For the first few centuries of its existence, the Vienna Boys’ Choir performed only for the imperial court. Nowadays, the well-drilled ensemble, having traded its cadet uniforms for jaunty sailor suits, is more inclusive: its trebles hail from all over the world and entertain audiences on five continents. At the boys’ annual holiday concert at Carnegie Hall, on Dec. 8, they apply their plangent sound to a grab bag of holiday-themed tunes that include “Adeste Fideles,” “Let It Snow!,” “O Holy Night,” and other duly polished chestnuts.
