What is it for?
This is a room which is acoustically like being high above the ground in the open air because there are no reflections from the walls, floor or ceiling. This means it is ideal for testing the response of loudspeakers or microphones because the room doesn’t affect the measurements. It is also the best place for virtual acoustics - generating auralisations of concert halls, city streets and other spaces. The anechoic chamber is immensely quiet which makes it ideal for testing very quiet products or people hearing very quiet sounds. Example application
Final year project student, Patrick Froment wanted to simulate the sound of rain on roofs. He needed to measure the sound of a single raindrop landing on a roof section without the effect of a room, so he used the anechoic chamber. He also needed a very quiet acoustic to measure the sound. Example application
The protection that ear muffs and earplugs provide varies from person to person, so they need to be tested on real people. To do this four loudspeakers are placed at the corners of a tetrahedron and a person sits so their head is at the centre. The loudspeakers then produce sounds that are used to test the person’s hearing threshold – the method is very similar to how your doctor might test your hearing. The threshold is tested with and without the hearing protectors, and the difference gives the product’s performance. If you buy some ear plugs from a DIY store, the chances are that the performance was tested in our chamber. How is it made?
We need to prevent sound getting into the room, and this can pass through the walls, or through the foundations of the building. The background noise level in the chamber is immensely low; this is probably the quietest place you’ll ever experience. e anechoic chamber is actually a room, within a room, within the Newton building. The walls, floor and ceiling of the inner chamber are made of heavy Accrington brick and concrete to prevent...