Hold On!

All this hype left very little time for the band to develop its vocal and performing talents, which is what this tour is all about. A vocal coach and a choreographer were called in to sharpen the girls' performance techniques. A nutritionist created a special balanced diet for the road. All this made them a bit nervous. ''In the beginning it can be kind of overwhelming,'' Chynna admits. ''But you learn to make everyone there feel a part of the show. Not just the first 20 rows.'' Besides, Carnie points out, it beats shaking hands with sponsors. ''This is the fun part,'' she says. ''The music comes naturally.''

''Let's really project tonight,'' Chynna bellows, throwing her voice into the back of cavernous Olympic Auditorium, where the band is doing a sound check for the Lake Placid concert. Eric Williams puts the girls through their vocal paces, greeting eech number with whoops and yells. Watching from the sidelines, management representative Steve Hoffman is moved to an extravagant prediction. ''This,'' he says, ''is going to be even bigger than New Kids.''

This evening, anyway, Hoffman turns out to be only slightly off. When Wilson Phillips hits the stage, the resort crowd is ready to howl. By the end of the first number, ''The Dream Is Still Alive,'' the people in the front row have raised their hands over their heads. Halfway into the next tune, a group of girls in the fifth row begins mouthing the words. When the singers launch into the opening bars of ''Hold On,'' the audience seems ready to erupt. A man in his early 30s rises from his seat, raises a paper cup to the stage, and screams, ''I looooooove you, Chynna!''

''It's such a rush doing a concert and seeing people actually mouthing the lyrics,'' says Carnie afterwards. ''It's like, holy s—, they actually know the words.''

Despite their choreographic training, the three singers are still finding their performance legs. Chynna, who has worked in films and television, is the liveliest stage presence, while Carnie seems tense and giggly and Wendy is stiff. All are strong vocalists, but they are still struggling to find a sharp focus for their fluid harmonies, and none of the three close friends is willing to take the vocal lead. ''Tonight was better than last night,'' Chynna notes, ''but we're still working on our blend.''

Whether they hit it or not, they have managed to impress their toughest critic — the man who created their harmonized California sound back in the early '60s. At home in Los Angeles, Brian Wilson is closely following his daughters' rise to stardom. Wilson, who has been under psychiatric care for much of the past decade, has had a strained relationship with his daughters since his 1980 divorce from their mother, Marilyn Rovell Wilson. He doesn't see his daughters, but he talks to them regularly — and to reporters about them. ''I'm so damned proud of Wendy and Carnie,'' he has said. ''I've been following their record's chart position like I used to my own songs.'' Ironically, the Beach Boys didn't chart at No.1 until their ninth single, ''I Get Around'' (1964); Wilson Phillips hit the top their first time out, suggesting that, commercially at least, the girls may outrun their famous parents.

Then again, perhaps not. Those who lingered outside after the concert in New Jersey were treated to an ironic sight: workmen replacing Wilson Phillips' name on the marquee with that of the next headliner — the Beach Boys. But by tten, Wilson Phillips' powder-gray tour bus was already whisking the trio to the next summer hot spot, the next radio promo, the next photo-op.