In this work, a new type of feedback control is presented which operates primarily in the frequency domain for use in 3D active noise control problems. Within the controller, a so-called time advance filter is designed to overcome the delay caused by the acoustics and the FFT. The filter is able to manipulate the phase response of the input so that the output appears time advanced. This nonlinear frequency domain feedback control method is shown to have more versatility, improved stability, and significantly reduced waterbed effect as compared to linear feedback control methods. An ultrasonic tracking system is also presented as a way to identify the location of a person's ear in real-time within a 3D environment. This position information is then provided to the controller which can adapt based on the user's position to achieve improved performance. Although ultrasonic tracking of a microphone is not new, this is the first time its potential for use in active noise control is shown.
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