Going into her seventh album, Sia Furler wanted to try “an experiment.” She would record self-written tracks already pitched to—but overlooked by—A-listers. “I feel like they’re hits, but nobody wanted them,” she said. She was right. This Is Acting dives headfirst into pop’s waters, but its bold and beguiling songs retain their author’s earthy edge. Sia’s cathartic voice is, as usual, the star—“Alive” and “House on Fire” pulverize all before them, the big-night-out anthem “Cheap Thrills” is a ton of fun, and “Reaper” (a Kanye West cowrite) is the sort of midtempo empowerment jam only she can nail so triumphantly.