listen to the sky

Standing silent and abandoned, a series of isolated and mysterious concrete structures line the south east coast of England. Known locally as “listening ears”, these structures, more properly called acoustic mirrors, are vestiges from great inter-war acoustic experiments that took place in both England and France - early warning systems against the possibility of an airborne invasion across the English Channel.

The acoustic mirrors tilted their faces to the sky and collected sound in giant concrete dishes. They were operated by trained listeners that endured cold nights at their listening posts, entombed in concrete bunkers, or high on listening platforms in front of the mirrors, to pick up distant noises from the sky. The acoustic mirrors were never used in wartime - the invention of radar and the increasing speed of aeroplanes rendered them obsolete within ten years of their erection.

Almost seventy years later, these now forgotten experiments have become the focus and the inspiration for a groundbreaking international art project - an attempt to re-invent this redundant technology for the 21st Century.

talk across the sea

In a project, which intertwines the remarkable origins of the historic mirrors with their presence today as poetic metaphors for cross-Channel relations, poised dramatically above the sea towards France - the artist Lise Autogena proposes to construct two new acoustic mirrors. One mirror will be placed in Folkestone, filling a gap in the existing chain of mirrors along the English coast. The other will be placed in Sangatte, on the coast of France, approximately 25 miles across the Channel.

Following the dimensions and form of one of the historic mirrors near Dungeness (see front page), the new mirrors will have a crucial contemporary twist. With the aid of the latest in acoustics and communications technology, visitors to the new mirrors will not only be able to listen to the sky - they will be able to talk across the sea to those standing on a listening platform in front of the other mirror, on the other side of the Channel.

The two mirrors will create a visual link, an invisible bridge between two countries and turn a long forgotten defence technology into a friendly instrument for communication across the English Channel.

acoustic technology

Visitors to the new mirrors will be able to climb up to a listening platform in front of the mirror, in the manner of the original listeners at the historic mirrors. Rather than straining for the sound of distant aeroplane engines, people will be listening to the sounds of the sea, as well as for voices speaking to them from across the Channel.

A new advanced acoustic technology will allow transmitted sounds from the other mirror to be audible only at a particular focal point in front of the dish - focused at the small area around the listener’s head. The person standing at the focus point will hear a complete “holographic” binaural sound image which will appear to be coming from the air all around them.

The binaural sound image will reproduce the sound in three dimensions, so that the listener will feel as if they are actually standing in the place where the voice was speaking. The transmitted sound will mix with the sounds of the sea and the Channel, which will be collected and amplified by the acoustic effects of the dish itself.

This innovative convergence of art, engineering and technology will create beautiful and enigmatic objects that will invite involvement, participation and consideration - a truly international project that will be freely accessible to everyone.

the english mirror

The original mirrors were fabricated on site. Concrete was cast into carefully built wooden shuttering, hung on metal frames. The mirrors were sited for optimum “listening” out to sea and across the Channel, and were therefore often found on cliff tops or on promontories jutting out towards the sea. The site of the new English mirror was similarly selected to fit with physical, technical and human considerations.

The new English mirror has been modelled on one of the original mirrors at Dungeness (front page). It has been granted planning permission in Folkestone’s newly landscaped Lower Leas Coastal Park, which provides an important recreational area in the town. Here it will be located adjacent to the coastal promenade, overlooking the sea towards France. The Acoustic Mirror project is an important means of linking the area’s rich architectural and historical heritage, to a contemporary piece of creative artwork.

The new mirror will be formed in high-specification reinforced concrete and prefabricated offsite. Sculpted steps, ramps and walls will allow the mirror to rise gracefully out of the landscape and an extensive, paved forecourt for listening will slope towards the sea. The design and landscaping will make reference to known astronomical observatories, such as the ancient Jaipur observatory in India and today’s Joddrel Bank in the UK.

The project will create a landmark, a focus for exchange and travel and a perceptible visual link between two countries. It will enhance a particular sense of place - in Folkestone, an affirmation of the area’s historical importance as the first defence against invaders, and role as a first point of contact outwards to European neighbours.

the french mirror

The new French mirror will be built in Sangatte, directly across the Channel from Folkestone. Sangatte Municipal Council is currently working to secure planning permission for the mirror near the historic site of Cap Blanc Nez. Here, the mirror will mark the entrance to a new coastal park and recreation area where it will stand on the chalk cliffs, overlooking the sea towards England.

This is also the site for the beginning of the old “Napoleonic” tunnel – a now redundant shaft and tunnel that extends for several kilometres under the Channel towards Folkestone. It marks the failed Victorian/Napoleonic attempt to join England and France under the sea – a project that was never completed. It was abandoned in 1883 due to hostility between the two countries, with a successful tunnel link not achieved until over 100 years later.

Today, somewhat like the old historic mirrors on the Kent coast, the old tunnel shaft lies derelict as a failed and forgotten technological experiment that never came into being.

culture / education

The history of the sound mirrors is a story of research trial and error that left a legacy of enigmatic, monolithic ruins, suggestive of previous civilisations and strange practices. The original acoustic mirrors listened to the sky in apprehension of an invasion, and our continuing fascination comes from their very human atmosphere of longing and solitude. The mirrors seem to be yearning for contact, an image that is echoed in today’s radio telescopes, listening for extra terrestrial voices.

The various facets of the Channel Communication Amplifiers project mean that it provides a great focus for educational projects, whether engineering, acoustic, scientific, artistic, historic, language or communications related, a pilot education programme is therefore currently being developed.

The Channel Communication Amplifier project offers an optimistic vision of the possibilities of human communication and provides obvious historical and geographical references that can be played into politics and the role of the UK and France in Europe today.

For the inauguration of the Channel Communication Amplifier project, we are hoping to stage an extraordinary event that will take place on both sides of the Channel. The event could involve performers from both France and the UK performing in front of each mirror for audiences on the other side of the Channel. The project has the capacity to become a cross-channel performance space – the first of it’s kind!