Rap first captured the interest of a broader audience with socially conscious broadsides like Grandmaster Flash's "The Message," and the temptation is to take the music most seriously when it's delivering similarly urgent communique's from the streets, as on Public Enemy's new "Yo! Bum Rush the Show." Rap's subject, though, is more often self-defining braggadocio, a style exemplified by L.L. Cool J, whose mastery of the form can't be ignored even if his ideas are slight. Commercially savvy acts like Lisa Lisa and Cult Jam avoid both kinds of tough talk, using the wiry hip-hop beat instead for upbeat love songs.

L.L. Cool J: 'Bigger and Deffer' "I dare any critic to call it noise," L.L. Cool J challenges on "The Do Wop," the rap-meets-doo-wop track on his second record, "Bigger and Deffer" (Def Jam FC 40793). The question isn't whether rap's mix of borrowed sounds, cheesy hip-hop percussion and chanted vocals is noise -- of course it is -- but whether this limited palette can create compelling records. L.L. Cool J (for "Ladies Love Cool James" Smith) certainly can -- his "Rock the Bells" was noise of the highest order, perhaps the most sonically intoxicating rap record since Run-DMC's early "It's Like That."

"Bigger and Deffer" doesn't have anything quite so powerful as "Rock the Bells," the most impressive track on Cool J's debut album, "Radio." Several songs in the same vein -- "Get Down," "The Breakthrough" and the first single, "I'm Bad" -- are solid, though, and "Ahh, Let's Get Ill" is a dizzying workout.

Several other songs match those for aural audacity, but are undermined by Cool J's youthful misogyny. His gentle, naive "I Need Love" describes an ideal relationship that most contemporary women would find suffocating, and "Kanday" and "The Bristol Hotel" reveal his simplistic notions of female sexuality. (The latter, about a low-rent trick pad, also stereotypes Japanese businessmen and includes a hoary "hey, that's my wife!" joke.)

Formally, one of rap's most important moments came when Run-DMC incorporated heavy-metal guitar into the sound with "Rock Box," an innovation that led not only to a wider audience for that group but ultimately to the commercial breakthrough of the Beastie Boys. Cool J covets a similar place in rap's evolution, and has decided to achieve it by grafting rap onto '50s rock with "The Do Wop" and "Go Cut Creator Go," which allows "scratch" artist Cut Creator to do his stuff amid snatches of "Rock Around the Clock" and Chuck Berry guitar riffs.

This offers Cut Creator an impressive showcase, but the synthesis nonetheless sounds contrived. At its best, though, "Bigger and Deffer" demonstrates that the rapper is far from exhausting his original style.

Lisa Lisa and Cult Jam: 'Spanish Fly' "This is for real," insists Cool J, "this ain't La-La Land." Lisa Lisa and Cult Jam come from nearby New York streets, but La-La Land seems their natural habitat. This Hispanic trio's second album, "Spanish Fly" (Columbia FC 40477), is one of the fastest breaking records of the year, perhaps because it marries the spare hip-hop sound to a sensibility as nonconfrontational as Olivia Newton-John's.

The six members of Full Force -- the instrumental, songwriting and production team that oversees Lisa and company -- dress like villains from a Conan the Barbarian movie, but their songs aren't remotely "bad." On cuts like "A Face in the Crowd," which deals with the heartbreak of discovering your superstar lover doesn't remember you, this record celebrates a fantasy world of glamor and celebrity.

Despite having its head in the clouds, "Spanish Fly" sagely keeps its dancing shoes in regular contact with the street. With Cult Jam's Mike Hughes embroidering Full Force's mostly electronic drums with Spanish-spiced percussion, songs like "A Fool Is Born Everyday" and "Everything Will B-Fine" are propulsively polyrhythmic. Even "Head to Toe," the easy-listening track that's become the record's first hit, has enough rhythmic vigor to redeem its sticky sentiment.

"Spanish Fly," though, sounds like the work of musicians who wouldn't think twice about checking their street beat at the door of mainstream acceptance.

Public Enemy: 'Yo! Bum Rush the Show' Where "Bigger and Deffer" sometimes loses its focus in stylistic experiments, Public Enemy's terse, hard-edged "Yo! Bum Rush the Show" (Def Jam BFC 40658) is a cohesive and consistently effective disc. Chief rapper Chuck D and "next voice" Flavor-Flav mesh seamlessly, and the musical accents -- from Terminator X's scratching to Vernon Reid's hard-rock guitar -- are well chosen and deftly integrated.

The album's weakness is one of attitude, not musical style. Emblazoned with the slogan "THE GOVERNMENT'S RESPONSIBLE" and featuring songs like "Rightstarter (Message to a Black Man)," "Yo!" comes on like a latter-day black-power statement. Its politics, however, are simplistic gripes ("the one who makes the money is white not black") and dubious calls for strong-arm action.

With its frequent references to old TV series Public Enemy seems more tube-smart than street-smart, which makes Chuck D's humorless, self-important manifestoes all the more suspect. Public Enemy needs an agenda as fresh -- in every sense of the word -- as its sound.