Before telling how it was the process to devise, design and create an anechoic chamber, it is necessary to think about the sound and its study. Undoubtedly, sound is something subjective, because each person has a different perception, hearing education and different taste. Hence, the sense of hearing and the brain interpretation influences each person?s hearing sense. We can consider it as a matter of subjective nature.
That's why, with the aim of making scientific measurements, there is a lot of research, technique and a very studied and developed technology in the field of sound. The aim is to find objectivity and science in this field.
But what is a scientific experiment? It can be considered scientific every experiment which is repeatable and gives the same results as long as the environmental conditions in which the test or experiment is performed are not modified. This requires that all the experimentation must be done in a very rigorous way, trying to preserve the conditions. After repeatedly measured a system, if there is coincidence on the results, we can consider that measure as good.Why do we need an anechoic chamber?
The sound is an air vibration; if the conditions where the air vibrates change, it is no longer possible to make rigorous measurements. To preserve these conditions, we have to invent a system which makes possible to avoid external influences (walls, roof, wind, movement of things, parasites noises, etc.). This can be done with a sealed enclosed area, which keep this area from external noise or any kind of influence. Even though, we will have walls. Whenever we have walls, the measures will not be real because the message that emit the sound system and receive the microphone of the system, hit the wall and rebound. This will interfere the measurement. In that case, we would be talking about the measurement of a system within an environment. Since we need to override the environment for accurate measures, we have to guarantee that our system is not receiving any external piece of information.
There are only three ways to avoid sound reflections on any surface: the surface does not exist, the system to be measured is off or the energy out of my system is absorbed and converted into heat by the surface. Obviously, the first two options are non-viable as we have to take a measurement. The only solution is to get materials that are able to absorb the vibration and then cover all surfaces of the room that will receive and reflect the sound. That will provide the test with a repeatable measurement, thus we can consider it as scientific.
The natural function of the energy absorption implies three variables:Composition of the material used to isolate.Thickness of this material which will influence the course the vibrations must do to pass through it.The size of this material area. The bigger this area is, the bigger the absorption capacity will be. The way to increase this surface is giving it a triangular shape. By doing so, the surface gets multiplied by three.
Human beings discovered that the surfaces reflect the sound when, shouting in an open area, received back a response 800 milliseconds after making that sound. This became known as "echo". This echo effect is lost when the distance between the subject and the surface against it is reflected is less than 6.88 meters. Any surface further than 6.88 meters returns echo, but if it is located nearer, it will return "reverb", a term referred to the echo that can?t be perceived by the human ear.
A surface that does not return any reflected energy is an "echo-free" surface, it means, "without echo", or "anechoic". That's why it's been called anechoic chamber: an echo-free chamber that does not reflect sound but absorbs it into the walls and transforms it into heat.
In an anechoic chamber, opposite to what many people may think, it is not possible for people to hear the sounds properly. Nobody?s ear has been educated to listen in a free echo environment or without external influences. When a sound is listened into an anechoic chamber, the feeling is very rare and not pleasant at all. An anechoic chamber has only sense when used for rigorous measures.Why Equipson choose to develop an anechoic chamber?
Equipson decided to develop this echo-free chamber to make a qualitative leap in its products. It is an essential tool to carry out the research that will lead to design and manufacture new products to fit market needs.
The first product launch entirely developed in the acoustic lab of Equipson is UDA 16, the new column loudspeaker with line array format. The company is currently developing new products that will be available in the following months. Besides, almost every product already on the market has been modified after being tested using the anechoic chamber. The anechoic chamber represents without a doubt an important improvement that enhances the design and production of the products.Teamwork
As in the majority of cases, the idea of building an anechoic chamber in the company headquarters comes up from the Product Manager, who knows deeply the market, what the customers? needs are, and detects which of these products best fit these needs.
Once detected these new products that meet market needs, the Product Manager discuss with the General Management and R+D team the possibilities of production and the time-to-market it requires.
Equipson anechoic chamber arised that way. It was considered by everyone to be a necessary and priority tool to develop, design and produce the new products of the company.