Blithely girlish and triumphant, “Raise Your Voice” captures that crystal-bright moment in every young woman’s life when she sets aside her childhood insecurities, steps forward and becomes the doted-on diva superstar she always knew she could be. Truly, a parable for our times.

It all amounts to an inevitable exercise in rebranding for Hilary Duff, nudging the 17-year-old singer/actress away from the adolescent sexlessness of “The Lizzie McGuire Show” toward something more flashy and synergistic.

Still, the promise of a long and fruitful entertainment career isn't exactly promising — for all her pitch-perfect warbling, Duff is still more Pia Zadora than Jennifer Lopez.

Though perfectly watchable, “Raise Your Voice” is notable only for how stubbornly it clings to formula. For the second time in five months, Duff (“A Cinderella Story”) plays a bright, ambitious teenager whose dreams are dampened by the fry grease at the diner owned and operated by her family.

Defying her salty, overbearing father (David Keith), Terri Fletcher slips away from her home in Flagstaff to spend the summer at an elite performing arts high school in scary, salacious Los Angeles. This, after tragically losing her supportive older brother (Jason Ritter, son of the late actor John Ritter) in a car accident.

Once enrolled, Terri — sweet, unassuming Terri, one should add — is bombarded with the usual dramas, rivalries and delicious romantic misunderstandings that invariably accompany a girl's first extended stay away from home.

She has a fling with a dishy British pianist (Oliver James from "What a Girl Wants"), catches the ear of a roguish music teacher (John Corbett from "Sex and the City") and makes enemies with the obligatory snobby rival (Lauren C. Mayhew).

She also forms an uneasy alliance with her roommate (Dana Davis), who is black, competitive and vaguely hostile — standard dorm-room issue for sheltered white girls, if this movie and the recent "First Daughter" are any indication.

Journeyman director Sean McNamara proves incapable of squeezing any actual substance out of Duff's performance, but there are other enjoyments. Still-sexy "Risky Business" babe Rebecca De Mornay is nicely cast as Terri's rebellious artist aunt, and Ritter provides the story with a sweet if brief spritz of unconditional sibling love.

The satellite characters could be the best thing about “Raise Your Voice” — particularly a pair of misfit musical prodigies (she’s a goth, he’s a spastic sample-junkie) to whom Terri plays matchmaker. Too bad they didn’t take center stage.