ABSTRACT

This chapter introduces the sound transmission through partitions and the importance of bending waves and discusses transmission loss and its calculation for single and double panels. It examines enclosures for keeping sound in and out, barriers for the control of sound out of doors and indoors and consider pipe lagging. When an enclosure is to be constructed, some advantage will accrue by lining the walls with a porous material. The use of an enclosure for noise control will produce a reverberant sound field within it, in addition to the existing direct sound field of the source. The sound field immediately outside of an enclosure consists of two components. One component is due to the internal reverberant field and the other is due to the direct field of the source. Barriers are placed between a noise source and a receiver as a means of reducing the direct sound observed by the receiver.