# US 11,122,350 B1 · Method and apparatus for on ear detect > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,350 B1 - Document ID: US11122350B1 - Status: Granted - Kind: B1 - Application number: 16/996,230 - Filed: 2020-08-18 - Granted: 2021-09-14 - Earliest claimed: 2020-08-18 - Assignees: Cirrus Logic, Inc. - Applicants: Cirrus Logic International Semiconductor Ltd. - Inventors: John P. Lesso - Web page: https://patentgrep.com/patent/US11122350B1 ## CPC - H04R 1/10: Earpieces; Attachments therefor {; Earphones; Monophonic headphones (H04R1/28 takes precedence; stereophonic headphones H04R5/033)} - H04R 1/1041: {Mechanical or electronic switches, or control elements (switches in general H01H)} - H04R 1/08: Mouthpieces; {Microphones;} Attachments therefor - H04R 3/005: {for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407)} - H04R 29/00: Monitoring arrangements; Testing arrangements {(for hearing aids H04R25/30; detection of loudspeaker connection H04R5/04; sound-field adaptation dependent on speaker detection H04S7/308)} - 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) ## Abstract A method for on ear detection for a headphone, the method comprising: receiving a first microphone signal derived from an first microphone of the headphone and determining, from the first microphone signal, a first resonance frequency associated with an acoustic port of the first microphone, the first resonance frequency dependent on a first temperature at the first microphone; receiving a second microphone signal derived from an second microphone of the headphone and determining, from the second microphone signal, a second resonance frequency associated with an acoustic port of the second microphone, the second resonance frequency dependent on a second temperature at the second microphone. ## Claims ### Claim 1 A method for on ear detection for a headphone, the method comprising: receiving a first microphone signal derived from an first microphone of the headphone and determining, from the first microphone signal, a first resonance frequency associated with an acoustic port of the first microphone, the first resonance frequency dependent on a first temperature at the first microphone; receiving a second microphone signal derived from an second microphone of the headphone and determining, from the second microphone signal, a second resonance frequency associated with an acoustic port of the second microphone, the second resonance frequency dependent on a second temperature at the second microphone; and determining an indication of whether the headphone is on ear based on the first and second resonance frequencies. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the indication of whether the headphone is on ear comprises comparing the first and second resonance frequencies. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the indication of whether the headphone is on ear comprises: determine the first temperature at the first microphone and the second temperature at the second microphone based on the respective first and second resonance frequencies; and determining the indication of whether the headphone is on ear based on the first and second temperatures. ### Claim 4 (depends on 1) The method of claim 1, wherein determining the indication of whether the headphone is on ear based on the first and second resonance frequencies comprises detecting a change in the difference between the first and second resonance frequencies over time. ### Claim 5 (depends on 1) The method of claim 1, further comprising filtering the first and second resonance frequencies before determining whether the headphone is on ear. ### Claim 6 (depends on 1) The method of claim 1 is, wherein determining the indication of whether the headphone is on ear comprises: determining one or more derivatives of the first resonance frequency over time. ### Claim 7 (depends on 6) The method of claim 6, wherein determining the indication of whether the headphone is on ear comprises: determine a change in the first resonance frequency based on the one or more derivatives and the first resonance frequency. ### Claim 8 (depends on 6) The method of claim 6, wherein a prediction filter is used to determine whether the headphone is on ear based on the one or more derivatives and the first resonance frequency. ### Claim 9 (depends on 3) The method of claim 3, further comprising: comparing the first resonance frequency to a first resonance frequency range associated with the first microphone over a body temperature range; and determining that the headphone is on ear only if the first falls within the first resonance frequency range. ### Claim 10 (depends on 9) The method of claim 9, further comprising: comparing the second resonance frequency to a second resonance frequency range associated with the second microphone over an air temperature range; and determining that the headphone is on ear only if the first resonance frequency falls within the first resonance frequency range and the second resonance frequency falls within the second resonance frequency range. ### Claim 11 A method for on ear detection for a headphone, the method comprising: receiving a first microphone signal derived from a first microphone of the headphone and determining, from the first microphone signal, a first resonance frequency associated with the acoustic port of the first microphone, the first resonance frequency dependent on a first temperature at the first microphone; detecting a change in the first resonance frequency over time; and determining an indication of whether the headphone is on ear based on the change in resonance frequency and the resonance frequency after the change. ### Claim 12 (depends on 11) The method of claim 11, wherein determining the indication of whether the headphone is on ear comprises: determine a first temperature at the first microphone based on the first resonance frequency; and determining the indication of whether the headphone is on ear based on the first temperature. ### Claim 13 (depends on 11) The method of claim 11, further comprising detecting an insertion event or a removal event based on the change in the resonance frequency and the resonance frequency after the change. ### Claim 14 (depends on 11) The method of claim 11, further comprising filtering the first resonance frequency before determining whether the headphone is on ear. ### Claim 15 (depends on 11) The method of claim 11, wherein determining the change in the first resonance frequency comprises: determining one or more derivatives of the first resonance frequency over time. ### Claim 16 (depends on 15) The method of claim 15, wherein a prediction filter is used to determine whether the headphone is on ear based on the one or more derivatives and the first resonance frequency. ### Claim 17 (depends on 12) The method of claim 12, further comprising: comparing the first resonance frequency to a first resonance frequency range associated with the first microphone over a body temperature range; and determining that the headphone is on ear only if the first resonance frequency falls within the first resonance frequency range. ### Claim 18 An apparatus for on ear detection for a headphone, the apparatus comprising: a first input for receiving a first microphone signal derived from a first microphone of the headphone; a second input for receiving a second microphone signal derived from a second microphone of the headphone; one or more processors configured to: determine, from the first microphone signal, a first resonance frequency associated with an acoustic port of the first microphone, the first resonance frequency dependent on a first temperature at the first microphone; determine, from the second microphone signal, a second resonance frequency associated with an acoustic port of the second microphone, the second resonance frequency dependent on a second temperature at the second microphone; and determine an indication of whether the headphone is on ear based on the first and second resonance frequencies. ### Claim 19 An apparatus for on ear detection for a headphone, the apparatus comprising: an input for receiving a first microphone signal derived from a first microphone of the headphone; one or more processors configured to: determine, from the first microphone signal, a first resonance frequency associated with the acoustic port of the first microphone, the first resonance frequency dependent on a first temperature at the first microphone; detect a change in the first resonance frequency over time; and determine an indication of whether the headphone is on ear based on the change in resonance frequency and the resonance frequency after the change. ### Claim 20 (depends on 1) A non-transitory computer readable storage medium having computer-executable instructions stored thereon that, when executed by one or more processors, cause the one or more processors to perform a method according to claim 1.