“But it doesn’t mean anything!” complains little Gretel in “The Sound of Music,” faced for the first time with the seven notes (do, re, mi, fa, sol, la, si/ti, do) of the tonal scale. And her governess, Maria, explains that you simply add words, “one word for every note.” The Estonian Philharmonic Chamber Choir, however, opened its concert Monday with a simple iteration of those seven notes, over and over, that wallowed in the pregnant potential of ambiguity, a foreshadowing and preparation of music-making to come, without any words at all.

The chorus stood around the nave of the National City Christian Church, surrounding the audience, and following the clear hand gestures of their director, the charismatic, gray-maned Tonu Kaljuste. “Do,” came from the women at the front of the church, “re” from the men at the back of it, and each section continued to chime in, at different volumes and in different octaves, each note overlapping with the note next to it, and sometimes with two or three at once, to create a small halo of dissonance, while the music continued up and up and up in an unbroken spiral of notes until it was finally silenced, on “do,” by the closing of Kaljuste’s hand.

The piece was called “Solfeggio,” it was written by Arvo Part, and it set the tone for an evening of music that balanced emotional directness with technical mastery.

The concert was a celebration of three composers’ anniversaries this year: 2015 marks Part’s 80th birthday, Sibelius’s 150th, and the 85th of Velja Tormis, who is lionized in Estonia for his folklike, raw-edged works. But few of the works here were familiar to much of the audience.

Part effectively follows Maria von Trapp’s “one word for every note” guideline, but each word becomes a small shining unit of its own, sometimes in a single voice and sometimes layered with sounds, each bound to the other words around it within an aura of resonance. In the seven works gathered here, most written in the past 20 years, some of the texts gallop out like incantations — for instance, “The Woman with the Alabaster Box” — but always with careful emotional calibrations; Christ’s final word is presented in a shimmering curtain of sound. “Virgencita,” the most recent of the works on the program, has a Spanish tinge, opening with a contrast between extreme high and extreme low. The final “Alleluia-Tropus” climbed ascending scales to a point of near-ecstasy, which remained sustained and fading away in the high voices as the rest of the chorus again swirled downward.
Against the purity of “Solfeggio” came the opening of the second half, Tormis’s “An Aboriginal Song,” which offers a wilder side of wordlessness, the barely tamed voices sustained by the underlying growl of a large primitive drum (struck by Kaljuste). Tormis’s verse songs have the familiar features of much folk music, along with its gimmicks, like the racing “Forced to get married,” which gets faster and faster until the chorus finishes with an inarticulate cry. In the midst of the Tormis songs came the Sibelius work: melodious, elegant, and evocative, closing with a love scene enacted not in wild passion, but with a kind of reverent awe between two of the chorus’s fine singers, while the others supported them in the background.

The program’s close, though, was a kind of primal scream, Tormis’s “Curse Upon Iron,” with two snarling male soloists, a ululating chorus, and Kaljuste’s drum beaten almost to the breaking point. You can’t take art much further in the direction of pure emotion without getting into EST-like catharses; this choir, however, returned to perfect decorum as soon as the music stopped, and welcomed the aplause.