The Sound Mirror is the forerunner of radar and was intended to provide early warning of incoming enemy airships and aircraft.
It worked by focusing the noise of aircraft engines onto a microphone which amplified the sound. The relatively slow aircraft of the time could be heard and located before they came into view.
The microphone would have been fitted to the metal post set in a concrete block in front of the mirror. An operator would use headphones to listen for an approaching enemy.
The Kilnsea Sound Mirror is one of only four known surviving examples in the north east of England and the only known example in the country that still retains the microphone mounting pole.
Unfortunately, the system was not very effective and the concept was abandoned.
An information board courtesy of Sunderland City Council describing a Sound Mirror in their area.
Click the image or this link to view a larger version (opens in a new window).
For those wanting to know the location of other sound mirrors, click the image above or this link (opens in a new window).
Click the above image or this link to view more about the Zeppelin raids on Hull (opens in a new window).