Abstract: Infinite acoustic baffle (10) comprising a box (12) and a loudspeaker (20) comprising a membrane (22) that is movable relative to the box (12), the box (12) and the membrane (22) defining a substantially closed baffle chamber (14); the loudspeaker (20) comprising an electrically controlled motor (30) for actuating the membrane (22) that is able to move relative to the box (12), the baffle also comprising a mechanism (50) for axially urging the membrane (22) away from its median rest position counter to the pressure force exerted on the membrane (22) by the gas contained in the box (12) characterized in that the mechanism (50) comprises a cam (54) that is movable relative to the box (12) along an axis (X-X) for displacing of the cam under the displacement action of the membrane (22) and at least one cam follower (58A, 58B) that is biased transversely to the cam (54) by at least one spring (60A, 60B) and bears on the cam (54), the cam (54) having at least one cam surface (56A, 56B) capable of converting the tra