Hythe sound mirrors

Two experimental acoustic mirrors were built on an area known as The Roughs just west of Hythe in Kent. A 20′ mirror was built first, then a 30′ mirror added nearby.

30 ft sound mirror, Hythe

30′ mirror

[Hythe sound mirror, May 2003]

The 30′ mirror is in poor condition and now fenced off, as much to protect vandals from it as to protect it from vandals. Unfortunately it is not scheduled, so its long-term future looks bleak – unless someone knows a rich sound mirror enthusiast…

[Hythe 30 foot sound mirror, May 2003]
The dish structure is made of metal mesh, supported by an angle-iron frame and covered with concrete, unlike other other mirrors which appear to be made of cast concrete with hidden steel reinforcing.

[Hythe 30 foot sound mirror, May 2003]
The listening chamber underneath the mirror.

[Hythe 30 foot sound mirror, May 2003]
In 2003 there was a large hole in one side of the mirror. By July 2010 a big chunk had come off.

30 ft sound mirror, Hythe

20′ mirror

The 20′ mirror was built in 1923. Landslips caused it the abandoned mirror to fall on its face, probably some time in the 1970s. This is it seen from the front, looking at what was the top of the mirror (4 July 2010).

20 ft sound mirror ruins, Hythe

20 ft sound mirror ruins, Hythe

[Sound mirror]
And this is the 20′ mirror from behind. Hythe can be seen in the distance (3 May 2003).

[Concrete blocks and fallen sound mirror]
The foundations of huts which once stood near the mirror. The mirror is visible to the right (3 May 2003).


The mirrors are on The Roughs, just west of Hythe in Kent. The 30′ mirror is easily visible from the Pennypot Estate. The easiest way to find them is to follow the paths along the banks of the Royal Military Canal, then head uphill at the stile. An approximate grid reference is TR138344.

View Larger Map

The 20′ mirror is a short distance east of the 30′ mirror. A footpath follows the contour of the hillside east from the 30′ mirror towards Hythe and passes the 20′ example. The remains of the huts are obvious, and the mirror lies on its front a few metres away. There is also a circular earthwork of some sort. An approximate grid reference is TR140345.

View Larger Map

The land belongs to the Ministry of Defence, and has permissive access. You can wander around, but there is no right-of-way and the MoD could close it off if they ever wanted to. In practice you can wander around freely. Just watch out for nettles and thistles!

On the slope just below the 30′ mirror there is another military building of some sort (possibly a radio D/F station, a correspondent suggests?)
30 ft sound mirror, Hythe

30 ft sound mirror, Hythe



13 thoughts on “Hythe sound mirrors

  1. I remember seeing the 20 foot mirror upright in about 1984 when I was in the CCF.
    We went to Shorncliffe camp for a weekend excersise and spent a morning learning fieldcraft on the roughs. The mirror was used as a checkpoint and we climbed around the back of it.

  2. I also remember a night exercise in the CCF close to the 20 ft mirror. The concrete post on which the microphone stood was still there and I climbed on top of it so my ear was approximately at the focal point. As a 16 year old I was amazed at the sounds of birds etc which were not even visible.

  3. I am cataloguing the RNIB archive collection and have come across a report:
    Experiments With Blind Listeners, (Hythe. June 29th – July 4th 1925). Acoustical Research Section.

    After practical exercises the report concludes “It seems clear from this series of experiments that blind (or nearly blind) listeners are markedly superior to normal listeners in every respect… In particular their power of discrimination and of holding on to a given sound in the midst of disturbing sound is very marked.”

    The War Office was so impressed that they gave authorisation to enlist blind men as privates in His Majesty’s Army as Sound Locators with the crews manning the devices. By the end of 1925 some 250 blind men had volunteered for military service.

    1. Hi Sean
      I realise you made this comment ages ago but I wonder if I could send you an email? I am working on a Sound Mirror related project and I’d love to know where you found that report so I could take a look at it/ any other reports you might have come accross. I’m on ellie.neville@teneo.com

      1. Probably the same retarded individuals who destroy most things. Unfortunately they seem to be everywhere now.

  4. Agree with the others here that the 20 footer was still upright in the early 1980s – I lived down the hill on Kingfisher Ave, Hythe and regularly explored both as a kid! Was fascinated by how different the two mirrors were (although in those days I thought they were radar dishes – this is long before Google!).

  5. I this evening walked along the Royal Military canal from West Hythe to the bridge that goes over the canal by the estate which includes Kingfisher Avenue. My son lived in Kingfisher avenue in the 80’s and used to use the bridge to take his daughter to see the mirrors. I could not see them this evening but may be my eyesight at 87 is not good enough. I am not sure where to look and I am less then 5 ft so I diffidently have a disadvantage. My son now lives in Lympne so I perhaps could get him to come and point them out to me but are they still standing. and are they still visible from the bridge area. Does any one know Please

    1. They are still there, but in a sorry state now. I remember these so well from my camping holidays with my parents when I was a child in the early 70s, I used to walk up to them every time we stayed on Willow Tree farm campsite, of course thats gone as well now…

  6. Did you know that the astonishing power of hearing in great grey owls is because they have evolved the same adaptation to collecting sounds as these sound mirrors? Their concave faces perform in the same way enabling them to hear and hunt mice rustling on the grass in the dark. As usual evolution got there first!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.