This is a stirring, gently edgy reminder that Corsica produces some of the most subtle and remarkable vocal music in Europe. A Filetta consists of six men who specialise in the complex, three-part polyphonic songs that have long been a part of the island’s musical tradition, but were in danger of dying out until revived during the nationalistic and cultural upheavals of the 1970s. That’s when the group started, performing religious songs and then traditional folk ballads, though they have now expanded their range to original material influenced by the old styles, with musical settings by founder member Jean-Claude Acquaviva. This set starts with a brooding, gently spooky piece from a French TV drama, moves on to a throbbing, quietly thrilling dance song, a delicate, hymnal-like piece written for a Polish Shakespearean project at the Edinburgh fringe, and laments for an air crash. A quietly compelling set.