In Part I of this paper sound transmission through double leaf lightweight
partitions was examined. It was shown that an important part of the overall
transmission is determined by structure-borne sound transmission between t
he two leaves of the wall. In this report. Part II of the paper, structural
coupling is examined in more detail. Two theories an presented. One is app
ropriate where the connection behaves as a series of points and the other w
here the connection behaves as a continuous line. It was found that an appr
opriate transition frequency between these two theories was where a half be
nding wavelength on the plate fitted between the nails or screws that form
the coupling. In the most common forms of construction the connection will
behave as a series of independent points for most of the frequency range. T
he continuous line model included the frame either as a beam or as a short
plate. It was found that the agreement with the experimental data was bette
r when the frame was modelled as a plate. There was good agreement between
the measured and predicted data for transmission between the two leaves of
the wall for a wide variety of structures. These theories can be incorporat
ed into a statistical energy analysis model to enable the sound transmissio
n throughout the entire structure to be predicted as was shown in Part I of
this paper. (C) 2000 Elsevier Science Ltd. All rights reserved.