The Garage Never Sounded So Good : Children’s music: Nine years ago, Joanie Bartels did a kids’ album for a Van Nuys label. From that modest beginning, her career has taken off.

When Joanie Bartels recorded her first children’s album in a garage in 1985, she was not expecting children’s music to become her full-time career. Nine years later, Bartels is near the top of the field, with a gold record to her credit, 2.5 million of her numerous recordings sold, a home video series and plans for a TV show.

The success of Bartels and her label, Discovery Music, the Van Nuys-based independent label that skillfully and shrewdly developed the singer, attracted the attention of entertainment giant BMG last year, which is now in the process of absorbing Discovery and its artists into its children’s wing, BMG Kidz.

These days, between audio and video recordings, Los Angeles-based Bartels, assured and youthful at 41, regularly crisscrosses the country to perform. Saturday, she will appear in concert at Six Flags Magic Mountain.

Parents and children, she said, should come prepared to “really let their hair down and have fun with a lot of dancing, silliness and sing-along stuff.”

Bartels, with a background in adult rock ‘n’ roll and jazz, makes intergenerational participation easy. She mixes musical styles, but rock ‘n’ roll oldies and original, humorous pop-style songs predominate, from ‘50s and ‘60s rock classics such as “La Bamba” and “Bare Footin’ ” to her own catchy ditties about “Silly Pie” and be-bopping Martians and dinosaurs.

Children’s music can be cloying in repeat doses, but Bartels has staying power with polished, easy vocals that are notable for their mellow clarity. Her obvious career savvy is partnered by a disarming enthusiasm.

“Part of it is that I’m still kind of a kid myself,” Bartels said. “I can get out there and still be goofy and silly and play. I think children get that . . . I love what I’m doing.”

She’s especially enthusiastic about her new “Simply Magic” videos. The first two in the series, “The Rainy Day Adventure” and “The Extra-Special Substitute Teacher,” have given Bartels a chance to show off her acting skills in a story format.

“What we’re hoping to do next is a pilot for a children’s TV show, ‘Joanie’s Juke Box Cafe,’ ” a sitcom-with-music based on her new audio series.

Bartels began her career by folk singing in Massachusetts coffeehouses. That led to regular gigs with rock and jazz bands and studio work as a backup singer.

In 1985, Ellen Wohlstadter, a young mother and head of production at RSO records, called Bartels with an idea for a lullaby album, the first in what would become the Discovery Music’s “Magic Series,” themed audio recordings--bedtime, bath time, travel time--for parents, infants and toddlers.

Bartels, one of many who auditioned, got the job, thanks to her “incredible voice” and her sincere interest in the project, said co-producer David Wohlstadter.

For Bartels, the rewards were unexpected. “What I had been doing was great, but none of it compares to what I’m doing now. It’s a much healthier lifestyle, much more positive.”

*

Bartels didn’t start out with star billing. Initially, the recordings weren’t even marketed in her name, because “no one knew who Joanie was,” David Wohlstadter said.

His wife “pounded the pavement” and successfully placed “Lullaby Magic,” the initial tape, on consignment in Westside and Valley specialty and juvenile stores as “an impulse buy” during the 1985 Christmas season. “That’s the point we knew we had found a niche and started exploiting it,” David Wohlstadter said.

A few years later as “more and more people” seeking Discovery Music recordings began asking for Bartels by name, “we started switching the direction of the marketing, toward developing Joanie as a children’s artist.”

Meanwhile, competition in the field was growing and major labels such as A&M; began signing artists.

“It was (Canadian children’s artist) Raffi who put children’s music on the map,” Bartels said, “so that it wasn’t just a $2.99 album you picked up at Kmart. He really started working with children and child development through music; he opened the door for a lot of artists on the national level.”

However, Discovery’s years of “focus, patience and grass-roots marketing” on behalf of a concept and a single artist are still a phenomenon in the hit-driven recording industry, which has signed artists, then dropped them when immediate results weren’t forthcoming. Discovery maintained its formula, using it to develop two other artists, Dennis Hysom and Bethie.

Now that the label and its artists are being “absorbed 100% by BMG,” Wohlstadter and his wife will be “exploring new opportunities in the children’s entertainment field . . . but in this transition period with BMG, we’re out pitching TV shows for (Bartels, Hysom and Bethie) to cable, network, syndication and PBS.”

Singing is Bartels’ first love, though. “My mom told me that when I was about 3,” Bartels said, “I saw Rosemary Clooney, probably on the Mitch Miller show or on Ed Sullivan. She said from that I was just transformed, and I said I wanted to sing like that.”

The story was straight from her press bio, but Bartels, laughing, had an irreverent addendum: “I’m sure part of it was that she looked like an angel with her blond, blond hair that probably, on our black-and-white TV set, looked like it was glowing.”

* Joanie Bartels, Six Flags Magic Mountain, Valencia, Saturday at noon and 1:30 p.m. Free with park admission; (805) 255-4111, (818) 367-5965.