The concerts showed much more — a virtuosic ensemble that could dazzle in everything from Bach to folk songs. Coming from a country where musical virtuosity is prized and where the choral tradition is closely linked to a sense of national identity, the 25-voice ensemble returns with newly-named artistic director Kaspars Putniņš in a program called “The Unorthodox Tradition.” The New York Times described the group as “so wondrously talented…the selections and performances were so fine that they left you feeling like an ingrate, greedily hungry for more.”