What is sound and sound paths

Sound

Sound is caused when objects vibrate in air. The movement in turn causes air particles to vibrate giving rise to rapid pressure fluctuations which are detected by the ear. Sound levels and sound insulation values are expressed in decibels (dB). The sound insulation properties of walls or floors vary with frequency and, as most sounds are a mixture of several different frequencies, certain frequencies within a sound are likely to be attenuated more effectively than others by a given construction (low pitched sounds are normally attenuated less than high pitched sounds). In view of this, the sound reduction characteristics of walls and floors are usually measured at a number of different frequencies across the hearing range and then converted to single figure rating values.

Sound paths

When a room is separated from another room, sound can travel by two routes; directly through the separating element (wall or floor) - direct transmission, and around the separating element through adjacent building elements - flanking transmission. The design of the junctions between separating walls, separating floors, external walls and the integration of the primary steel frame and services are all important aspects to consider in order to avoid flanking sound transmission. It is straightforward to develop a wall or floor construction that will provide the necessary acoustic performance. However, ensuring that the junctions do not provide a weak point for sound transmission must not be overlooked.