At first glance, Aeon's two-CD set Johannes Ockeghem: Missa Cuiusvis Toni seems like it has to be the longest recording of a renaissance mass in the history of mankind, and one wonders what wealth of additional material would be in play to stretch a single mass setting out to fill two discs. A quick explanation would be that Lucien Kandel's Ensemble Musica Nova is a group that specializes in divining hidden extended works from the mostly relatively short pieces in medieval and renaissance sources. A good example is the disc-long exploration of Dufay's motet Flos florum for Zig Zag Territories, which places the work in the context of several other related pieces owing to a shared use of cantus firmus. In this instance, not one Ockeghem mass is heard, but four; however, the same source work is used for all. Missa Cuiusvis Toni (Mass in All of the Tones) has some "puzzle" notation elements that introduce variant ideas into the mass setting when sung on differing church modes. Here it is heard on the tones of "ré," "fa," "mi," and "sol"; each mass takes roughly 30 minutes to perform, and each one is significantly different from the next. Ockeghem's motet Intermerata Dei Mater is also included, for good measure, as filler on the second disc.
A striking feature of this disc is that the masses are performed outside of a liturgical context. One would have to go back quite some time to find a major early music group performing a renaissance mass without its usual framing material; incipits, propers, chant sections, what have you. As long ago as 1970s musicologist Denis Stevens was saying that early masses should never be done without some relation to the liturgy, and this has become for the most part the rule. However, a full liturgical context within this case for all four masses would probably require four discs rather than two, and would tend to obscure the important similarities between these realizations. The very act of figuring out Ockeghem's cryptic puzzle notation is in itself a thing of wonder, but it wouldn't mean much if the performances were as smooth and pristine as they are; Ensemble Musica Nova's sound is well intoned, fluid, and suitably devotional. If one were to go back to the days when ensembles sang masses straight out of the book with no incipits, one would note a tendency for such groups to sing the music considerably faster and more recklessly. By comparison, nothing about Ensemble Musica Nova's performance of these works is antiquated. They are both effortless and pure, and Aeon's sound is warm and well suited to the program at hand.