(WILLIAMSTOWN, Mass.) – On Tuesday, August 14, 2012, at 8 pm, the Carpe Diem String Quartet will perform Mendelssohn’s String Quartet Opus 80 as their traditional work in The Clark’s popular chamber music series. In celebration of The Clark’s Unearthed exhibition, Carpe Diem will be joined by award-winning pipa player Yihan Chen in a performance…