“Vergessene Technologien – Riesenohren aus Beton” (Forgotten technologies – Giant ears of concrete) is a 23 May 2011 German-language article by Solveig Grothe on the website of Spiegel. It has a history of sound mirror development between the wars, and features some photos of sound mirrors from the Sound Mirrors Flickr group (used with the permission of the photographers).
With reinforced concrete shells the size of a house, the British listened in the 20s and 30s for enemy aircraft. The acoustic experiments along the coast gave the island extraordinary architectural monuments – and an interception technique to which was used to the outbreak of World War II.
Und jetzt, die artikel auf Englisch: Listening for the Enemy, Giant Ears on the British Coast