It’s undoubtedly one of the smaller audiences in recent memory for the Lumineers at Boettcher Concert Hall on Thursday afternoon. Roughly a dozen onlookers, most of them busy tinkering with camera equipment, are scattered across the 2,362 plywood seats available in the stately round symphony hall. The stage is far from sparse though: behind the five members of the Lumineers sit roughly fifty musicians wielding a variety of string, brass, and percussion instruments. On first glance, it does not seem the most natural combination: the folk quintet’s shabby-looking name-labeled kick drum at center stage and singer Wesley Schultz’s road-battered Guild guitar juxtapose sharply with the polished luster of the violins and cellos a few yards away.
 
By now, anyone who attended the Lumineers’ Sunday night show at Red Rocks can surmise the reason behind this rehearsal: the Colorado Symphony joined the commercially and critically successful Denver-based quintet for the second of their sold-out homecoming shows. The collaboration is the most recent in a series of popular rock and classical crossovers for the Colorado Symphony, a list whose participants include flamenco duo Rodrigo y Gabriela, Phish frontman Trey Anastasio, Ben Folds, and most notably, Denver indie folk act DeVotchKa, who released a live album with the Symphony last year. The success of this particular alliance, along with the prodigious efforts of DeVotchKa multi-instrumentalist and composer Tom Hagerman, played an integral role in bringing in the Lumineers on this rainy afternoon.
 
“DeVotchKa’s been a tremendous collaboration for us,” says Tony Pierce, Vice President of Artistic Administration for the Symphony. “That’s how Tom got involved with this gig.”
 
Hagerman, who studied music theory and composition at the University of Colorado-Boulder, wrote the orchestra arrangements for the Lumineers/Colorado Symphony performance. Around the time of the release of the Lumineers’ self-titled debut album in April 2012, Pierce first approached Schultz and drummer Jeremiah Fraites about joining forces with the Symphony.  When it came time for the band to choose an arranger, Hagerman’s resume as a DeVotchKa member stuck out. Though the band was on the road at the time, Hagerman took painstaking efforts to ensure they heard his work composing string, horn, and percussion backing to the songs on The Lumineers.
 
“Tom would write a chart for a song and put a MIDI file in a Dropbox that they could listen to while they were out on the road,” explains Pierce. Fraites was initially skeptical of the “video game-like” sound of the computer files. “It was almost off-putting,” recalls the founding member. “But now being here at Boettcher, it has sounded amazing. It’s really surreal.”
 
For a group with renowned success in folk music, a typically minimalist genre, the five members of the Lumineers (Schultz, Fraites, cellist Neyla Pekarek, bassist Ben Wahamaki, and pianist Stelth Ulvang) had to put a certain degree of trust in Hagerman to maintain their signature easygoing Americana sound while interposing the sophistication of classical symphony music. “It’s strange because they’re on sheet music, and we have this policy where if something goes wrong, it’s no big deal,” explains Schultz. “We’re a little loose that way.”
 
Eventually, they decided to go all in and use the Symphony to its full potential. “We have a tendency to really micromanage,” claims Fraites. “We’re really driven about the sound we want. But with this, it was like: Let’s get the whole orchestra out.  We could have brought out twelve people but we said let’s bring out as many as we can. And Tom has done such a great job of orchestrating it all.”
 
The Boettcher rehearsal is not without its hitches: the transition into the chorus of “Big Parade” in particular delays the session for several minutes. Colorado Symphony Resident Conductor Scott O’Neil is concerned about what he perceives to be an extra beat, and there is an extended back-and-forth between him and the band members. Pekarek, who the other members describe as the act’s “secret weapon” on vocals, appears most comfortable with O’Neil’s direction, likely due to her choice of instrument. But Schultz repeatedly stops the up-tempo song as the issue persists, and eventually Hagerman, heretofore one of the few onlookers, hops onstage to mediate. The mastermind behind the operation quickly resolves the problem, bridging the gap between folk-ster and fugue-ster. As the practice concludes with “Submarines”, embellished with a lovely bassoon opening, a sense of triumph fills the nearly empty concert hall.
 
The Lumineers have played Red Rocks before, opening for Cake in July of 2012. By this time, the band was a marquee name in its own right, and on their way to reaching number 2 on the Billboard 200 Album chart for their Grammy-nominated debut and number 3 on the Hot 100 chart for single “Ho Hey” (Spotify has the song tallied at nearly 100,000,000 plays).  They had also expanded from a trio to a five-piece with the additions of Ulvang and Wahamaki, who they met after a show at Boulder’s Fox Theatre. Although nearly every Colorado act dreams of playing the famous outdoor amphitheater, the experience was notably slapdash.  “Our soundcheck was cancelled, and we didn’t even meet Cake,” remembers Fraites. “It was like one foot in, one foot out.” But the band opened to a full crowd, and the members looked forward to their next chance to perform there, this time as headliners.
 
“I just remember thinking…it’s gonna be cool to play there at night someday,” adds Schultz.
 
Since the Cake show, the Lumineers have sold out shows all over the country, performed at the Grammies last February, headlined numerous summer festivals, and released a deluxe edition of their debut. The two full-house home state performances at Red Rocks arrive on the eve of a massive world tour that will include dates in Europe, Australia, and Japan. For their remaining US dates this year, the band is bringing along another Denver music staple: Nathaniel Rateliff.
 
“When we’re asked what we are listening to, we almost always say at least say one Denver band,” says Pekarek. “I think the music scene here is so thriving.” The success of the Lumineers has certainly played a significant role in bringing national and international attention to the Colorado music scene, and the numerous sold out shows remaining this year should expose many to the work of Mr. Rateliff. But it’s not simply the songwriter’s geographical proximity that earned him the opening spot.
 
“Denver has a few musicians we really like that much,” says Schultz. The band also booked Denver folk act Paper Bird as openers for the Saturday night show. “It’s not just a handout. It’s because we think these bands are great.”
 
Furthermore, the Sunday night show exposed the nearly 10,000 people in attendance to some of the Lumineers’ biggest fans: the Colorado Symphony. Pierce is excited for the precedent set by Sunday night’s collaboration and previous work like the Beck Song Reader performance with Rateliff last June.
 
“It’s us integrating ourselves into the music community in a new way” he explains. “It helps to push us to a tipping point with a new audience.”