The Mann Center is a concert hall that only operates during the summer months. It has 4,700 seats under cover and more than 8,600 spaces on the lawn and outdoor seating. For those not in close proximity to a calculator, that’s a capacity of around 14,000 audience members. To put this in perspective, the last time either of these bands played in Philadelphia, they were performing to a crowd five times smaller.

I suppose that with a critically lauded new album and the exponentially growing popularity of their anthemic song “Wake Up,” that this huge turnout was to be expected. Still, it was unsettling to see a band that I had learned to love as a church-basement-playing musical collective with rising potential was now playing at a venue one step down from a place U2 might sell out. I wondered if Arcade Fire would forget about its humble beginnings, start licensing “Keep The Car Running” to Toyota commercials and become too much of a mold of the aforementioned arena-rock regulars. Would I have to watch helplessly as my indie-byronic-heros shout “Are Y’all ready to rock?” to a screaming amphitheater, devoid of irony?

With all qualms aside, I settled down in an oddly slanted seat at the front of the outdoor seating section as Spoon took the stage. I can’t imagine a more perfect opener for Arcade Fire. Although they have evolved past the dirty garage sound of their early recordings for a more expansive musical palette, the energy of their concerts still mirrors their most vicious days. Lead vocalist Britt Daniel’s powerful voice translates surprisingly great in the live setting. It ranged from a wild, sharp snarl, like in “Written In Reverse,” to a seductive croon on “I Summon You.” The setlist was a pretty satisfying one- they played many fan favorites, like “You Got Yr Cherry Bomb,” new hits (“Nobody Gets Me But You”) and even took tracks off the underplayed Kill The Moonlight. The band added a three-person horn section to their lineup, which made the hooks on “Rhythm and Soul” and “Jonathan Fisk” much more muscular and apparent.

By the time Arcade Fire took the stage, (9 pm to be exact), every seat in the venue was filled, and I had completely forgotten about my reservations about the show.  Their set went above and beyond expectations. There was a minimum of eight musicians on stage at once, all of whom were constantly moving:  passionately whacking additional drums, shouting into megaphones or dancing and thrashing about to their music. Each member of the band switched instruments, so a glance away from the stage might result in the bassist’s move to a stack of synths, or the violinist’s new occupation on the drum set.

Aside from the clichéd opening song “Ready To Start”, the setlist was well-chosen. It relied nearly equally on material from The Suburbs, which was met with enthusiasm from the audience despite most members not knowing the lyrics to an album that hadn’t officially dropped yet, and from Funeral, whose tracks hit the crowd most powerfully during the show. Only three songs from 2007’s Neon Bible were played, but it was easy to forget about the politically charged tracks left out from the set list when surrounded by great new songs and Funeral’s classics.

The show’s strongest point was inarguably the closer: hearing 14,000 euphoric fans screaming along to the wordless chorus of “Wake Up” is one of the most fruitful concert experiences one can have. Lead singer Win Butler came off most passionate on “Neighborhood #1 (Tunnels)”, Butler along with the simple piano figure which rose to powerful heights, had the audience in a chokehold. The penultimate Suburbs track “Sprawl II (Mountains Beyond Mountains)” sounded especially strong, with violinist, drummer and Butler’s wife Regine Chassange who reasserted herself as a valuable element of the group by taking vocal duties on the pounding anthem.

One of the more interesting moments of the night was when Arcade Fire took the late punk rocker Jay Reatard’s “Oh It’s Such a Shame,” and turned it into a sweeping, cathedral tribute. During the Generation-Y bashing “Rococo,” there is a line which asks of the kids, “What is that god awful song?” which is usually followed by repetition of the title lyric, but instead Butler went into a refrain of “I gotta feeling/ tonight’s gonna be a good night.” Low blow, Arcade Fire, low blow.

Just like in that song, there was somewhat of an awkward generational gap at the show. Their music has qualities to appeal to classic rock fans turned off by most modern music: the band’s raw passion evokes Bruce Springsteen, and their music is way too catchy for fans of U2 and David Bowie to ignore. Arcade Fire’s music conveys emotions and themes that connect with a newer generation of teenagers and twenty-something year olds, making them the unofficial anthem writers of the new millennia. They embrace a grandeur and hugeness that many classic rock bands do, while also conveying a sense of topicality and youthfulness without any hipster-pretentiousness, making their music and spirit something that fans of any age can enjoy. These factors are what brought together members of the audience, which seemed to have an almost one to one ratio of fans in their youth to fans over thirty.

By the end of the night, my nerves about my cherished little indie band from Canada had melted away. I came to the realization that Arcade Fire wasn’t “selling out”, they were getting what they deserved as musicians. This band makes music grand, orchestral, dramatic, and creates a rich emotional sound big enough to fill a stadium. Now they are doing just that.