The sound mirrors – and this website – got a mention in the Observer’s travel section on 5 April 2009. The piece formed part of the Military sites” category in a series about Secret Britain – “All around us lie overgrown and forgotten sites with fascinating stories to tell, says Iain Sinclair”.

Acoustic mirrors, various locations

In the middle of a field in Kilnsea, Yorkshire there is a 15-foot-high concave concrete structure resembling a satellite dish. It’s actually an acoustic (or sound) mirror, used during the first world war to detect enemy engine sounds. They are a common fixture along the British coast, including at Kilnsea (OS map ref: TA 411167), Hythe in Kent (OS map ref: TR138344) and Denge on the Dungeness peninsula (OS map ref: TR070215), which recently featured in the new Prodigy music video, Invaders Must Die.
Source Observer