Linda Ronstadt has every right to sing traditional Mexican songs, as she does on "Canciones de mi Padre" (Asylum, 60765-1). After all, her family is part Mexican, and she did grow up in Tucson, listening to her father sing these songs around the house. Moreover, her big, gorgeous soprano voice is the perfect instrument for these flamboyant mariachis about melodramatic love affairs.

Ronstadt will focus some much-needed attention on the rich tradition of Mexican folk music with this project, much as her friend Paul Simon generated interest in South African music with his "Graceland" album. Still, no listener should be so foolish as to mistake Ronstadt's studied version of these mariachi standards for the real thing.

Since she stepped down from her unofficial title as "Sweetheart of the Rodeo" in 1980, Ronstadt has turned into a musical tourist: She visited the fringes of new-wave rock with the Cretones on "Mad Love"; she traipsed through opera with Joseph Papp on "Pirates of Penzance" and "La Bohe`me"; she accompanied Nelson Riddle on a package tour through the great American show standards of the mid-20th-century on three different albums.

On the Riddle collaborations, at least, she turned in respectable performances. Yet no one would mistake Ronstadt's well-sung but unadventurous readings of Cole Porter and George Gershwin for the inspired versions by Billie Holiday and Ella Fitzgerald, and no one should mistake her similar treatments of these Mexican songs for the definitive versions by Lola Beltran or Lydia Mendoza.

Ronstadt's album concentrates on the mariachi tradition, which flourished in the northwestern states of Mexico at the turn of the century and became a national craze after the Mexican Revolution of 1920 brought the country's indigenous popular culture to the fore. The original string-band instrumentation of violins, guitars, vihuelas (small five-string guitars) and guitarrons (huge six-string bass guitars) was eventually supplemented by brass and harp as mariachis became the sound-track music for Mexican cowboy movies in the '30s.

Not surprisingly, Ronstadt has chosen vocal showcase pieces rather than the spirited dance tunes that dominated the music. It's quite a treat to hear her belt out the heartbreaking ballad "Por Un Amor" or hold out the trilling embellishments on the huapango standard "La Cigarra." She sprints through the torrent of syllables on the rodeo song "La Charreada" as if she were once again singing Gilbert and Sullivan.

As well as she sings, though, Ronstadt approaches these pieces with the antiseptic precision of a respectful outsider. She sings every note so perfectly and properly that she drains the songs of their humor and sexuality. And as soon as you take the sex and wit out of barroom music, it goes dead, turns "classical." It's as if Kiri Te Kanawa had tackled the Patsy Cline songbook.

There are few redeeming moments: Ronstadt's brothers Pete and Mike join her for some nicely understated harmonies on their father's favorite song, "Dos Arbolitos"; mariachi veterans Pedro Rey and Heriberto Molina relax Ronstadt into some sensual harmonies on the lazy waltz "La Barca de Guayamas"; Daniel Valdez, the screenwriter of "La Bamba," joins Ronstadt for a simple duet on the moving union song "El Sol Que Tu Eres." Unfortunately, these are exceptions among the 13 performances.

The top musicians from four of Mexico's most popular mariachi bands have joined forces to create expert if conservative arrangements. Noted mariachi arranger Ruben Fuentes coproduced the album with Ronstadt's longtime collaborator Peter Asher.

A much better introduction to Mexican folk music can be found on the traditional tunes scattered throughout the first three albums of Los Lobos. For the real thing, though, the best place to look is Arhoolie Records (10341 San Pablo Ave., El Cerrito, Calif., 94530) which has done a better job with Mexican music than any other North American record company.

You can hear the roots of the mariachi style on two recent Arhoolie releases. "The Earliest Mariachi Recordings, 1908-1938" (Folklyric, 9051) collects 16 songs by four of the most influential pioneering ensembles; included are 1935 recordings by an early version of Mariachi Vargas de Tecalitlan, the same group that backs up Ronstadt on her album. "Mariachi Coculense de Cirilo Marmolejo, 1933-1936" (Folklyric, 9052) collects 14 more songs by this group.

As with recordings of Appalachian string bands or Louisiana Cajun bands from the same period, it takes a while to adjust to the tinny sound and fiddle-heavy arrangements of these records. Once you do, however, the pleasure of these high-spirited, rhythmically hypnotic performances is undeniable.

Arhoolie also specializes in the Mexican American border music known as conjunto, a sound much closer to that of Los Lobos. Steve Jordan's new album, "El Corrido de Johnny el Pachuco" (Arhoolie, 3023), is a good example of the blend of mariachi, country and rhythm and blues that have gone into conjunto. Jordan anchors every tune with a melodic and rhythmic riff from his button accordion, and he sings with a bluesy, grainy tone that fits his songs about rough-and-tumble border taverns.

The album is filled with traditional polkas and rancheras, but the title song is a Staggerlee-like tale of a Texas drug smuggler. The album ends with two songs in English, Buck Owens' "Together Again" and Woody Guthrie's "More Pretty Girls Than One"; Jordan incorporates them into his sound as if they had been written by Mexican mariachi bands a half century ago.

Even better than Jordan, though, is the uncontested king of conjunto, Flaco Jime'nez, who won a Grammy Award this year with "Ay Te Dejo en San Antonio" (Arhoolie, 3021). Like the late zydeco master Clifton Chenier, Jime'nez (in the wake of his father Santiago) has dominated his field with an accordion that seems to sing even as it pumps out compelling dance rhythms.

Santiago Jime'nez wrote the title tune, a ranchera that Los Lobos recorded on 1983's "And a Time to Dance." Flaco Jime'nez makes the rhythms on these two-steps, polkas and waltzes seem light-footed and sweet as he tosses in embellishments and counter-rhythms without ever losing the main dance beat. His longtime rhythm section responds sympathetically, picking up the secondary beats and incorporating them into the primary bounce. The vocal harmonies suggest all the humor and sexuality that are missing from Ronstadt's record.