A device (30a-30f) for processing an input signal (Si), generating an output signal (So) designed to feed a loudspeaker, directly or indirectly, through an amplifier, wherein said device includes a processing line (Lt) comprising: a module for estimating the expected movements (Da) of the loudspeaker as a function of the input signal (Si); and a module for determining an adaptive control signal (CmdA) to be transmitted to the loudspeaker, i.e., a signal determined digitally from an expected displacement of the membrane; and the processing device (30a-30f) further comprises: at least one transmission line (L1, L2, L2') of the input signal (Si) delivering at least one non-adaptive control signal (Cmdl, Cmd2), i.e., a signal originating, directly or indirectly, from the input signal (Si); and an adder delivering the output signal (So) by summing the adaptive control signal (CmdA) and the at least one non-adaptive control signal (Cmd1, Cmd2), wherein the determination module is configured to solve a system of coupled differential equations aimed at determining the signal to be transmitted to the loudspeaker in order to obtain the expected displacement of the membrane, the system of coupled differential equations representing the loudspeaker, considered as a nonlinear transducer, characterized in that the coupled differential equations also represents the environment of the loudspeaker. a module for estimating the expected movements (Da) of the loudspeaker as a function of the input signal (Si); and a module for determining an adaptive control signal (CmdA) to be transmitted to the loudspeaker, i.e., a signal determined digitally from an expected displacement of the membrane; and the processing device (30a-30f) further comprises: at least one transmission line (L1, L2, L2') of the input signal (Si) delivering at least one non-adaptive control signal (Cmdl, Cmd2), i.e., a signal originating, directly or indirectly, from the input signal (Si); and an adder delivering the output signal (So) by summing the adaptive control signal (CmdA) and the at least one non-adaptive control signal (Cmd1, Cmd2), wherein the determination module is configured to solve a system of coupled differential equations aimed at determining the signal to be transmitted to the loudspeaker in order to obtain the expected displacement of the membrane, the system of coupled differential equations representing the loudspeaker, considered as a nonlinear transducer, characterized in that the coupled differential equations also represents the environment of the loudspeaker. at least one transmission line (L1, L2, L2') of the input signal (Si) delivering at least one non-adaptive control signal (Cmdl, Cmd2), i.e., a signal originating, directly or indirectly, from the input signal (Si); and an adder delivering the output signal (So) by summing the adaptive control signal (CmdA) and the at least one non-adaptive control signal (Cmd1, Cmd2), wherein the determination module is configured to solve a system of coupled differential equations aimed at determining the signal to be transmitted to the loudspeaker in order to obtain the expected displacement of the membrane, the system of coupled differential equations representing the loudspeaker, considered as a nonlinear transducer, characterized in that the coupled differential equations also represents the environment of the loudspeaker.