German ensemble proves to be an irresistible force

Akademie für Alte Musik Berlin
Presented by the Bank of America Celebrity Series and Boston Early Music Festival
At: Jordan Hall, Friday night

The Akademie für Alte Musik Berlin is finally making its American debut tour, 23 years after its first brave concerts in a hostile East German environment. It has long since become one of the leaders of the European early-music scene. It collaborated with mezzo Cecilia Bartoli on her best-selling disc of Gluck arias and has made many prize-winning discs of its own.

On Friday night, the 17 musicians came to Jordan Hall loaded for bear. Some of them were playing the baby rattle when the ensemble was founded, but all were determined to conquer America's early-music capital -- and they did. This is a crack outfit that plays with unflagging, almost exhausting, energy.

The program was a diverse collection of famous pieces by Bach and less familiar works by a 20-year-old Handel (a suite from the opera ''Almira"), Vivaldi (a concerto for two oboes), and Geminiani (a concerto grosso based on the famous Spanish dance melody ''La Follia").

The group's intonation is accurate even at high speed; the musicians play over a full dynamic range, with captivating gradations of pianissimo. If some of the rhythms felt relentless, the inflections within them were irresistible. There is no conductor, but the ensemble is superb -- it's as much fun to watch these performers listen to one another as it is to hear them play. One of the concertmasters, Stephan Mai, danced to launch each movement of Bach's First Orchestral Suite. Georg Kallweit and Midori Seidler were vigorous soloists in the Bach double concerto, Xenia Loeffler and Michael Bosch the limber oboists. Cellist Jan Freiheit contributed some dazzling solo work to the Geminiani.

There were two encores: a slow ''Air" by Telemann, and a brisk one by Erlebach that featured Loeffler on the recorder and was pointedly announced by one of the violinists as ''from our latest CD . . ."