The highly regarded new music ensembles Eighth Blackbird and the Pacifica Quartet, along with soprano Tony Arnold, play a free program on Sunday, March 16, at 3 PM at the Chicago Cultural Center, featuring works by David Karl Gompper (Butterfly Dance), Kaija Saariaho (Lonh), Henri Dutilleux (Ainsi la nuit), and Krzysztof Wolek (Changing Lands). Below, Eighth Blackbird records part of Steve Reich’s new Double Sextet, set to premiere this month.