# US 11,445,290 B1 · Feedback acoustic noise cancellation tuning > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,445,290 B1 - Document ID: US11445290B1 - Status: Granted - Kind: B1 - Application number: 17/027,258 - Filed: 2020-09-21 - Granted: 2022-09-13 - Earliest claimed: 2019-09-27 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Scott C. Grinker; Vladan Bajic; Brian D. Clark; Tom-Davy W. Saux; Hanchi Chen - Web page: https://patentgrep.com/patent/US11445290B1 ## 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)} - G10K 11/178: by electro-acoustically regenerating the original acoustic waves in anti-phase - G10K 11/17825: {Error signals} - G10K 11/17857: {Geometric disposition, e.g. placement of microphones} - G10K 11/17875: {using an error signal without a reference signal, e.g. pure feedback} - H04R 1/1016: {Earpieces of the intra-aural type} - G10K 11/17881: {the reference signal being an acoustic signal, e.g. recorded with a microphone} - G10K 2210/1081: Earphones, e.g. for telephones, ear protectors or headsets - G10K 2210/3023: Estimation of noise, e.g. on error signals - G10K 2210/3025: Determination of spectrum characteristics, e.g. FFT - G10K 2210/3028: Filtering, e.g. Kalman filters or special analogue or digital filters - G10K 2210/3214: Architectures, e.g. special constructional features or arrangements of features - G10K 2210/3215: Arrays, e.g. for beamforming - 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 ## Abstract A method performed by an in-ear headphone that includes a speaker and an internal microphone. The method receives a microphone signal from the internal microphone that indicates a current sound pressure level (SPL) in an ear canal of a user. The current SPL is a result of a control leak from the in-ear headphone into an ambient environment that reduces a SPL in the ear canal between 2 dB and 25 dB at a frequency within a frequency range than if otherwise not present. The method determines an active noise cancellation (ANC) filter based on the microphone signal and generates an anti-noise signal using the ANC filter. The method drives the speaker using the anti-noise signal to reduce the current SPL in the ear canal of the user as much as 25 dB at a frequency within the frequency range. ## Claims ### Claim 1 A method performed by an in-ear headphone that includes a speaker and an internal microphone, the method comprising: receiving a microphone signal from the internal microphone that indicates a current sound pressure level (SPL) in an ear canal of a user, wherein the current SPL is a result of an opening that extends through an enclosure of the in-ear headphone such that an inside portion of the enclosure directly connects to an ambient environment outside the enclosure, thereby reducing a SPL in the ear canal; determining an active noise cancellation (ANC) filter based on the microphone signal; and generating an anti-noise signal using the ANC filter; and driving the speaker using the anti-noise signal to reduce the current SPL in the ear canal of the user by as much as 25 dB at a frequency within a frequency range. ### Claim 2 (depends on 1) The method of claim 1, wherein the frequency range is 20 Hz-1200 Hz. ### Claim 3 (depends on 1) The method of claim 1, wherein the opening reduces the SPL in the ear canal to zero below 20 Hz. ### Claim 4 (depends on 1) The method of claim 1, wherein the enclosure includes a front volume and a back volume, wherein the opening is a port that allows a path between the front volume and the ambient environment. ### Claim 5 (depends on 4) The method of claim 4, wherein the port is a first port and the path is a first path, wherein the in-ear headphone further comprises a second port that allows a second path between the back volume, the front volume, and the ambient environment. ### Claim 6 (depends on 1) The method of claim 1, wherein the enclosure also includes a main port that is configured to direct sound output by the speaker into the ear canal of the user, wherein the main port has a cross-sectional area that is at least twice a cross-sectional area of the opening. ### Claim 7 (depends on 1) The method of claim 1, wherein the microphone signal is a first microphone signal, wherein the in-ear headphone further comprises an external microphone, wherein the method further comprises receiving a second microphone signal from the external microphone that includes sound of the ambient environment; and generating a filtered audio signal that includes at least a portion of the sound of the ambient environment by filtering the second microphone signal with an acoustic transparency filter; and driving the speaker with the filtered audio signal and the anti-noise signal. ### Claim 8 (depends on 1) The method of claim 1, wherein the opening is positioned on an ear tip of the in-ear headphone. ### Claim 9 An in-ear headphone comprising: a speaker; an internal microphone; an enclosure that comprises the speaker and the internal microphone; an opening that extends through the enclosure to directly connect an inside portion of the in-ear headphone to an ambient environment outside the enclosure; a processor; and memory having instructions which when executed by the processor causes the in-ear headphone to receive a microphone signal from the internal microphone that indicates a current sound pressure level (SPL); determine an active noise cancellation (ANC) filter based on the microphone signal; and generate an anti-noise signal using the ANC filter; and driving the speaker using the anti-noise signal to reduce the SPL in an ear canal of the user as much as 25 dB at a frequency within a frequency range. ### Claim 10 (depends on 9) The in-ear headphone of claim 9, wherein the frequency range is 20 Hz-1200 Hz. ### Claim 11 (depends on 9) The in-ear headphone of claim 9, wherein the opening reduces the SPL in the ear canal to zero below 20 Hz. ### Claim 12 (depends on 9) The in-ear headphone of claim 9, wherein the enclosure includes a front volume and a back volume, wherein the opening is a port that allows a path between the front volume and the ambient environment. ### Claim 13 (depends on 12) The in-ear headphone of claim 12, wherein the port is a first port and the path is a first path, wherein the in-ear headphone further comprises a second port that allows a second path between the back volume, the front volume, and the ambient environment. ### Claim 14 (depends on 9) The in-ear headphone of claim 9, wherein the enclosure further comprises a main port that is configured to direct sound output by the speaker into the ear canal of the user, wherein the main port has a cross-sectional area that is at least twice a cross-sectional area of the opening. ### Claim 15 (depends on 9) The in-ear headphone of claim 9, wherein the microphone signal is a first microphone signal, wherein the in-ear headphone further comprises an external microphone, wherein the memory has further instructions to receive a second microphone signal from the external microphone that includes sound of an ambient environment; generating a filtered audio signal that includes at least a portion of the sound of the ambient environment by filtering the second microphone signal with an acoustic transparency filter; and driving the speaker with the filtered audio signal and the anti-noise signal. ### Claim 16 An article of manufacture comprising a non-transitory machine-readable medium having instructions stored therein that when executed by a processor of an in-ear headphone cause the headphone to receive, from an internal microphone of the in-ear headphone, a microphone signal that indicates a current sound pressure level (SPL) in an ear canal of a user, wherein the in-ear headphone comprises an opening that extends through an enclosure of the in-ear headphone such that an inside portion of the enclosure directly connects to an ambient environment that is outside the enclosure, thereby reducing a SPL in the ear canal; determine an active noise cancellation (ANC) filter based on the microphone signal; and generate an anti-noise signal using the ANC filter; driving a speaker of the in-ear headphone using the anti-noise signal to reduce the current SPL in the ear canal of the user as much as 25 dB at a frequency within a frequency range. ### Claim 17 (depends on 16) The article of manufacture of claim 16, wherein the frequency range is 20 Hz-1200 Hz. ### Claim 18 (depends on 16) The article of manufacture of claim 16, wherein the enclosure includes a front volume and a back volume, wherein the opening is a port that allows a path between the front volume and the ambient environment. ### Claim 19 (depends on 18) The article of manufacture of claim 18, wherein the port is a first port and the path is a first path, wherein the in-ear headphone further comprises a second port that allows a second path between the back volume, the front volume, and the ambient environment. ### Claim 20 (depends on 16) The article of manufacture of claim 16, wherein the enclosure also includes a main port that is configured to direct sound output by the speaker into the ear canal of the user, wherein the main port has a cross-sectional area that is at least twice a cross-sectional area of the opening. ### Claim 21 (depends on 16) The article of manufacture of claim 16, wherein the microphone signal is a first microphone signal, wherein the in-ear headphone further comprises an external microphone, wherein the non-transitory machine readable medium has further instructions to receive a second microphone signal from the external microphone that includes sound of the ambient environment; generate a filtered audio signal that includes at least a portion of the sound of the ambient environment by filtering the second microphone signal with an acoustic transparency filter; and drive the speaker with the filtered audio signal and the anti-noise signal.