They shuffle into a corner room in an aging Bangor office building the same way they slouch into classrooms all week long. Instead of carrying backpacks, they clutch cases that cradle instruments and sheets of music composed before their grandparents were born.

The boys and girls greet each other with glances, nods, hugs. The nine teenagers, ranging in age from 12 to 17, don’t seem unhappy to be giving up part of their coveted Friday nights to practice. In fact, the members of the Bangor Youth Chamber Ensemble seem anxious to begin rehearsing as they place folding chairs in a circle, unpack their instruments and music and begin to tune.

Into the center of the circle steps their teacher Sam Glazman, founder and conductor of the chamber group as well as the man who has taught all but one of them for years. Rapidly, he helps them tune, wasting no time with idle chatter.

He orders them to get out their parts for Johannes Brahms’ “Hungarian Dances” and leads them through the first piece the way a gym teacher puts students through warm-up exercises.

“Stop. That was very slow,” he observes. “Now, we’ll take it at the real tempo.”

Glazman stands in the center of the circle, tilting his head to better hear the first violins. He taps one foot and snaps his fingers while conducting.

The players rapidly glance up to follow him, then return their eyes to the music. The pace is faster than the first time through. The mistakes are few and only discernable to a trained ear until they near the end.

“Stop. Stop. Stop,” demands Glazman. “You forgot the end. Ya, pah, pah, pah, pum. But don’t lose the character. Always play with a bit of fire. Now, one, two, ready, go.”

Aliza Thibodeau, 12, is the youngest in the group. A seventh-grader at the William S. Cohen Middle School in Bangor, she has been taking private lessons from Glazman for just two years. Like the others in the chamber group, she was invited to join by her teacher.

The classical music she plays with Glazman is a far cry from the rock ‘n’ roll she grew up listening to in her parents’ east side home in Bangor. While her mother, Tania Erickson, a librarian at the Bangor Public Library, played the piano occasionally, it was her father, Tom, who cranked up the stereo and spun the records he had hoarded as a teenager that now are collectors’ items.

The 46-year-old dad never listened to classical music before his daughter began playing it.

“At first, I thought, ‘Well, that’s nice, and all well and good,'” he says. “But, she got better and better and now, it’s amazing to me. I learn these songs she plays and I get them stuck in my head. I love the stuff she’s doing. It’s nice to come home. Tania will be on the piano and then Aliza’ll play the violin. It just fills the house up with music.”

Jack Keenan of Bangor has played the violin since he was 6 years old. A student at Bangor High School, he plays at St. Mary’s Catholic Church on Sundays and in the school orchestra. He says that playing in the smaller chamber group is “more like a one-on-one experience” than performing with a larger orchestra.

“It’s quite incredible because some people in the group play much better than me,” says Keenan. “To hear people with a sound like that inspires me to play better and practice more. At home, I listen to a lot of jazz and hip-hop. Jazz can be played on violin.”

For six years, 16-year-old Mackenzie Gass of Bangor has taken viola lessons from Glazman. She says that because he knows the members of the group so well, he selects music that challenges the players, but doesn’t frustrate them because it’s far beyond their abilities.

“Sam is very strict. You have to listen or you’ll fall behind, and then he’ll get mad at you, so you have to be alert,” says Gass, who also plays in the Bangor High School orchestra. “But, I like the fact that he can focus in on us more individually than the conductor of an orchestra can. Plus, everyone in the group’s really close. Several of us started in together about four years ago, so we know each other very well.”

Claire Blanke, 17, of Bangor is the oldest in the group and a senior in high school. She is the only member of the ensemble who is not a student of Glazman’s. He teaches violin and viola but not cello. Blanke met him at a summer camp in seventh grade. When he needed a cellist for the group, he called her.

“I like Mr. Glazman,” she says. “He’s nice and he pushes his violins pretty far. In a small group like this, you have to depend on yourself more and you have to be stronger than you otherwise would be. It’s a good thing I’m out in a year. He might try to keep me around.”

Glazman, a native of Lithuania, came to Bangor from Canada about six years ago on a trip with a group of high school students. He made friends, connected with members of the Bangor Symphony Orchestra and opened his studio in the Exchange Building. Four years ago, he formed the chamber group, but until last year, they’d performed mostly at recitals.

Last fall, he felt the group was ready to perform in more public forums and, along with seven parents, took the ensemble to New York City where the adolescent musicians performed at two elementary schools in Brooklyn. Most of the children never had heard classical music before. In the thank-you letters they sent Glazman, the children wrote about how the music had affected them.

“It was a really fun trip. We played in front of a lot of students,” says Ryan Lena, 15, of Orono, first violinist in the chamber group and a student at John Bapst Memorial High School. “I think that we made an impact on these students’ lives and how they see this music. Maybe we even influenced whether or not they play an instrument.”

The group did its first paid performance on Valentine’s Day at the Penobscot Country Club in Orono. They haven’t decided whether to split the money evenly, so they’d each get $20, or bank it for a future trip, according to Aliza Thibodeau.

Glazman’s next goal is to expand the group’s horizons with more paid engagements so the teens can begin to get a feel for what the life of a professional musician is like.

“I saw them grow up, so I can scream at them and laugh with them,” he says after a rehearsal. “On Friday evenings, everybody’s tired and worn out, but each one of them gives the maximum to me and that’s very, very rewarding.”

Other members of the Bangor Chamber Group are Joanna McFarland, Hannah Siegel, Michelle Dempsey and Andrew LeClair, all of Bangor. For information on the Bangor Youth Chamber Ensemble, call 947-1779.