By Chris Heard
BBC News Online entertainment staff
An art installation consisting entirely of the sound of human voices is the latest major exhibition at London's Tate Modern gallery.
Visitors to the Tate Modern are greeted by a mixture of spoken texts
Created by US artist Bruce Nauman, Raw Materials is made up of 22 segments of spoken text played over loudspeakers into the museum's vast turbine hall.
The voices range from a man repeatedly shouting "thank you" to the words "work" barked out over and over like a yelping dog.
Other texts include a joke, snippets of opera, excerpts of prose and a whispered chant that borders on the menacing.
Taken from some of Nauman's previous works over the past 40 years, they are piped out simultaneously in "bands" across the empty space of the turbine hall.
The large turbine hall remains almost empty - physically at least
It is a far cry from the space's previous four installations, which have typically been big, bold, expressive visual works.
Past exhibits have included a giant life-like foggy sunset by Danish-born artist Olafur Eliasson and Anish Kapoor's Marsyas, one of the world's largest indoor sculptures.
In the latest installation, Nauman's noises blend with the ever-present low humming sound emitted by the building's generators from its former life as a working power station.
The result, if you are standing towards the centre of the hall, is a cacophonous mix of seemingly abstract noises. It brings to mind a farmyard of overexcited animals, or the droning characters from a zombie horror movie.
Walking through the apparently empty space can be disorienting.
Artist Nauman, 62, is interested in the use of language
Physically, it may be just floor and walls - but the bombardment of sound from either side has an unsettling effect on your progress.
Even the loudspeakers are flat and anonymous, merging into the fabric of the building and creating an impression that the dialogue is coming out of nowhere.
Nauman, 62, an award-winning artist who lives on a ranch in New Mexico, has worked in media including film, video, neon and sculpture.
With Raw Materials, he is looking at the use of language and what the spoken word reveals about the human condition.
Mark Lawson, presenter of BBC Radio 4's Front Row arts show, said he was impressed by Nauman's piece and its distinctiveness from previous works.
"Everyone so far has thought of filling [the hall], and of course the illusion here is that it's empty," he says.
"As you walk around, it's as full as it's ever been - and it's full of sound. It feels like being inside a radio. It could feel like being inside someone's memory."
Bruce Nauman's Raw Materials can be experienced at Tate Modern from 12 October to 28 March.