What happened to rock music? Not the sagging, moldering corpses of Stevie Ray and Jimi, still propped up and sucked off on classic-rock radio. Just straightahead rock music like the Replacements or the Ramones, played with a certain fearlessness about trying new things. Answer: Carlos (Wednesday, November 21, at the 15th Street Tavern, with the Album Leaf and Sparkles), a Bay Area foursome that is most instantly comparable to Big Star with its fun but not overly simple songs. And while it's apparent that Carlos was raised on a diet of obscure rock/pop, the band has an energetic, hook-laden song style that is also quite original: The players find joy in the prefab ruins of the modern world, making catchy but distorted slacker anthems. Big drums and roughly shining guitars abound. The crowning jewel is "Papa Star," with its crunchy climb-down chords and curving lead licks like swipes of a sarcastic cutlass between lines: "Momma's sad when Daddy's gone/ Papa's gonna be a rock-and-roll star/Once upon a time in the back of his car..." It's sophisticated garage-band rock, or maybe it's nouveau classic rock. Either way, it's rock. Turn off the Fox and try these guys on for size.