If Nikka Costa wasn’t born singing, she raised her voice in song fairly soon thereafter.

“I think my umbilical cord was a microphone,” she says, only half joking.

She sang an opening set for Don Ho when she was five years old, recorded her first album when she was seven, performed in front of 300,000 people (with the Police, in Chile) at the age of eight, and shared a stage (at the White House) with her godfather, Frank Sinatra, at the age of nine. She and her father, Don Costa, scored a hit with the duet “Out Here on My Own” the same year.

Back then, she was a jazz girl. She knew Gershwin the way some little girls know Barbies.

“I had an early, early career sounding like a chipmunk singing torch songs with my father and an orchestra,” Costa once told a biographer.

Costa has been in the music industry for 29 of her 36 years. Her father was an arranger, singer and guitar player who worked with Sinatra, Sara Vaughn, and Paul Anka. She grew up in houses where Quincy Jones and Sly Stone would drop in to say hello. Don Costa died suddenly of a heart attack when Nikka was just 10. Her subsequent life was a musical odyssey that included a teenage bubblegum pop phase and a sojourn as a singing star in Australia in her early 20s.

Of late, however, Nikka Costa has concerned herself mainly with getting extremely funky. And though she has just produced the finest, grittiest, most honest record of her career – “Pebble to a Pearl”, released in October of last year – it didn’t happen in the manner anybody might have predicted when she was first heralded as the Next Big Thing.

Costa released two highly regarded but mysteriously ignored records for Virgin Records in the first part of this decade. There was a big buzz about her. She was named MTV’s new artist of the year in 2001, and her 2005 record “can’tneverdidnothin’” featured guests Lenny Kravitz and Prince on several tracks. Before Amy Winehouse, Duffy, and Joss Stone were heralded as so-called “neo-soul” singers, Nikka Costa was on the scene.

But the scene wasn’t quite ready. The recording industry was in tumult – Virgin went through four presidents in the course of her two records – and nobody knew quite what to make of this young singer with a retro soul feel, a redhead with voice like Aretha’s, a sharp-edged lyrical ability and a smart-assed funky edge. At one point, she was sent out on tour to open for Brittany Spears. It was hard to tell who was more freaked out by this, Costa or Spears’ fans – teenage girls who came prepared for costume changes and choreographed sugar-coated pop and were unexpectedly exposed to blistering live funk. “I think we scare a lot of them,” Costa told a San Antonio newspaper after one of the shows.

Indicative of the confusion was Virgin’s mishandling of her second record – a promo copy released in 2004 was pulled back and reconfigured, with different songs and ordering, before its official release in 2005. Everybody at the company apparently had a different opinion about what to do with Nikka Costa.

The singer herself had a better idea: she broke free from the label. Finally, she truly was out on her own. What she did next was gather a bunch of crack session musicians – including legendary soul drummer James Gadson – and head into the recording studio to get really and truly Old School.

“We made it ourselves,” she said in an interview this week. “So there were no suits anywhere near us –there were no suits in and out of the studio. We did it fast. We recorded 15 songs in five days. It was straight to tape, we were all in one room…it was just a big purge. It came from feeling liberated and happy to be free and do whatever, just not being told anything from any outside source.”

She wasn’t making music for some radio niche or to satisfy the dictate of some industry executive or yet another marketing strategy. Costa was making music to satisfy her own sound sense. She made an unadulterated soul record – with greasy guitar licks, surging organs, a bounce and a swagger behind soaring, exuberant singing – and when it was completed she formed her own label. It was called GoFunkyYourself! Records, Inc.

Without self-consciously trying to create some bygone sound, Costa just sang what came most naturally. The result is a record that sounds like it could have been made in the heyday of soul music, back when Stax and Motown and Atlantic were in their prime – the kind of music that had helped shape Costa when she was forming her own formidable voice.

“Obviously, I grew up around jazz and Big Band with my dad working with all those guys, and I love that music,” she said. “It’s part of my roots. But then when I became a teenager…Once I heard Stevie Wonder and Aretha Franklin and Chaka Kahn and Etta James, I was just done. It just made me feel good. I liked that it was like a combination of joy and sorrow – even when you are down, it’s like, let’s be joyous. It’s like religious music, like gospel – that kind of rise above it all feeling. Even the more commercial side of soul music in the ’60s, they were singing from where their gut was, you know? I just felt that, and I liked it. It gives me a feeling.”

What happened next was a beautiful convergence. Stax Records, the recording home of Otis Redding, Booker T and the MGs, Sam and Dave, and the Staples Singers, had been defunct for decades. But a few years ago, the label was revived. Some former Virgin employees who’d joined the new Stax caught wind of Costa’s new project. When Stax executives heard the record, they wanted it – without remixes, repackaging, exactly as it was. Thus “Pebble to a Pearl” found its perfect home, and Costa became a Stax recording artist.

“It definitely made a lot of sense, especially with the style of the record,” Costa said. “And it was purely coincidental. It was kind of, at that time, a match made in heaven. And of course, how cool is it to be on Stax? It’s historic.”

Costa’s voice, of course, is the first thing that jumps out. She has that effervescent, uncontainable quality so few singers in this world possess; with its soulful rasp and gritty power, her voice alone is an astonishment. But she also possesses a real sense of craft as a songwriter. Take “Stuck To You,” the new album’s opener. It’s one of those songs that is so easy and so fun that it seems like it’s always existed. It begins with a drumbeat straight out of Motown, and then a nice rolling piano joins in and the funk kicks in and we are off and running: “If you a star I be your Milky Way/If you a bar I drink up every day/If you the town I be the talk/If you the talk baby I be the walk…You be the time I be the clock/You be the tick I be the tock…”

The music has an irresistible groove – that’s enough, really – but there also usually something going on lyrically. “Keep Wanting More” is a concise little manifesto against consumerism that isn’t the least bit preachy just because it’s so goddamned funky (“Tired of oozing sentimental like a candy store/Tears trickling down like blood from a sore/’Cause your sun don’t shine anymore/It’s just a manufactured star on a worldwide tour…”). Or “Bullets in the Sky,” a reminder that the Iraq war isn’t over for the families who have soldiers fighting, despite our national lack of attention to it (“You can say the war is over/Try and sell that to a mother…”).

“I don’t want to be preachy and I’m not a heavily political person,” Costa said. “I am just a new mom, and every night we are watching CNN…I just felt, ‘God, as an artist, it is unbelievable nobody is talking about this.’ In the ‘60s and ‘70s all the artists were addressing what was happening in a really cool way, not in a preachy way. It’s just harder now because everyone is so cynical. I just related to it as a mother – wherever you are from, whether its here, or Afghanistan or Iraq, if your kid goes to war, your worry is the same…It’s not over, but a lot of people are tired of it – it’s like, move on to the next thing, to the ‘Octomom’ or whatever.”

She also performs the fine musical service of reviving a lost soul gem, the album’s only cover, a song called “Loving You” that was originally done by Johnny Guitar Watson. Costa heard the song while getting a tattoo and had a hard time tracking it down to its origins. When she brought it up during her recording sessions, her drummer, James Gadson – who has played with everyone from Aretha to B.B. King to Martha Reeves and Herbie Hancock – knew exactly what she was talking about.

“He’s like, ‘I used to play with Johnny Guitar Watson,’ and I was like, ‘Oh my god, well let’s do ‘Loving You!’,” she recalled. “And now I’m shitting myself because I’m singing ‘Loving You’ in front of James Gadson and I’m hoping I’m not slaughtering it.”

Hardly. The song has a sensual, Al Green kind of vibe, a slow rolling beauty that has the feel of a real classic. The record itself, in fact, has the feel of a classic. The title song, which was also written with her young daughter in mind, offers this advice: “Be yourself and liberate the world/Don’t be a pebble, be a pearl…” Janis Joplin was known as Pearl, and Costa definitely has a little Joplinesque boldness and verve. She’s free.

“What the hell is that?” she said, when asked about “Pebble to a Pearl. “Well, it’s be yourself – don’t shrink yourself to kind of make others feel more comfortable. Be as much as you want to be, be as big as you want to be, be everything that you want to be…But don’t dim the light inside of you. I think people do that a lot for whatever reason, whatever they are trying to protect or whatever they are afraid of. I was just thinking, well what would I want to tell my kid and her friends about life? Go for it. Don’t live halfway.”

There is a pervasive theme of persistence in the face of challenge, of being true to oneself, and it’s pretty clear these are songs sung from experience. As Costa sings in “Keep Pushin’:

“People wanna know/Why I’m so persistent/Swim against the tide/Resisting the system/Don’t I wanna be riding the charts/All she gotta do is forget about art/Shaking their fingers but I’m holding steady/Goin’ ’bout my bi’ness/ I’ll wait till they’re ready…”

She’s waited. Are you ready?

Nikka Costa performs at Saint Rocke June 13 at 9 p.m. $25. See saintrocke.com or nikkacosta.com for more information.