Active adaptive noise cancellation with a feedforward open headset

Stephane Boucher, Bruno Paillard, Andrée L'Esperance

Abstract


Active noise-reduction headsets currently on the market use feedback-type controllers. This choice of configuration results in the active control of only low-frequency harmonics (usually under 1000 Hz). Moreover, no discrimination is made by feedback algorithms and any predictable acoustic signal, within the control band, is attenuated. Consequently, in addition to cancel the noise, the feedback-type headset will affect speech, alarms and other predictable useful signals, resulting in a discomfort sensation for the user. Also, in order to allow those headsets to attenuate higher frequencies, they are often combined with a passive attenuation shell, with consequence that the user does not hear any useful signal and has almost the feeling of being deaf. A solution to this problem is to use a feedforward controller instead of a feedback controller, thus allowing the headset to: Actively cancel high frequency components of a harmonic disturbance, Cancel only the disturbance without modifying useful signals, and Be light and comfortable (the headset can be of open type, since no passive attenuation is required).

Keywords


Adaptive control systems; Algorithms; Headphones; Active adaptive noise cancellation; Feedforward open headsets

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