Yo-Yo Ma's international ensemble forms the heart of the 'Music of Strangers' doc

With a documentary called "The Music of Strangers: Yo-Yo Ma and the Silk Road Ensemble," there's no doubting that wonderful sounds will be in store. But that's not all that's on offer.

For, as directed by Morgan Neville, "Strangers" turns out to be as concerned with emotion as with performance,...