Active sound attenuation system with on-line adaptive feedback cancellation

In an acoustic system having an input for receiving an input acoustic wave and an output for radiating an output acoustic wave, an active attenuation method for attenuating undesirable said output acoustic wave by introducing a cancelling acoustive wave from an output transducer, and for adaptively compensating for feedback to said input from said output transducer for both broad band and narrow band acoustic waves without pre-training, comprising:

• sensing said input acoustic wave with an input transducer;
• sensing the combined said output acoustic wave and said cancelling acoustic wave from said output transducer with an error transducer 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 specified value;
• modeling the feedback path from said output transducer to said input transducer with the same said model, without a separate model pre-trained solely to said feedback path, by modeling said feedback path as part of said model such that the latter adaptively models both said acoustic system and said feedback path, without separate modeling of said acoustic system and said feedback path and dedicated pre-training of the latter with a broad band acoustic wave.