Staying True to Earthy Country Roots : Music: Emmylou Harris has done a lot to widen the appeal of country music, without compromising the integrity of its sound.

Emmylou Harris is as responsible as anyone for broadening country music’s once-limited appeal.

In a recording career that spans nearly two decades, she has consistently crossed over to mainstream pop audiences--but not with diluted, homogenized pablum.

Harris has steadfastly remained true to the spirit of traditional country and its gritty, earthy roots. She has freshened it up, livened it up, but never compromised its inherent integrity.

“I think as soon as you start trying to cross over, you’re dead,” said Harris, who will appear Sunday night at Humphrey’s on Shelter Island. “Pop music is popular music, and all kinds of music can be popular.

“I believe the music that has the most staying power is unusual and different, not homogenous, so I’ve never been interested in crossing over. I think the way you cross over is to find your albums in the living rooms of people who also listen to all kinds of other, different music.”

Harris’ philosophy about country music stems from her apprenticeship with the late Gram Parsons, the founding father of country-rock. Parsons came up with the amalgam in 1966, with the International Submarine Band, and later refined it with the Byrds (on 1968’s “Sweetheart of the Rodeo” album) and the Flying Burrito Brothers. The two met, by chance, in 1970, in Washington. Harris, a native of Birmingham, Ala., had just moved south from New York, a refugee of the waning Greenwich Village folk scene. Parsons was in the midst of his final tour with the Flying Burrito Brothers.

“I was playing a little folk club, and the Flying Burrito Brothers were playing down the street,” Harris recalled. “They came in after their show, and the next night, when they were in Baltimore, Gram came in again. He was talking about doing a solo album, and he told me he wanted a girl singer.

“So, between sets, we just sat backstage in this little basement club, sitting on kegs of beer, singing some songs, and he told me he wanted me on his album.

“I thought nothing of it--people are always promising you things, and I was thinking, ‘you’ll call me, right.’ But he kept in touch, and finally, I got a ticket to come to L.A. and work on his album.

“And that started my apprenticeship in the world of Gram Parsons and his music.”

Upon her arrival, Harris said, Parsons played her a bunch of old country songs, just to show her where his heart was at.

“I just became a complete convert,” she recalled. “I felt I had struck a mother lode, this incredible vein of gold that never ended. I remember thinking to myself, how come I never heard these people before?

“I can’t explain what the sound was like, the harmonies and the songs--and then to discover there was more music like this. And, once I started listening to those songs and learning those songs, that was the way I looked at music--through the eyes of a harmony singer.”

Harris continued to record and tour with Parsons until his untimely death, of a booze- and drug-induced heart attack, in 1973. A few months later, intent on keeping alive his legacy, she formed her own band and eventually landed a recording deal with Warner Brothers Records.

Since then, Harris has interpreted myriad traditional country tunes on her records, including “When They Ring Those Golden Bells,” “Tennessee Waltz” and Hank Snow’s “I’m Movin’ On.”

She’s also written originals in the same style, with the same spirit, and covered an eclectic array of pop songs--from the Beatles’ “Here, There, and Everywhere” to Donna Summer’s “On the Radio”--that she’s turned into instant country classics.

“It’s mainly the lyrics; there has to be something in the lyrics to make me want to sing a song,” Harris said. “I don’t worry if it’s country or not, I just figure out a way to do it.”

Harris’ latest album, “Duets,” is, as its name suggests, a collection of duets she has recorded over the years. Among them are “Love Hurts,” with Parsons; “All Fall Down,” with George Jones; “Star of Bethlehem,” with Neil Young; and “That Lovin’ You Feelin’ Again,” with the late Roy Orbison.

“The people at Warner Brothers had been talking to me for years about how many duets I’d done, and why don’t we do a compilation,” Harris said. “So, finally I said, sure, and we took 10 old sides, and then I wanted to put some new things on it as well.”

Appropriately enough, one of those “new things,” “The Price I Pay,” is a duet with the Desert Rose Band, fronted by Chris Hillman, the ex-Byrd who brought Gram Parsons into the band and then left with him to form the Flying Burrito Brothers.

“I’ve always wanted to do something with him,” Harris said, “ever since Gram introduced us.”