There are plenty of potentially effective ways to structure a biographical documentary, but when you’re dealing with someone who was as frequently judged and misjudged as operatic soprano Maria Callas, it feels right simply to let her speak. Director Tom Volf profiles Callas through archival interviews, along with plenty of previously unpublished correspondence, diaries and memoirs (narrated by Joyce DiDonato) to unravel the reality behind the legend who practically inspired the creation of “diva” as a derogatory term. To Volf’s credit, he doesn’t stint on the performance footage, offering ample evidence for Callas’ gifts as both singer and performer. But he’s most interested in allowing her to set the record straight about infamous incidents that gave her a reputation as difficult, about her failed marriage, or about the complexities of her relationship with Aristotle Onassis. What emerges is a portrait of a woman unapologetic about putting a focus on her career, even as she acknowledges the sacrifices that focus entails, and the media scrutiny that comes with it. At 119 minutes, the pace drags somewhat, but it’s worth the opportunity to appreciate Callas’ public and private voice. By Scott Renshaw