The influence of viscoelastic properties in sound propagation is analyzed. A generalization of Oldroyd viscoelastic model for incompressible solutions is made for the case of compressible fluids, introducing viscoelastic effects in normal stresses. This generalized model allows us to obtain an integro-differential equation for the small oscillations of pressure in the sound wave. The dispersion relations obtained from this equation are valid in any range of frequency and contain as particular case results reported in the literature