Bach Sinfonia steady and sure in Mass performance

Led by its founder, Daniel Abraham, the Bach Sinfonia launched its 20th season with a marvelous, technically sure account of J.S. Bach's monumental Mass in B Minor, BWV. 232. (It was never publicly performed or even published in the composer's lifetime.) Saturday's performance played to a capacity audience at Montgomery College's Cultural Arts Center in Silver Spring. But Abraham veered away from what we have come to expect today.