Steven Vella of St Nicholas College in Malta has built a model of it.

A while ago I built a 4 mm/ft model of the somewhat smaller Kilnsea mirror.

Although “not part of architectural history proper,” a series of moss and graffiti covered ruins along England’s southeastern coast belies one of the more grandly misguided displays of national insecurity to be produced by the tumult of the twentieth century. The remains are as imposing and impenetrable as any fortress—yet these were not traditional fortifications meant to withstand an enemy onslaught, a fact that renders their solidity largely palliative.

They were, essentially, ears.

(where it says one in Boulby that had somehow been transformed into a private residence, it should presumably read “Selsey”)

Meanwhile, Peter Frost has sent this photo of the Abbot’s Cliff sound mirror, which he came across whilst walking towards Dover from Capel-le-Ferne in Kent.

Paul Wells of doverpast.co.uk has found something in Gibraltar which looks rather like a sound mirror. But is it, or is it something else?

Here are some photos and some background details of its history, expanding on my other page of photos of the mirror, and also some details of how to find it.

A recent photo of the sunderland mirror, by Phil Thirkell.

There is a reference to sound mirrors (and this website!) in the University of Florida’s Journal of Undergraduate Research, Volume 9, Issue 2. November/December 2007.

Nikolas Zawodny’s paper on the Design and Fabrication of a Phased Acoustic Array to Analyze Noise Generation of Aircraft Components does what it says on the tin, though there appears to be lots of hard sums involved.

Early techniques of airframe noise analysis involved the concept of an “acoustic mirror,” which consisted of a single microphone positioned in the acoustic far field of a large concave elliptical mirror. The origin of acoustic mirrors can be traced back to the north and southeast coasts of England in the early 1920s, where they were used to provide early warning of incoming enemy aircraft planning to attack coastal towns. These coastal “listening ears” were eventually rendered obsolete with the development of faster aircraft and the invention of radar.

The date is actually slightly out, as some mirrors were built during World War I.

A Russian-language page on the Autogena proposal for modern cross-Channel sound mirrors, with some rather familiar looking photos. “слушающие уши” seems to be listening ear, and “звуковые зеркала” is sound wall. Google translates the title of the article as “Stone ears teach people to shout through the English Channel”.

The vodka is good, but the meat is rotten?

The picture was taken before the cliffs were eroded so far that the mirror fell onto the beach below, which is thought to have happened in about 1978-79.

The mirror is on the extreme left of the picture. The design is similar to the mirrors at Selsey and in the northeast, suggesting a First World War date for its construction.