'Just when you think you've heard everything, there's. . . ."

That sentence, uttered by a listener at the Crossing's "Seven Responses" concerts Friday and Saturday at the Philadelphia Episcopal Cathedral, could've been completed many different ways. The Crossing choir premiered newly written companion pieces to the 1680 Buxtehude oratorio Membra Jesu Nostri, each movement of which meditates on the crucified Christ's distressed body, but in these concerts, were interspersed with recently composed "responses" from one of seven current composers.

In the well-designed performance area, the Crossing sang the new pieces in a foreground area with the International Contemporary Ensemble, and migrated to the slightly background transept area of the church for the Buxtehude movements with Quicksilver baroque instrumentalists. Plus mood-setting lighting. It was one of the new-music events of the year.

The Buxtehude movements were interspersed with the new pieces and created their own miniaturist world, thanks to director Donald Nally's keen sense of baroque-era style and excellent solo contributions from Crossing members. New pieces were such a contrast that I never caught myself measuring them against Buxtehude. David T. Little's "dress in magic amulets, dark, from my feet" focused on the nails used in the crucifixion in a piece ending in a long crescendo, not unlike the finale of his Dog Days, its effects aided by hammers pounding on automobile brake drums. In contrast, Anna Thorvaldsdottir's "Ad Genua/To the knees" was expansive, ethereal and full of effectively low-key melodies - all leaving you dumbfounded as to how its effects were achieved.

On the more earthly side, Caroline Shaw's "To the Hands" quoted recent statistics about misplaced persons with music resembling the Philip Glass opera Einstein on the Beach, while Lewis Spratlan's "Common Ground" fearlessly addressed the deteriorating ecology of the planet. The messages seemed to weigh down the piece's musical fantasy but were at home in this high-concept concert.

Hans Thomalla's "I come near you" had musical surfaces that felt mesmerizingly static but with below-the-surface restlessness that covertly kept the piece moving forward. "Ad Cor" (To the heart) by Pelle Gudmundsen-Holmgreen portrayed the heartlessness of the world in spoken words with the harsh chill of indifference.

The piece I most eagerly anticipated surpassed expectation: "My soul will sink into you" by Latvian composer Santa Ratniece. Like NASA's New Horizons spacecraft, Ratniece delivers revelations from places one vaguely knows about but has no way to find. In a celestial harmonic cloud encompassing words taken from the letters written by medieval saints, Ratniece had subtle English horn solos wafting by and key words characterized by the flavor of the surrounding harmonies. Vocal lines were studded with Arabic-sounding grace notes. Just when I thought I'd heard everything. . . .