The invention relates to a method and a device for passive and active acoustic reduction, including m electro-acoustic bars (41) side by side and separated by gaps (D), thus constituting an open-work acoustic barrier combining passive and active noise-reduction. Each electro-acoustic bar (41) includes a plurality of acoustic reduction elements (70) arranged, side by side, each acoustic reduction element (70) including a microphone (62) and a loudspeaker (61) disposed inside a box (60) made of a passive acoustically absorbent material or including a passive acoustically absorbent material, the microphone (62) and the loudspeaker (61) being connected to control electronics (73) capable of receiving a measurement of the transfer function between the microphone (62) and the loudspeaker (61) and of computing a feedback control electronic filter for each acoustic reduction element (70) from the transfer function between the microphone (62) and the loudspeaker (61), and acting, within each acoustic reduction element (70), to enable the loudspeaker (61) to be electro-acoustically looped to the microphone (62) by amplifying the feedback in order to obtain real-time acoustic absorption for a predetermined, range of frequencies.