Consisting of three siblings and the violinist Rainer Schmidt, this Salzburg quartet makes “music that challenges convention… with a beauty that brings you to your knees” (Hamburger Abendblatt). Having recorded the Beethoven quartets over the better part of three decades, the Hagens apply their singular sound—lean and direct, with fleet tempos and less vibrato—to the master’s graceful Quartet in G Major, Op. 18, No. 2 and foundational works by Bartók and Brahms.