Sia’s unique, amazing vocals in Chandelier are “dissected” by people who really know what they are talking about.
Audio Source: the podcast hosted by musicologist Nate Sloan and songwriter Charlie Harding: https://switchedonpop.com/episodes/paper-planes-chandelie-timbre-constance-grady
A wider analysis of emblematic songs and artists in today’s pop music you can find in their new book “Switched On Pop: How Popular Music Works, and Why it Matters” (2020). Chapter 5 titled “A voice without a face” is the one about Sia: https://www.amazon.com/Switched-Pop-Popular-Music-Matters/dp/0190056657
Photo source: Sia – Chandelier, live on SNL (2015): https://www.youtube.com/watch?v=8Hg_rIqOZHc