(CBS News) OSSINING, N.Y. - At one music workshop, the lessons are not surprising, but the students' resumes are.
Daniel Barthels, Denis Martinez and Kenyatta Hughes are part of a rather unusual group of musicians.
The unlikely school of music is located in Ossining, along New York's famous Hudson River Valley, inside the famous maximum security prison commonly known as Sing Sing.
"Playing an instrument keeps you disciplined," Martinez observes.
"It gave me a way to say things that I couldn't perhaps articulate in words," says Hughes.
Daniel Levy teaches several-hour-long Musical Connections classes twice a month.
The program is funded by the world-renowned Carnegie Hall's Weill Music Institute.
Working with the prison, its mission is to make music accessible and - just maybe - something more.
"I'm not a social worker, I'm not a therapist," Levy says. " ... But my instinct is that this work has the potential to help people change."
Isn't he helping to reward people who've done wrong?
"I thought about that in the beginning," Levy responded, "and it almost made me not want to do the work. ... (But) if I can help them self reflect or transform through making music, then I want to be involved with that."
"I do music, and that's my way of expressing myself now," says inmate Danny Barthels, 25, "but I didn't have anything to identify myself with. And drugs and crime is the road that I went down."
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He's now proficient with the violin. These days, when he gets angry or frustrated, his instrument is his outlet.
He's among 16 students hand-selected from a prison population of 1,600.
It seems hard to believe that someone who could one day stick a gun in someone's face ... could really be transformed by music. Should people believe that?
"Ahh -- I think they should - because it happens," Barthels says.
It happens by learning read and write their own music - a bit of "freedom," they say, in a place where that's rare.
As the workshop progresses, Carnegie Hall sends in more musicians to work with the students and perform their pieces.
Martinez wrote a song called "Dear Mother," which he practiced with professional singer Leeann Westover. The song is an open letter of apology to his mom.
"I always had a creative inkling, but I used to take this energy and destroy more than I used to create," he says.
Hughes says, "Ii couldn't think of anything that I had done that I was actually done that I was proud of like I'm proud that I accomplished this."
He got to share one of his works with jazz great Charlie Porter.
Asked directly if music can really change him - Hughes, who's doing time for murder, replied, "I think it must because -- with all due respect, I'm not a murder. I'm a musician. I can never undo what I've done, but when it's something of this magnitude, you need something of extraordinary magnitude to counterbalance that, to give you a new identity."
One discovered through music.
The program is just three years old, and it's hard to quantify whether it works, but there's no doubt it does bring something beautiful to a rather unlikely place.
Carnegie Hall says 90 percent of those who start the program stay in it.
Levy challenges the participants not just to play music, but to compose it. Most learned after they went to prison, and their families had never heard them play - until now - on TV.
To see Seth Doane's report and hear the music performed by the prisoners, click on the video in the player above.