There are 3 main ways that sound travels through a building: Reflected, Absorbed and Transmitted. 

• •  Reflected. This is where the sound reflects or bounces off a surface.

• •  Absorbed. This is where the sound is absorbed into a surface.

• •  Transmitted. There are 2 types of transmitted sound. Direct and indirect.

•  

Direct is when the sound path is direct and travels directly through the surface being tested. Indirect is when the sound travels around the surface. This can also be known as flanking, usually under doors. 

The diagram below shows both types of sound transmission. 

Sound is a type of energy made by vibrations. These vibrations create sound waves that move through mediums such as air, water and wood. When an object vibrates, it causes movement in the particles of the medium. This movement is called sound waves, and it keeps going until the particles run out of energy. 

There are 2 different types of noise tested for by 2 different types of tests.

• • Airborne

• • Impact

  Airborne: This is noise that is airborne, music, conversation etc.
•  

• Impact: This is the noise created by noise created against a surface, footsteps or banging. Airborne noise is tested through walls and floors, and impact noise is tested through floors only. 

The building should be tested as soon as it is complete, as all the final finish has been completed and the best chance of a successful result is possible. Once the property becomes occupied and lived in the fabric of the building will change.