It seems fatally seductive for non-Californians to make sweeping generalizations about California, and about Los Angeles in particular. As a transplanted Californian who still retains a good deal of affection for his home state, this writer has always been amused or annoyed by such generalizations, depending on their nature and tone.

The tendency applies to any aspect of California life you can think of, but sweeping theories about Southern California music are certainly common. If we were to listen to some people, all California music is "laid back," hedonistically escapist and practiced exclusively by white people (often female) with a folk-country-rock backing.

Yet, an almost random survey of recent new albums by Los Angeles pop musicians reveals a far wider panoply than that. Indeed, almost as wide as a similarly selected swatch of New York records might do.

Of course, there are a few disks that reinforce the stereotypes; after all, any stereotype has to have some truth to it or it wouldn't have been coined in the first place. The Beach Boys deserve a special position as progenitors of the whole Southern California mellow, laid-back scene. They're not country rock, but they started out epitomizing the surf-and-fun syndrome, and for all their musical evolution since, they still do. The group's latest disk, appropriately enough for this article, is called "L.A. (Light Album)."It's not all as bad as the extended disco single that leads off side 2 might suggest. But the Beach Boys have had severe trouble coming up with viable new material since Brian Wilson stopped composing regularly. The songs here are better than some recent albums by the group; they're gentle, tuneful and innocently charming. But they're pretty trivial, too.

The country-folk-rock style inaugurated by Gram Parsons and the Byrds and carried out by Linda Ronstadt, the Eagles, Jackson Browne and many others has recently shown signs of mutation; even the original practitioners have gone off in other directions. Still, a nice latter-day incarnation of the style can be found on Leah Kunkel's debut album, "Leah Kunkel." Mrs. Kunkel is the wife of one of the premier drummers on this circuit, Russ Kunkel, who co-produced this disk along with Val Garay, Miss Ronstadt's engineer; it's a small world. She's been an admired backup singer in Los Angeles for years, and this album is never less than tuneful, appealing and sweet. It's also not really very interesting.

Lowell George is one of the mad geniuses of the L.A. folk-rock scene. Well, "mad" is perhaps a bit strong, and his erratic productivity has cast doubt on his "genius." But along with Ry Cooder and Mr. Browne, Mr. George is a quirkily telling composer and a musician deeply interested in rural roots. His work with his own band, Little Feat, has trailed off of late. But now there is a solo LP, "Thanks I'll Eat It Here," which enlists a number of well-known L.A. names and emerges as a strong, personal and decidedly interesting statement.

Joni Mitchell has long been an insider/outsider on this scene. An insider, because she came out of the Laurel Canyon folk circle and evolved along with Crosby, Stills and Nash. An outsider, because she's something of a loner, anyhow, and because she's moved steadily in the direction of jazz in recent years.

Miss Mitchell's fans are still awaiting her latest album, which will be a collaboration with the late Charles Mingus. In the meantime, there's Rickie Lee Jones, whose jazz-ish singer -songwriter idiom on her "Rickie Lee Jones" debut album recalls Miss Mitchell, although more accessible, less original and more mannered. Miss Jones, who was the musical guest on the "Saturday Night Live" TV program last weekend and who has a song on Mr. George's album, also brings to mind the jazzier side of Laura Nyro. yet she does so with a tough-on-the outside, sof on the inside persona that has its charms.

The official debunker of the folk-rock scene for years in Los Angeles was Frank Zappa, who always denied fiercely that those people had any lock on the area's musical style. Mr. Zappa's idiosyncratic blend of jazz-rock, Dada doggerel and theatrics is curiously charming but also curiously insubstantial. Every once in awhile he enjoys a novelty hit single, and in between he churns out his albums, which lie somewhere in that gray area between art, self-indulgence, comedy and "product."

There are two new Zappa albums out now. One is his last for his old label, DiscReel, and the other is a two-disk set on his own Zappa label. the first, called "Sleep Dirt," is a worthy collection in his jazz-rock style, with hardly any lyrics at all and hence, less potentially commercial. The second, "Sheik Yerboutl" (as in "shake your booty"), is a two-disk set seemingly chock full of commercial stuff, including some disco. At least it will appeal to Mr. Zappa's fans. But here he's let himself go so freely into the realm of high-school obscene humor that radio airplay will be extremely difficult for much of the set. Funny, but unplayable.

Mr. Zappa has always had his followers among musicians, overt or covert--people who either consciously or unconsciously emulate his stance as a scabrous California eccentric, debunking the aspirations to paradise all around them. Tom Waits is like that, and so is Tonio K., a new rocker who made his New York debut recently at Great Gildersleeves on the Bowery, and who has a song that includes an amusingly violent denunciation of Jackson Browne.

Tonio K.'s self-conscious stage name, reminiscent of Thomas Mann and Frank Kafka, suggests a collegiate literary bent, and his debut album, called "Life in the Foodchain," is indeed overflowing with words. But as with the early Bruce Springsteen or Mr. Waits (or, a bit, with Rickie Lee Jones), many of those words are clever, and the rock is tight and tough. Since he's also very appealing in live performance, one suspects Tonio K. will be heard from again.

Los Angeles has its primordial heavy-metal rock and rollers, too. Van Halen, whose second disk is called, rather prosaically, "Val Halen II," is just such a band. If you're in the mood for screaming macho rock howlings and power-driven electric guitar attacks, here's a band for you. There are worse.

There's punk/new-wave rock in Los Angeles, too, plus an eager network of "fanzines" to support the scene (and even an eager supporter of fanzines themselves, in Greg Shaw). The Dickies, on their "Incredible Shrinking Dickies" LP (which comes on yellow vinyl), hint at the manic intensity of the Ramones and some of the British punk bands and add a nicely loony pop-rock humor. Disposable, but cute.

Our image of "L.A. rock" is so lily-white that we can sometimes forget that black people live there, too, plus a lot of Chicanos. War is a black band that's had healthy hits in the funk idiom, and is trying to do the same with disco (as is most everybody else). Whether the group's new "The Music Band" album will be commercially successful is hard to say. But it's interesting in its way, and one of the things that makes it so is its deliberate attempt to embrace Latin musical styles and Chicano concerns.

And, finally, we have a black band with a strong disco flavoring called Raydio. The group comes mostly from Detroit (as in New York, most Los Angelenos come originally from somewhere else), and its second album, "Rock On," is really first rate. This is a group that combines the tough passion of rock and rhythm-and-blues with the buoyancy of disco, and the results are so convincing that they stake a better claim for the diversity of Los Angeles music than any mere article could ever do.