The field of building acoustics really consists of two disciplines: room acoustics, which deals with sound propagation within a room; and building acoustics, which concerns sound propagation between rooms. Typically, room acoustics is related to the quality of sound, e.g. concert hall acoustics, while building acoustics is related to elimination of unwanted sound, i.e. when you want to hear as little as possible of what is going on in adjacent rooms. Sound Insulation Testing can also be a requirement for those who adhere to the Guidance in the 1997 Irish Building Regulations.
