This work deals with the attenuation of sound in dilute suspensions of rigid particles when the hydrodynamic mechanism of the acoustic-wake effect is considered. The study extends a previous model by considering asymmetric flow-field conditions around the particles, caused by other neighbor particles along the direction of propagation of the acoustic field. The attenuation coefficient is derived from the force equation for a spherical particle in an incompressible fluid that is oscillating at low frequencies and amplitudes within the range of Reynolds numbers of 0.1 < Re < 1. It acquires higher values than those obtained for the Stokes regime (Re << 1), increasing up to about 8% at Reynolds numbers close to the unity. In the study we found the particle size as a significant parameter on the sound attenuation, together with concentration of particles.