LOS ANGELES has long harbored some of rock 'n' roll's most reclusive, most brilliant studio wizards: Phil Spector, the Beach Boys' Brian Wilson and Steely Dan's Donald Fagen and Walter Becker. Now Fleetwood Mac's Lindsey Buckingham and Christine McVie must be added to this select company. "Mirage" (Warner Bros. 23607-1), the fifth and latest album by the current Fleetwood Mac lineup, carries on this pop baroque tradition splendidly.

Spector, Fagen, Becker and McVie come from elsewhere, but they (and Buckingham and California native Wilson) have found Hollywood the most conducive environment for manufacturing their dreams. This is the appeal of their art: By the sheer force of their imagination they have created complex, new worlds on record where seemingly disparate elements harmonize perfectly. For many American suburbanites--forced to compensate for their drab world by acts of imagination--these records are reassuring proof that it can be done.

If you subtract the three dreary Stevie Nicks tracks, the nine remaining cuts on "Mirage" marry the melodic accessibility of "Fleetwood Mac" and "Rumors" with the experimental boldness of "Tusk." Christine McVie's four songs feature the intoxicating romantic melodies of her famous singles, but Lindsey Buckingham's production fleshes them out with more intricate imaginative detail than they ever had before. Buckingham's own five songs are clearly rooted in the bouncy simplicity of early rock 'n' roll. He then proves how a little jingly melody and basic lyric wish can be musically expanded into the grand importance they have subjectively for the wisher.

The album's first single is "Hold Me" by McVie and singer-songwriter Robbie Patton. Much like the Beach Boys' "Help Me, Rhonda," the song builds from heartbroken verses aching with sustained notes to a punchy, repeating chorus making a plea for love. McVie has constructed one contagious melody for the first verse and still another for the chorus. The body of the song is sung as a duet between McVie's hopeful alto and Buckingham's anxious tenor. Buckingham takes over on the tag: He plays a slow, high guitar solo that extends the plea beyond words; he pits a groaning bass vocal against the pretty, high harmonies.

McVie's "Love in Store" has a couple more gorgeous mid-tempo melody hooks. Buckingham once again expands the romantic moment--this time with layers upon layers of odd, twangy guitars. On "Only Over You" (dedicated to Beach Boy Dennis Wilson) and "Wish You Were Here" (written with John Mayall's drummer Colin Allen), McVie's melodies are suffused with angelic choirs that give the romantic themes the swooning feeling they need.

If McVie's songs are romantic without irony, Buckingham's songs are romantic with irony. Long a musical wizard, Buckingham is finally developing skill at words, too. He now strips his lyrics to simple catch phrases that sound as if they came from "Teen Angel" of 1962, but in fact suggest far more than they explain. "Can't Go Back" suggests in short four-word lines the inevitable but impossible desire to return to one's youth. The irresistible opening theme--a cabaret piano phrase answered by a circus synthesizer phrase over a fast heartbeat rhythm--suggests that it may indeed be possible via one's musical imagination. Buckingham's synthesizer-treated vocal bends in and out of focus magically.

"Book of Love" and "Oh Diane" are even more rooted in the pre-Beatles' era. But the innocence is lined with irony--Buckingham suspects that God knows no more about love than we mortals; he suspects his Diane is slipping away with time. The potential of the original doo-wop harmonies are heightened by Buckingham's control over his greater options in the studio. As his lead vocal fades on each line in "Book of Love," the harmony vocals rise in a crossing arc. Two of Buckingham's biggest influences have been the Beach Boys and the Kingston Trio. He practices his odd brand of folkie-surf music on "Empire State" and "Eyes of the World."

Stevie Nicks is the album's big disappointment. Once one of the band's best writers, she has deteriorated into penning overly long tales about vaguely defined dream landscapes with minimal melodies and the blandest of chord progressions. Whereas McVie and Buckingham evoke dreams through the lovely complexity of their music, Nicks simply talks about dreams and gypsies and evokes very little. Nevertheless Nicks is still an excellent harmony singer, and her echoing vocals on McVie's "Love in Store" give the song an incredible lift. And let's not forget Fleetwood Mac's two founding members; drummer Mick Fleetwood and bassist John McVie are still important to their band . The rhythm tracks on "Mirage" are sparer yet far more effective than the rhythm work on the solo albums by Buckingham and Nicks last year.

Heart is another West Coast rock quintet with two female singer-songwriters. This Seattle band's co-leaders, sisters Ann and Nancy Wilson, have indisputable talent but seem to have little idea of how to apply it. They can rock out as well as any hard-rock band, and they even pen an appealing melody now and then. But too often their ambitions outstrip their intelligence and lead them into totally wrongheaded songs. Heart's newest album, "Private Audition" (Epic FE 38049), contains one great song, a couple near misses and a bunch of embarrassments.

The great song is "Bright Light Girl," a hippie tribute to an idealistic woman. It is graced by a gorgeous melody hook kicked home by the tight-charging band. Ann Wilson's siren voice cries out the catch chorus with convincing sincerity, while Nancy Wilson's echoing vocal brings out the pop harmonies. "Fast Times" is a furiously paced hard-rock charger that never pauses long enough for excess or indulgence. "The Man Is Mine" blends a big beat with lush vocal harmonies.

By contrast, the title tune is an ill-advised attempt to mimic Broadway's backstage songs. Even worse are the ballads that descend to mawkish sentimentality without compensating melodies. Sue Ennis' lyrics awkwardly attempt great meanings and end up sounding silly. "Angels," dedicated to John Lennon's son Sean, is full of trite advice about death over trite acoustic guitars and spacy harmonies. "America" reduces great historic movements to throwaway cliche's and then tries to puff them up with pompous synthesizer chords.