Mary Bridget Davies has nailed the art of singing like the legendary Janis Joplin.

“It was literally scientific,” Davies says. “I asked myself, ‘How does she do that? How?’ I spent years on and off playing with it. I had the raw material to re-create the sound, but it took a while to really do it. I blew my voice out figuring out ‘How do I crack this code?’”

She eventually cracked it and for the past seven years has starred in “A Night With Janis Joplin,” for which she received a Tony nomination. The musical, an imagined concert headlined by Joplin, visits Stifel Theatre Tuesday and Wednesday. It’s full of staples such as “Piece of My Heart,” “Me and Bobby McGee,” “Cry Baby,” “Mercedes Benz” and “Summertime.”

“What I love the most about the show — it’s like Janis’ ultimate concert she could have given if she wanted to,” says Davies, 41. “And though it’s called ‘A Night With Janis Joplin,’ it’s not just her. You assume it’s her all night. It’s also Aretha Franklin, Etta James, Odetta and Bessie Smith — a whole ensemble of women. That’s the treat.”

She says the show takes the audience along for Joplin’s journey to stardom, with the music that helped shape her.

“There’s monologues in between, it’s fun and it clips along at a good pace,” Davies says.

Of the show’s 26 songs, 23 involve Davies. Her favorite is “Ball and Chain,” a Big Mama Thornton blues song. “The way Janis does it is so different and so great,” she says. “Janis Joplin’s version is the white psychedelic version of it.”

Davies says it was crucial that “A Night With Janis Joplin” also tell the story of and give credit to the women who influenced Joplin. Otherwise, “it would just be an impersonation show, a sad and underdeveloped concept,” she says. “This is why we added the women who shaped her. She found it important, since she was a white woman in music getting all the attention, but, ‘hello, these are all the people who did it before me.’ She would herald these women.”

“A Night With Janis Joplin” got its start in 2012 as “One Night With Janis,” where it was performed in Washington, D.C., and Cleveland before being retooled for Broadway.

For its 2013 Broadway opening, the title was altered, and the cast was filled out. And additional music and some original music made it feel like a totally different show.

In its review

”A Night With Janis Joplin” — the New York Times praised Davies’ performance as a “positively uncanny vocal impersonation” — played Broadway for 141 performances over eight months. The original plan was for a two-year run. A move to off-Broadway was scrapped at the last minute.

The show has the blessing of Joplin’s estate, which Davies says oversees everything from a quality control perspective.

“I know there were different shows about Janis in the past,” she says. “But her siblings were like, ‘We’re telling the story right.’”

Davies has toured with Joplin’s band Big Brother and the Holding Company. And before “A Night With Janis Joplin,” she starred in a touring production of “Love, Janis” in 2006 as that show was winding down.

Davies discovered Joplin’s music as a child in Cleveland. While she was busy trying to listen to Salt-N-Pepa and New Kids on the Block, her parents played music by Joplin and John Lee Hooker.

“When people ask me which Janis Joplin songs I know, I say, ‘Which ones do you want to hear?’ I’ve been preparing for this role my entire life.”