SOUND ATTENUATION OF CONCRETE MASONRY WALLS.

This article deals with the sound barrier performance to be expected from several commonly used concrete masonry constructions, and comments on the rating methods used to grade these properties. A test series to measure the acoustic performance of several types of concrete masonry wall constructions using New Zealand materials is described with the results obtained and these are used to illustrate certain general features of sound transmission behavior. All the results are expressed in terms of sound transmission class (stc) ratings. The stc rating expresses the sound level difference in dB between a source and a receiving space, when the sounds are principally in the speech frequency range.