The aim of this book was to develop an effective system to improve the sound transmission loss of lightweight partition walls. Effective in this context means that the system would be lightweight, economical,and readily installed with current site practice. The accepted wisdom in the area of sound reduction is to drape the entire area of the partition with a sound absorbing membrane material and the work of this book proceeded on this premise. However during the course of the experiments it was found that the assembly detail at the stud had a much more significant effect than the membrane material on sound reduction. It transpired that the main effect of the membrane material was to provide damping under the screws at the stud and if the material was compressed too much the damping was compromised. The book reports on the introduction of a new ?sacrificial layer? which, when incorporated into the stud assembly allows the full damping effect of the membrane material to manifest itself.The book therefore proposes a strip or wad consisting of layers of membrane material and ?sacrificial layer? to be mounted on the stud prior to the plasterboard.