ABSTRACT
One of the most used solutions for the design of exhaust silencers in reciprocating internal combustion engines is the inclusion of absorbent materials, most notably when the objective is not only the reduction of the level, but also the enhancement of the sound quality of the noise [1]. The influence of the absorbent materials is mainly related to its broadband attenuation characteristics which, together with its relatively low effect on silencer backpressure, have contributed to the increasing use of the dissipative silencers in other applications related with gas flows, such as heating, ventilation and air conditioning systems.
