Cambridge Concentus surprised in many ways in its all-Bach hour-long afternoon program at First Church Cambridge, where it is in residence. Its unusually and pleasantly short program on February 6 began with a short partita, and without further ado — not even a moment taken for applause — the young, dedicated ensemble dove right into a Brandenburg Concerto. One of Bach’s shortest cantatas came next. That was the concert.

Another surprise — the A-Minor Partita for Solo Flute BWV 1013 — began with listeners looking over their shoulders to discover that traverse flutist Teddie Hwang was playing from the balcony in the back of the church, her round and velvet-like tones floating through the large open space. Sumptuous sound it was, and the First Church’s acoustics promoted every note. A Sarabande and Bourrée Anglaise was almost it, but a cadenza by Graham Dixon, yet another surprise, extended the dance — but not by much, for it was short as well.

The opening of Brandenburg Concerto IV, BWV 1049 was as deliciously light as can be imagined, delightful and so refreshing. “Drawn from a new generation of early-music performers committed to infusing recent scholarship with an energetic performance style,” the lightness of playing once again caught me off-guard. Wonderful! The third movement, “Presto,” received some of the best interplay of the afternoon, between Cynthia Marika Holmqvist, solo violin, and the two recorder performers, Ching-Wei Lin and Jeanine Krause. Out of the continuo playing of Leon Schelhase, harpsichord, and David Miller, violone, emerged clean and clear lines almost always distinct within the textures that thinned and thickened around them.

But it was the Aria, Was willst du dich, mein Geist, entsetzen, Wenn meine letzte Stunde Stunde schlägt? (“Why should you recoil, my spirit, when my last hour strikes?”) that leapt out of this relatively brief encounter with Bach and Cambridge Concentus, due to tenor Patrick T. Waters’s lean, heart-rending singing. Why could he not go on longer and longer? Melismas were tight as could be. And those heart-wrenching moments, as at the close of the inquiring aria, summoned mind as well to the very core of the text’s message.

The other soloists in the diminutive cantata Liebster Gott, wenn werd ich sterben BWV 8 (“Dearest God, when will I die?”), soprano Ulrike Präger, mezzo-soprano Thea Lobo and bass Ulysses Thomas, were all impressive in their spiritual expressiveness and sonic strategy.

But not every surprise was a happy one for this orchestra and chorus that specializes in music of the seventeenth and eighteenth centuries. Their short Sunday outing February 6, although thoughtful and in ways adventuresome, should have been given at another venue. It is with the greatest reluctance that I must offer my view on the acoustics of First Church, Cambridge. For the flute solo, there could not have been a better match. Not so, for the intricacies of Bach’s polyphonies, instrumental or choral. Counterpoint got tangled up, harmony distorted. I could hardly hear Thomas’s bass voice over the instruments — and I was no more than fifty feet away from Concentus vocalists and instrumentalists.

Not everything that happened was due to the overly live church’s auditory drawbacks. Tuning troubles are forgivable, sometimes even welcome as expression from another era. Looming large, however, was the missed rhythmic hierarchy of Bach. Both the basic drive and larger architectural definition of his music received little attention. Confidence in the credentialed performers/performances got a bit shaky — the talks before two of the pieces, though short, were scattered.

That being said, Cambridge Concentus shows potential.

David Patterson, Professor of Music and former Chairman of the Performing Arts Department at UMass Boston,  was recipient of a Fulbright Scholar Award and the Chancellor’s Distinction in  Teaching Award. He studied with Nadia Boulanger and Olivier  Messiaen in Paris and holds a PhD from Harvard University. www.notescape.net