You thought encore performances only occurred at rock concerts, where the screams and chants of die-hard groupies eventually convince the stars to return to the stage. Despite a definitive absence of screaming and chanting in Jordan Hall at the New England Conservatory (NEC) on Sunday, March 1, the Berlin Symphony Orchestra bestowed the rare gift of an encore performance upon its audience. Brought to the NEC in the midst of the 1997-98 BankBoston Celebrity Series, the orchestra, with conductor Joseph Silverstein and piano soloist Derek Han, already possessed a well-packaged program of Brahms, Mendelssohn and Schumann--one could not have asked for a more fitting embellishment than a bit of Beethoven.

As a world-class orchestra that has been performing for a little more than three decades, the Berlin Symphony was directed on Sunday by Joseph Silverstein, who currently heads the Utah Symphony. An unusually liberal expression of enthusiasm in the conductor was immediately apparent; his smiles were a welcome divergence from the stoic grimaces of most highly-acclaimed conductors. Also absent was any indication of restraint within the orchestra; the woodwinds leapt directly into Brahms' Variations on a theme by Haydn only a few moments after Silverstein took his position at the front of the stage.

St. Anthony's Chorale--the thematic foundation for the eight variations of Brahms' composition--was introduced with a regal cadence perfectly suited to the gilded atmosphere of the concert hall. Sometimes called Variations on Saint Anthony's Chorale, the piece suffers from an identity crisis, although the crisis involves the composer and not any aspect of the music itself, which remains a brilliant showcase of the woodwinds and horns. Musicologists have yet to determine whether the theme was actually written by Haydn or by his student Ignaz Pleyel. Regardless of the nature of his piece's thematic roots, Brahms effectively unearthed a simple, hymn-like melody and molded it into an intricately layered set of variations. Even if the talents of the oboe, clarinet, flute and bassoon players did receive the spotlight in most of the theme's airy permutations, the constant alteration of the string players' style-from pizzicato to spiccato to longer, lyrical bowstrokes--carried the listener through the eight variations and finale, all executed with swift precision under Silverstein's direction.

After a quick rearrangement period, Derek Han emerged from backstage to take his place at the grand piano now obscuring the conductor. Touring with the Berlin Symphony Orchestra in its current debut tour of the United States, Han's accomplishments range from graduating from The Juilliard School at 18 to playing at a gala event for President Nelson Mandela last season. During the opening strains of Mendelssohn's Piano Concerto No. 2 in D Minor, Han fixed his gaze upon the baton, bobbing his head slightly and effortlessly threading his melody into that woven by the full orchestra. Every note in the cascading arpeggios of the concerto resounded under Han's steady fingertips, and the interchange between pianist and orchestra was seamless. Pausing to wipe his brow, cheeks and hands during every rest, Han attacked each section of Mendelssohn's work with unfaltering strength and decisiveness, even though the piece seems to be continually in transition, full of arpeggios and climbing scales. His energy was rewarded by waves of applause from the audience, who brought him back onstage twice after his initial departure.

Following a 20 minute intermission, the orchestra plunged directly into what would have been the final piece of its program, Schumann's Symphony No. 1 in B-flat Major, "Spring." Here the layering of textures is much deeper than in Brahms' work, with a fanfare from the trumpets heralding the arrival of a multitude of entrances from all sections of the orchestra. Mimicking the bustle of springtime with trilling ornamentation and a robust tone, the Berlin Symphony Orchestra lost none of the momentum it received with Derek Han's performance; even the more placid Larghetto was imbued with the anticipation of motion and activity to be delivered in ensuing Scherzo. At the piece's conclusion, Joseph Silverstein returned three times to receive the praise of his listeners, a handful of whom stood to applaud the orchestra and its smiling conductor.

Unfortunately, a handful of listeners also left the hall at this point, perhaps in hopes of avoiding catastrophic parking conditions at the conservatory. Perhaps Joseph Silverstein's smiles hinted at the surprise, but no one seemed to expect the conductor to return a fourth time, as indicated by the donning of coats across the balcony and mezzanine. Silverstein did return a fourth time, though, and with the same vigor he exhibited almost two hours earlier at the concert's commencement, led his group into an encore performance of Beethoven's Egmont Overture. The overture acted as the perfect capstone to an already well-rounded program, its melody passed from woodwinds to strings, undulating through major and minor keys while the timpani underscored the excitement in the audience. This time there were rounds of bravos from the listeners for the orchestra and its beaming conductor, who repeatedly mouthed "thank you" to the appreciative crowd of concert-goers.

They may not be The Peking Acrobats or The Chieftains--other names on the diverse BankBoston Celebrity Series roster--but they can certainly surprise and entertain an audience, which is exactly what Joseph Silverstein, Derek Han and the Berlin Symphony Orchestra accomplished by tossing in a wholly unexpected encore performance. They may not draw the types of listeners who normally request encores of the performers, but orchestras--especially those with unfailing energy like that of the Berlin Symphony Orchestra--should have every right to be as impulsive as they wish.