For their second album, La Quintina premiere an unknown Mass by English Renaissance composer Nicholas Ludford (c1490-1557), performed by three crystal-clear singers and a sprightly organetto. It’s not so straightforward, though, for this is also an immersion into improvised musical practices via squares (square note notation). Little known today, the concept is simple enough: a pre-existing tune such as a popular song forms the basis for melodic invention. Squares are therefore a deliberately incomplete notation, an invitation to imagine two-part polyphonic music floating above. You could liken it to a cantus firmus Mass made up on the spot but within a very specific tradition, of which La Quintina and Jérémie Couleau have made a decade-long study. Intriguingly, though, there are also sections of polyphony borrowed from other sources and retexted (contrafactum) in this programme that flow seamlessly with the many faburdens and discant sections.

A Marian theme is established with a 15th-century carol from the Selden manuscript: Nowel syng we bothe al and som with an added faburden-style voice. There’s some enchanting singing here, especially from countertenor Sylvain Manet, and it’s made more vivid by the early English pronunciation. The Mass is smooth to the point of hypnotic and – if you listen on headphones – full of atmospheric creaks and wheezes from the organetto bellows. I love the gently gliding chains of chords of the faburdens, and the fact that much of the textural busyness is taken by the instrument, which excels in the sprightly diminutions. Cleverly woven throughout are sections from the Mass upon the Square by William Whitebroke (c1500 1569).

At times I find the organetto slightly intrusive, especially in solo sections of the Gloria. The aesthetic shift from precise, confident singing to the panpipey vibe of the instrument’s expressive tuning takes some adjustment from the listener. Special mention must go, however, to the glorious cadence ending the sequence ‘Post partum Virgo’, where voices and pipes combine to create something more than the sum of their parts. La Quintina are definitely an ensemble to watch out for.