It’s the rhythm, stupid. Oh, and in No Doubt’s case, a platinum-blond peach of a female singer, Gwen Stefani, who breaks up the asexual baggy-shorts-and-balloon-pants monotony of alt-nation guy rock (311 included). Both Tragic Kingdom and 311 are ear candy with good beats, not just bludgeon-by-numbers guitars, and both bands are remarkably adept at genre juggling. No Doubt have a spry, white-suburban take on ska and Blondieesque pop; 311 have a tight, sinewy sound that for all of its obvious Beasties-cum-Chili Peppers traits has a potent reggae undertow. So why snipe at either group for lack of depth? Because power ballads are irritating swill, and No Doubt’s “Don’t Speak” is no exception (the high-pitched rippling in Stefani’s voice, more effective with fast songs and sunnier hooks, doesn’t help). And you have to wonder about the substance beneath the sweat when 311 fire off lines like “I reserve the right to be as trite as I want.” Hey, it’s a free country.