# US 12,003,921 B2 · Hearing aid comprising an ITE-part adapted to be located in an ear canal of a user > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,921 B2 - Document ID: US12003921B2 - Status: Granted - Kind: B2 - Application number: 17/862,992 - Filed: 2022-07-12 - Published: 2023-01-26 - Granted: 2024-06-04 - Earliest claimed: 2021-07-13 - Assignees: Oticon A/S - Applicants: Oticon A/S - Inventors: Lars Bramsløw; Svend Oscar Petersen - Web page: https://patentgrep.com/patent/US12003921B2 ## CPC - H04R 25/356: {Amplitude, e.g. amplitude shift or compression} - H04R 25/505: {using digital signal processing} - H04R 2225/025: In the ear hearing aids [ITE] hearing aids - H04R 2460/11: Aspects relating to vents, e.g. shape, orientation, acoustic properties in ear tips of hearing devices to prevent occlusion - H04R 2460/15: Determination of the acoustic seal of ear moulds or ear tips of hearing devices - 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 hearing aid comprises a) an ITE-part adapted for being located at or in an ear canal of the user, b) a forward path for processing sound from the environment of the user. The forward path comprises b1) at least one first input transducer providing at least one first electric input signal representing said sound as received at the respective at least one first microphone, said at least one first input transducer being located to allow picking up sound from the environment of the user, b2) an audio signal processor comprising a gain unit for applying a frequency and/or level dependent prescribed gain to compensate for a hearing impairment of the user to said at least one first electric input signal, or a signal or signals originating therefrom, and configured to provide a processed signal in dependence thereof, b3) an output transducer for providing stimuli perceivable as sound to the user in dependence of said processed signal. The hearing aid further comprises c) at least one second input transducer providing at least one second electric input signal representing said sound as received at the at least one second input transducer, the at least one second input transducer being located in said ITE-part to pick up sound at the eardrum of the user, d) a correlator configured to determine a correlation measure between the at least one second electric input signal, or a signal originating therefrom, and a signal of the forward path and e) a gain modifier configured to modify said gain of the gain unit in dependence of said correlation measure. A method of operating a hearing aid is further disclosed. ## Claims ### Claim 1 A hearing aid configured to be worn at, and/or in, an ear of a user, the hearing aid comprising an ITE-part adapted for being located at or in an ear canal of the user, wherein said ITE-part comprises a mould or earpiece comprising a ventilation channel or a plurality of ventilation channels, or a dome-like structure comprising one or more openings, allowing an exchange of air with the environment, when said ITE-part is located at or in the ear canal of the user; a forward path for processing sound from the environment of the user, the forward path comprising at least one first input transducer providing at least one first electric input signal representing said sound as received at the respective at least one first input transducer, said at least one first input transducer being located to allow picking up sound from the environment of the user, an audio signal processor comprising a gain unit for applying a gain, including a frequency and/or level dependent prescribed gain to compensate for a hearing impairment of the user, to said at least one first electric input signal, or a signal or signals originating therefrom, and configured to provide a processed signal in dependence thereof, an output transducer for providing stimuli perceivable as sound to the user in dependence of said processed signal, at least one second input transducer providing at least one second electric input signal representing said sound as received at the at least one second input transducer, the at least one second input transducer being located in said ITE-part to pick up sound at the eardrum of the user, wherein the hearing aid further comprises a comb filter effect gain modification estimator configured to provide a modification gain to said gain unit for application to the at least one first electric input signal, or to a signal originating therefrom, in dependence of a comb filter effect control signal to thereby suppress the comb filter effect in the ear canal, the comb filter effect gain modification estimator comprising a correlator configured to determine a correlation measure between the at least one second electric input signal, or a signal originating therefrom, and a signal of the forward path; wherein said comb filter gain modification estimator is configured to provide said modification gain in dependence of said correlation measure; a comb filter effect gain controller configured to determine said comb filter effect control signal in dependence of one or more of a) a time delay of said forward path, b) an effective vent size of the ITE-part, c) a sound class signal indicative of a current acoustic environment around the hearing aid, and d) a property of said at least one first electric input signal; wherein said comb filter effect control signal is configured to activate or deactivate said comb filter gain modification estimator and, if activated, to apply said modification gain only to a critical frequency range below a threshold frequency expected to be prone to the comb-filter effect. ### Claim 2 (depends on 1) A hearing aid according to claim 1 wherein said correlator is configured to operate in the time-domain. ### Claim 3 (depends on 1) A hearing aid according to claim 1 comprising at least one analysis filter bank configured to provide said at least one electric input signal in the frequency domain in a time-frequency representation (k, l), where k is a frequency band index, k=1, . . . , K, and l is a time index. ### Claim 4 (depends on 1) A hearing aid according to claim 1 wherein the gain modification estimator is configured to operate in a multitude of frequency bands. ### Claim 5 (depends on 1) A hearing aid according to claim 1 wherein said comb filter gain modification estimator is configured to provide said modification according to a gain rule or gain map so that: said modification gain decreases when approaching a cross-correlation value of −1 from above, and said modification gain increases when approaching a cross-correlation value of −1 from below. ### Claim 6 (depends on 1) A hearing aid according to claim 1 wherein said effective vent size of said ITE-part is determined to correspond to dimensions of a single ventilation channel exhibiting an acoustic impedance equal to said ventilation channel or plurality of ventilation channels or one or more openings through the ITE-part. ### Claim 7 (depends on 1) A hearing aid according to claim 1 wherein said effective vent size of said ITE-part is determined in advance of use of the hearing aid or adaptively during use. ### Claim 8 (depends on 1) A hearing aid according to claim 1 wherein said threshold frequency (fTH) is determined in dependence of said effective vent size of the ITE-part and the processing delay of the hearing aid. ### Claim 9 (depends on 1) A hearing aid according to claim 1 wherein said threshold frequency (fTH) is in the range between 1.5 kHz and 3 kHz. ### Claim 10 (depends on 1) A hearing aid according to claim 1 wherein said time delay of said forward path of the hearing aid is determined in advance of use of the hearing aid or adaptively during use. ### Claim 11 (depends on 1) A hearing aid according to claim 1 wherein said threshold frequency is determined in advance of use of the hearing aid or adaptively during use. ### Claim 12 (depends on 1) A hearing aid according to claim 1 wherein said signal of the forward path being used to determine said correlation measure is the processed signal. ### Claim 13 (depends on 1) A hearing aid according to claim 1 wherein said correlator and said comb filter effect gain modification estimator are configured to operate in a plurality of frequency bands. ### Claim 14 (depends on 1) A hearing aid according to claim 1 comprising an environment classifier for classifying a current acoustic environment around the hearing aid and providing a sound class signal in dependence thereof. ### Claim 15 (depends on 1) A hearing aid according to claim 1 wherein said comb filter effect control signal is configured to only activate the comb filter gain modification estimator in certain acoustic environments where broadband sound is present or dominating as indicated by said sound class signal. ### Claim 16 (depends on 1) A hearing aid according to claim 1 wherein said comb filter effect control signal is configured to only activate or deactivate said comb filter gain modification estimator when said property of said at least one first electric input signal is above a threshold value in said critical frequency range below said threshold frequency. ### Claim 17 A method of operating a hearing aid comprising an ITE-part adapted for being located at or in an ear canal of the user, a forward path from a first input transducer to an output transducer via an audio signal processor, the first input transducer being configured to provide a first electric input signal representative of sound in an environment of the user at the first input transducer, the audio signal processor being configured to apply a prescribed gain to said first electric input signal, or to a signal or signals originating therefrom, to compensate for a hearing impairment of the user, and to provide a processed signal in dependence thereof, the output transducer being configured to provide stimuli perceivable by the user as sound in dependence of said processed signal, a second input transducer located in the ITE-part to pick up sound at the eardrum of the user, the second input transducer providing a second electric input signal representing sound as received at the second input transducer; the method comprising determining a time delay of the forward path through the hearing aid from an acoustic input of the input transducer to an acoustic output of the output transducer; selecting one or more frequencies or frequency ranges expected to be prone to the comb-filter effect in dependence of said time delay; calculating a current value of cross-correlation between said second electric input signal, or a signal originating therefrom, and a signal of the forward path; creating a gain rule or gain map for determining a gain modification in dependence of cross-correlation; determining a current gain modification in dependence of said current value of the cross-correlation; applying said gain modification to said first electric input signal or to a signal originating therefrom. ### Claim 18 (depends on 17) A method according to claim 17 wherein the correlation function is provided in the complex domain as complex values comprising a real and an imaginary part, and wherein a critical region for a given frequency or frequency range selected as being prone to the comb-filter effect is defined in terms of the real and imaginary parts of said complex cross-correlation function. ### Claim 19 (depends on 18) A method according to claim 18 wherein the critical region is around (Re, Im)=(−1, 0) and defined to extend between respective minimum values (CCRe,min, CCIm,min) and maximum values (CCRe,max, CCIm,max) on the real axis and the imaginary axis, where the minimum and maximum values of cross-correlation along the real axis are smaller than −1 and larger than −1 respectively (CCRe,min<−1