A rectangular attenuator is basically two or more bats placed adjacent to each other, with given airway passages between them. These bats are inserted into a galvanized sheet steel box with either Mez or angle iron flanges at each end, for coupling the assembly to matching duct work. As the name implies, attenuators are used to attenuate the noise generated from fans serving the application.
Splitter silencers or rectangular attenuators as they are sometimes referred to are used extensively in larger ducted ventilation systems.
This type of silencer is almost always coupled directly to the fan. Examples are air handling units or large centrifugal fans commonly used in the distribution of air in factories, warehouses and shopping malls.
Rectangular or splitter silencers are more efficient than round silencers and also have better attenuating characteristics. They can be made to almost any size. Airways between 100mm and 150mm are recommended between the bats and air velocities should never exceed 10m³/sec though the unit.