In cases where noise emitted from air inlet or exhaust openings must be reduced effectively Baffle Silencers are used. Such silencers (attenuators) consist of a rectangular or cylindrical casing with sound reducing internals (splitters or baffles). When the noisy fluid (air, gas or steam) stream through the gaps of the baffles, the noise waves penetrate the absorber material of the baffle. The sound waves will be absorbed (reduced) after attenuation and damping. The difference between the loud inlet and attenuated outlet is called insertion loss. The set up and the dimensions of the silencer baffles depend on streaming situation of the fluid and acoustic requirements.
Generally the set-up of the baffles is as follows: