Choral singing is something Simon Carrington knows a lot about. The newly appointed director of choral activities at the New England Conservatory was a founder of the King's Singers, and served with that popular British male a cappella ensemble as co-artistic director and as principal baritone for 25 seasons. He sang in more than 3,000 concerts, and he participated in almost 70 recordings. Since he retired from the King's Singers in 1993, he has been active as a choral conductor.

Carrington's debut concert last fall at NEC is still being talked about. On Wednesday, his second program was a Christmas concert full of unusual music. The full chorus sang two contrasting works, Respighi's "Lauda per la Nativita del Signore" and Vaughan Williams's "Fantasia on Christmas Carols"; the chamber chorus sang another pair, Bach's Cantata 150 (repeated from concerts with Benjamin Zander and the Boston Philharmonic) and Francisco Guerrero's ineffably beautiful motet, "Ave Virgo Sanctissima."

The performances were notable for discipline, taste, and stylistic diversity; anyone who assumed that Carrington would be interested in creating an English-style chorus would have assumed wrong. That's just one thing this group can do. Carrington - now gray-haired, but still tall, lean, and charismatic - had the students singing confidently in four styles and in four languages.

The Bach Cantata, sung with great expressivity, featured a pure-toned soprano solo by Jeanne LaRoque Jolly and a nimble cello solo by Rafael Popper-Keizer. Respighi's piece is inward and refined in craftsmanship, and full of beautiful, simple colors in the accompaniment - woodwinds, triangle, and piano. Stephen Marc Beaudoin sang the Shepherd with a plaintive, attractive timbre, and the voice of Sipra-Celine Agrawal grew truer and sweeter the higher she sang as the Angel; Laura C. Stuart brought a good voice to Mary, but an uneven vibrato compromised her intentions.

The Vaughan Williams featured an admirably straightforward baritone soloist, Daniel Cilli, who never pushed his voice, and a remarkable cello solo by Michael Katz, whom Carrington almost forgot to acknowledge. The piece is a warmhearted and sometimes slightly corny reworking of English folk songs including, "Come all you worthy gentlemen."

The most rapturous moment came from the unaccompanied motet by Guerrero, a 16th-century Spanish master. This found the chamber chorus singing with suspended tone, flexible phrasing, and elegant blend. Carrington's concerts are ones to watch out for - Feb. 7 brings seven Buxtehude Cantatas, and on March 14 there are works by John Adams, Arvo Paert, and Daniel Pinkham.