Passive Attenuators are used for a wide range of applications, usually involving the movement of air such as in ducting or through a room.
The most common use of Reactive Attenuators is for combustion engine exhaust systems, such as in vehicles or generators, where they are usually supplemented by passive attenuation to provide attenuation across a broader range of frequencies.
Active attenuation is becoming more widely used, mainly for specialist applications such as noise-cancelling microphones, ear muffs, and to reduce noise in cars and aircraft.
Noise Control Engineering projects make most use of passive attenuation for a range of similar purposes, such as reducing noise from fans within duct systems, from equipment which may be indoors—e.g. in a plantroom—or outdoors, and improving speech privacy.