A few years back, Emmylou Harris, Linda Ronstadt and Dolly Parton got together and found that their friendship translated into exquisite ensemble singing. A little of their studio work found its way onto each of their albums, but an assortment of contractual problems kept them from pulling a Crosby, Stills and Nash. Now that Parton is no longer with RCA, the Trio Project has been resurrected and the singers have been at work in Los Angeles on an album that will be released by Warner Bros., probably in the fall. Ronstadt and Harris both record for WEA family labels.

"It's a lot of fun and they sound great," says John Starling, the former Seldom Scene vocalist who has been acting as the project's musical director. "People will pick up on their enthusiasm and their inability to cop an attitude. It's really been a community project." Starling wouldn't mention any specific songs, but he said the album is being produced by George Massenburg; among the musicians are Ry Cooder, David Lindley, Albert Lee and Mark O'Connor. The album will feature lots of traditional country songs, with an emphasis on harmony singing, but it won't be bluegrass, Starling says, because "everybody's afraid to do that."

Starling, an ear, nose and throat specialist who left the Scene five years ago for a private practice in Alabama, expects to move to Frederickburg, Va., soon. When he does, Washington fans, who have been limited to catching him during an occasional stopover at the Birchmere, will be hearing Starling's soaring tenor more often. "I'm going to have a little more time to play," he says, "and a little more wherewithal to play, as well." RCA's Falling Stars

Having lost Parton and Waylon Jennings to other labels, RCA must be wondering about the big bucks it has spent recently to lure some of pop's biggest names away from other record companies. Three of those acts -- Diana Ross, Kenny Rogers and Barry Manilow -- are coming off some of the worst albums of their careers. Ross' "Eaten Alive" peaked at No. 45 (her worst since 1978's "Ross") and is nose-diving out of the Top 200. Rogers' "Heart of the Matter" has done well in the country charts (No. 1 for six weeks), but peaked on the pop charts at No. 51, his lowest position since 1978's "Love or Something Like It." And Manilow's "Manilow" peaked at No. 44, the lowest charting album in his 12-year career. Purple Rain

The cover is about as purple as it can be. It's called "Minneapolis Genius: 94 East," and Prince's name is prominently displayed. However, this record deserves not a lyric label but a "caveat emptor" sticker. Yes, these 1977 recordings do feature Prince, but they're really Pepe Willie sessions, Willie being another Minneapolis multi-instrumentalist (he also wrote all six songs on the album).

Prince, who doesn't sing a note, plays guitar, keyboards and synthesizers, but except for the liquid funk groove of "If You Feel Like Dancin' " there's little here for the Prince completists (you can tell that's an old song because otherwise it would be called "If U Feel Like Dancin' "). Also featured is bassist Andre Cymone. Most of the cuts are workmanlike, with an unidentified saxophonist providing leads on two songs, and a dreadful Brazil '66 vocal duo dominating another two. The only distinctive Prince is on "Dancin' " where he delivers some stinging guitar leads.

According to Billboard columnist Nelson George, such leads are noticeably absent on Prince's upcoming "Parade" album. Under conditions that were at once mysterious and hilarious, George was allowed to preview the record in New York, and he reports that it moves Prince away from his rock and neo-psychedelic stance and returns him to his black influences. He points to cuts such as "Girls and Boys," "Kiss" and "U Need Another Lover" as "dead in an early '70s R&B pocket," with all three songs featuring Prince's old falsetto vocals. The rest of the album sounds like a sound track to Prince's upcoming "Under the Cherry Moon" movie and includes songs such as "New Positions," "Do U Lie?" "Venus de Milo" and "Christopher Tracy's Parade." There's another cut titled "Sometimes It Snows in April," which you may remember was Prince's reply to how he'd follow up "Purple Rain." The film, incidentally, is tentatively scheduled for Easter release.

And, finally, Prince will be sponsoring the first mile of the upcoming Hands Across America project, to the tune of $13,200 (that pays for 1,320 people holding hands to fight hunger in America). Let's Hear It From the Girl

Deniece Williams, with eight albums under her belt, will be sharing her skills as a singer, composer and producer tomorrow at Howard University, where she is guest artist-in-residence. Williams will lead four-hour workshops in commercial music tomorrow, March 6 and April 3 as part of the department of music's Continuing Studies in Music program. The workshops, in the Fine Arts Building, are free, but seating is limited and by reservation only; call 636-7082. Other workshops will feature background singer Ullanda McCullough (Feb. 20), video/commercial producer Eric Meza (March 20) and arranger/producer Leon Pendarvis. Call 636-7082 for information and reservations.