Airborne and Structure-Borne Sound
The aim of our articles are to break down acoustic terms and concepts as simply as possible, without going too far into the mathematics and every nitty gritty technicality, that acousticians usually love to get stuck into.
So please, if you’re an architect, contractor, developer, planner… or really anyone who occasionally needs to dabble in acoustic design and assessments… then read on…
Got a question?
Is there an acoustic, noise, or vibration related topic or problem that you would like explained? Send us an email and we’ll write an article about it.
What's the difference between Airborne and Structure-borne Sound?
Airborne sound is sound that travels via the air and through separating structures between rooms. For example, airborne sound across a lightweight floor would pass through the plasterboard ceiling, into the floor void, through the floorboards and into the room.
Structure-borne sound is where sound travels via a rigid structure, rather than through the air. It is usually most prevalent when vibrating machinery/plant (including household appliances such as refrigerators, televisions, and washing machines) is rigidly fixed to a structure, transmitting vibrations into the structure via the connection.
However, structure-borne sound is also excited by airborne noise. For example, taking the example of a lightweight floor again, airborne sound transmits from below into the plasterboard ceiling. Some sound energy passes through to the air void in the floor, and some of the remaining energy transmits through the plasterboard as structure-borne sound, subsequently passing into the floorboards via the timber joists, and radiating sound into the room above, as shown in the diagram below.