Inline duct silencers reduce fan and airflow noise travelling through round ventilation ductwork. A aluminium casing surrounds non-combustible sound-absorbing material, while the perforated inner airway allows sound energy to be absorbed without blocking the airflow path. Rubber-sealed spigots provide an airtight connection to compatible ducts, and the silencer can be installed in any orientation. The range is particularly effective when paired with inline fans in noise-sensitive residential or commercial spaces.