Active attenuation system with on-line modeling of speaker, error path and feedback pack

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 acoustic 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 on-line without off-line pre-training, and providing both adaptive error path compensation and adaptive compensation of said output transducer on-line without off-line 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 spaced from said output transducer along an error path 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;
• modeling the feedback path from said output transducer to said input transducer with the same said model 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 without a separate model pre-trained off-line solely to said feedback path;
• providing an auxiliary noise source and introducing noise therefrom into said model, such that said error transducer also senses the auxiliary noise from said auxiliary noise source;
• modeling both said error path and said output transducer on-line with a second adaptive filter model, and providing a copy of said second adaptive filter model in said first mentioned adaptive filter model to compensate for said output transducer and said error path.

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

• an error transducer sensing the combined said output acoustic wave and said acoustic wave from said output transducer and providing an error signal;
• an adaptive filter model adaptively modeling said acoustic system on-line and having an error input from said error transducer and outputting a correction signal to said output transducer to introduce said cancelling acoustic wave such that said error signal approaches a given value;
• an auxiliary noise source introducing auxiliary noise into said adaptive filter model which is random and uncorrelated with said input acoustic wave;
• and
• a second adaptive filter model having a model input from said auxiliary noise source and an error input from said error transducer.

In an acoustic system having an input for receiving an input acoustic wave and an output for radiating an output acoustic wave, active attenuation apparatus for attenuating undesirable said output acoustic wave by introducing a cancelling acoustic 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 on-line without off-line pre-training and for providing both adaptive error path compensation and adaptive compensation of said output transducer on-line without off-line ore-training, comprising:

• an input transducer for sensing said input acoustic wave;
• an error transducer spaced from said output transducer along an error path and sensing the combined said output acoustic wave and said acoustic wave from said output transducer and providing an error signal;
• a first adaptive filter model adaptively modeling said acoustic system on-line without dedicated off-line pre-training, and also modeling the feedback path from said output transducer to said input transducer on-line without dedicated off-line pre-training, said first 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 said cancelling acoustic wave such that said error signal approaches a given value;
• an auxiliary noise source introducing auxiliary noise into said adaptive filter model;
• a second adaptive filter model adaptively modeling both said error path and said output transducer on-line without dedicated off-line pre-training;
• and
• a copy of said second adaptive filter model in said first adaptive filter model to compensate for both said error path and said output transducer adaptively on-line.