transmission loss

5.35  transmission loss; propagation loss. Reduction in magnitude of some characteristic of a signal between two stated points in a transmission system. Annotation 1          The characteristic is often some kind of level, such as power level or voltage level; in acoustics the characteristic that is commonly measured is sound pressure level. Thus, since the levels are expressed in decibels, transmission loss should likewise be expressed in decibels. Annotation 2          It is imperative that the characteristic concerned (such as sound pressure level) be clearly identified because in all transmission systems more than one characteristic is propagated. Annotation 3          See 10.46 for transmission loss in architectural acoustics.