Cantica Symphonia are a mixed vocal and instrumental ensemble long associated with the works of Guillaume Dufay, to whom they have devoted five discs. Giuseppe Maletto and the group now offer a whole album of works by Heinrich Isaac (c1450-1517) which includes the first recording of the Missa Misericordias Domini and a selection of motets, four of which are also previously unrecorded. That there is so much of Isaac’s output still to be explored on record should come as little surprise: not only was he prolific but he has often been eclipsed by his more famous contemporary, Josquin Desprez.

The disc opens with a sizeable setting of Ave regina caelorum, set to a spacious texture for four voices. The singers choose sprightly tempi for each invocation and create a bubbling sense of urgency through each of the carefully plaited lines. The Mass maintains this thoughtful but subtly urgent style, carefully balancing overall texture while maintaining the clarity of each vocal line and preserving the vocal personality of each singer. The voices are extraordinarily well matched and this CD continues Glossa’s tradition of recording with a single microphone pair. The sound is considered and mellow, yet each individual moment is brilliantly engaged, and it crackles with energy throughout.

Of the remaining motets, Inviolata and O decus Ecclesiae stand out for their sheer magnitude, and the addition of instruments to voices moves us from an intimate chapel sound towards a greater sense of occasion. Sinewy fiddles add a strident grain while sackbuts and slide trumpets bring both grandeur and wistfulness in equal measures. Inviolata in particular clearly presents Isaac’s slow, patient cantus firmus almost like a rope around which garlands of polyphony are woven, and in O decus Ecclesiae changeable tempi, unexpected on first hearing, gradually reveal themselves as wonderful moments of rejoicing and excitement.