The Bangor Symphony Orchestra, featuring guest pianist Anthony di Bonaventura, offered a mixed bag of musical expression Sunday night at the Maine Center for the Arts. Although the BSO delivers some of the best live classical concerts in central Maine, Sunday’s concert was somewhat disappointing.

One of Mozart’s most monumental works, the Piano Concerto No. 9, K. 271, in E-flat major, was the first selection on the program. A bold and demanding piece, this concerto requires a most intimate relationship between soloist and orchestra. Di Bonaventura and the BSO string section kept this connection clear and eloquent. Director Werner Torkanowsky controlled the tempo and kept the piece at a lovely pace whether the theme was lively and upbeat or melancholy.

The first two movements, however, lacked the vitality and detail that this concerto should showcase. The brilliance of Mozart’s movement between seriousness, elegance, joy and playfulness largely escaped the BSO in this number.

Beginning with a whip snap, Ravel’s Piano Concerto in G Major, was a much heartier presentation. Showering trills and amazingly free piano passages livened the mood of the evening and caught the distinctly 20th century sound of this piece. In particular, the jazzy and unconstrained presto finale achieved the spirited depths of Ravel’s music.

Without a doubt, the highlight of the evening was Rachmaninoff’s Symphony No. 2, Opus 27, in E Minor. Opening with a slow, somber introduction and moving through sentimental yet lively moments, the piece is a testament to the romanticism of the period in which it was written. The full orchestra took the stage for this symphony and delivered a rich and robust rendition of Rachmaninoff’s score.

The incredibly sweet adagio in the third movement was handled beautifully by the BSO. Serene, slow, provocative, these are perhaps some of the most lovely strains of music that Rachmaninoff wrote, and the BSO captured these themes with charming clarity.

Overall, the volume of the full orchestra carried the second half of the concert. But the evening, though entertaining, did not achieve the peaks of emotion that these masters of classical music breathed into their compositions. The BSO musicians are among the finest in the state, but on Sunday night seemed unenthusiastic about their own performance. If Torkanowsky could evoke as much glorious emotion as his conducting suggests, then perhaps the concert would have generated the electricity of the music.