POP MUSIC REVIEW : Wild Child a Winner : Music: Group’s magical mimicry of the Doors is fueled by David Brock’s powerful portrayal of Jim Morrison, whose bad-boy antics became a rock legend.

Some kind of incredible leap--of faith? confidence? chutzpah? dementia?--must precede one’s decision to inhabit the discarded skin of a rock ‘n’ roll legend. A leap at least prodigious enough to span the chasm between the kid who plays air-guitar in front of his bedroom mirror and the grown man who trundles onto a stage to impersonate a dead celebrity for paying customers.

The touring impersonators who quickly come to mind--guitarist Randy Hansen and his Jimi Hendrix show, various Beatlemania groups, the platoons of Elvises--can establish the proper illusion simply by closely approximating the familiar style of their inactive models.

But Wild Child, the Doors knock-off that played to a sold-out Bacchanal Saturday night, faces a double jeopardy. Not only must the band replicate the sound committed to vinyl and to memory by the controversial late-’60s quartet, it also must compete with the silver-screen facsimile in Oliver Stone’s current movie, “The Doors.”

Dueling fake-o’s.

The greatest challenge falls to Wild Child front man David Brock, who for years toiled in relative anonymity until Stone canonized the Doors’ vocalist/poet, Jim Morrison. Wild Child was little more than a traveling oddity before word of the film started a groundswell of Doorsmania. Now the band packs ‘em in wherever they play. That puts the pressure squarely on Brock.

Against sobering odds, Brock must convincingly assume the Morrison mantle--the voice, the limp-defiant posture, the diabolical anima, the sexual heat, the joyless glare--at a time when actor Val Kilmer is getting good notices for doing all that in his film portrayal of the man. Lest Brock forget who’s in the pole position, there’s Kilmer’s hirsute Morrison-mug beaming from billboards and theater marquees all over the country.

So the question hanging in the Bacchanal air was whether Brock would withstand the scrutiny of the suddenly curious, or wither under the stare of several hundred people thinking “OK, let’s see it” in unison.

Conclusion: The guy did it, and with such precision and feeling and sweaty intensity that it got a little eerie.

Brock begins with two advantages over Kilmer: He isn’t associated with any previous employment, and he looks more like Morrison. The hair, the cheekbones, the sullen, deep-set eyes. Pretty close. Add a pair of black leather pants and an untucked, rumpled white shirt--and the murky lighting of a smoky club--and you’re there. But what’s amazing is that Brock sings like Morrison, enough to imperil the snowflake analogy about no two sets of vocal chords being able to produce the exact same tone.

For two hours, beginning at 11 p.m., Wild Child ran through some obvious (“Love Her Madly,” “Light My Fire”) and not-so- obvious (“Not to Touch the Earth”) selections from the Doors songbook. From the outset,

Brock siphoned all of the room’s attention and energy to himself.

Clutching the microphone, his eyes closed, his body an attenuated figure of draped ennui, the singer captured all the nuances of Morrison’s vocals. The mellifluous baritone croon would explode into a cauterizing shriek-speak, then inch its way back down--voice slightly hoarse, cracking--to settle into a sneering, condescending nasality. Brock’s phrasing and articulation (“here” is split into two syllables), sodden physical movement and crucified-angel posturings were so uncannily like Morrison’s as to effectively blur the margins of reality.

After four or five songs, Brock even taunted the crowd. By then, the audience had not so much suspended disbelief as dropped it on the floor. They were ready to take orders. “Are you guys losers, or what?” Brock screamed in a barrage of expletives. “I wanna see some action! I wanna see this floor filled with people dancing and having a good time!” A cheer went up and fans from all points of the club descended on the already crowded area in front of the stage. From that point on, the night was Brock’s.

Launching into the Doors’ blues-funky “Wild Child,” the song’s namesakes fused the throng into a writhing mass, which made it easier to scan for clues as to the assemblage’s demographic makeup. There were people in their 20s wearing tie-dyed clothes, people in their 30s dressed in sportswear, mid-life crisis types in Republican suits and ties accompanied by women with ready-to-wear hairdos and respectable cloth coats. An odd cross-section of Americana had sacrificed its Saturday night routine to drink and groove to a copycat band.

The three musicians who “perform” the roles of Doors keyboardist Ray Manzarek, drummer John Densmore and guitarist Robbie Krieger were competent, which is to say they never surpassed the skill level of the original musicians and occasionally fell a bit short. The fact that they made little effort to look, or act, like their real-life counterparts (the bearded keyboardist stood throughout the show; the clean-shaven Manzarek played seated) kept the focus on the group’s figurehead.

With the audience in tow, Brock indulged in the sort of licentious behavior that got Morrison in trouble 20 years ago, but which is only shooting par in today’s rock milieu. A cover of Ellis McDaniels’ “Who Do You Love” was tame enough, but a bawdy version of “Gloria” left little to the imagination and presumably exhausted Brock’s dirty-word vocabulary. The crowd loved it.

A credible rendition of the Weill-Brecht tune, “Alabama Song (Whisky Bar)” segued into “Back Door Man” (both from the Doors’ first album) and set the stage for the inevitable closer, “Light My Fire.” Entreated for an encore, Wild Child returned to play a rollicking “Roadhouse Blues” and a faithful reading of the 11-minute dirge-rocker “The End” that was a cornerstone of the Doors’, and especially Morrison’s, mystique. As it turns out, that was only temporarily the end. Wild Child returns to the Bacchanal on March 28.