The housequake is initiated by an Australian vocal quartet that can only be described as cute, even if they're getting a little old for that. But Human Nature was a boy band back in the day, so they're used to it. And also used to gals at the foot of the stage such as Lilly, who told Toby Allen, "I love your shoes, and your legs, and your bottom."

The four high-school friends from Sydney -- Allen, Phil Burton and brothers Andrew and Michael Tierney -- rode the teen-pop wave in 1997 and 1998, opening overseas tour dates for Michael Jackson and Celine Dion. When all that faded, the group relaunched itself in 2005 with an album of Motown covers.

As serendipity would have it, Motown -- at least as done with any real budget -- was the missing piece of the Las Vegas entertainment picture. Mandalay Bay came close to signing a Motown revue helmed by pop choreographer Jamie King before opting to go with "The Lion King."

Until word of mouth can spread the news on Human Nature, it's up to the songs themselves and Smokey Robinson. His name is above the title to "present" the group in all advertising, and he introduces the group from a video screen.

It's fitting the old showroom was synonymous with "Legends in Concert" (which moved next door to Harrah's Las Vegas). With four voices to choose from, Human Nature can assign the lead vocal to whomever sounds most like the original. They even tackle the girl-group songs, such as the Supremes' "Stop! In The Name Of Love."

The group hard-charges for 80 minutes, pausing only to change their sharp-dressed retro wear a few times as they dance through every minute in studious lock-step choreography. They don't even break stride when they storm right off the stage and onto the tables of the front row.

Old habits die hard. After group founder Andrew Tierney talks about the oddness of "four white Aussies singing Motown," he ends by saying, "it's just ... Human Nature," flashing that boy-band grin that must have slain the tweeners back in '97.

Anybody who bought a ticket knowing what the guys look like probably will "listen without prejudice," as George Michael once implored. And you can't speak ill of timeless classics performed with sweat equity and a six-piece band (with two horns) that overcomes the low-tech trappings.

But the charm might wear off sooner for some than for others. There's no attempt to put the songs in any context and rare is the attempt to vary the pace: a stirring a capella rendition of "People Get Ready," or Michael Tierney sitting on the piano for a stripped-down "Please Mr. Postman."

And the group often forgets the most important thing: They called it "soul" for a reason.

Human Nature treats all Motown equally, blending one song into the next with a sameness that makes it hard to find much variety in this variety show. There was a big range within the Motown factory, between the cotton-candy pop of the Jackson 5's "ABC," the grown-up urges of the Temptations' "I Can't Get Next To You" or the troubled social current of Marvin Gaye's "What's Going On."

They all sound pretty much alike here, with the guys grinning their way through each lyric like they're trying to beat Donny and Marie in a smiling contest.

But at least they sound good. By the barnstorming finale of Edwin Starr's "Twenty-Five Miles" and the Four Tops' "Reach Out (I'll Be There)," it's hard to argue with the singing, the showmanship and -- as another group of white harmonizers might have put it -- the good vibrations.

Contact reporter Mike Weatherford at mweatherford@ reviewjournal.com or 702-383-0288.