When it comes to powerhouse singer-songwriter supreme Sia, it's all about that voice.

From her early days as a quirky Adelaide-bred singer on the rise with albums like Some People Have Real Problems to the chart-topping This Is Acting superstar she is today, the power and depth of her delivery has never changed.

Accordingly, we've gone and gathered up just some of Sia's most impressive vocal moments, from crooning "Soon We'll Be Found" live on Letterman all the way up to her recent, soul-shaking performance of "Alive" on X Factor UK. Beyond the wigs and the intricate artistic performances on stage, there's a singer with one incredible set of pipes.

Watch Sia's best live vocals above, and check out some compilations from other pop stars below.

See Sia, Behind the Wigs: