AbstractThe best method of noise control is elimination of the noise at its source by modification of the noise producer; in certain cases this may not be possible since the normal functioning of the noisy device would be impaired. Alternatively the source may be enclosed, either completely or partially so as to shield the observer from the source. A third method involves the treatment of surfaces in the room containing the observer and noise source to absorb the noise as it is propagated through the room. Finally the observer, or at least his ears, may be enclosed by a soundproof booth or the wearing of ear defenders.Examples of the successful quietening of pieces of machinery will be discussed, including the couch roll of a paper making machine. A reduction of 15–20 decibels in sound pressure level has been achieved without interference with the paper making qualities of the rol