Stephen Layton leads his ace professional choristers deep into Arvo Pärt’s musical meditations on sound and silence. They begin with the Estonian composer’s setting for choir and organ of one of the most revered of all sacred texts, the Latin Mass. His Berliner Messe (Berlin Mass), originally written in 1990 to mark the 90th of Germany’s “Katholikentage” or “Catholic Days,” signals God’s loving kindness with simple chant-like melodies and equally simple harmonies that evoke something infinitely greater than the sum of their individual parts. Polyphony and organist Andrew Lucas are at their finest in the “Sanctus” and sublime “Agnus Dei,” resonant and clear in tone, utterly unified in ensemble, while Layton’s feeling for ritualistic drama and his choir’s ability to articulate emotions unlock the shattering power of Pärt’s seven Magnificat Antiphons.