. I don’t make the most of my surroundings anyway. I don’t really explore or go the beach or hike, I just go to the studio. If I was a normal person I’d probably love it.”

Now back in New York (“I’m an east coast guy”) all eyes are on the stint of TV live slots as warm ups for the massive run of dates the band have planned for the end of the year, where the album’s meaning really comes to life.

“When I listen to Lost In The Dream, which is rare, I’ve got so used to the way we play it live, with so much more intensity, I forget that this is where we started,” Granduciel says. “So where are these songs gonna end up? Which is exciting for me.”

Having featured earlier and more integrally on both writing and recording sessions for the album, the band – bassist Dave Hartley, keyboardist Robbie Bennett, drummer Charlie Hall and multi-instrumentalists Anthony LaMarca and Jon Natchez – are a unit surely destined for the big-text festival slots and outdoor spaces these songs feel written for.

Their sound might summon the past glories of the American rock canon but they’re the ones pushing it forward. A natural spokesman Granduciel might not be, but records this complete speak for themselves.

Follow Sam Briggs on Twitter @sambriggs.