J. D. Quirt
A. C. C. Warnock
R. E. Halliwell
J. A. Birta
Acoust. Group, Inst. for Res. in Construction, Natl. Res. Council Canada, M27, Montreal Rd., Ottawa, ON K1A 0R6, Canada
The work to be presented is part of a large series of measurements studying sound transmission through double panel walls. The wall surfaces in this work were of 16-mm gypsum board. Studs of 38-x89-mm wood or 90-mm light steel were used with spacing between stud centerlines varying from 30 to 120 cm. The spacing between screws used to attach the gypsum board was varied with the smallest separation used being 20 cm. Transmission loss was also measured for studless constructions. Transmission loss contours showed prominent dips at frequencies influenced by stud and screw spacing. Sound absorbing material added to the cavity had only a minor effect on these resonances suggesting that they are associated with panel resonances and not with the cavity between the panels. A selection of the data from this work will be presented and discussed.