Patent ID: 12002447

Abstract:
A noise cancellation system for an ear-mountable playback device having a speaker, a feedforward microphone and an error microphone comprises a filter chain for coupling the feedforward microphone to the speaker, the filter chain comprising a series connection or parallel connection of a coarse filter and a fine filter, and a noise control processor. The fine filter is formed of a set of sub-filters having a predefined frequency range, wherein the predefined frequency range of each of the sub-filters together forms an effective overall frequency range of the fine filter. The noise control processor is configured to calculate an error signal based on a first noise signal sensed by the feedforward microphone and on a second noise signal sensed by the error microphone, to perform an adaptation of coarse filter parameters of the coarse filter based on the error signal, and to perform a limited adaptation of fine filter parameters of each of the sub-filters based on the error signal, wherein limits of the limited adaptation comprise the predefined frequency ranges of the sub-filters and at least one of a gain limit and a Q factor limit.