This Week (11-8 at noon & 11-13 at 10 PM) on Curtis Calls, from the graduation recital of violinist Timmy Chooi: Beethoven's "Spring" Sonata and Edvard Grieg's Sonata No. 3 in c minor. Then Timmy's brother Nikki, a 2012 Curtis graduate, joins him for Pablo de Sarasate's "Navarra." Performances from student recitals at the Curtis Institute, Wednesdays at noon and Monday evenings at 10.