The differences between contact and airborne noise and sound absorption and insulation
When choosing the right material or product for your noise problem, you need to determine what type of sound it is; airborne or contact noise. Once you know that, you can choose a material/product in the category sound insulation, sound absorption, vibration isolation or a combination of these three. We are happy to explain a number of concepts to you, so that you can make the right choice.
The difference between airborne noise and contact noise
- Airborne noise
irborne sound is a vibration in the air which is perceived as a sound. For example, airborne noise can be the sound of moving parts of a rotating pump. It comes directly from the sound source as opposed to contact sound which is indirectly audible. Airborne noise can cause a wall or glass plate to vibrate, causing the sound to leave or enter a room. Sources of airborne noise include the TV, voices, speakers, wind noise and acoustic instruments. The acoustic isolation of airborne noise is done by applying sound insulation, often heavy materials with a high density, often in combination with sound absorption.
- Contact sound
Contact noise is spread by vibrations in matter. The sound source contacts a foundation such as floor, wall or bodywork and thus transmits resonances. In the house, for example, contact noise can be heard when a washing machine is running, walking noises and closing doors. In vehicles, the engine, chassis and tyres can transmit contact noise to the bodywork. In boats and yachts, engines and aggregates can be the source. The acoustic isolation of contact noise is done by placing anti-drumming material or vibration insulation. Contact noise is best addressed directly at the source.
The difference between sound absorption and sound insulation
- Sound insulation
Sound-insulating materials ensure that sound remains inside or outside a certain space. The application of sound insulation is called acoustic insulation (not to be confused with thermal insulation). Some examples where acoustic insulation is used are, enclosures of appliances and machines. In vehicles against engine and driving noise. In ships and yachts for reducing engine and propeller noise. In homes for insulating neighbour noise in the form of wall, floor and ceiling insulation. Sound is not isolated by foam or wool but by materials with a high density (mass) or in a combination of mass-spring system as is the case with floating floors.
- Sound absorption
Sound-absorbing materials absorb vibrations in the air so that sound is less dispersed within a room. Acoustic panels allow you to improve the acoustic properties of a room. The result is less reverberation, which greatly reduces the noise level. Sound absorption can also be applied in enclosures and enclosures for appliances and machines. Sound absorption is also found in ships, yachts and vehicles for absorbing engine noise. For these applications you use different materials than for room acoustics, namely acoustic plates. These are products with certain properties such as heat resistance, specific top layers and certifications such as CE and IMO.