The happiest place to hear Bach's cantatas is not always the best place. These nearly 200 pieces are denizens of the church. With all its acoustical distortions and abortive sightlines, the church created this music and is served by it. Controlled concert environments let us hear more, more clearly, but at the same time less completely.

Sir John Eliot Gardiner, his Monteverdi Choir and the English Baroque Soloists have avoided nonecclesiastical settings during their Bach Cantata Pilgrimage, a yearlong tour that continued Wednesday night at St. Bartholomew's Church on Park Avenue. It ends there on New Year's Eve, its musicians having canvassed Europe as missionaries for Bach's great Protestant art. The Third Day of Christmas brought five of his many settings for the season.

This was period-instrument, historically inclined performance for the right reasons. Bach's music survives, indeed flourishes, in the hands of Leopold Stokowski or doo-wop quartets, but there is something about the whole-grain sound of wooden flutes and oboes that reinforces the aural roughness of the pieces in their natural setting.

Bach's cantatas have a wonderful inelegance. Jesus' militancy against his enemies in ''Selig ist der Mann'' moves with the relentless accents of a battle scene. Choruses literally jump with joy; their music dances with heavy shoes, not ballet slippers.

Much to the distress of singers, Bach wrote vocal lines much as he wrote instrumental ones -- what is natural for the second being very awkward for the first. Yet it is precisely this quality that makes the arias with oboe, flute or violin obliggato into true duets. They match.

Sir John takes up this relationship in his conducting. He may ardently pursue the Baroque practices of quick tempos and short phrases, but he also listens to Bach's instruments and his vocal writing.

They tell him that both human and artificially created voices have a tendency to sing. The Thomanerchor, here recently to sing Bach's Christmas Oratorio with the New York Philharmonic, put out the different idea that these voices danced exclusively, and that to extend phrases across bar lines without the interruptive thump of strong-beat accents was somehow illegal.

It is hard to argue with a choir's provenance that reaches back to Bach's own church in Leipzig, but I did argue at the time and do now. Sir John's chorales moved swiftly but in long breaths, naturally.

What I think those excellent if terribly earnest young German singers missed was the sheer joy of Bach's church music, something these more grown-up and sophisticated British performers on Wednesday radiated from every bone in their bodies.

Their physical situation was awkward. Singers and players crowded the church's choir, jostling one another and sitting haphazardly where there was room to do so. Yet again the inconvenience of the church setting somehow added to the substance of the evening.

The program began with ''Sehet, welch eine Liebe hat uns der Vater Erzeiget'' and ended with the Sanctus from the B minor Mass and an encore. The familiar Sanctus with its festive trumpets and deliberate power made a rousing summing up, and the Monteverdi Choir's deft negotiation of the intricate fugal textures was a delight.

The vocal soloists stepped out of the chorus: Gillian Keith, Joanne Lunn and Katharine Fuge were the heartfelt sopranos; Robin Tyson and William Towers the excellent male altos. James Gilchrist and Peter Harvey, tenor and bass, were vivid voices with excellent diction. Kati Debretzeni, violinist; Rachel Beckett, flutist; and Xenia Lofler, oboist, were among the instrumental soloists.

Photo: Sir John Eliot Gardiner conducting the Monteverdi Choir and the English Baroque Soloists in Bach cantatas at St. Bartholomew's Church. (Hiroyuki Ito for The New York Times)