The three volumes, taken as a whole, are both the largest collection of its kind, in terms of program, and at least arguably the most thorough & detailed attempt to study rhythmic articulation within this broad repertory. (Although not collected in such a fashion, Antoine Guerber has also performed & recorded such repertory extensively, most recently in a majority of tracks on Sanctus.)
Although the result is rather stark in its emphasis on unaccompanied voices, often solo, and not all of the material might be captivating on first hearing, there is such a wealth — again, across the three volumes, although I've only listed the third — of melodic-rhythmic ideas here that the program takes on a highly probing quality.
As one might expect, the interpretation became more sophisticated with each volume, quite notably so, and so I have elected to list only the third (and, it would appear, final) album. (However, the process of refining the articulation is itself of interest, and so the full set retains an appeal. It's uncharacteristically experimental in mood given the prominence of the production.) Moreover, now that I've chosen to create a Latin Lyrics section in the secular list, one can not only question the secularity of this music (leading, as it does, to the Notre Dame repertory, which is considered to be almost canonically sacred), but must note that some of it (a minority) is in French. (One shouldn't make too much of the categorical limits here anyway, as it's a rough scheme that is hopefully convenient....) The conductus is often performed together with organum, which is explicitly sacred, and so perhaps I should have retained that association, and so compared to e.g. Potter's earlier Leonin. Perhaps the most appropriate question in response to this mini-debate is actually whether we have any real understanding of secularity per se anyway....
That said, that the conductus form itself — the functional nature of which is still being debated — served as something of a laboratory for melodic exploration seems obvious after hearing this collection. The result might thus be of more interest to specialists than to anyone else, but there are many intriguing ideas here. It would be interesting to investigate this style alongside other world lyrical traditions, and indeed that seems like a reasonable followup step — if indeed the collection is complete (not the repertory, but the project) at three volumes.
Todd M. McComb Updated: 9 July 2018