An active acoustic control method for attenuating disturbing narrow-band noise with at least one counter-noise loudspeaker and at least one error microphone in a space forming a material electroacoustic system, the method implementing, in a computing element, a control law with an internal model and disturbance observer with a model of the electroacoustic system, previously obtained by an identification method. The current configuration of the electroacoustic system can vary over time, a nominal configuration of the electroacoustic system is previously determined, a corresponding nominal model Mo(q−1) or Mo(k) previously identified, the control law with an internal model and disturbance observer is implemented in real time, a modifier block Δ(q−1) or Δ(k) is applied to and associated with the nominal model, and the nominal model remains the same during the variations of the current configuration of the electroacoustic system, and the modifier block is varied in real time during these variations.