TORONTO -- It was spring 2011 when Arcade Fire -- months from a stunning Grammy Award win for album of the year, which pretty much certified the Montreal band had climbed to the highest of rock's craggy peaks -- went down to Haiti and got upstaged.

They were in Cange, a lush remote village positioned on the edge of Lake Peligre. They were there primarily to visit sites where Partners in Health was working to help in the aftermath of 2010's catastrophic earthquake. But they also played a couple shows -- mostly tossing off cover songs -- as an opener for the rasin (Haitian roots music) band Ram.

And those spirited gigs had a profound effect.

"We played and it was really fun," multi-instrumentalist Will Butler recalls in a recent telephone interview. "And then Ram came out and played and everyone came out and danced and it was this massive party. And it was out of control and amazing -- not like, out of control like someone on coke was stabbing someone in the eye with a pen or anything. But out of control like six-year-olds and 95-year-olds were dancing and old ladies on crutches and stuff.

"It was just a real town-wide celebration. And we were like, oh, it would be nice to be able to go to rural Haiti and play a show that people would really dance to.

"That definitely set a challenge for us, which we took up on some of the songs," he added. "I want to be able to play this for a roomful of strangers in a different country, who have never heard Arcade Fire, and just have them dance to it."

And so the seeds were planted for "Reflektor," the indie innovators' rather transformative, sprawling fourth disc that hits stores this week.

In particular, the trip triggered an interest in exploring traditional Haitian rhythms. After the tour behind "The Suburbs" had wrapped, the band went to a New Orleans studio with percussionists from Ram and basically did their homework. They listened closely to a range of their rhythms, tasking the drummers with weaving their styles with the propulsive percussion work of New Order's "Age of Consent," for instance, or analyzing the different way fills are dispensed. They made loops of those sessions, some of which wound up on "Reflektor," some of which only served as "inspiration for further experimentation."

The unconventional rhythmic heartbeat of the record is the first thing that stands out -- watch how the syncopated reggae strut of "Flashbulb Eyes" segues into "Here Comes the Night Time," a thrilling mix of breakneck Haitian pounding and an easy tropical amble.

"The Suburbs" had already woven some German-inspired beats into the band's formula, but taking things further required a new level of rehearsal and consideration.

At times, "it was like a giant Motown session," says Butler, who grew up with frontman brother Win in suburban Houston before relocating to Montreal. "We had to know how to play it live in order for it to make any sense at all. 'Cause there's so many frickin' layers."

The scope of what they tried to tackle on "Reflektor" is hardly surprising -- outsized ambition might have always been Arcade Fire's distinguishing quality.

Influential 2003 debut "Funeral" consisted of 10 anthems of the apocalypse, with a cathartic grandeur that seemed to eclipse the small clubs they almost immediately outgrew. Chart-topping follow-up "Neon Bible" was more fractured musically but so pointed in its commentary on a post-9/11 world in seeming tragic decline, it invited comparisons to U2's save-the-world grandiosity (both positive and negative). "The Suburbs" shed the previous record's distorted clutter for the band's most broadly accessible set of tunes, and yet it was still a 63-minute concept record, hardly a compromised grasp at commercial success.

On the double-disc "Reflektor," only four of 13 songs clock in under five minutes, with many stretching far beyond. The first disc is giddily accessible at times, featuring several songs -- distorted thrasher "Normal Person," sun-drenched groover "You Already Know" and the stinging gallop "Joan of Arc" -- that Butler points out might have fit in on any of the band's records.

Sure, it's ambitious -- David Bowie shows up to sing but one line on the disco-at-dawn title track -- but not necessarily a major change, Butler says.

"If we were better musicians and knew better, who knows what 'Power Out' would have sounded like back in the day," Butler says of the old "Funeral" highlight. "It doesn't feel like a crazy departure for me. It was just something we were interested in doing. Well obviously, there's a ton of new stuff, but it kind of just felt like we'd learned things and we wanted to apply some of the stuff we'd learned."

With LCD Soundsystem mastermind James Murphy producing alongside longtime collaborator Markus Dravs, the songs have a foot-shuffling euphoria about them (as well as a luxuriant sonic sheen) even as they stretch their figurative legs.

(Butler says Murphy managed to penetrate the cloistered band's defences, noting: "Normally if you get a comment from an outside person on a sound or on songwriting, it's of little value because it's just not helpful. Even if they're right, if you don't know who they are, you're like 'yeah yeah yeah, whatever.' But this is someone we really trusted ... and we'd liked the music he made, we liked the music he'd produced. So there was an element of trust there, which was nice.")

It's the second disc where the band reclines languorously, mostly putting the dancefloor grooves behind in favour of patiently plaintive tunes.

The epic twosome "Awful Sound (Oh Eurydice)" and "It's Never Over (Oh Orpheus)" constitute 13 minutes of propulsive drums and pinprick guitars. They've led some to in the media to muse that the entire record is intended as a Greek tragedy, but Butler -- seemingly choosing his words carefully -- explains otherwise.

"Kind of late in the process, Win watched the film 'Black Orpheus' ... which is Carnival and Greek mythology and really amazing music that you can dance to. It suddenly felt like that element could kind of bind the record together and could kind of unite some of these disparate concepts, if there was something a little more universal behind it.

"Something along those lines is the truth," he adds, laughing. "Something like that feels right."

Regardless, the record is thematically heavy, musically beguiling and -- to put it rather inelegantly -- really long. So even if it's not a major departure, Butler acknowledges that it might take a while for listeners to get a clear view of "Reflektor."

"I always think about 'OK Computer,"' he says of Radiohead's classic 1997 left-turn. "(It's) only 45 minutes but it still took me like a year and a half to work through. And that was like, my favourite album. But I didn't even listen to the second side for like eight months."

And he insists that Arcade Fire didn't feel burdened by the achievements of their last record -- the No. 1 chart position, the Brit, Juno and Grammy awards for album of the year, the sensational sales. No, this uncommonly driven band has always drawn motivation from within, he says: "There's so many of us. There's so many artists in this band that there's always a ton of internal pressure to make something great."

But the hoopla surrounding "The Suburbs" did give the band a bigger platform. And even from their humble beginnings in Montreal, Arcade Fire has never been a band that shied away from the large and lofty, whether in the form of sound, stages or statements.

"Like a shark, we want to keep moving forward," Butler says. "You don't necessarily want to get bigger for money's sake or popularity's sake, but you do want more people to hear your music if you think your music is good and would have something relevant to say about life.

"Me and Win grew up in the suburbs of Texas and we only heard what was on the radio," he adds. "So it's like, maybe now future Win and Will could hear us on the radio at some point. That would be nice."