Grown-ups, gather your wits about you and repair to a different room: The Kidz Bop gang has returned for yet another installment, and if you think your 7-year-old has already had enough of the high-energy vocal flim-flamming, well, guess again. No self-respecting second-grader can resist a custom recasting of Daniel Powter's infectious "Bad Day." Ditto that where Madonna's "Hung Up" is concerned. Most appealing of all, though, may be the kiddification of the ballads: here's a rendition of Kelly Clarkson's "Because of You" that sounds ready-made for basement karaoke, or at least an electrifying lip sync into a hairbrush. And James Blunt's ever-popular "You're Beautiful" somehow takes on a tinge more urgency when it is sung, as it is here, by a chorus of chirpy-voiced, spaniel-eyed little admirers. Though the series is an easy target for cranky, musically discriminating adults, they should lay off. If not for the Bop (that won't stop), when would they find time to seal themselves off with the latest "NOW" disc? --Tammy La Gorce