Soundproofing glossary definition of Flanking transmission

Flanking transmission :

Flanking sound transmission is the term used to describe the movement of sound through the structures that flank the barrier that your trying to sound proof. In the case of wall insulation the flanking structures are the floors and ceilings. In the case of soundproofing floors and ceilings, its the walls. In designing for sound insulation care should be taken to ensure that flanking transmission via the associated structure does not downgrade the performance of the partition or wall to a level below that required in use.