“They have to be heard to be believed,” said the Washington Post of piano duo Christina and Michelle Naughton. The twin sisters pay tribute to their homeland with the album American Postcard. It offers music by four US composers: John Adams (his Roll Over Beethoven, a work the Naughtons premiered in 2016), Aaron Copland, Conlan Nancarrow and Paul Schoenfield. As the sisters explain, “These pieces show the diversity and variety of American music. But one thing that ties them together is an exuberance that, to us, feels deeply American.”