When the Portland Bach Festival began two years ago, it proved an enlivening addition to the city’s summer concert schedule, with everything going for it. In Bach, the festival had a comfortably familiar and unassailably popular composer to celebrate, and a repertory so vast it would take decades to explore fully. The festival’s founding directors – violinist Lewis Kaplan, who ran the Bowdoin International Music Festival for 50 years, and Emily Isaacson, the director of the Oratorio Chorale – assembled varied programs and an ensemble of highly regarded musicians from Portland and around the country, with which they presented first-class performances.

But tensions between the two founders quickly began pulling the festival apart, and this past winter, relations ruptured completely. Each side had its grievances, as well as its partisans, but they wisely avoided airing the details of the dispute publicly.

For listeners, who have no reason to take sides, this is actually good news. Although Isaacson and Kaplan differed about how the festival should be run, they both believed strongly in the concept and the music, and as a result Portland now has two Bach festivals, running back to back.

Isaacson’s Portland Bach Experience had its formal opening (after a handful of curtain-raising events last month) on Friday evening at the Episcopal Church of St. Mary in Falmouth and runs through June 17. Kaplan’s Bach Virtuosi Festival opens on June 17 at St. Luke’s Cathedral in Portland and runs through June 24.

So far, I don’t see a downside, so long as the audience can absorb two weeks of concerts instead of one. Most of the musicians and vocal soloists from the original festival have followed Kaplan, but there is hardly a shortage of fine period instrument performers these days, and Isaacson assembled, drawing on that same pool of musicians from around the country, an excellent orchestra of her own.

For her opening concert, she chose two works with a bright, celebratory quality, thanks in large part to their vibrant trumpet and timpani flourishes. The Orchestral Suite No. 3 (BWV 1068) represented the secular side of Bach’s output; the Magnificat (BWV 243) was drawn from his copious output of sacred settings.

The Orchestral Suite offered a good opportunity to focus on the new ensemble, which seems admirably experienced in the niceties of Baroque performance practice. Throughout the suite, the ensemble’s three superb trumpeters (Steven Marquardt, Perry Sutton and Robinson Pyle) maintained the ebullient spirit of the music, with the support of some sharp timpani accenting (Jonathan Hess), fine reed playing (oboists Priscilla Herried and David Dickey), a warm, appealingly textured string sound, and a solid continuo group, in which Ray Cornils was the harpsichordist.

It was also an opportunity to hear Isaacson outside her usual choral conducting context. It took her a few moments to settle into that role. In much of the Ouverture, with its dotted rhythms and rich textures, she seemed to be battling to hold the ensemble together, rather than shaping the music’s phrasing or balances. She fared better in a trim reading of the Air, where she let the string melody sing, without overemphasizing it, and her brisk readings of the remaining dance movements – a Gavotte, Bourée and Gigue – were vigorous, tightly unified and carefully accented.

Those qualities enlivened the Magnificat performance as well, for which Isaacson used a 23-voice choir, plus soloists. Again, the trumpet trio commanded the attention in the opening movement, and at various points in the work where Bach wanted to evoke the glory and power of heaven, the choir produced a lovely, flexible sound in the five movements where it held the spotlight.

There were revelatory moments, including one in the closing Gloria Patri, where the faint echo of a Renaissance sensibility – something musicologists often say was close to Bach’s heart, despite being hidden beneath layers of Baroque decoration – came through, briefly, in the choral writing.

The soloists – soprano Sarah Brailey, mezzo-soprano Kate Maroney, tenor Stefan Reed and bass David Tinervia, with one of the choristers, soprano Susanna Molisky, joining Brailey and Maroney for the trio setting of Suscepit Israel – were well-matched and all delivered shapely, focused performances.

The program will be repeated Saturday evening and Sunday afternoon at the Episcopal Church of St. Mary in Falmouth.

Allan Kozinn is a former music critic and culture writer for The New York Times who lives in Portland. He can be contacted at:

allankozinn@gmail.com

Twitter: kozinn