Common definition to capture sound pressure at a point on behalf of a device typically used within the context of building services and flow distribution systems. To indicate sound values from an instance of IfcDistributionFlowElement at a particular location, IfcAnnotation instance(s) should be assigned to the IfcDistributionFlowElement through the IfcRelAssignsToProduct relationship. The IfcAnnotation should specify ObjectType of 'Sound' and geometric representation of 'Annotation Point' consisting of a single IfcPoint subtype as described at IfcAnnotation. This property set is instantiated multiple times on an object for each frequency band. HISTORY: New property set in IFC Release 2x4.