Abstract: The method of sound processing according to the invention takes into account the quantum effect of the propagation of the sound in the material from which the theatre walls are built, what allows to reconstruct the timbre of the processed sound. The sound processed with the method according to the invention is clearer, deeper and stronger than the original. The method consists in the digital filtering of the sound with the aid of finite impulse response obtained from pairs of signals delay-attenuation computed for the trajectories originating from the sound source and composed from the trajectory segments in the air and in the material of theatre walls. The method thereof is characterized by the fact that the first directions of the trajectory segments in the air are selected randomly and the next ones are determined according to the rule that the reflection angle from the theatre wall is the same as the incidence angle till the moment when the trajectory reaches the listener's location.