# US 10,873,809 B2 · Dynamic control of multiple feedforward microphones in active noise reduction devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,809 B2 - Document ID: US10873809B2 - Status: Granted - Kind: B2 - Application number: 16/422,239 - Filed: 2019-05-24 - Published: 2020-11-26 - Granted: 2020-12-22 - Earliest claimed: 2019-05-24 - Assignees: Bose Corporation - Applicants: Bose Corporation - Inventors: Richard L. Pyatt; Emery M. Ku - Web page: https://patentgrep.com/patent/US10873809B2 ## CPC - H04R 1/1083: {Reduction of ambient noise (active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06)} - H04R 3/04: for correcting frequency response - G10K 11/17827: {Desired external signals, e.g. pass-through audio such as music or speech} - G10K 11/17873: {using a reference signal without an error signal, e.g. pure feedforward} - G10K 11/17885: {additionally using a desired external signal, e.g. pass-through audio such as music or speech} - G10L 21/0216: characterised by the method used for estimating noise - H04R 1/10: Earpieces; Attachments therefor {; Earphones; Monophonic headphones (H04R1/28 takes precedence; stereophonic headphones H04R5/033)} - H04R 3/005: {for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407)} - H04R 3/02: for preventing acoustic reaction {, i.e. acoustic oscillatory feedback (specially adapted for hearing aids H04R25/453)} - H04R 5/027: Spatial or constructional arrangements of microphones, e.g. in dummy heads - H04R 5/04: Circuit arrangements, {e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments (combinations of amplifiers H03F3/68; stereophonic systems H04S)} - G10K 11/178: by electro-acoustically regenerating the original acoustic waves in anti-phase - G10L 2021/02166: {Microphone arrays; Beamforming} - H04R 1/406: {microphones} - H04R 2201/107: Monophonic and stereophonic headphones with microphone for two-way hands free communication - H04R 2420/01: Input selection or mixing for amplifiers or loudspeakers - H04R 2430/01: Aspects of volume control, not necessarily automatic, in sound systems - H04R 2460/01: Hearing devices using active noise cancellation - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract Technology described in this document can be embodied in an earpiece of an active noise reduction (ANR) device. The earpiece includes a plurality of microphones, wherein each of the plurality of microphones is usable for capturing ambient audio to generate input signals for both an ANR mode of operation and a hear-through mode of operation of the ANR device. The earpiece further includes a controller configured to: process a first subset of microphones from the plurality of microphones to generate input signals for the ANR mode of operation, process a second subset of microphones from the plurality of microphones to generate input signals for the hear-through mode of operation, detect that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation, and in response to the detection, process the input signals from the second subset of microphones without using input signals from the particular microphone. ## Claims ### Claim 1 An earpiece of an active noise reduction (ANR) device, the earpiece comprising: a plurality of feedforward microphones, wherein each of the plurality of feedforward microphones is configured to generate signals representing ambient audio for both an ANR mode of operation and a hear-through mode of operation of the ANR device; and a controller configured to: process signals received from a first subset of microphones from the plurality of feedforward microphones to generate input signals for the ANR mode of operation, process signals received from a second subset of microphones from the plurality of feedforward microphones to generate input signals for the hear-through mode of operation, detect, based on the signals received from the second subset of microphones, that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation, and in response to the detection, process the signals received from the second subset of microphones without using signals received from the particular microphone to generate the input signals for the hear-through mode of operation. ### Claim 2 (depends on 1) The earpiece of claim 1, wherein the ANR mode of operation provides noise cancellation of ambient sound and the hear-though mode of operation provides active hear-through of a portion of the ambient sound. ### Claim 3 (depends on 1) The earpiece of claim 1, wherein the ANR mode of operation comprises feedforward ANR. ### Claim 4 (depends on 1) The earpiece of claim 1, wherein processing the signals received from the first subset of microphones comprises processing the signals received from all microphones in the plurality of feedforward microphones for generating the input signals for the ANR mode of operation. ### Claim 5 (depends on 1) The earpiece of claim 1, wherein processing the signals received from the second subset of microphones comprises processing the signals received from all microphones in the plurality of feedforward microphones for generating the input signals for the hear-through mode of operation. ### Claim 6 (depends on 1) The earpiece of claim 1, wherein the first subset of microphones is the same as the second subset of microphones. ### Claim 7 (depends on 1) The earpiece of claim 1, wherein the first subset of microphones is different from the second subset of microphones. ### Claim 8 (depends on 1) The earpiece of claim 1, wherein detecting that a particular microphone of the second subset of microphones is acoustically coupled to the acoustic transducer comprises: determining that the magnitude of a tonal signal detected by the particular microphone relative to one or more of other microphones in the second subset satisfies a frequency-dependent threshold condition. ### Claim 9 (depends on 1) The earpiece of claim 1, wherein in response to detecting that a particular microphone of the second subset of microphones is acoustically coupled to the acoustic transducer, the controller is configured to adjust a gain applied to an input signal of another microphone of the second subset of microphones. ### Claim 10 (depends on 1) The earpiece of claim 1, wherein the controller is further configured to: process signals received from a third subset of microphones from the plurality of feedback microphones to generate input signals for a voice pick-up mode of operation; and execute a beamforming process using the corresponding input signals generated by the microphones of the third subset. ### Claim 11 A computer-implemented method comprising: processing signals received from a first subset of microphones from a plurality of feedforward microphones disposed on an earpiece of an ANR device to generate input signals for an ANR mode of operation; processing signals received from a second subset of microphones from the plurality of feedforward microphones to generate input signals for a hear-through mode of operation, wherein each of the plurality of feedforward microphones is configured to generate signals representing ambient audio for both the ANR mode of operation and the hear-through mode of operation of the ANR device; detecting, based on the signals received from the second subset of microphones, that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation; and in response to the detection, processing the signals received from the second subset of microphones without using signals received from the particular microphone to generate the input signals for the hear-through mode of operation. ### Claim 12 (depends on 11) The method of claim 11, wherein the ANR mode of operation provides noise cancellation of ambient sound and the hear-though mode of operation provides active hear-through of a portion of the ambient sound. ### Claim 13 (depends on 11) The method of claim 11, wherein processing the signals received from the first subset of microphones comprises processing the signals received from all microphones in the plurality of feedforward microphones for generating input signals for the ANR mode of operation. ### Claim 14 (depends on 11) The method of claim 11, wherein processing the signals received from the second subset of microphones comprises processing the signals received from all microphones in the plurality of feedforward microphones for generating input signals for the hear-through mode of operation. ### Claim 15 (depends on 14) The method of claim 14, wherein detecting that a particular microphone of the second subset of microphones is acoustically coupled to the acoustic transducer comprises: determining that the magnitude of a tonal signal detected by the particular microphone relative to one or more of other microphones in the second subset satisfies a frequency-dependent threshold condition. ### Claim 16 (depends on 11) The method of claim 11, further comprising: in response to detecting that a particular microphone of the second subset of microphones is acoustically coupled to the acoustic transducer, adjusting a gain applied to an input signal of another microphone of the second subset of microphones. ### Claim 17 (depends on 11) The method of claim 11, further comprising: processing signals received from a third subset of microphones from the plurality of feedback microphones to generate input signals for a voice pick-up mode of operation; and executing a beamforming process using the corresponding input signals generated by the microphones of the third subset. ### Claim 18 (depends on 11) The method of claim 11, wherein the first subset of microphones is the same as the second subset of microphones. ### Claim 19 (depends on 11) The method of claim 11, wherein the first subset of microphones is different from the second subset of microphones. ### Claim 20 One or more non-transitory machine-readable storage devices having encoded thereon computer readable instructions for causing one or more processing devices to perform operations comprising: processing signals received from a first subset of microphones from a plurality of feedforward microphones disposed on an earpiece of an ANR device to generate input signals for an ANR mode of operation; processing signals received from a second subset of microphones from the plurality of feedforward microphones to generate input signals for the hear-through mode of operation, wherein each of the plurality of microphones is usable for capturing ambient audio to generate input signals for both an ANR mode of operation and a hear-through mode of operation of the ANR device; detecting, based on the signals received from the second subset of microphones, that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation; and in response to the detection, processing the signals received from the second subset of microphones without using signals received from the particular microphone to generate the input signals for the hear-through mode of operation.