(CNN) -- Blues singer Rita Chiarelli has played every kind of venue during her award-winning career: nightclubs, music festivals, concert halls.
But of all those locales one remains unforgettable: the Louisiana State Penitentiary at Angola.
Chiarelli, an Ontario native, went to Angola with the intention of playing solo for the prisoners, but wound up performing and recording with inmates, an experience she says changed her.
"I had no idea that I would be so moved and that my heart would be opened up so much from spending time with these guys," she said.
Chiarelli's unlikely collaboration with Angola's prison musicians is documented in the film "Music from the Big House." She is touring North America, showing the film and performing for audiences.
Chiarelli said she arranged to get a tour of Angola a decade ago after learning of its rich musical history. The legendary blues/folk artist Huddie William Ledbetter (better known as Leadbelly) plied his 12-string guitar from behind the walls of Angola. His music came to light through the efforts of folklorists John and Alan Lomax, who recorded Leadbelly and other inmates.
"I saw where Leadbelly was probably incarcerated," she said. Angola "haunted me, you know, the Mississippi River flowing through it and ... I was just haunted by these images. And that all this music had come from this place."
Chiarelli said she began to wonder whether there were any musical inmates currently serving time at Angola. The answer was a resounding yes.
"We have 10 or 12 bands" comprised of prisoners, Warden Burl Cain confirmed to CNN. He said he didn't hesitate when Chiarelli pitched him on the idea of performing with the inmates, and having a documentary crew film it.
"When she talked about a blues concert, that got our attention. We were excited about that," Cain said. "It was a real morale booster for the inmates in the (music) program. She stood for the blues and we like that music here."
"I think that the wardens trusted me," Chiarelli said. "I met with them several times and I convinced them that my aim was true. Honestly I felt that it was really important historically to once again document music that was going on at Angola."
The documentary shows her working intensively with musicians in three bands in a variety of styles -- blues, country and R&B.
"They were really great (musicians). A few of the vocalists -- I was very, very impressed," Chiarelli said. "I mean they just have so much soul and they give it when they're performing."
As they rehearsed for a concert in the prison chapel, Chiarelli developed a close rapport with her bandmates, a bond that is evident in the film. Some of them reveal on camera how their lives got off track, putting them behind bars.
"They opened up and told us their stories, which was the wondrous part of the film," Chiarelli said. "It's really moving to see a fellow that's in there for murder tell his story, tell his circumstances, realize that there's victims -- that a lot of people have been hurt through his actions. It's emotional."
Most of the musicians (singers Ray Jones, Albert Patterson, Emanuel Lee, bassist Laird Veillon and drummer Calvin Lewis, for instance) are serving life sentences without the possibility of parole.
"Ninety-five percent of them are going to die here," Cain said. "It's really important to give them encouragement and hope. ... You can do the time if you have hope."
For many, hope comes in the form of playing in a prison band.
"It's something that's really kept me going," Jones told filmmakers. He's been locked up in Angola for 32 years.
Chiarelli said her documentary reveals "how these inmates feel when they're performing ... and the release of anger and frustration and everything that happens through the power of music."
She said making the film made her mindful of not only the victims of the crimes committed by the men, but also of the prisoners' capacity for redemption.
"Through the film we see the humanity of these folks and realize that sometimes it's not always bad people that do bad things," she said. "Sometimes good people zig instead of zag and end up in a situation where something horrible happens."
Chiarelli said her experience "moved me deeply and just opened my heart to realize that sometimes people need to be forgiven, that maybe, you know, some people have a right to be forgiven."
She is aware that's a controversial proposition, one she is prepared to let audiences debate. So far she is encouraged by the reaction.
"A lot of them (moviegoers) come out of (screenings) and are moved to tears," she said. "And I think a lot of them, their outlook is changed."