Organist Matthew Dirst, a UI graduate who is now a doctoral candidate at Stanford University, will perform at WILL-FM's next Second Sunday concert. The free concert will be at 2 p.m. March 12 at St. John the Divine Episcopal Church, 1011 S. Wright St., Champaign. Dirst is the first American musician to win international prizes in both organ and harpsichord. At Stanford, he is completing a dissertation on Bach's "Well-Tempered Clavier." Included in the program are Felix Mendelssohn's Sonata in A major: "Con moto maestoso," and Vincenzo Bellini's Sonata in G major. The concert will be broadcast live on WILL-FM (90.9) with host John Frayne.