Like "Jingle Bell Rock" on steroids, the Trans-Siberian Orchestra puts a heavy-metal spin on holiday music. The group boasts 23 members, including eight vocalists and an eight-piece string section, and its annual Christmas spectacular features fireworks, flame pots, artificial snow, and enough flashing lights to stun a small elephant.

It's fun for the whole family, assuming none of your family members has a weak heart.

Equal parts Phantom of the Opera and Switched-On Bach, the TSO's music blends classical motifs with Christmas carols and original songs, strung together by a basso narrator. It's the musical equivalent of a protein shake; there's something good for you in there, but it's not easy to pinpoint what.

There's no question the approach pays off. The group's 1996 album, Christmas Eve and Other Stories, has sold more than two million copies, and last year's winter tour generated upward of $40 million. (There are now two touring versions of the TSO, the better to maximize holiday revenue.)

The audience for Saturday afternoon's show at the Wachovia Center cut across all demographic lines. There were moms in bedazzled jeans and grandparents in Christmas sweaters, kids with braces and beefy dudes in Harley tees. On the way out, one dad was already strategizing for next year, trying to figure out which seats would afford the best view of the laser show.

What does all this have to do with Christmas? That's a fair, if not entirely answerable, question. Christmas Eve, which the TSO performed in its entirety during the first half of a nearly three-hour show, features an occasionally coherent story line involving lonely barfly and a wandering angel, with copious references to God and an occasional nod to the birthday boy. But between the shredded Stravinsky and bombastic Bach, the most that emerges is a vague exhortation to be nice.

In the concert's second half, the TSO expanded its repertoire, including an incongruous "Proud Mary" and a stab at Carmina Burana. But the non-holiday material drew a muted response from the crowd. Without the spirit of Christmas at their backs, the TSO was out of season.