The Sound of My Voice suffers from some of the usual problems that come with documentaries about musicians. Most notably, we never get a full version of any songs, just excerpts. We get plenty of examples of Linda Ronstadt's remarkable voice, but each time, we're left wanting more.
Still, this is preferable to standard biopics that invent life events to match the songs the artist produces. And you don't have to worry about someone else singing for Ronstadt ... that's her on the soundtrack.
Ronstadt fans can rest assured, though. They will enjoy the musical moments, and the presentation of her life in music is straightforward, if mostly on her side. You will come away with a better understanding of why Ronstadt moved so easily between so many genres. As she says at one point, "People would think I was trying to remake myself, but I never invented myself in the first place." Gilbert & Sullivan, classic pop standards, Mexican canciones, all of these were part of her musical upbringing. However it might have seemed to audiences, Ronstadt was just singing what she knew.
The film presents a who's who of musicians and industry people who rhapsodize about Ronstadt. There is, in fact, too much of this ... every repeated gushing story takes the place of the music we came to hear.
Epstein and Friedman sidestep the issue of Ronstadt's tour of South Africa during the cultural boycott of that country. It is mentioned once, she gives a brief statement about politics and singing, and it's forgotten.
The Sound of My Voice isn't great, but fans won't care. And the final scene, of Ronstadt singing gently with family as she suffers from Parkinson's disease, is moving.
For those who want to read a detailed analysis of Ronstadt's music from a critic/fan, I recommend the 1978 essay "Living in the USA" by John Rockwell.