Soundproofing: What It Is and How to Achieve It

What is soundproofing?

Soundproofing is the process of developing acoustic treatments with the aim of suppressing, reflecting, diffusing, or absorbing sound waves, either directly at their source (using products that, for example, allow insulation on automobile engines, pipes and ducts, or in industrial machine rooms) or at their destination (using technologies such as double-glazed windows or insulating materials to reduce unwanted noise from outside in offices and apartments). In other words, soundproofing refers to the method used to counteract the ability of sound to travel from point A to point B through its reduction or absorption. Today, these techniques are regularly applied in recording studios and are becoming quite popular in residential structures as well, especially in condominiums or complexes with many apartments. To fully understand the concept, it is useful to see how sound is reduced or suppressed. This process occurs in three different ways:

Space: the farther one is from a given source, the more difficult it will be to hear the sound it produces. For example, if one is called from one side of the street to the other, it will be quite difficult to hear perfectly what the other person is saying. This occurs due to the space between the two speakers and due to other factors such as, for example, traffic. Space, in fact, affects the propagation of sound waves.
Mass: The more mass present between the origin and destination of a given wave, the more difficult it will be to hear the sound produced by the source once it has reached its destination point. For example, if one keeps the windows open at home and wants to reduce the sound produced by traffic, it will be sufficient to close the windows to reduce the volume in the room.
Attenuation: attenuation refers to the sound reduction process in which sound waves are forced to pass through different layers of materials with different densities, thus obstructing the path taken by the waves themselves and, ultimately, absorbing the sound before it can propagate through the air. Attenuation therefore aims to limit the ability of the sound wave to spread by obstructing its passage through the presence of various structures. This process ends with the absorption of the wave.

Soundproofing, therefore, operates in two different ways: it absorbs sound or reduces it.

Sound Absorption

The first method consists of absorbing the sound present in a given room or coming from outside. Some tools used are sound-absorbing panels and polyurethane foam. Sound is absorbed by traveling directly on the porous surface of sound-absorbing panels or other materials. There are many methods to soundproof rooms and absorb sound. For example, panels or foam can be placed on the outside or inside of a wall.

Sound Reduction

Alternatively, if complete soundproofing of an environment proves particularly difficult, sound can be reduced. Thick walls, polyurethane foam, dividers, and curtains are just some of the tools that can be used in this case. Often, materials that allow proper sound reduction are made of wood or fiberglass. Other methods used include the construction of double walls or double doors. Doubling walls and doors will allow the material present to better block acoustic waves. The air between the two, forming a kind of bubble, helps reduce sound. However, an important aspect must be clarified. For windows or doors to function as desired, one must ensure that the seals of the fixtures do not allow the passage of air from outside (with the entry of air, sound would also enter). Theoretically, the perfect way to soundproof a room is to build a smaller room inside the main one, preventing sound from traveling. This system is often called “room within a room” or acoustic decoupling. Each room is built with heavy and solid materials. It is important not to put the outer wall and the inner wall in contact, otherwise sound waves would be allowed to pass directly from one wall to the other. In some cases, the inner walls are also covered with sound-absorbing materials to further limit the diffusion of acoustic waves.

Conclusions

The importance of soundproofing within one’s home or building should not be underestimated. The earlier it is planned, the easier it will be to implement and achieve the desired results. Whether the intention is to block sound coming from outside or the objective is to prevent sound waves from leaving a room, soundproofing the environment in question is certainly the right choice, allowing a work or domestic environment free from noise pollution.