A Tool to Manipulate Sound

The Anechoic Chamber

While I was a student in 1979, I was lucky to be taken to the Physics Department of the now John Moores University. The main point of the visit was to see the anechoic chamber. I took it as an experience, it was clearly a method of controlling noise levels and could be used to manipulate senses. Together with the control of light, there was a major sensory control available. One of the elements of my architecture course was “Environmental Sciences” and sound control was probably the junior partner in what was actually a very necessary part of learning about how to design buildings.

Sound attenuation needs to be at appropriate levels in order to maintain privacy, there are guidelines and regulations for different types of buildings. But reverberation is something which can be manipulated for effect. Texts are available with the design of concert halls or recording studios, and the like, in mind. Technical creativity would not be something a normal architects would need to master. (Note any assembly area should really have consideration of the surfaces and this has been done since Roman times.

I have had a couple of experiences which I didn’t expect from more modern buildings as a result of reverberation. One, Notre-Dame du Haut at Ronchamp provided a feel of greater presence where you needed to be quiet or reverence. The space “demanded” respect. Apart from the visual space the reverberation was similar to the massive stone built cathedrals of Europe and this was down to reverberation time. The second was an education building which I visited (as a guest and competition judge). The noise made by the students after classes finished was amazing. It was exiting and uplifting. Like an underground station but in a smaller space with fewer people. Anyway I enjoyed the experience and felt it was very appropriate as part of the inspiration of students and the building up of team spirit. (Note: Why do you whisper when you go into an old church or cathedral? Answer: because if you make a noise it bounces off the hard reflective surfaces of the stone some distance away. You, and everyone else in the space will hear the noise of your wittering. You therefore "keep the noise down" an a spiritual space is created.)

I suspect the acoustic performance of both of these projects was by accident. Especially the second project. Later on in the same building, I was in an audience of a special performance when the sound like a heard of elephants broke through from an adjoining space illustrating the design team’s lack of mastery of attenuation!

Back to the chambers. The anechoic chamber is used to test antennas, music speakers and things like that, but I am researching to try and find out if there are any for having fun in. A recording studio will incorporate many of the features of the anechoic chamber.

Basically the unit is designed to absorb sound waves to allow a measured source to be evaluated without reflections or interference from outside of the immediate environment (a “free field”). These days we have noise cancelling headphones and anechoic chambers can employ this type of technology to improve performance. The 2005 Guinness book World Records had the US National Institute of Standards and Technology Orfield Laboratory (Gaithersburg, Maryland) anechoic chamber as the quietest place on Earth. To cut a long storey short, the human ear would perceive the environment as being devoid of any sound! A bit like outer space really, but a bit warmer.

There is enough information out there to make a need for risk assessments for anyone working in an anechoic chamber to be maintained free from the risk of being trapped or not knowing of what was going on outside the room for instance if there was a fire.

So here we have it. We have the technology to create a space where you can’t hear anything, even yourself. This for me, is inspirational and allows the creation of ideas where the denial of one’s voice could reflect a message or empathy. Even a panic or fear.

We could of course, simply be more aware about how pingy or flat a space can be as well as the wide or tall visual things.

Anechoic Chamber Salford University