When Arnold Schoenberg’s Second String Quartet had its world premiere in December 1908 in Vienna, the audience was incensed—the composer’s bold move to abandon tonality seemed too radical a step. But even 120 years earlier, Mozart had written music that still sounds surprising, even revolutionary to this day, in the introduction to his “Dissonance” Quartet. Barbara Hannigan and the Belcea Quartet juxtapose these groundbreaking works with Hindemith’s rarely performed vocal cycle Melancholie and Webern’s Opus 5.