Opening a pop album with a callback to The Sound of Music is a risky move, but Gwen Stefani knows how to make gambles pay off. The chant-powered “Wind It Up” launches Stefani on a whirlwind trip through exciting new territories, although she makes sure to take the occasional breather. The Akon-assisted title track updates soda shop sing-alongs for the 21st century, while “Yummy” backs Stefani’s teasing boasts with a bouncing ball beat. “Wonderful Life,” meanwhile, reinforces her status as one of pop’s prime power balladeers.