Sound velocities and densities of lithium, sodium and potassium bromides and some tetraalkylammonium iodides have been determined in dimethylsulphoxide (DMSO), dioxane and DMSO + dioxane mixtures at 2 MHz at 25-degrees-C. The derived parameters namely adiabatic compressibility (beta), apparent molal compressibility (phi(K)), intermolecular free length (L(f)) and specific acoustical impedence (Z) have been computed from the experimental data. The limiting molar compressibility (phi(K)0) and experimental slope (S(K)) have also been obtained from the plots of (phi(K)) versus concentration.