Frequency (Mirrored)

25 Jan 2020 - 15 Mar 2020

An exhibition of new sculpture by Lincolnshire-based artist, Iain Edwards, in the Courtyard Gallery

Acoustic Mirrors, also known as 'listening ears', were large concrete structures, built years before the invention of Radar and were the very first and rather crude early warning system developed by Britain. Most of these Acoustic Mirrors are scattered across the British coastline and were built in the 1920's and early 1930's to detect German aircraft. The mirrors effectively gave Britain a fifteen minute advance warning of an impending attack, which allowed for anti-aircraft defences to be employed.

The parabolic shape collected and magnified sound waves and by focusing them at the loci of the broad concrete sphere, a listener could discern the sound of distant aircraft engines using the then state of the art – stethoscope. An operator using a stethoscope would be stationed near the Acoustic Mirror and would need specialist training in identifying different sound frequencies. Distinguishing the complexity of sound frequencies was so difficult that the operators could only listen for around 40 minutes.

Mechanical waves, such as sound, require a medium through which to travel.
In refection a wave encounters an obstacle and is reflected back.
In refraction a wave bends when it enters a medium through which it has a different speed.
Sound waves have crests and troughs. The distance between these is called the wavelength.
How many of these wavelengths pass through a specific point during a unit of time is called the:

FREQUENCY (Mirrored)

This installation comprises:

2 x Synthetic Mirrors
Granular Frequency/Audio – Run Time / 80 minutes


This new exhibition has been developed in collaboration with Aviation Heritage Lincolnshire and 'Bastion in the Air: A Century of Valour'.