Lightweight building techniques are currently progressing fast and using such structures for multi-storey multi-family dwellings is becoming part of the industry standard. Partitions in lightweight buildings are often constructed as plates on frame structures made of either wood or steel. In any case the low frequency sound transmission is often an issue that needs attention. The present paper utilizes a finite element model of a single-stud double-plate panel structure to investigate how different couplings between the plates and the frame structure affect the direct sound transmission. Four different coupling configurations are considered: 1) All structural contact points are completely tied; 2) only nodes on the centre lines of the structure are tied; 3) a narrow strip of tied elements connect the frame to the plates; 4) evenly spaced discrete elements are tied. In all cases the interaction between non-tied elements is neglected. The investigations are performed as param- eter studies focusing on the effect of change in the model. The finite element model utilizes solid continuum elements for the entire structure. The computations are carried out in frequency domain in the range below 500 Hz and the load acts as a diffuse field on one side of the panel. The obtained results indicate that in order to accurately model sound transmission through a double-plate panel structure, the choice of coupling is an important factor.