The third concert in the Four Seasons Chamber Music Festival’s 15th season was to have presented string quartets, but a guest musician’s illness caused artistic director Ara Gregorian to pare down the program to string duos and trios. The result was most satisfying. Joined by violinist Axel Strauss and cellist Michael Kannen, Gregorian presented a fine string trio and duo by Beethoven, an exciting duo by Martinů and a rich and rewarding serenade for trio by Ernst von Dohnányi.

Beethoven’s String Trio in C minor, Op. 9, No. 3, was filled with wonderful moments, including, oddly enough, some brief silences between phrases that added drama and tension to the playing. The composition also provided some interesting structural contrasts in which a pair of instruments moved to the forefront while the third instrument provided subtle support, for instance, or in which one instrument played an exposed line while the other two provided support. Musically, the piece was by turns lyrical and vigorous, and the three musicians gave a splendid reading. The singing tone of Strauss’ violin in the upper register was balanced nicely by Gregorian’s viola and Kannen’s cello in lower registers. Each player had moments to bring his instrument forward, and the three also handed off lines to each other, as well as overlapping each other. Especially nice was the blend of instruments at the hymn-like opening to the second adagio con espressione movement. Strauss had fine exposed lines in the fourth finale: presto movement.

The Beethoven duo (nicknamed “eyeglasses” and numbered “without opus, 32”) is scored for viola and cello, and Gregorian and Kannen were a fine pair, whether on expansive lines or on phrases requiring either fast bowing or fast fingering or both. With the two instruments closer to the baritone/alto range than tenor/soprano, the music takes on a richness of sound, and the interplay between the two musicians provided interesting exchanges, some echoing phrases and stylish harmonies.

Gregorian exposed the audience to another composition by Ernst von Dohnányi (1877-1960) that shows why he is highly regarded for his writing for chamber ensembles. This four-movement “Serenade for String Trio,” Op. 10, has some contemporary sounding sections, but it is quite accessible as it employs a wide variety of string-playing techniques throughout. The opening Marca movement is bright but quite brief, featuring drone-like phrases in the viola and a relatively spare melody line in the violin. The second Romanza movement has a long and somber melody line in the viola, played over plucked violin and cello, while the third Scherzo movement is quite busy, brimming with almost nervous energy. It opens with a fugue-like statement, and that descending line is repeated frequently during the movement. Strauss often played a slower melody line over Gregorian’s and Kannen’s busier lines. The three players handled the demands of this movement quite well, whether in unison or in harmony. The final Tema con variazioni-Rondo movement provides a slower, more introspective feeling until the closing and is quite lovely. Some of the variations are played at a faster tempo, but the more memorable portion was a slow violin-viola duet played beautifully over plucked cello. The Rondo portion, with its dance-like opening and occasional gypsy-sounding music, might have been a fifth movement in some other composer’s work; it brought this relatively little-known piece to a sparkling conclusion.

Bohuslav Martinů’s Three Madrigals for Violin and Viola, H. 313, gave Strauss and Gregorian a chance to present a more contemporary sound (the piece was written in the late 1940s) than one usually hears at a Four Seasons concert, with some pretty seriously fast fingering required of both players. Portions sound like Eastern European or gypsy melodies (some phrases in the second poco andante movement mimic the sound of a balalaika, for example), portions contain near-dissonance, portions are quite lovely. The pieces cover a wide range of dynamics, from soft and subtle to bold and lively. Standing rather than sitting, Gregorian and Strauss gave a spirited reading, each fully engaged in his own part and that of his partner. The long ascending figure in the allegro movement was especially well played by both musicians; this movement by itself, with its shifts in mood and tone, was one of the concert’s highlights.