An active noise reduction (ANR) component for provision in an earphone housing is disclosed. The device includes a driver and a sensing microphone, the driver and sensing microphone being housed in a component housing. The earphone housing has an outlet passageway from the ANR component to an auditory canal. The ANR component is adapted for use with a controller to provide active noise reduction to the auditory canal over a predetermined range of physical dimensions or acoustic parameters of the housing outlet passageway. The ANR component can thus be used with different housings which simplifies the design process for producing ANR earphone products.