It’s not surprising you have to get past metal detectors and put your bag through X-ray machines to get into Cook County’s Juvenile Temporary Detention Center.

But once you’re inside, the school there looks pretty much like any other. The walls are lined with colorful signs and quizzes marked with A-pluses. There is one telling poster, though - it orders young men to walk down the hall in a straight line with their hands behind their backs.

Chicago Symphony Orchestra musicians walked these same brick walls recently, to perform. Two musicians, oboist Lora Schaefer and bass player Dan Armstrong,  worked with a group from England called Music in Prisons that paired them with 8 teen boys at the detention center.

Some of the teens had had exposure to music, but others had not. The musicians taught them the very basics on a guitar, bass, piano and drums. The teenagers wrote rap lyrics to the melodies they created.

“I’ve exercised every patient bone in my body this week – and then some,” said Jonathan McCormick, coordinator of programs at CSO’s Institute for Learning, Access and Training. He has a background playing tuba, but he joined the workshop, teaching the young men how to play piano.“We often talk about with the institute transforming lives through active participation in music, and we see that in the way that the kids relate to each other, the way they relate to us,” said McCormick.  “Because of music, really we’re all just – friends.”

One of the young performers, 16-year-old Cedric, used to play drums in church.

He gathered with the other young men in a corner, waiting for the concert to begin. Two security guards stood nearby. Most of teens at the center are awaiting trial. They’ve been charged with everything from drug possession to murder.

Another teen, Ricky, who’s also 16, has been in the center for almost 11 months. His only exposure to playing music before was messing around with his cousin’s guitar.

His dad, Robert had never seen Ricky perform. He sat in the front row. “This is the first time he’s done it, and we were surprised like, whoa,” he said. “My son, plays good? Ok, I want to see it to believe it.”

Six musicians from the CSO tuned their instruments on a stage inside the Center’s Chapel –  a brown-bricked room with not much more than plastic chairs, while the teenagers took their places.

They played the drums, keyboards bass and guitars, while CSO musicians joined with the cello, bass, oboe and violin. Some of the kids rapped.

Over the course of four songs they explored several themes, including “Turning Point” and “Hopes and Dreams,” rapping about feeling lost, screwing up and finally finding love.

Lisa, Cedric’s mom, could not contain herself. She cried, nodded her head and tapped her feet to the beat throughout the performance.

“What this is (is) wonderful, I am so grateful, I am so ecstatic,” she said. “I’m looking at all the different instruments, and then I’m listening to the words which were deep, real deep, sad, and then it got better. And then it got great. And so it’s just a beautiful thing.”

Ricky’s dad was pleased, too. He gave Ricky a hug after the performance,

“For me, seeing him for the first time playing instruments, he did pretty good. I mean they all did good. I’m proud of him, he did good,” he said.

The CSO program aims to transform lives with music, but neither of the teens had a sense whether this experience would change them.

Ricky did say he was excited he got to play different instrument and learned something new.