Back from treatment for a pinched nerve, the warm yet magisterial violinist Hilary Hahn joins two distinguished colleagues in an intriguing recital. Alongside the Van Cliburn gold medalist Yekwon Sunwoo, she eases in with Beethoven’s sunny Sonata in F Major (“Spring”), op. 24—a perennial favorite that belies Beethoven’s struggles with hearing loss at the time it was written. (The unsent cry from the heart known as the Heiligenstadt Testament, expressing his anguish at his deafness as well as his resolve to fulfill his artistic destiny, was written a year after the sonata.) Then the German baritone Matthias Goerne, torchbearer of the art-song tradition, joins in for more Beethoven, with an advertised assist from Hahn. But what will they play? None of Beethoven’s original songs calls for string accompaniment. That leaves the composer’s dozens upon dozens of arrangements of international folksongs, set for voice and piano with optional violin and cello parts. Written for the domestic market of the pre-phonographic age, the material gave amateurs at home great leeway. No cello? No problem. Very theoretically, Goerne might even attempt them with fiddle alone. Who knows? When convinced of the validity of an experiment, he dives in fearlessly. To close, the three soloists band together for an as-yet-untitled new half-hour work by the Indian-American Angeleno Reena Esmail, whose Western-Hindustani fusion has an ever-expanding circle of fans pricking up their ears. —Matthew Gurewitsch