Sound transmission through multilayered elements was investigated in this experimental study by applying the ISO 140 Part 3 and ASTM methods. 28 wall samples were measured with various layer configurations composed of gypsum board, steel plate, vinyl damping material, glasswool and airgap. Effects of some physical parameters were investigated by comparing the data presented in terms of frequency dependent TL and the single-number ratings, as Rw and STC values. Results confirmed that the multi-layered walls with non-identical layers provide higher insulation compared with the double- layered elements. Doubling of the cavity-width results in 6-11 units increase in insulation ratings depending on the layer types. Addition of vinyl layer on a single steel plate, is 4 dB increase in TL at mid frequencies and max 8.5 dB at 5000 Hz and a negligible effect for the double walls. Filling glasswool in double walls reveals higher efficiency in gypsum boards compared to double steel plates.