Before carrying out any acoustic treatment, it is essential to understand the principles on which soundproofing is based on in order to achieve the best results. First of all, we need to distinguish between the different types of noise that can enter our homes. Sound can be classified into two groups:
– Airbourne noise: As the name suggests, this is the sound that is transmitted through the air, either through walls, floors or ceilings, i.e. the sound that passes directly through the partitions. Examples of this type of noise include people talking or watching television and external traffic noise.
– Structural noise: This is noise that is transmitted by impact noise or flanking.
Impact noise is that which results from direct excitation (by impact or friction) in the building. Examples of this type of noise include footsteps, dragging furniture and lifts opening and closing. These are the most annoying and difficult to attenuate.
Flanking noise is produced from the longitudinal vibrations that are radiated into the receiving enclosure. An airborne sound can cause vibrations in the structure and these can be transmitted to other rooms. This is what we call airborne or structural excitation.
If we only insulate where we control the airborne transmission, the structural transmission will still allow the noise to reach the home. We would therefore be achieving inefficient insulation.
Once the different types of noise have been identified, it is essential to know the acoustic system that we need to install in order to avoid these nuisances. The acoustic insulation also has the advantage of preventing the noise generated from the house reaching the outside world, so privacy is gained as is thermal improvements, which translates into energy savings. It is therefore more than justified to invest in acoustic insulation, which will increase the value of the house.
Generally speaking, the installation of this type of insulation means that useful or usable space is lost, so it is a priority to choose an acoustic system that takes up as little space as possible and insulates efficiently. This is undoubtedly a difficult choice, but it is the system as a whole that will allow the user to achieve these results. In other words, it is the sum of all of these materials that will provide the required efficiency.
Understanding the factors that affect sound insulation will help determine the material required:
– The mass factor offers sound wave resistance, and is provided by the plasterboard panels (approx. 800kg/m3) and the bituminous sheets (approx, 1600kg/m3) placed between the panels.
– Rigidity factor is provided by a galvanised steel structure.
– Airtightness factor is provided by the acoustic strips placed around the perimeter of the system.
– Acoustic absorption factor is provided by rock wool, mineral wool, polyester fibres etc.
– Elasticity factor is provided by acoustic dampers.
– The space factor is also fundamental, since the greater the thickness, the greater the insulation.
As far as the sound absorption factor is concerned, we recommend using materials with densities between 15 and 35kg/m3, i.e. materials that are not very dense, because the material must be porous so that the sound wave penetrates the materials and the friction converts the sound energy into thermal energy.
Regarding the acoustic dampers, the choice of these will determine the type of metal structure profiles to be used. AMEC Acoustics is aware that space is a handicap in construction and has developed the FTD range of vibration dampers, which allow direct acoustic ceilings and wall cladding to be installed in the smallest possible space, with excellent results.
