In the four years since Australian powerhouseSia's last LP, her sound has become ubiquitous, even if her face hasn't. She's written hits forBeyoncé, Katy Perry andRihanna – the vocal dips and midtempo melancholy of "Diamonds" are Sia's signatures – and this album will likely be just as ubiquitous. Her knack for heart-swelling choruses shines through on a set of tracks you might play while winning a marathon: There's triumph in her tiniest tics, like the echoingwoo-ooh on the outro to "Big Girls Cry" or the sweetened trap toms of "Elastic Heart." You can't see what Sia looks like in the cover art, but she sounds like a superstar.