The Estonian Philharmonic Chamber Choir captivated a near-capacity audience Sunday afternoon at the Cathedral of the Sacred Heart. The attraction almost certainly wasn’t the program, which featured no work in the standard choral literature, but a sound that literally absorbed the listener, even though it was produced by just two dozen voices in a vast space.

That’s a tribute to the collective quality and sonority of these voices — you could hear why this group is rated among the world’s finest small choruses — and to the skill of Kaspars Putninš, the ensemble’s director, in “playing” the cathedral’s resonant but often diffuse acoustics.

Most selections were slowly or moderately paced, and vocal diction was largely irrelevant to most listeners, as all but one selection were sung in Estonian, Russian, Finnish or Latin. (Texts and translations were provided in the program book.) The spoken narration of “Tower Bell in My Village,” a concerto for voices by the Estonian composer Veljo Tormis, was not clearly audible to most of the audience, but the dream-narrative text (from poems by Fernando Pessoa, translated from Portuguese to English) communicates more by tone than content.

The bulk of the program was devoted to big names of classical music — Tchaikovsky, Sibelius and Arvo Pärt, the Estonian who may be the most widely esteemed living composer — mostly represented by pieces not known to any but their most fervent fans.

The Estonians made strong cases for three sacred choruses by Tchaikovsky, audibly in the tradition of Russian Orthodox chant but leavened with the composer’s distinctive romantic expressiveness, and even stronger cases for Sibelius as a choral composer. “Rakastava” (“Beloved”) ranks among the Finnish master’s greatest works in any format, and “Sydämeni laulu” (“My Heart’s Song”) and “Saarella palaa” (“Fire on the Island”) aren’t far behind.

The chorus’s mastery of Pärt’s austere but spacious lyricism glowed in “Solfeggio,” an Easter-appropriate sequence of “Nunc dimittis” (“Lord, now lettest thou servant depart in peace”), “The Woman With the Alabaster Box” and “Dopo la vittoria,” a hymn of thanksgiving on the baptism of St. Augustine.

The most striking performance of the afternoon came at the end: Tormis’ “Curse Upon Iron,” a vividly dramatic adaptation of the incantations in the Finnish epic “Kalevala.” Punctuated by percussive choral exclamations and hard beats from a hand drum that sound like bursts of artillery, the piece, with modern poets’ additions to the text, is transformed from an ancient’s shaman’s call to battle into a fervent cry against war.