The through transmission method of longitudinal ultrasonic pulses was used to investigate the collective acoustic properties of a porous media model of cohesionless spherical particles. The results of this investigation showed dispersion and filtering effects for the transmitted acoustic waves. At low frequencies the wave velocity decreased with increase in frequency and particle size. In contrast at high frequencies the wave velocity decreased with increase in particle size, for relatively large particles (kR>>1). Calculated results from existing theoretical models for porous media by M. A. Biot, were compared to the experimental results. It was found that new modifications of the existing theoretical model for porous media were necessary in order to interpret the data in a quantitative manner.