Proof, from the New York Times: On a recent Sunday afternoon, 17 people with sheet music gathered in a semicircle in the Graybar Passage at Grand Central Terminal. People streamed by. After a brief warm-up, the group’s conductor, John Hetland, dressed in dark jeans and a green plaid shirt, lifted his hands and the chorus began its a cappella rendition of a polyphonic hymn, “Kyrie,” by the 15th-century German composer Heinrich Finck. The hallway filled with sound, the baritones roiling like cumulonimbus... Read more