Candlelight, the first in a series of Head Space albums from The King’s Singers, stems from the seemingly eternal human urge to sing together, as well as the transcendent peace that it can bring to both performers and listeners. The ancient sacred service of compline, or nocturnal prayer, a moment for serene contemplation of the closing day, provides the frame for an anthology of music that ranges from the medieval Latin antiphon Salve nos, Domine (Save us, O Lord) and Abbess Hildegard’s mystical chant O Euchari to haunting contemporary choral prayers by Arvo Pärt, Judith Bingham, and Anna Thorvaldsdottir. In a world of distractions, intrusive sounds and equally intrusive thoughts, the “silence” of John Cage’s 4′33″ invites listeners to be present with whatever’s happening in the moment. Robert Parsons’ sonorous setting of the Ave Maria emerges from the post-Cage stillness like the tenderest of spring blooms, lovingly tended by an ensemble on peak form.