Janet Cardiff: The Forty Part Motet, 2001

Janet Cardiff The Forty Part Motet, 2001. Re-working of Spem in Alium Nunquam habui, 1575, by Thomas Tallis.
40 track sound recording, 40 speakers, 14 min. Museum of Modern Art, 2001. Gift of Jo Carole and Ronald S. Lauder in memory of Rolf Hoffmann. © 2012 Janet Cardiff. Photo: Thomas Griesel. Courtesy of the artist and Luhring Augustine, New York and Galerie Barbara Weiss, Berlin.

Janet Cardiff's 2001 sound installation, The Forty Part Motet, was part of Peter Eeley's 2011 September 11 exhibit at MoMA PS1. However, it had been been installed MoMA in October 2001, and became the soundtrack to the processes of emotional reckoning in New York following the 11th of September. 

Eeley says, 'That work for me will always be tied to 9/11, since I encountered it here in the weeks following the attacks. Earlier in the year, Janet had created a spatial adaptation of a 16th-century piece of choral music by Thomas Tallis, recording each member of a choir individually and piping each voice into its own speaker, the group of which she arranged in a circle. Sitting in the middle of the room, we hear the full song, but, wandering among the speakers, the voices of the specific singers emerge more strongly.
The experience of hearing a collective song and the individual voices constituting it immediately summoned for me, and for others, the dead of 9/11 and their sublimation into the grief of national tragedy. I decided to simply put the piece back in the same room where it was in 2001—in part to think about what history has changed, and what it has allowed to stay the same.'

On You Tube there are a zillion different versions, mostly people recording while wandering around picking up voices from individual speakers, in cathedrals, churches, large empty spaces, controlled gallery spaces, always the same: banks of black speakers on stands arranged in a big circle.  

Not even tourists can distract from what is a pretty powerful experience, even in a 2-minute hand held extract.

and another, with discussion, at the Howard Assembly Room, Leeds.