Ever since Kim Gordon sang about her friend Goo, she has epitomized what's great about Sonic Youth as a rock band.

Forget the special tunings and the blasts of feedback-fortified guitar catharsis and Steve Shelley's rigorous time-keeping, all of which are present on their new album and as excellent as ever. What has maintained SY's distinctiveness since it became a song-and-jam band on "Daydream Nation" is Kim's adolescent flippancy, the way she snarls a throwaway line like "What a waste/you're so chaste."

Since Thurston Moore and Lee Ranaldo aren't great singers either, it's more than just her artless resolve that makes Kim's five vocal performances stand out on "Rather Ripped," probably the most conventional album they've ever made. She'll test a lyric's truth with sarcasm, sexual innuendo, playfulness, or whatever it takes to sell the idea. Since so many of the songs address love directly, it's natural to assume that Thurston and Kim, who are married, have each other in mind when they sing them. Kim's seem more honest, or, at least, less abstract. It's one way to act your age, even if you're a rock kid at heart.