Acoustic mirror

Pairs of large parabolic acoustic mirrors which function as "whisper galleries" are displayed in science museums to demonstrate sound focusing.

During World War II on the coast of southern England, a network of large concrete acoustic mirrors was in the process of being built when the project was cancelled owing to the development of the Chain Home radar system.

[1] Before World War II and the invention of radar, acoustic mirrors were built as early warning devices around the coasts of Great Britain, with the aim of detecting incoming enemy aircraft by the sound of their engines.

Other examples exist in other parts of Britain (including Sunderland, Redcar, Boulby, Kilnsea and Selsey Bill), and Baħar iċ-Ċagħaq in Malta.

The acoustic mirror programme, led by Dr William Sansome Tucker, had given Britain the methodology to use interconnected stations to pinpoint the position of an enemy in the sky.

The system they developed for linking the stations and plotting aircraft movements was given to the early radar team and contributed to their success in World War II.

4.5-metre-high (14 ft 9 in) WW1 concrete acoustic mirror near Kilnsea Grange, East Yorkshire, UK. The pipe which held the "collector head" (microphone) can be seen in front of the structure.
Acoustic mirrors at RAF Denge
A parabolic whispering dish that is part of an installation at Jodrell Bank Observatory
A pair of smaller acoustic mirrors in a park in Muiderberg
Magħtab acoustic mirror ( Maltese : il-Widna : "the ear") on the north coast of Malta ( 35°55′51.78″N 14°26′37.03″E  /  35.9310500°N 14.4436194°E  / 35.9310500; 14.4436194  ( Location of the Magħtab sound mirror on Mata ) )