The Hilliard Ensemble is a British male vocal quartet devoted to the authentic performance of early music. Founded in 1974, the group is named after the Elizabethan miniaturist painter Nicholas Hilliard. Although most of its work focuses on music of the Medieval and Renaissance periods, the Hilliard Ensemble also performs contemporary music, working frequently with the Estonian composer Arvo Pärt and including in its concerts works by John Cage, Gavin Bryars, Giya Kancheli, and Heinz Holliger.
The Idea of North is an Australian a cappella quartet, originally composed of Trish Delaney-Brown (Soprano), Megan Corson (Alto), Nick Begbie (Tenor), and Andrew Piper (Bass). They formed in 1993, while studying music at the Australian National University in Canberra, with their first album The Idea of North recorded in 1997. They followed this up with their second album The Sum of Us. When Megan left to move to Melbourne in 2002, they recruited Naomi Crellin to fill the slot.