Dave Grohl is a great musician. Dave Grohl is not a great filmmaker.

“When you’re young, you’re not afraid of what comes next. You’re excited by it,” he says at the beginning of his first foray into film, “Sound City.” It’s a unpromising beginning to what turns out to be a fascinating documentary. The Foo Fighters frontman (and Nirvana drummer) might not have a way with words himself. But he’s a friendly face, one able to get a lot of cool people to say very interesting things on film. Which is why “Sound City” proves to be a great documentary.