POP MUSIC SPECIAL : Aerosmith: The Rock of Ages : After two decades, the archetypal ‘70s band is as popular as ever and influencing a new generation of imitators

When Cher struts and frets at the MTV awards, you reflexively flash back to the generic kohl-eyed pop waif she used to be. It’s part of her charm. Everybody knows her history: the hideous clothing, the stream of bad music and frightful boyfriends she’s gone through make her somehow stronger, more authentic, even when she’s posing as a popsie.

Redemption isn’t quite so easy for rock ‘n’ roll bands. Once America expected authenticity from its Rock Gods: Their lyrics are supposed to be heartfelt, their neuroses genuine, their central nervous systems jacked up with several thousand dollars worth of exotic additives that fans could enjoy vicariously through 20-minute drum solos or whatever. An arena concert was one of the great rituals of the ‘70s, a potent communal contact high.

Toward the end of the decade, punk stripped away the bloated flesh of rock ‘n’ roll excess, leaving bare the naked bones of corporate greed, and many of the most popular musicians of the ‘80s were those self-reflexive artists--such as Madonna and Prince, and in Britain, the Pet Shop Boys--who celebrated music as commodity. In place of sincerity, you saw knowing irony; instead of the bombast, you heard intentionally banal pop hooks.

Which brings us to Aerosmith.

Aerosmith was the archetypal ‘70s band: Steven Tyler the poutiest singer, Joe Perry’s guitar leads the most obtuse, “Dream On” the song that takes you back the quickest to the back seat of a Camaro. Aerosmith not only gave its fans riffs that cranked, but also gave them one more good one per song than they had to.

Yet Aerosmith is probably the archetypal ‘90s band too. Note that its new album was No. 6 last week.

Aerosmith’s history is well known. This band turned high school locker-room jive into a horny opera of possibilities, a symphony of teen-age groins and lips and thighs that’s been going on since the group formed in New Hampshire in 1970. (Its biggest hit, “Walk This Way,” is about, well, gettin’ to third base; its latest single, “Love in an Elevator,” was supposedly inspired by real-life ups and downs.) They once made music that described an America of infinite sexual possibility to a segment of America that really wanted to believe it was true.

The Aerosmith formula, some 20 years after its inception, has never been more popular. Four Aerosmith-influenced albums--by Warrant, Skid Row, Motley Crue and Aerosmith itself--are among the season’s biggest hits. And old Aerosmith hits sound almost new when you hear them on KNAC-FM or MTV’s “Headbangers”’ Ball. Old Aerosmith beats, always popular with hip-hop deejays, pop up on cuts by Tone Loc and L.L. Cool J.

Where the Who and the Stones basically crank out exercises in nostalgia (does anybody, including Mick Jagger, really expect anything new from the latest Stones LP?), Aerosmith is still the Aerosmith of our time--the way that Springsteen is still the Springsteen and Ozzy is still the Ozzy. And in this era of decidedly finite sexual limitations, people seem to need a shot of Aerosmithsonian bawdiness more than ever.

Yet, Aerosmith’s status was so low a few years ago that it apparently couldn’t even get a record deal. Aerosmith went into a Spinal Tap sort of decline after Perry quit to go solo in 1979. The rhythm guitarist, Brad Whitford, quit to start a band with a guy who used to back up Ted Nugent. Tyler got into a bad motorcycle accident, keeping the band off the road for a year.

The group then made a couple of spectacularly mediocre records, and at one point (with Perry and Whitford back) went out on a “No Product” tour. Their career was finally brought back from the dead in 1987 when Run-DMC’s rap version of “Walk This Way” restimulated interest in the original.

Ironically, in the ‘70s Aerosmith never seemed as authentic as some other bands--everybody assumed they were ripping off the Yardbirds and the Stones. So their segue into and out of the deeply inauthentic ‘80s is less jarring than it might be. (Check out the Bee Gees’ new one, a blatant New Order swipe right down to the typeface on the album jacket, to see how jarring it might be.)

Most rock ‘n’ roll intellectuals used to hate Aerosmith because they wrote tight, commercial radio songs in an era when “pop” was the dirty word that it certainly isn’t now.

Their sound, sort of straightforward, bluesy and laden with hooks, created more or less the template for contemporary hard rock from AC/DC through Guns N’ Roses (whose “Welcome to the Jungle” bears the relation to “Back in the Saddle Again” that “Inna-Gadda-da Vida” does to “Sunshine of Your Love”).

Today’s hard-rock bands mine Aerosmith for riffs, poses and song structures in the way the ‘60s British Invasion rockers plundered the Delta blues. Van Halen was sort of an Aerosmith with a Louis Prima influence and better guitar. Motley Crue is a rougher Aerosmith with better makeup.

Aerosmith were notorious substance abusers, even by ‘70s standards. Now, of course, they’re clean, just like Keith Richards. Redemption. Thumbing through a stack of old clippings, you notice that Tyler needed two bottles of champagne to get him through routine press interviews, even in Ohio.

In Penelope Spheeris’ film “Decline of Western Civilization . . . the Metal Years,” Tyler and Perry (who’ve called themselves “the Toxic Twins”) are weirdly competitive about who used to do more cocaine--”I must have snorted up Peru,” Tyler says--in the way that the newly religious can be about the magnitude of past sins. This year, their positive example may have inspired even Motley Crue to sobriety.

Aerosmith is perfect rock ‘n’ roll for the age of limits, great but not awesome, solid but not too original. The riffs are tricky, but not all that hard to play. The sexy innuendo of the lyrics is clever, but not unapproachably so. Tyler’s voice is expressive but decidedly untrained . . . and he has no copyright on the use of scarfs. To be a Led Zeppelin or Metallica requires at least a dram of demonic inspiration, but anybody can aspire to be an Aerosmith.

And they do.