Musician and producer Nick Franglen â€“ one half of electronica legends Lemon Jelly and subterranean ambient explorers Blacksand â€“ will collaborate with many thousands of pedestrians to create a 24-hour piece of improvised music on London Bridge, starting and ending at midnight.
From his performance space, tucked under the northern arches of the bridge itself, Franglen will play Theremin through a series of looping effect and delays to provide long, complex washes of sound that will be output to speakers around him.
The pedestrians crossing the bridge above will be unwitting players of the Soundbeam â€“ a sensor device that will cut the music when the beam is broken by movement. Like an audio camera obscura, the flow of the music will stutter and flicker with the shadow of people as they pass by the Soundbeam, relaying ghostly evidence of life and movement on the bridge above.
Responding to the ebb and flow of foot traffic at either end of the day - be they the massed choir of commuters at Rush Hour, or the lone late-night reveler making their way home - Hymn to London Bridge charts a day in the life of London's ancient arterial crossing.
Cinematographer Bevis Bowden, who has recently collaborated with Velvet Underground legend John Cale on his stunning audio-visual installation for the Venice Biennale, will film the performance.
An edited version of the music will be available for free download on the weekend of The Mayor's Thames Festival, and a filmed loop of the performance will be projected somewhere along the river during the weekend itself (11 and 12 September).
The Theremin is an early 20th century Russian electronic instrument, played without contact. The player moves his hands in the space around the instrument's antennae to produce notes of varying pitch.
Made by Fred Mundell of British Theremin makers Fundamental Designs, the Theremin being played for this performance is a custom built development of the successful Skywave H1 Theremin that was used extensively at Southbank Centre during during Ether 2010.