Acoustical properties of wool

Wool is a natural product which is safe and pleasant to work with and has useful acoustical properties. The acoustical properties have been investigated to find the most suitable applications and to see whether if could be used in some applications in place of man-made mineral fibres. Wool is inherently a low flow resistivity material, practically producible forms having densities between 10 and 100 kg/m(3) with flow resistivities from 500 to 15 000 MKS Rayls/m. To achieve useful acoustical performance, wool materials must be used in relatively thick layers - typically more than 50 mm. Measurements have shown that woollen materials can increase the transmission loss of stud walls by up to 6 dB or more. Woollen materials can be used as duct linings, where their low flow resistivity is an advantage. They can achieve high absorption coefficients for control of room reverberation. Copyright (C) 1996.