Guitarist John Della-Selva had just finished an elegant solo and it was Debbie Duncan's turn. She scatted the sounds of a guitar, as if her voice were controlled by fingers as adept as Della-Selva's galloping on a fretboard. Then she looked up, opened her eyes and resumed singing the hopelessly optimistic standard "Blue Skies," her fingers snapping along in rhythm.

Duncan, a pre-eminent Twin Cities jazz vocalist of long standing, is into it even if absolutely no one at the packed Famous Dave's Sunday brunch applauds after each selection.

On this day, Duncan and her combo are sticking to up-tempo tunes. She's not in the mood for ballads because her sister just passed away and she doesn't want to be down.

Duncan has something to be positive about: her first new album in 12 years, "Full Circle," and two nights of release parties at the Dakota Jazz Club this weekend.

"I really like this album," she proclaimed the other day. "And I'm picky, picky, picky, picky, picky. Ridiculously picky."

In many ways. Duncan used to accept nearly every gig that came along. In the mid-'90s, she was the workingest singer in town, performing nearly every night in a variety of styles. Sometimes three assignments a day. But gone are regular gigs with Dr. Mambo's Combo and the old Rupert's Orchestra. She now averages about one performance a week. It's a choice.

"I'm definitely jazz," she said succinctly. "I'm not R&B. I don't think about screaming anymore. Debbie Duncan is 66. She ain't screaming. I'm sorry."

Over coffee on a recent afternoon, her jewelry screamed "musician" — mismatched music-note earrings in both ears; a G-clef symbol pinned to her cap and a microphone pendant on a necklace.

Minneapolis move

Raised in Detroit, she came to the Twin Cities in 1984 to fill in with Rupert's Orchestra for six weeks. She's never left.

"Debbie Duncan is one of a kind, a world-class singer and talent, in my opinion," said Andrew Walesch, a Twin Cities singer/pianist and music director at Crooners Lounge, where Duncan plays regularly. "Debbie is the consummate entertainer who seamlessly blends informality and class. She has an innate sense of swing and starts the night swinging so hard you can feel the walls shaking. Then she puts the room at ease by saying, 'How y'all doing?' "

Della-Selva, who has worked with Duncan on and off since the early '90s in various musical styles, agrees.

"She's the real deal. She's as good as it gets," he said. "She's a blues singer at heart like Miles Davis was a blues trumpeter. They know jazz. She calls tunes I've never heard. It's a deep well she draws from."

Duncan figures she knows 600 to 700 songs from a repertoire of 1,000 titles she's sung over the years. For instance, at Famous Dave's last weekend she accommodated a brunch-goer's request for "Nice Work If You Can Get It" even if Della-Selva had to wing it.

Not only is Duncan performing less, but her voice has changed.

"My voice has lowered," she said. "What's that they say? A wine gets fine with age. I'm that. I find phrasing and space in songs where I used to pretty much fill up every spot. I continue to learn."

Her phrasing is indeed wiser, her scatting more adventurous.

One thing that hasn't changed is her humor. It's still biting. An audience might not experience it. But her friends and fellow musicians do.

For example, there was the time that rock star Slash of Guns N' Roses sat in with Dr. Mambo's Combo at Bunkers in Minneapolis. He played an extra-long guitar solo during a blues song that Duncan was singing and afterward in the dressing room, she told her bandmates that she wasn't impressed by "Hash or Gash or whatever his name is," the story goes.

She knows she's funny.

"I thought about being a comedian but I'm not gonna do it," Duncan said with a straight face.

She's not a joke teller but more of a reactionary commentator who will zing when something strikes her fancy.

"Stuff just comes in my head," she explained. "That part of me is truly from a jazz place and I am in the moment. I very seldom sing a song the same way twice. Hell, I can't remember what I did. So I don't have to worry about that."

Flute major

When Duncan headed to Wayne State University, she started out as a flute major. She sang jazz in clubs in Detroit at age 19 or 20 (teaching herself to scat to keep the gig), tried to make it in the music industry in Los Angeles for several years and arrived in Minneapolis 34 years ago.

Duncan appeared in one theater vehicle at the Ordway but hasn't been able to plug into what she calls the Twin Cities musical theater clique.

She doesn't have an agent but she yearns for more out-of-town gigs. Through musician connections, she's performed in New York and Qatar, of all places. She's booked for a jazz festival next year in Memphis, where she was born before her family moved to Michigan a few months later.

In addition to her occasional singing gigs, Duncan teaches. She has some voice students at Walker West Music Academy and also works with youths at We Care Performing Arts.

Some of her performances are with her brother, William Duncan, a gospel organist and singer who moved to Minneapolis about 10 years ago.

Thanks in part to her brother, she is returning to the flute. He and her sister gave Duncan a new flute for Christmas since her previous one was lost long ago to a housing move.

"I'm thinking of myself as an intermediate flute player," Duncan said. "Vocals just came naturally even though I studied [flute] in college."

Recorded at the Dakota

The singer's new, crowdfunded album was recorded live at the Dakota in November. Duncan describes it as "a little bluesy but it's pretty much straight-ahead jazz." There are songs associated with Peggy Lee, Billie Holiday and Michael Jackson, among others.

"No one will probably recognize 'The Way You Make Me Feel' till I hit the chorus," she said of the Jackson hit. "It's slowed waaaaaay down. It's just bass and percussion and snare drums."

Keyboardist Adi Yeshaya produced the project. He and all but one of the musicians on the live album will be joining Duncan this weekend.

"This [album] I would listen to. I don't like to listen to myself," said the singer, who also recorded her first album live at the Dakota. "I'm a little proud of this one."

In addition to her album release shows this weekend, Duncan has something else to look forward to: the NCAA men's and women's basketball Final Four. She's an avid hoops fan.

"I watch all basketball. Except I don't like the G League," she said referring to the NBA's minor league. "I like professional. I like the college ball when it gets a little closer to the playoffs. And I love women's basketball. I'm a serious Lynx fan. I was a Lynx fan when they first started."

But when told that her Friday and Saturday engagements at the Dakota conflict with the Final Four, Duncan didn't miss a beat.

"Damn, I'm going to have to tape it," she said. "And stay away from people so no one tells me what happened."

Debbie Duncan
What: Album release party for "Full Circle."
When: 7 p.m. Fri.-Sat.
Where: Dakota Jazz Club, 1010 Nicollet Mall, Mpls.
Tickets: $25, 612-332-1010, dakotacooks.com.