Basic concepts in acoustics
The sound insulation of walls and floors in a building is often of major concern for the people using the building. This chapter summarizes the most important basic concepts used in building acoustics. Moreover, basic knowledge of sound insulation is also important in other branches of acoustics, e.g. in the development of vehicles, ships and aeroplanes. The decibel scale is also used for many acoustic parameters, e.g. vibratory acceleration, vibratory velocity and sound intensity. Sound insulation is divided into airborne sound insulation, where the noise source is in the air inside or outside the building, and structure-borne sound insulation, where the noise source is located at a building structure. The most important case of structure-borne sound insulation is the impact noise sound insulation, which includes noise generated by people walking. Examples of external airborne noise sources are traffic and industrial noise, where the windows of a building are of major interest.