“What is music?” documentarian Daniel Anker asks members of the Philadelphia Orchestra at the beginning of this 2005 group portrait, and though the answer is beyond the reach of words, the skillful intermingling of voices becomes its own reply. Anker is most interested in the tension between individual and group expression: one member declares, “I'm not doing it for anyone else—I'm doing it for me”; another insists that no one can experience music fully without the communion of an ensemble. Some of the interview subjects are shown pursuing their own interests—from jazz to bluegrass to running marathons—yet each illuminates the demands and rewards of the symphonic collaboration. The talk is focused and articulate, the music glorious. 90 min.