Active acoustic attenuation system with reduced convergence time

In an acoustic system having an input for receiving an input acoustic wave produced by an acoustic source, and an output for radiating an output acoustic wave, an active attenuation method for attenuating undesirable said output acoustic wave by introducing a cancelling acoustic wave from an output transducer, comprising:

• sensing said input acoustic wave with an input transducer and providing an input signal;
• sensing the combined said output acoustic wave and said cancelling acoustic wave from said output transducer with an error transducer and providing an error signal;
• modeling said acoustic system with an adaptive filter model having a model input from said input transducer and an error input from said error transducer and outputting a correction signal to said output transducer to introduce the cancelling acoustic wave such that said error signal approaches a given value as said adaptive filter model responds to said input signal by updating weights of a coefficient weight vector from an initial nonconverged value in a nonconverged condition of said filter model at turn-on thereof to a converged value in a converged condition of said filter model, said filter model also responding to said input signal as the latter changes in response to changes of said input acoustic wave such that said weights are further updated during further convergence of said model to a new converged value;
• reducing convergence time of said filter model to a new converged condition in response to changes of said input acoustic wave, by providing new updated weight values according to a sensed parameter of said acoustic source without waiting for convergence of said filter model, such that said filter model converges in a shorter time.