A Filetta

A Filetta is an all-male singing group that performs traditional music from Corsica. This group was created in 1978 by Michele Frassati. He enlisted Corsican singers so that the traditional Corsican singing style (polyphony) would not be forgotten by everyone. To assert its Corsican identity, the group's name refers to a kind of fern that grows on the island of Corsica.

source: Wikipedia