Until recent seasons, Bach cantatas were absent from mainstream Philadelphia concerts. That was remedied by regular installments from Choral Arts Philadelphia and, more periodically, by the Bach Gamut Ensemble headed by Koji Otsuki and shepherded along by the Philadelphia Chamber Music Society. The latter presented an evening of solo cantatas on Wednesday at St. Mark's Church. But traditions take time to build; Gamut is maybe halfway toward establishing a convincing personality in this repertoire.

The concert had two cantatas and isolated arias with first-class singers - soprano Sarah Shafer and baritone John Moore - with everything in the right places though with a layer of reticence that's inevitable with performers still finding their way into a deeper sense of what the music might be saying. Those answers aren't so easily found with the cantatas, whose often-dated texts leave you asking what other dimensions these works, written mostly for Sunday services and special occasions, might have to show us.

Starting the concert with Ich habe genug, an introspective cantata about saying goodbye to life, wasn't the catchiest way to begin. Moore's baritone was rich, the comprehension level of the text was high, and the energy level was excellent, but personal identification was only superficial.

Well-rehearsed but score-bound, the performances mixed modern and period instruments with no ill effects. Otsuki played some obbligatos on the long-obsolete piccolo cello (it looks like a fat viola and is strapped onto the player like a guitar) in duets with the double bass that were interesting in a way that Bach always is but that were a first sketch of what they could be. The star of evening was oboist Mary Lynch: She played with beautifully shaded tone at all registers of her instrument and had clearly taken this music to heart.

The most accomplished overall performance was of the most ambitious cantata - Mein Herze schwimmt im Blut - with Shafer giving one of her better performances in these early years of her post-Curtis Institute career. She seemed to inhabit the penitent world of the cantata with the kind of elegant simplicity that opened doors for the audience to discover the piece's meaning for themselves. The church setting allowed one to enjoy her not on any distant, elevated stage but almost at eye level with the audience. At times, I was sure she was singing to me. I'm sure others felt the same way.

The audience, filling the church to an extent I've rarely seen in concerts there, suggested there's great interest in these works and seemed happy with what they was given - as though they're learning the music, in their own way, along with the musicians. It's nice to think we're all in this together.