Visit to a Semi-Anechoic Chamber / Cone-of-Silence

Visit to a Semi-Anechoic Chamber / Cone-of-Silence


Today some of us managed to have the brief opportunity to visit an anechoic chamber in Imperial College at the Centre for Bio-inspired Technology. However, I must admit that I would classify it more as a semi-anechoic chamber as it had a solid floor (probably due to the need to hold heavy laser equipment and other machinery in the room). Nevertheless, it was very interesting to see it in person.


Radiation absorbent material (RAM)

To me, the room itself is visually impressive for its many striking angles. Which of course brings me to thinking of other “anechoic chambers” or radiation absorbing materials and its functions – not just for sound, but also other waveforms such as microwaves or radio waves (in the case of radar). The “look” of such rooms is not so much a design as it is functional. This sort of faceted/angular plane alignment helps reduce the “signature” of the interior space/object, because a curved surface usually reflects waves in a number of different directions whereas a singular plane will reflect them in one direction. As a result many examples of stealth ships and planes designed for military use have a particular look in order to minimise the directions in which radar signals will be reflected. Because there are only sharp angles and planes, this form of “purpose shaping” (as they call it) means that the surfaces that will inadvertently reflect energy can be designed to create some sort of “cone-of-silence” with regards to the object, as well as its intended direction of motion.

Lockheed F-117 Nighthawk (Image source: Wikimedia Commons)


Visby Corvette (Image source: Wikimedia Commons)
Thanks to the guys at Imperial for letting us visit their room and thanks to Sam for organising the visit.