Abstract: The device for extracting a useful acoustic signal from a composite acoustic signal including nuisance components includes: first sensor component for picking up the composite acoustic signal; second sensor component for picking up, in real-time, the reference acoustic signal, which is substantially correlated with the nuisance components of the composite acoustic signal; adaptive filtering component; and extraction component. The coefficients of the filtering component are adapted in real time according to an algorithm chosen so as to minimize the energy of the composite acoustic signal as a function of the energy of the reference acoustic signal, until the signal leaving the output of the extraction component corresponds substantially to the useful acoustic signal selectively rid of the nuisance components.

Abstract: The invention relates to a method and to apparatus for attenuating externally originating noise reaching the eardrum while still enabling communication via an electro-acoustic path. Apparatus according to the invention comprises passive attenuation means disposed about each ear and delimiting a cavity (10). In addition it includes active attenuation means comprising a loudspeaker (6) placed inside the cavity (10) and a microphone (8) placed in the external ear duct or at the inlet thereto, said loudspeaker and microphone being interconnected by a constant gain amplifier (11) and an active analog filter (12) of the polynomial type, with the passive components thereof being designed to provide a given transfer function. One application lies in the construction of protective headsets fitted with incorporated loudspeakers enabling electro-acoustic communication.