Nearing the end of Cloud Cult's Friday night concert at Orchestra Hall, lead singer Craig Minowa expressed an insecurity: "We were really nervous about going into the orchestra setting," he said to the crowd. "We were like, 'Will they clap? Or will it be really quiet?'"

But Cloud Cult's audience — from young children hoisted on their parents' hips to elderly fans including Minowa's 95-year-old grandmother — spent almost the entire concert on their feet producing screams powerful enough to demand two encores.

Minowa's (for-naught) worries stemmed from memories of the last time they played Orchestra Hall as part of a 24-hour concert when their 1 a.m. spot drew 30 people.

"This is a stark contrast," he said to the nearly sold-out audience. "It's something you would never even dream of. It's beyond dreams."

Despite concerns about the venue's formality, musicians and fans reveled in the acoustics that allowed listeners to distinctly hear even feet tapping and fingers hitting strings.

And there were plenty of strings to hear. The Minneapolis-based band features electric and acoustic guitar, violin and cello, as well as piano, horns and percussion. Oh, and live painting onstage.

Accompanying songs that ranged in style from percussion-heavy rock numbers to violin-horn duets to piano and acoustic ballads were multimedia presentations matching the beat and subject matter of the songs.

Although a few complained about muffled lyrics, audience members held an overall consensus that the band's message of optimism and overcoming tragedy — Minowa and his wife, Connie, lost a two-year old son in 2002 — was inspiring, and their songs' simple power was amplified by the numerous possibilities Orchestra Hall allowed that other venues didn't.

Many in the audience had seen the band play at First Avenue in Minneapolis. Craig Delin, 34, who drove six hours from Thunder Bay, Ontario, has seen the band play four times.

Three young fans praised Cloud Cult for its musical complexity. "They have a really mature sound, and I really like the metaphors [in their lyrics]," said Eleni Sophocleus, 13, with her friends, Grace McEnery, 14, and Emma Wellik, 13.

Ushers said while of course the screaming fans were a strange sight to behold at the classical music hall, the behavior was unusual even for the few rock events they hold.

Rhiannon Dominik, 17, said the only other times she'd been to Orchestra Hall were on school field trips to traditional performances.

"It's not that boring, put-you-to-sleep, sit-still-and-be-quiet type concert," she said. "It's get-up-and-be-loud!"

A dedicated follower of the band, Kathryn Schaefer, 40, described the concert in two words: "Extraordinary perfection."

"It's bringing it back to the roots of the music, the true music, with the acoustics," she said. "It's something that makes you feel better when you leave."

With teary eyes, Mark Allister, 53, raved about the emotional camaraderie formed in the crowd, as the band acknowledged that everyone has suffered loss. At the end of the concert, Cloud Cult played "Dance For the Dead," asking the audience to honor their lost loved ones, singing: "This is the dance to bring the dead to the living. Can you hear them come?"

"They're beloved," Allister said. "They take emotional risks that others don't."

Shannon Frid, Cloud Cult's violinist, said both the emotional and musical qualities of the performance were amped up because of the special venue. The stakes were higher.

"It was unbelievable — the most amazing show we've ever done," she said. "There's been so many famous musicians who've played here, like Yo-Yo Ma."

She said, as a strings musician, it was an honor.

"It's Orchestra Hall," she said, eyes wide and head shaking in disbelief. "It's Orchestra Hall."