With community choral singing wafting everywhere in the Boston air Sunday, Seraphim Singers elected to celebrate its 20^th anniversary at The Basilica and Shrine of Our Lady of Perpetual Help (Mission Church) Mission Hill. Offering generous helpings of favorites from its extensive repertoire spanning 500 years, including a world premiere, the ensemble under Jennifer Lester met the challenges of contrapuntal complexity, double choruses, pungent harmonies, and long a cappella stretches with soaring ease.

In the diffusely resonant high-domed sanctuary, though, that soaring ease felt applied a bit too consistently. Greater attention to text and differentiation of style and sound could have colored the varied offerings more vividly; one wanted more than piling-on of beautiful lines. How about some grittiness and shoutouts? Lamentation, terror, rejoicing, and repose could have been better telegraphed.

Beginning with the Josef Rheinberger’s gorgeous Abendlied, the lines were drawn; in one a cappella work after another, a dreamy quality predominated, broken by periodic swells. The 30-odd singers rarely produced an unsightly sound. The straight-toned women could have fooled us as choirboy manqués if they had not come down from their loft. Aside from a few overly enthusiastic bellows from the tenors, the men sang with fine musicianship and no wool. Pitch rarely sagged or sharpened. Execution was textbook.

For Byrd’s Kyrie and Gloria from his Mass for Four Voices, Lester led the singers to bloom into a seamless layered sound, quite as through stained glass. But the rhythm was too straight-ahead, and the chordal effects did not add the texture they should; sections did not contrast to noticeable effect. Yet the Catholic reverence moved some Mission visitors to kneel.

Schaffe in mir Gott ein rein Herz (Create in me a pure heart) allowed Brahms’s consolations to pour forth in great measure, even as some disagreements about pitch diminished the harmonic punch of the fugal middle section’s tribute to Bach. The affirmation in “Restore me” lacked the last measure of dramatic conviction despite some high-proof whiskey moments from the tenors.

We then advanced to one of the more demanding sings of the afternoon. Bach’s (usually) accompanied motet, Singet dem Herrn ein neues Lied (Sing to the Lord a new song) S.225, challenges with its three complex movements (fast-slow-fast) of double chorus. If the organ accompaniment had been more imaginatively orchestrated (Heinrich Christensen played from the handy Bärenreiter continuo realization on quiet stops), the choir may have been induced to sparkle a bit more. While we prefer to hear this work with instrumental support, we got, as throughout the afternoon, clean and accurate execution. The interpretation suffered from lack of consonants, though, and from failure to articulate the powerful text sentiments, vitiating the rejoicing in the Lord as much as, in the chorale section, it glossed over the frailty of life. No Luftpausen or fermatas or surprises of expression came either to clarify or enliven.                      

Finally Christensen’s solo turn in Langlais’s Incantation pour un jour saint fully excited the voluminous space and made us take notice. Suddenly we were in a realm of drama and drive, as the 50+ stop Hutchings roared, purred, shimmered, smoldered and took no prisoners. This gave the choir a chance to process from loft to front of the church to begin the next set with the pungently spacy mystical longings of Penderecki in Song of the Cherubim; the choir now in our faces, it wafted tone in incensing waves of power, even if the quiet, serene portions, supported and projected as they were, became marred by noise of the air handlers. Lester kept everyone firmly on the rails through the complicated rhythms.

Benjamin Britten had an idiosyncratic approach to setting text, so it is disappointing to report that his English here was no better-articulated than Penderecki’s Polish. The chorus had no trouble at all with Britten’s angular lines, on the other hand, which came to us like overheard conversation. During the scary and almost hallucinogenic weirdness of “The world is changed with the grandeur of God / It will flame out, like shining from shook foil” (Hopkins), votive candle sales shot up in the transept.

More self-indulgent dreaminess came to us in Pärt’s Magnificat; nevertheless, the execution of the pungent harmonies once more drove home the fact that this group can do a cappella complexity with seemingly little effort. And by the time we got to Nunc Dimittis of Gustav Holst, the uniformity of applied style had begun to grate. Did we really need to hear Tallis’s Lamentations after an hour and a half of innig, plaintive guilelessness? Not I.

The exceptions to the reined-in affect arrived most vividly in the last two selections. Composer James Woodman has never written anything less than a perfectly crafted note, according to my choralman-organist pewmate. In the world premiere of his Annunciation (a Seraphim commission in celebration of its 20^th), Woodman’s vivid text painting of Edwin Muir’s poetry, both for the strong accompanying organ part and for the chorus, set up a lively competition between vocal pipes and organ pipes that awakened us after the not quite lamentable enough Lamentations of Jeremiah. As it had in the Langlais earlier, the organ spoke with power and color under Christensen’s expert management. Those pipes gave us all the missing consonants and the last word. But the final stanza of sung text might summarize the entire event:

But through the endless afternoon
These neither speak nor movement make
But stare into their deepening trance
As if their gaze would never break.

The closer, the Kyrie and Sanctus-Benedictus from Langlais’s Messe Solenelle (1951), eventually left us feeling thankfully sanctified after having first survived a terrifying blast from the organ as the first of its emphatic calls and answers with the chorus in the pleading Kyrie. Indeed the organ was central, as one would expect from that virtuoso organist / composer. It was more than okay that Christensen occasionally covered the singers; hearing him channel a French cathedral organist instead of presiding as the Last Puritan at Kings Chapel afforded us guilty pleasures. The Sanctus barrels through a mighty mystical and haunting crescendo for which the Seraphim Singers had kept surprising power in reserve. The Benedictus, too, patiently builds on distant mythical musings before the last Hosanna rang out in full cry, to salutary effect as the afternoon’s ultimate benediction.

Lee Eiseman is the publisher of the Intelligencer.