The intrepid orchestral ensemble The Knights continues its multi-year Rhapsody commissioning project, inspired by the centennial of Gershwin’s Rhapsody in Blue. The Knights invite several of today’s most visionary composers to each create an original rhapsody, which artistic directors Colin Jacobsen and Eric Jacobsen describe as “one of the most ecstatically joyful expressions of art ... [a] combination of virtuosity, improvisation, and unfettered imagination.” In this program, pianist and master improviser Aaron Diehl joins the ensemble, conducted by Eric Jacobsen, in a world premiere by Michael Schachter, a new suite by Keith Jarrett and arranged by Michael P. Atkinson, and the rhapsodic Gershwin masterpiece. The orchestra also treats audiences to Beethoven’s exhilarating Fourth Symphony.