Steve Reich’s music about 9/11 was written especially for Kronos Quartet. It is the main work in a concert full of emotion and tragic beauty. In the rest of it program Kronos plays their renditions of the old soundtrack to director Darren Aronofsky’s drug movie, Requiem for a Dream , and the evocative violin piece Flow by Laurie Anderson. Over the 30 years of its existence Kronos has given the classical string quartet a complete make-over. According to the American quartet, the leader in its field, string instruments are suitable to play all styles.