For more than 15 years now, Nashville singer Maura O'Connell has been celebrated as much for her rich, expressive soprano as for the delicate and challenging material she chooses to sing.

More than once, she's been called a champion of unheralded songwriters, often recording their music before the rest of the music world catches on.

"I don't think songwriters need me to be their champion," she says, "because they're good on their own. But I gladly take that as a compliment, to tell you the truth."

Looking through the credits of the albums she has recorded since 1989's stellar Helpless Heart, it's essentially a roll call of the most talented songwriters in Nashville and beyond -- Karla Bonoff, Paul Brady, Mary Chapin Carpenter, Shawn Colvin, John Gorka, Nanci Griffith, John Hiatt, Hugh Prestwood and Cheryl Wheeler, to name just a few.

She's also in tune with the new batch of talent now coming to light. For her last two albums, released on Sugar Hill Records, she has offered songs written by Patty Griffin, Kim Richey, Jim Lauderdale, Leslie Satcher and Ron Sexsmith, as well as young Nashville writers Clare Burson, Hillary Lindsey and Mindy Smith.

But here's the ironic part: Though she's drawing from the pens of young writers, her newest album, Don't I Know, considers the ups and downs of growing older.

"I'm 45, and you have a different perspective on life at that time," she says. "Both of my parents are gone and dear friends have parted. … When you're young and life is fun, it's great to have an upbeat record and not really delve into the depths of lyrics. I mean, I always did, but you know what I mean? It's difficult to find adult love songs -- if I can call them that. You have to root around more."

Produced by Jerry Douglas, Don't I Know features beautifully somber songs with titles such as "There's No Good Day for Dyin'," "Going Down in Flames" and "When Being Who You Are (Is Not Enough)." She also reveals that it has taken her years to sing the album's mournful title track, written by Tim O'Brien and Pat Alger, without breaking down in sobs.

Yes, she's fully aware of what you are thinking right now: "I'm sure I'm going to be asked if I'm depressed, because of this record, but a lot of the time you want a place to put all that stuff. And for me, the songs are a great place to go to have someone speak your emotions."

O'Connell moved from Ireland to Nashville in 1986, inspired by the eclectic roots music of the band, New Grass Revival, who soon became frequent collaborators. She issued a debut album on Rounder Records in 1988, but it was her time at Warner Bros. Nashville where she emerged as a first-rate musical interpreter. At the time, singer-songwriters such as Iris Dement, Lyle Lovett and Kelly Willis were signing major-label deals, and TNN: The Nashville Network was showcasing acoustic music on shows such as American Music Shop. O'Connell remembers taping two episodes of the series, including one with the Chieftains.

"It was a great band. Man, it was a great time. There was a real sense of possibility and change. That kind of died away," she adds with a laugh. "There was a great sense of being something different, about a movement. I think that was the start, to some degree, of the idea of Americana music."

A respected figure in the current Americana scene, O'Connell also sang high harmony on "Down to the River to Pray" from the O Brother, Where Art Thou? soundtrack. She also appeared in the Martin Scorsese film Gangs of New York and its companion soundtrack and got four free trips to Rome out of the deal.

O'Connell, who says she's always traveling, is particularly looking forward to two shows later this month in New York City. The venue, a world music club called Satalla, is hoping to attract the crowds that often frequented the Bottom Line, which was shuttered in January.

Asked how often she played the Bottom Line, O'Connell says, "At least once a year for the last God-knows how long. I was so sad. The last time I was up there, about a year and a-half ago, they were concerned at that stage. I thought things were going to work out. It was a home for a lot of people, and they were all great to me, always. They let me start off slow and build there. It was a great nurturing club, and there are lots of nurturing clubs."

She continues, "The music business has changed a lot, but there are still places that are great, like the Birchmere in Washington D.C., and the Ark in Ann Arbor, Mich., and McCabe's in L.A. These are clubs that nurture new acts, that are listening and have their mind open to songwriters like Mindy [Smith], and [non-songwriters] like me too, thank God. There are places around the country that keep people like myself and Cheryl Wheeler and John Gorka. We haven't become obsolete because there are still good places where we can still go play."

Later this summer, she'll also be playing festivals, listening rooms and festivals in the following cities: Philadelphia; Portland, Ore.; Seattle; San Francisco; Laytonville, Calif.; Schenectady, N.Y.; Des Moines, Iowa; and Covington, Ky., near Cincinnati.