LAST YEAR, Emmylou Harris unplugged the Hot Band, abandoning the electric sound of the aptly named band she'd fronted for 15 years for the all-acoustic sound of the Nash Ramblers. This sea change was the result of a lingering bronchial infection that forced Harris to reexamine her approach to performing.

"I wasn't just physically sick, I was really tired of what I was doing," Harris said last week from Nashville, "and it took me getting sick to realize that I had been down that one road of creativity -- I'd plowed that field -- and it was time to do something different. Getting sick just made me see the whole picture."

Rather than just taking a rest from performing, Harris retooled with a band led by mandolinist/fiddler Sam Bush (a founder of New Grass Revival) and dobro/banjo/guitar player Al Perkins, perhaps best known from the Flying Burrito Brothers, the seminal country-rock band that Harris had almost joined at the very start of her career in 1971 (they broke up a week after asking her to join). With dobro and mandolin subbing for pedal steel and electric guitar, and former Sea Train drummer Larry Atamanuik working mostly with brushes instead of sticks, the sound not only is kinder to Harris's vocal cords but showcases her smoky soprano to greater effect.

"I feel that it's more natural," Harris says. "To compete with electric instruments, you have to throw your voice into a different gear that is slightly unnatural, at least for me. The nature of these instruments allows more room for the vocals and I feel I'm really singing better now that my voice is stronger and I don't strain it."

And, Harris adds, moving from electric to acoustic backing hasn't really diluted the dynamics because "this band plays very aggressively."

From her arrival on Washington's folk circuit in the late '60s and early '70s, there's always been a strong acoustic strain in Harris's music, and though her reputation was made in country rock (particularly the two albums recorded with Gram Parsons before his death in 1973), bluegrass has been a cultivated root since she was turned on to it in the early '70s by John Starling of the Seldom Scene. "Hanging out with the Scene at the Red Fox and Childe Harold, playing music into the night -- that was where I went to bluegrass school," says Harris.

It was also Starling who turned Harris on to Ricky Skaggs; in 1979, Skaggs and Harris rocked Nashville with the rootsy "Blue Kentucky Girl" album -- many date country's neo-traditionalist movement from its release. In 1980, Harris dug even deeper into the past with a collection of classic (and acoustic) bluegrass tunes titled "Roses in the Snow."

"One major label executive was convinced that it was going to be the end of my career," Harris recalls. "He literally told me, 'This is it if you put this record out.' I told him I really had no choice because that's what was happening with me creatively right then, that it was more important that I follow my heart. I also felt it might set me back, but I sort of hoped that I could come back from it. Fortunately it turned out to be one of my most successful records, though at the time no one expected it to do well."

Twenty albums and dozens of awards into her career, Harris was able to elicit a different response from Jesse Ed Norman, the Warner Bros. Nashville chief, who was so taken with the sound that he convinced the Grand Ole Opry folks late last year to let Harris and the Nash Ramblers record the live album "At the Ryman" in the fabled but now shuttered Ryman Auditorium, the Opry's home base from 1943 to 1974. Closing in on its 100th anniversary, the Ryman remains a major tourist attraction, country music's Carnegie Hall.

Harris has always been expansive in her song selection, and her new album is no exception, ranging from Stephen Foster's 140-year-old "Hard Times Come Again No More" and several Bill Monroe and Louvin Brothers classics to Steve Earle's "Guitar Town" and Bruce Springsteen's "Mansion on the Hill."

"I see songs in an unbroken progression," says Harris. "No matter when they were written, if they hold up lyrically, then I see them as fair game. Foster's song is so timely -- all we had to do was change the word 'cabin' because that dated the song a little bit but it didn't change the spirit at all. I'm happy that there are no restrictions on the songs that we can do, and it gives me so much more room for my voice. And I really enjoy working with these guys; they're very creative and it's wonderful to set yourself a certain limitation, using just acoustic instruments, and see what comes up. You end up with a style that's a product of your limitations and you've got to have those."

The new album also includes "Calling My Children Home," a Monroe classic originally recorded by the Country Gentlemen and re-recorded but never released by the Trio, Harris's collaboration with Linda Ronstadt and Dolly Parton. Ironically, Harris never saw the hometown Country Gentlemen "until I was out working and we played gigs together. Growing up, it wasn't the kind of thing where you got in the car and went up to D.C. by yourself to watch people play, not my generation of young women."

The Nash Ramblers -- who also include guitarist and harmony singer Randy Stewart and bassist Roy Huskey Jr. (his dad was the Opry bassist for many years) -- also supported John Starling (who has rejoined the Seldom Scene) and banjoist Carl Jackson on the Grammy-winning Sugar Hill album, "Spring Training." Harris, who contributed a few vocals to that album, says that "it was turned down by every major label and I think it's one of the best country records of the year, though it won in the bluegrass category. It really embraces both country and bluegrass."

As does Harris, currently president of the Country Music Foundation, the historic/educational group that doesn't follow the common Nashville line of ignoring bluegrass "except when they have to honor Monroe. And that's terrible," Harris notes. At the Foundation, "there is perspective and the whole history of country music is looked upon with the proper amount of respect and passion."

Harris's most recent passion has been for buckdancing, the stiff-arms/flying-feet country dance that she performed with 80-year-old Bill Monroe on the Nashville Network concert special (now on Warner Home Video), filmed while she was recording her new album at the Ryman. "For somebody who's been dancing in their basement for a year on hard concrete, to get on that wonderful wooden stage was just like heaven," says Harris, who travels with a three-foot-square practice board.

So look out, Paula, Janet and Madonna?

"Oh yes," Harris laughs. "I'm sure it's just going to sweep the nation."

EMMYLOU HARRIS & THE NASH RAMBLERS -- Appearing Friday and Saturday at the Birchmere. Harris & the Nash Ramblers return to the Birchmere May 1 with John Starling and Carl Jackson. Call 202/432-7328 or 703/549-5919. To hear a Sound Bite from "At the Ryman," call 202/334-9000 and press 8101.