Tchaik 5, indeed. But never mind, the focus here is on the West Coast premiere of the grandest symphonic fresco yet by Mason Bates, a Bay Area composer who also spins platters in the sizzlingest local discos. Co-created with the filmmakers Gary Rydstrom (writer/director) and Jim Capobianco (story artist/animator), the 25-minute adventure—subtitled The Making of the Orchestra—was commissioned to celebrate the centennial of the Chicago Symphony Orchestra’s concerts for children; its purpose is to take audiences inside the instruments of the orchestra to reveal how they work. A 21st-century American answer to Benjamin Britten’s still delectable Young Person’s Guide to the Orchestra? Heaven knows, we could use one. The world-premiere performances takes place in Chicago on March 27 and 28, at Orchestra Hall, during the school day. But why should kids have all the fun? The three reprise performances in San Francisco, conducted by Teddy Abrams, are set for after dark. —M.G.