by Johnny Loftus 　　The Bratz line of "lifestyle fashion" dolls have been stealing significant chunks of Barbie's market share since at least 2003. What are they all about? Well, they're the hip to Barbie's square, Eliza Dushku to Kirsten Dunst in Bring It On, "Girls with a Passion for Fashion," and a jeweled empire of merchandising for creator of MGA Entertainment. Rock Angelz is the brand's first foray into music entertainment. It features uncredited vocal stand-ins for Roxxi, Jade, Cloe, Sasha, and Yasmin singing buoyant pop songs in the vein of Hilary Duff's Metamorphosis album. (In fact, the lead vocal on "Change the World" could be Duff.) Angelz also taps songwriters like Jörgen Elofsson, Matthew Gerrard, and Joacim Persson -- pros who've worked with Duff, Britney Spears, Kelly Clarkson, and U.K. pop-tarts S Club 8 -- and pieces of each of those artists have gone into the Rock Angelz mix. But the basic sound here has treated hard rock guitars mixed really loud, blaring over canned drumbeats but always making way for the Bratz' affirming lyrics. "You don't need to be who you're not/All that you need/Is all that you've got," Sasha sings over the crackling guitars of "All About You," "Just believe in yourself." "Who I Am" is the story of a misunderstood girl who's sick of the assumptions and naysayers, and "Rock the World" espouses the freedom of dreaming big. "Pretend that you can save the world today/And hey! Don't wait until your bedtime." That's good advice for anyone, but Rock Angelz is clear about its target demographic. The CD booklet's 12 pages of Rock Angelz merch -- including the "Stylin' Keychain Purse," "Crazy Cool Charms," and Bratz-branded karaoke machine -- help to clarify. The songs run into one another after awhile, and could use a few more hooks. They start to sound like the product they are. But the Bratz' million-kilowatt positivity is hard to deny.