LENOX — Bach composed his sacred cantatas for performance in Lutheran services on specific days of the church calendar. Tanglewood stitched four of these sometimes rarified works together for a kind of devotion of its own: the first classical concert of the new season.
A week before the Boston Symphony Orchestra was to arrive on campus, the Tanglewood Music Center culminated a weeklong Bach performance seminar on Monday night by presenting an array of its student singers and instrumentalists in the cantata program. They were conducted, and led in the seminar, by John Harbison, the Pulitzer Prize-winning composer who has long been prominent as a Bach conductor with Emmanuel Music in Boston. He is also, of course, a longtime faculty member and new-music leader at the music center, bringing a composer's mind and ear to the music of others.
So the concert was, first of all, part of an educational enterprise, giving incoming students an intensive immersion in Bach before the weightier repertoire to come. A sizable audience that cheered the performers on in Ozawa Hall was a bonus.
The cantatas were Nos. 57, 116, 163 and 187, centering on Christmas and Trinity. Harbison's Bach was intimate and devout, eschewing opportunities for display even in coloratura passages. Everything came in a small frame. Even in the baritone's rapid-fire, heroic challenge to the "enemy" in No. 57, the singing and playing were cleanly articulated and restrained in sentiment.
Singers rotated as soloists and joined as a small chorus, whose work was exemplary — clear and balanced yet expressive in the interweaving lines and the affirmations of the chorales. The chamber orchestra, on modern instruments, likewise played in a close approximation of baroque style, with only light vibrato in the strings.
If the solo voices were uneven in quality and execution, that was understandable. Probably few of these singers had had intensive training or experience in Bach style before coming to Tanglewood. Each was immersed in the music.
The two post-intermission cantatas, Nos. 163 and 187, offered more variety than the first pair. Among the features in 163 were a striking use of the continuo group (cellos, double bass and small organ) and a smoothly flowing duet.
"Gratias!" the heartfelt chorus sang at the close of the final chorale, in 187. Enough said.