In the 1920s the British military used these vast concrete parabolic 'sound-mirrors' to detect approaching aircraft. The 'Listening Ears' at Denge have recently been designated as a historical preservation site by English Heritage, the government quango in charge of protecting national landmarks. From Wikipedia: Acoustic mirrors did work, and could effectively be used to detect slow moving enemy aircraft before they came into sight. They worked by concentrating sound waves towards a central point, where a microphone would have been located. However, their use was limited as aircraft became faster. Operators also found it difficult to distinguish between aircraft and seagoing vessels. In any case, they quickly became obsolete due to the invention of radar in 1932. The experiment was abandoned, and the mirrors left to decay. The gravel extraction works caused some undermining of at least one of the structures. Watch more pics here: Sound mirrors - Denge Watch more implementations of acoustic mirrors here: Ñëûøàùèå óøè Àíãëèè - Ïðèêîëû íà ßÏëàêàëú
Hi Alex, There's another thread on here somewhere about them.....They are just walking distance from my mum and dad house on the coast. Cheers Andy
Hi Alex, There's another thread on here somewhere about them.....They are just walking distance from my mum and dad house on the coast. I've tried to find it using search - but no luck, if mods know where it is - let's move posts there.
I knew if I looked hard enough I would find it eventually. Here is the previous link. Hard to find as buried in Battle of Britain thread. http://www.ww2talk.com/forum/battle-specifics/6167-battle-britain-new-facts-6.html Regards Tom
I knew if I looked hard enough I would find it eventually. Here is the previous link. Hard to find as buried in Battle of Britain thread. http://www.ww2talk.com/forum/battle-specifics/6167-battle-britain-new-facts-6.html Now, it has its own thread - yeehaa!
Here is some more information. Acoustic Radar. Early warning sound mirrors on the British coast Regards Tom
That is so COOL!!! I want one!!! ... might be helpful to know when to shut the laptop when mum is coming up the stairs... :p
Some extra info and a shot of the one nearest to my parents - I will find a way to reach it one day ! Sound mirrors
It's quite easy to get to - but go sooner rather than later, the MoD have a policy of letting this one deteriorate and then it will be demolished. It has been laser scanned and modelled in 3D so it will always exist in the virtual world though.
A fascinating story about pre-radar acoustic technology: "In the early summer of 1934, the rolling green hills of the county of Kent were no longer as contemplatively idyllic as they once were. For nearly 12 years, William Sansome Tucker had been coming to the lonely coastal area in the southeast of England to attend to his experiments -- but in those days of May, his role had changed into that of an event manager rather than a scientist. New visits were constantly being arranged, and the physicist was fully occupied organizing the arrival and departure of his guests. "They included senior officials from the Air Ministry as well as well-known scientific colleagues such as the Scotsman Robert Watson-Watt, all of whom wanted to see for themselves the progress being made in the field of acoustic detection. Above all, they wanted to see the imposing technology that had made it possible to track planes in the sky before they were detectible to the human ear or, astonishingly, even the eye. 'The traumatic experiences suffered during World War I were all too fresh in British minds; memories of German bombers and airships dropping their destructive payloads over the country's cities. The lack of an effective air defense had been a major weakness for the UK during the war. Now the Nazis were in power in a newly-rejuvenated Germany, and nothing good could be expected of their expansionist plans. Should there be an attack on Britain, it would come, the military believed, from the skies. The detection and tracking of enemy aircraft was therefore a top priority." Listening for the Enemy: Giant Ears on the British Coast - SPIEGEL ONLINE - News - International
Short notice I know, but you are interested (and local) there is an open day tomorrow, just one of two days per year. 2018 Denge sound mirror open days | Sound Mirrors
There is a WWI acoustic mirror for Zeppelin detection at Fulwell in Sunderland which is grade II listed Sunderland sound mirror | Sound Mirrors
