The dynamic response and the sound radiation of truss core panels are investigated in this paper. The spectral element model for the truss core panel is developed. The element model is established by employing shape functions derived directly from the solution of distributed parameter models for each beam element. Forced vibrations of a fluid-loaded beam in a rigid baffle are considered. The spectral formulation can be easily and efficiently coupled with the Fourier transform (FT) based analysis of the structure’s sound radiation in a surrounding acoustic medium. Hence the proposed formulation is an efficient numerical tool for the analysis of the dynamic and acoustic performance of the considered truss core sandwich panels. The comparison of the sound characteristics selected as sound transmission reduction index to the psychical parameters of the truss core beam is carried out.