Sound attenuation device and method

An attenuation device intended for attenuating sound waves generated by a source emitting sound waves of which the frequencies are between f1 and f2 and of which the pressure levels are between n1 and n2,

• the attenuation device comprising at least one acoustic absorber comprising at least one membrane, with the acoustic absorber having at least one first face and at least one second face separate from the first face, with the acoustic absorber being configured to have a behavior in non-linear deformation when it receives sound waves of which the frequencies are between f01 and f02, with the range f01−f02 covering at least 50% of the range f1−f2 and of which the pressure levels are between n01 and n02, with the range n01−n02 covering at least 50% of the range n1−n2;
• with the attenuation device being configured in such a way that the first face of the absorber is in acoustic communication with the source;
• with the attenuation device being comprising at least one coupling element for coupling the second face with the source, the coupling element being configured to transmit to the second face a maximum of power for sound waves of which the frequencies are higher than f1 and configured to transmit to the second face sound waves of which:
• the instantaneous acoustic pressure that is exerted on the second face is according to the instantaneous acoustic pressure of sound waves emitted by the source,
• the phase and/or the amplitude results in that IP1−P2I>k.IP1I during at least one portion of the operating cycle of the source, with P1 and P2 being the instantaneous acoustic pressures of the sound waves arriving respectively on the first and second faces at the same time and with k>0.2.