Many of today's top pop songwriters grew up in show-music homes. Their parents sent them to classical piano lessons and preached the virtues of George Gershwin and Cole Porter; the children rebeled by playing folk songs on guitar. As this younger generation has grown up, however, they've reclaimed their Gershwinesque roots and incorporated a strange hybrid of confessional lyrics, strong dance beat, ambitious chord progressions, rural guitars and urbane arrangements. Call it "soundtrack-folk-rock."

New albums by Judy Collins, Wendy Waldman and Karla Bonoff illustrate how hard it is to find the proper balance between show music and folk rock in this new hybrid genre. Collins has gone the furthest in tilting the balance toward old-fashioned show styles. On her last three albums she has nearly obliterated her original identity as a folksinger and has remade herself as a refined pop singer.

Collins' new album, "Times of Our Lives" (Elektra), is the best effort yet of her second career. Though half the songs lapse into the hollow contrivances that plague show music, the best compositions approach the sublime symmetry of art songs. As her repertoire has shifted from folk to old-fashioned pop, Collins' singing style has shifted from naturalism to artifice. Instead of shading husky notes for emotional impact, she holds ringing soprano tones in precise counterpoint to the piano. On her last two albums, Collins seemed to be struggling with this transition in vocal styles. Now she's got it.

The songs are organized around the theme of a divorced, middle-aged mother who finds solace in family ties even as she seeks a second romance. Collins wrote five songs herself--the most ever on one album--and uses three others by her young prote'ge', Hugh Prestwood. Only two songs--her "Grandaddy" and Prestwood's "Drink a Round to Ireland"--hint at her folkish past. Collins' best song is "Mama Mama," a daughter's plea that her mother understand why she had to get an abortion. Without ever using the word "abortion," Collins deftly implies the circumstances that forced the decision and sings out the need for approval. The song neatly marries folk's wrenching honesty with art song's controlled understatement.

The album's best song is Anna McGarrigle's "Sun Son." Similarly understated, it presents the bittersweet fantasies of a young boy shuttled between his divorced parents. It also features the record's surest rhythms. Too many of the other songs have no particular rhythm at all, but simply drift off into the haze of romantic cliche' and easy-listening formula. While strong songs glow under Collins' new style, lesser songs disappear into inconsequence.

Wendy Waldman is one of the very best of these "soundtrack-folk-rock" songwriters. Though a lightweight lyricist, she composes compelling melodies, arranges ambitious harmonies and delivers resonant vocals. Her five fine solo albums for Warner Bros.--especially the 1975 gem, "Wendy Waldman"--were unjustly neglected. It's been four years since her last album, and her new record, "Which Way to Main Street" (Epic), sounds like a record born of commercial desperation.

Much like Fleetwood Mac, Waldman is at her best on southern California beach-rockers full of sunny optimism and pastoral harmonies. Her newest producer, Eddie Kramer, tries to make her sound like a hard-hitting, echo-booming rocker like Heart or Quarterflash. It doesn't work. It also wastes the Gershwinesque side of her talents. Again and again on "Which Way to Main Street," promising melodies are ground into dust by sledgehammer arrangements. The catchy up-tempo "Heartbeat" is quickly derailed by Peter Frampton's insensitive lead guitar. Her off-beat "X-Ray Eyes" is similarly sabotaged by the novelty synthesizer effects. The ambitious chord constructions of the title song are drowned out by a heavy-handed rhythm arrangement.

Still Waldman is able to salvage several lovely songs from these sessions. Tellingly, they are the songs on which Kramer doesn't bother to imitate current hit records and gives Waldman a reprieve to be herself. "Lovin' You Out of My Life" boasts four different strong melodies: a lazy, lamenting verse, a quickening transition into an assertive chorus plus an eccentric parenthetical bridge. "Does Anybody Want to Marry Me?" is rescued from self-pity by a chorus melody that rings so strong and so true that it speaks to anyone who's secretly asked the same question.

If the albums by Collins and Waldman mix strong successes with embarrassing failures, Karla Bonoff's new album, "Wild Heart of the Young" (Columbia), is consistently boring. She seems to combine the least exciting aspects of stale standards and indulgent folk-rock. Bonoff has written good songs (notably "Someone to Lay Down Beside Me" for Linda Ronstadt). Bonoff was also once part of an acoustic folk quartet named Bryndle that included Waldman, Andrew Gold and Kenny Edwards. All three help out on her new album, as do three Eagles. All this help, Edwards' tasteful production and even some good melodies by Bonoff are wasted. Bonoff is simply a tiresome, lackluster singer.