PIANIST Barbara Higbie is discovering her voice. Known primarily as a musician -- she's released several Windham Hill albums with Darol Anger, the Anger/Higbie Quartet and Montreux -- Higbie's performed on more than 20 recordings, and has played classical, jazz, folk, Irish and African music, and even busked on Paris streetcorners.

But the quietly extraordinary solo album "Signs of Life," recently released on Windham Hill, is the first time Higbie has let her real voice be heard.

"I've been a closet songwriter for years, since I was 14," says Higbie, who appears Monday at Blues Alley. "But I was extremely shy about singing. The thought of singing my songs in front of people . . . it's much safer to do instrumental music."

The album's gentle power is enhanced by that sense of vulnerability, as Higbie confides in her songs.

"The songs came out of my late 20s, a pretty depressing period," says Higbie, 32, from her San Francisco home. "A lot of the ways I had done things weren't working anymore, and a lot of things were slipping away -- the band {Montreux}, relationships, even longtime friends. I wrote to comfort myself."

And as is sometimes the case with these things, Higbie ended up comforting others in the process. "Signs of Life" opens with "Waiting Song," a gently impassioned plaint about waiting for The Right One, a feeling everyone will recognize and empathize with.

Writing the song seems to have done the trick for Higbie, who recently married a recording engineer.

"Maybe you just have to write a song about it!" she laughs. "I wrote 'Waiting Song' mostly for a friend of mine, and she found someone, too."

Perhaps if you just sing along to it, something will rub off. Regardless, anyone who has endured a gray day will be encouraged by Higbie's plain-spoken lyrics, which are encouraging without cloying (don't call her new age); quite personal, yet so open and universal they allow listeners to imagine themselves singing them, too. And Higbie's voice, lovely and emotive, but not overly trained or polished, at times reminiscent of Joni Mitchell, Carole King and Karla Bonoff, is one of those naturals that's easy to sing along with.

The youngest of six kids, but the only professional musician in the family, Higbie grew up in Speedway, Ind. Higbie was actually a fiddler first -- she placed in the National Women's Fiddle Championships in the late '70s, and wrote all the string and horn arrangements for "Signs of Life."

Her family moved to Ghana for two years when Higbie was 13, then back to Orange County in Southern California. "The less said about which, the better," Higbie says.

The precociously multicultural Higbie felt alienated in the southern California mall culture and began writing songs, singing them for herself. She went to Mills College in Oakland and majored in economics, with the intention of going back to Africa and helping out there. But while studying French at the Sorbonne, Higbie played fiddle for change in the streets, she says, "I realized I could make a living at this!"

Returning to the Bay Area, Higbie became a force in the area's jazz, new acoustic and women's music scenes. The Boston Globe named her 1983 duet album with Teresa Trull one of the 10 best albums of the year. And with Marshall, Michael Manring and drummer Tom Miller, Higbie formed the category-eluding, is-it pop-jazz-or-new age? quartet Montreux.

After several albums with Montreux, Windham Hill urged Higbie to step out front and record her own album, with her own songs, in her own voice. Higbie chose Steve Douglas to produce, a session sax player for the Beach Boys and Phil Spector and "an authentic kind of guy," and he achieved an appropriately warm ensemble sound on the album, which features many of Higbie's old friends.

"I wanted it to be a very intimate sounding thing, and have some energy, too," Higbie says.

In her charmingly self-deprecating way, she adds, "I've been taking vocal lessons since, and I wish I could do the whole album over now. I think I'm a pretty raw singer, I don't have tons of technique. I think of myself as just your average person who just got the nerve to do this."

BARBARA HIGBIE -- Appearing Monday at Blues Alley. Call 202/337-4141.