subject: How To Reduce Airborne And Impact Noise [print this page] There are many factors that can affect the acoustic properties of buildings when trying to increase the overall level of soundproofing, however in this article we are going to look at two areas of concern when considering effective acoustic insulation, airborne noise and impact noise.
Acoustic insulation
Before we look at the two main types of noise transmission through buildings, it is worth clarifying what we mean by acoustic or sound insulation as opposed to sound absorption. Briefly put, sound absorption aims to reduce the amount of reverberation within a room to improve the overall sound quality and intelligibility, whereas sound insulation, or soundproofing as its commonly known, aims to reduce the overall level of sound that travels from one area to another within the building or structure.
Airborne noise
Airborne noise as the name suggests is noise or sound that travels through the air, into the structure of a building then out again into adjoining rooms. This can emanate from irritating sounds within a building, like shouting, speakers or pets, or from external sources like aircraft, traffic, trains etc. They key to minimising these kinds of airborne noises is usually to provide a dense surface, followed by a sealed cavity, followed by an additional dense surface which should help to break up and reduce the airborne noise as it travels through the offending surface (be it a wall, floor, ceiling, or combination of the three).
Impact Noise
Impact noise can occur in many different ways. From slamming doors, drawers or moving furniture to stamping feet, dropped objects or DIY, the sound created by the impact will migrate through construction materials. Whilst impact noise is primarily transmitted through floors, it is also possible for it to be transferred through walls and general building structures. Typically it is much harder to control than airborne noise, and the loudness and character of the noise will depend on a number of factors from the nature of the object striking the surface, the resilience of the surface, how rigid the assembly supporting the surface is and of course the force of the blow itself.
Different construction techniques are required to reduce impact noise as opposed to airborne noise and the easiest way to achieve a significant reduction is to add a cushioning layer that will absorb the vibrations caused by the impact.
Please bear in mind that air tightness is a key attribute of effective sound insulation as sound behaves a lot like water in the way it can leak out through gaps and holes so always check that everything is properly sealed.
