Patent ID: 8693700

Claim:
An active noise reduction device comprising: an electronic signal processing circuit including: a first input for accepting a first signal; a second input for accepting a second signal; an output for providing a third signal; and a feed-forward path from the first input to the output including: a fixed compensation linear filter; and a variable compensation filter having an input for receiving a control parameter that applies a selected linear filter from a family of linear filters that vary in both gain and spectral shape and are selectable by the control parameter; and a feed-forward controller for determining the control parameter by calculating a control signal using the first signal and the second signal and then using the control signal to determine the control parameter a device body configured to form a cavity when coupled to the anatomy of a wearer; a first microphone configured to sense the sound pressure level outside of the cavity and generate the first signal; a second microphone configured to sense the sound pressure level inside of the cavity and generate the second signal; and a driver configured to receive the third signal and provide sound pressure to the inside of the cavity, wherein each linear filter in the family of linear filters represents a deviation from an average of a plurality of different positions of the device body on the anatomy of the wearer.