San Francisco Classical Voice

Music Director Warren Stewart kept a low profile in this straightforward and complete reenactment of a liturgical event, allowing the chanted psalmody to unfold on its own and providing gentle guidance for the “composed” sections. As we have come to expect from this well-disciplined group, intonation was usually dead on, and the Latin phrases unfolded in streams of incantation that rarely strayed from perfect togetherness. In the polyphonic sections, cadences fell into place with snappy precision, bearing evidence of painstaking concentration and exacting work. The accomplished group of 26 capable singers is led by a professional solo quartet consisting of Ruth Escher, soprano, Suzanne Elder-Wallace, alto, Mark Mueller, tenor, and Hugh Davies, bass.

Part of plainchant's captivating effect, transporting the listener to level of serene contemplation, is the impression creating by many voices intoning perfectly tuned unions and octaves. Stewart has clearly worked hard with his singers to achieve a sense of thinking and breathing as one, and his mixed group — perhaps a bit larger than one would probably have found in a Cathedral choir in Guerrero's day — demonstrated the fruits of this hard labor, with remarkable unanimity of motion and phrasing. The vocal quality of the chanting, however, sometimes featured a rather hard-edged quality somewhat removed from the mellifluous, warm sound that can make plainsong so magical in its spiritual uplift.

The psalm singing was led by Davies, who acted as cantor, intoning the solo prayers and providing the opening “incipit” of each chant. The psalmody often began with a slightly rough attach, and the gap of silence between the two halves of each chanted psalm verse seemed a tad long, as Davies paused to indicate the next entrance. It was only at these junctures that entrances became a bit ragged, a problem that might have been ameliorated by a more favorable singing formation with the chanters facing one another. This might also have allowed a more flexible, less rigid contour to the vocal lines. Still, there was admirable blend in the multi-voiced sections, with slight dominance of men over women and a few weak alto entrances in the counterpoint.

Hearing a group of psalms chanted in succession highlights the subtle differences that the various “psalm tones” — specific chant formulas with their beginnings, middles and ends — can create in mood and character. Guerrero's reverential verse settings incorporate these melodic formulas into their vocal fabric in ingenious ways, reserving the most elaborate writing for the Doxology that concludes each psalm with “Gloria Patri” (Glory to the Father).

Highpoints in Guerrero's Vespers included the hymn “Christe Redemptor Omnium,” with a high-lying melody that showed the men's voices to good effect. The centerpiece of any Vesper setting is the Magnificat. Here the short sections of polyphony took on a brash, slightly nasal vocal quality — useful for keeping intonation under tight control but lacking in tonal allure. Guerrero saved his best and most elaborate music for last, with a setting of the Marian antiphon “Alma Redemptoris Mater,” with the voices resounding with fullness and rich coloration. As is only fitting, the Vespers concluded as darkness fell on Potrero Hill, ending a pleasurable visit to Renaissance Spain.