The internal shape of a polyurethane filter is similar to a sponge or foam with polyhedral face in different orientations with each other. The polyurethane filter due to its chaotic pattern has almost identical properties with the classic soundtraps and soundproof foams which are widely used in music studios. The theoretical background covers the effect of attenuation of the sound waves while they bounc from the one face of the filter to the other. The polyurethane filter sheet can be formed as egg carton enhancing the effect of sound trapping. Generally the air filters have unlimited abilities due to their material and pattern. The sound trapping is but one example of the abilities of these mechanically amazing materials.