Patent Publication Number: US-11388529-B2

Title: Hearing assistance system with own voice detection

Description:
CLAIM OF PRIORITY 
     The present application is a Continuation of U.S. patent application Ser. No. 16/290,131, filed Mar. 1, 2019, now issued as U.S. Pat. No. 10,652,672, which is a Continuation of U.S. patent application Ser. No. 15/651,459, filed Jul. 17, 2017, now issued as U.S. Pat. No. 10,225,668, which is a Continuation of U.S. patent application Ser. No. 14/976,711, filed Dec. 21, 2015, now issued as U.S. Pat. No. 9,712,926, which is a Continuation of U.S. patent application Ser. No. 14/464,149, filed Aug. 20, 2014, now issued as U.S. Pat. No. 9,219,964, which is a Continuation-in-Part (CIP) of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 13/933,017, filed Jul. 1, 2013, now issued as U.S. Pat. No. 9,094,766, which application is a continuation of U.S. patent application Ser. No. 12/749,702, filed Mar. 30, 2010, now issued as U.S. Pat. No. 8,477,973, which application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/165,512, filed Apr. 1, 2009, all of which are hereby incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     This application relates to hearing assistance systems, and more particularly, to hearing assistance systems with own voice detection. 
     BACKGROUND 
     Hearing assistance devices are electronic devices that amplify sounds above the audibility threshold to is hearing impaired user. Undesired sounds such as noise, feedback and the user&#39;s own voice may also be amplified, which can result in decreased sound quality and benefit for the user. It is undesirable for the user to hear his or her own voice amplified. Further, if the user is using an ear mold with little or no venting, he or she will experience an occlusion effect where his or her own voice sounds hollow (“talking in a barrel”). Thirdly, if the hearing aid has a noise reduction/environment classification algorithm, the user&#39;s own voice can be wrongly detected as desired speech. 
     One proposal to detect voice adds a bone conductive microphone to the device. The bone conductive microphone can only be used to detect the user&#39;s own voice, has to make a good contact to the skull in order to pick up the own voice, and has a low signal-to-noise ratio. Another proposal to detect voice adds a directional microphone to the hearing aid, and orients the microphone toward the mouth of the user to detect the user&#39;s voice. However, the effectiveness of the directional microphone depends on the directivity of the microphone and the presence of other sound sources, particularly sound sources in the same direction as the mouth. Another proposal to detect voice provides a microphone in the ear-canal and only uses the microphone to record an occluded signal. Another proposal attempts to use a filter to distinguish the user&#39;s voice from other sound. However, the filter is unable to self correct to accommodate changes in the user&#39;s voice and for changes in the environment of the user. 
     SUMMARY 
     The present subject matter provides apparatus and methods to use a hearing assistance device to detect a voice of the wearer of the hearing assistance device. Embodiments use an adaptive filter to provide a self-correcting voice detector, capable of automatically adjusting to accommodate changes in the wearer&#39;s voice and environment. 
     Examples are provided, such as an apparatus configured to be worn by a wearer who has an ear and an ear canal. The apparatus includes a first microphone adapted to be worn about the ear of the person, a second microphone adapted to be worn about the ear canal of the person and at a different location than the first microphone, a sound processor adapted to process signals from the first microphone to produce a processed sound signal, and a voice detector to detect the voice of the wearer. The voice detector includes an adaptive filter to receive signals from the first microphone and the second microphone. 
     Another example of an apparatus includes a housing configured to be worn behind the ear or over the ear, a first microphone in the housing, and an ear piece configured to be positioned in the ear canal, wherein the ear piece includes a microphone that receives sound from the outside when positioned near the ear canal. Various voice detection systems employ an adaptive filter that receives signals from the first microphone and the second microphone and detects the voice of the wearer using a peak value for coefficients of the adaptive filter and an error signal from the adaptive filter. 
     The present subject matter also provides methods for detecting a voice of a wearer of a hearing assistance device where the hearing assistance device includes a first microphone and a second microphone. An example of the method is provided and includes using a first electrical signal representative of sound detected by the first microphone and a second electrical signal representative of sound detected by the second microphone as inputs to a system including an adaptive filter, and using the adaptive filter to detect the voice of the wearer of the hearing assistance device. 
     The present subject matter further provides apparatus and methods to use a pair of left and right hearing assistance devices to detect a voice of the wearer of the pair of left and right hearing assistance devices. Embodiments use outcome of detection of the voice of the wearer performed by the left hearing assistance device and the outcome of detection of the voice of the wearer performed the right hearing assistance device to determine whether to declare a detection of the voice of the wearer. 
     This Summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description. The scope of the present invention is defined by the appended claims and their legal equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  illustrate a hearing assistance device with a voice detector according to one embodiment of the present subject matter. 
         FIG. 2  demonstrates how sound can travel from the user&#39;s mouth to the first and second microphones illustrated in  FIG. 1A . 
         FIG. 3  illustrates a hearing assistance device according to one embodiment of the present subject matter. 
         FIG. 4  illustrates a voice detector according to one embodiment of the present subject matter. 
         FIGS. 5-7  illustrate various processes for detecting voice that can be used in various embodiments of the present subject matter. 
         FIG. 8  illustrates one embodiment of the present subject matter with an “own voice detector” to control active noise canceller for occlusion reduction. 
         FIG. 9  illustrates one embodiment of the present subject matter offering a multichannel expansion, compression and output control limiting algorithm (MECO). 
         FIG. 10  illustrates one embodiment of the present subject matter which uses an “own voice detector” in an environment classification scheme. 
         FIG. 11  illustrates a pair of hearing assistance devices according to one embodiment of the present subject matter. 
         FIG. 12  illustrates a process for detecting voice using the pair of hearing assistance devices. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope is defined only by the appended claims, along with the full scope of legal equivalents to which such claims are entitled. 
     Various embodiments disclosed herein provide a self-correcting voice detector, capable of reliably detecting the presence of the user&#39;s own voice through automatic adjustments that accommodate changes in the user&#39;s voice and environment. The detected voice can be used, among other things, to reduce the amplification of the user&#39;s voice, control an anti-occlusion process and control an environment classification process. 
     The present subject matter provides, among other things, an “own voice” detector using two microphones in a standard hearing assistance device. Examples of standard hearing aids include behind-the-ear (BTE), over-the-ear (OTE), and receiver-in-canal (MC) devices. It is understood that MC devices have a housing adapted to be worn behind the ear or over the ear. Sometimes the MC electronics housing is called a BTE housing or an OTE housing. According to various embodiments, one microphone is the microphone as usually present in the standard hearing assistance device, and the other microphone is mounted in an ear bud or ear mold near the user&#39;s ear canal. Hence, the microphone is directed to detection of acoustic signals outside and not inside the ear canal. The two microphones can be used to create a directional signal. 
       FIG. 1A  illustrates a hearing assistance device with a voice detector according to one embodiment of the present subject matter. The figure illustrates an ear with a hearing assistance device  100 , such as a hearing aid. The illustrated hearing assistance device includes a standard housing  101  (e.g. behind-the-ear (BTE) or on-the-ear (OTE) housing) with an optional ear hook  102  and an ear piece  103  configured to fit within the ear canal. A first microphone (MIC  1 ) is positioned in the standard housing  101 , and a second microphone (MIC  2 ) is positioned near the ear canal  104  on the air side of the ear piece.  FIG. 1B  schematically illustrates a cross section of the ear piece  103  positioned near the ear canal  104 , with the second microphone on the air side of the ear piece  103  to detect acoustic signals outside of the ear canal. 
     Other embodiments may be used in which the first microphone (M 1 ) is adapted to be worn about the ear of the person and the second microphone (M 2 ) is adapted to be worn about the ear canal of the person. The first and second microphones are at different locations to provide a time difference for sound from a user&#39;s voice to reach the microphones. As illustrated in  FIG. 2 , the sound vectors representing travel of the user&#39;s voice from the user&#39;s mouth to the microphones are different. The first microphone (MIC  1 ) is further away from the mouth than the second microphone (MIC  2 ). Sound received by MIC  2  will be relatively high amplitude and will be received slightly sooner than sound detected by MIC  1 . And when the wearer is speaking, the sound of the wearer&#39;s voice will dominate the sounds received by both MIC  1  and MIC  2 . The differences in received sound can be used to distinguish the own voice from other sound sources. 
       FIG. 3  illustrates a hearing assistance device according to one embodiment of the present subject matter. The illustrated device  305  includes the first microphone (MIC  1 ), the second microphone (MIC  2 ), and a receiver (speaker)  306 . It is understood that different types of microphones can be employed in various embodiments. In one embodiment, each microphone is an omnidirectional microphone. In one embodiment, each microphone is a directional microphone. In various embodiments, the microphones may be both directional and omnidirectional. Various order directional microphones can be employed. Various embodiments incorporate the receiver in a housing of the device (e.g. behind-the-ear or on-the-ear housing). A sound conduit can be used to direct sound from the receiver toward the ear canal. Various embodiments use a receiver configured to fit within the user&#39;s ear canal. These embodiments are referred to as receiver-in-canal (RIC) devices. 
     A digital sound processing system  308  processes the acoustic signals received by the first and second microphones, and provides a signal to the receiver  306  to produce an audible signal to the wearer of the device  305 . The illustrated digital sound processing system  308  includes an interface  307 , a sound processor  308 , and a voice detector  309 . The illustrated interface  307  converts the analog signals from the first and second microphones into digital signals for processing by the sound processor  308  and the voice detector  309 . For example, the interface may include analog-to-digital converters, and appropriate registers to hold the digital signals for processing by the sound processor and voice detector. The illustrated sound processor  308  processes a signal representative of a sound received by one or both of the first microphone and/or second microphone into a processed output signal  310 , which is provided to the receiver  306  to produce the audible signal. According to various embodiments, the sound processor  308  is capable of operating in a directional mode in which signals representative of sound received by the first microphone and sound received by the second microphone are processed to provide the output signal  310  to the receiver  306  with directionality. 
     The voice detector  309  receives signals representative of sound received by the first microphone and sound received by the second microphone. The voice detector  309  detects the user&#39;s own voice, and provides an indication  311  to the sound processor  308  regarding whether the user&#39;s own voice is detected. Once the user&#39;s own voice is detected any number of possible other actions can take place. For example, in various embodiments when the user&#39;s voice is detected, the sound processor  308  can perform one or more of the following, including but not limited to reduction of the amplification of the user&#39;s voice, control of an anti-occlusion process, and/or control of an environment classification process. Those skilled in the art will understand that other processes may take place without departing from the scope of the present subject matter. 
     In various embodiments, the voice detector  309  includes an adaptive filter. Examples of processes implemented by adaptive filters include Recursive Least Square error (RLS), Least Mean Squared error (LMS), and Normalized Least Mean Square error (NLMS) adaptive filter processes. The desired signal for the adaptive filter is taken from the first microphone (e.g., a standard behind-the-ear or over-the-ear microphone), and the input signal to the adaptive filter is taken from the second microphone. If the hearing aid wearer is talking, the adaptive filter models the relative transfer function between the microphones. Voice detection can be performed by comparing the power of the error signal to the power of the signal from the standard microphone and/or looking at the peak strength in the impulse response of the filter. The amplitude of the impulse response should be in a certain range in order to be valid for the own voice. If the user&#39;s own voice is present, the power of the error signal will be much less than the power of the signal from the standard microphone, and the impulse response has a strong peak with an amplitude above a threshold (e.g. above about 0.5 for normalized coefficients). In the presence of the user&#39;s own voice, the largest normalized coefficient of the filter is expected to be within the range of about 0.5 to about 0.9. Sound from other noise sources would result in a much smaller difference between the power of the error signal and the power of the signal from the standard microphone, and a small impulse response of the filter with no distinctive peak 
       FIG. 4  illustrates a voice detector according to one embodiment of the present subject matter. The illustrated voice detector  409  includes an adaptive filter  412 , a power analyzer  413  and a coefficient analyzer  414 . The output  411  of the voice detector  409  provides an indication to the sound processor indicative of whether the user&#39;s own voice is detected. The illustrated adaptive filter includes an adaptive filter process  415  and a summing junction  416 . The desired signal  417  for the filter is taken from a signal representative of sound from the first microphone, and the input signal  418  for the filter is taken from a signal representative of sound from the second microphone. The filter output signal  419  is subtracted from the desired signal  417  at the summing junction  416  to produce an error signal  420  which is fed back to the adaptive filter process  415 . 
     The illustrated power analyzer  413  compares the power of the error signal  420  to the power of the signal representative of sound received from the first microphone. According to various embodiments, a voice will not be detected unless the power of the signal representative of sound received from the first microphone is much greater than the power of the error signal. For example, the power analyzer  413  compares the difference to a threshold, and will not detect voice if the difference is less than the threshold. 
     The illustrated coefficient analyzer  414  analyzes the filter coefficients from the adaptive filter process  415 . According to various embodiments, a voice will not be detected unless a peak value for the coefficients is significantly high. For example, some embodiments will not detect voice unless the largest normalized coefficient is greater than a predetermined value (e.g. 0.5). 
       FIGS. 5-7  illustrate various processes for detecting voice that can be used in various embodiments of the present subject matter. In  FIG. 5 , as illustrated at  521 , the power of the error signal from the adaptive filter is compared to the power of a signal representative of sound received by the first microphone. At  522 , it is determined whether the power of the first microphone is greater than the power of the error signal by a predetermined threshold. The threshold is selected to be sufficiently high to ensure that the power of the first microphone is much greater than the power of the error signal. In some embodiments, voice is detected at  523  if the power of the first microphone is greater than the power of the error signal by a predetermined threshold, and voice is not detected at  524  if the power of the first microphone is greater than the power of the error signal by a predetermined threshold. 
     In  FIG. 6 , as illustrated at  625 , coefficients of the adaptive filter are analyzed. At  626 , it is determined whether the largest normalized coefficient is greater than a predetermined value, such as greater than 0.5. In some embodiments, voice is detected at  623  if the largest normalized coefficient is greater than a predetermined value, and voice is not detected at  624  if the largest normalized coefficient is not greater than a predetermined value. 
     In  FIG. 7 , as illustrated at  721 , the power of the error signal from the adaptive filter is compared to the power of a signal representative of sound received by the first microphone. At  722 , it is determined whether the power of the first microphone is greater than the power of the error signal by a predetermined threshold. In some embodiments, voice is not detected at  724  if the power of the first microphone is not greater than the power of the error signal by a predetermined threshold. If the power of the error signal is too large, then the adaptive filter has not converged. In the illustrated method, the coefficients are not analyzed until the adaptive filter converges. As illustrated at  725 , coefficients of the adaptive filter are analyzed if the power of the first microphone is greater than the power of the error signal by a predetermined threshold. At  726 , it is determined whether the largest normalized coefficient is greater than a predetermined value, such as greater than 0.5. In some embodiments, voice is not detected at  724  if the largest normalized coefficient is not greater than a predetermined value. Voice is detected at  723  if the power of the first microphone is greater than the power of the error signal by a predetermined threshold and if the largest normalized coefficient is greater than a predetermined value. 
       FIG. 8  illustrates one embodiment of the present subject matter with an “own voice detector” to control active noise canceller for occlusion reduction. The active noise canceller filters microphone M 2  with filter h and sends the filtered signal to the receiver. The microphone M 2  and the error microphone M 3  (in the ear canal) are used to calculate the filter update for filter h. The own voice detector, which uses microphone M 1  and M 2 , is used to steer the stepsize in the filter update. 
       FIG. 9  illustrates one embodiment of the present subject matter offering a multichannel expansion, compression and output control limiting algorithm (MECO) which uses the signal of microphone M 2  to calculate the desired gain and subsequently applies that gain to microphone signal M 2  and then sends the amplified signal to the receiver. Additionally, the gain calculation can take into account the outcome of the own voice detector (which uses M 1  and M 2 ) to calculate the desired gain. If the wearer&#39;s own voice is detected, the gain in the lower channels (typically below 1 KHz) will be lowered to avoid occlusion. Note: the MECO algorithm can use microphone signal M 1  or M 2  or a combination of both. 
       FIG. 10  illustrates one embodiment of the present subject matter which uses an “own voice detector” in an environment classification scheme. From the microphone signal M 2 , several features are calculated. These features together with the result of the own voice detector, which uses M 1  and M 2 , are used in a classifier to determine the acoustic environment. This acoustic environment classification is used to set the gain in the hearing aid. In various embodiments, the hearing aid may use M 2  or M 1  or M 1  and M 2  for the feature calculation. 
       FIG. 11  illustrates a pair of hearing assistance devices according to one embodiment of the present subject matter. The pair of hearing assistance devices includes a left hearing assistance device  1105 L and a right hearing assistance device  1105 R, such as a left hearing aid and a right hearing aid. The left hearing assistance device  1105 L is configured to be worn in or about the left ear of a wearer for delivering sound to the left ear canal of the wearer. The right hearing assistance device  1105 R is configured to be worn in or about the right ear of the wearer for delivering sound to the right ear canal of the wearer. In one embodiment, the left and right hearing assistance devices  1105 L and  1105 R each represent an embodiment of the device  305  as discussed above with capability of performing wireless communication between each other and uses voice detection capability of both devices to determine whether voice of the wearer is present. 
     The illustrated left hearing assistance device  1105 L includes a first microphone MIC  1 L, a second microphone MIC  2 L, an interface  1107 L, a sound processor  1108 L, a receiver  1106 L, a voice detector  1109 L, and a communication circuit  1130 L. The first microphone MIC  1 L produces a first left microphone signal. The second microphone MIC  2 L produces a second left microphone signal. In one embodiment, when the left and right hearing assistance devices  1105 L and  1105 R are worn by the wearer, the first microphone MIC  1 L is positioned about the left ear or the wearer, and the second microphone MIC  2 L is positioned about the left ear canal of wearer, at a different location than the first microphone MIC  1 L, on an air side of the left ear canal to detect signals outside the left ear canal. Interface  1107 L converts the analog versions of the first and second left microphone signals into digital signals for processing by the sound processor  1108 L and the voice detector  1109 L. For example, the interface  1107 L may include analog-to-digital converters, and appropriate registers to hold the digital signals for processing by the sound processor  1108 L and the voice detector  1109 L. The sound processor  1108 L produces a processed left sound signal  1110 L. The left receiver  1106 L produces a left audible signal based on the processed left sound signal  1110 L and transmits the left audible signal to the left ear canal of the wearer. In one embodiment, the sound processor  1108 L produces the processed left sound signal  1110 L based on the first left microphone signal. In another embodiment, the sound processor  1108 L produces the processed left sound signal  1110 L based on the first left microphone signal and the second left microphone signal. 
     The left voice detector  1109 L detects a voice of the wearer using the first left microphone signal and the second left microphone signal. In one embodiment, in response to the voice of the wearer being detected based on the first left microphone signal and the second left microphone signal, the left voice detector  1109 L produces a left detection signal indicative of detection of the voice of the wearer. In one embodiment, the left voice detector  1109 L includes a left adaptive filter configured to output left information and identifies the voice of the wearer from the output left information. In various embodiments, the output left information includes coefficients of the left adaptive filter and/or a left error signal. In various embodiments, the left voice detector  1109 L includes the voice detector  309  or the voice detector  409  as discussed above. The left communication circuit  1130 L receives information from, and transmits information to, the right hearing assistance device  1105 R via a wireless communication link  1132 . In the illustrated embodiment, the information transmitted via wireless communication link  1132  includes information associated with the detection of the voice of the wearer as performed by each of the left and right hearing assistance devices  1105 L and  1105 R. 
     The illustrated right hearing assistance device  1105 R includes a first microphone MIC  1 R, a second microphone MIC  2 R, an interface  1107 R, a sound processor  1108 R, a receiver  1106 R, a voice detector  1109 R, and a communication circuit  1130 R. The first microphone MIC  1 R produces a first right microphone signal. The second microphone MIC  2 R produces a second right microphone signal. In one embodiment, when the left and right hearing assistance devices  1105 R and  1105 R are worn by the wearer, the first microphone MIC  1 R is positioned about the right ear or the wearer, and the second microphone MIC  2 R is positioned about the right ear canal of wearer, at a different location than the first microphone MIC  1 R, on an air side of the right ear canal to detect signals outside the right ear canal. Interface  1107 R converts the analog versions of the first and second right microphone signals into digital signals for processing by the sound processor  1108 R and the voice detector  1109 R. For example, the interface  1107 R may include analog-to-digital converters, and appropriate registers to hold the digital signals for processing by the sound processor  1108 R and the voice detector  1109 R. The sound processor  1108 R produces a processed right sound signal  1110 R. The right receiver  1106 R produces a right audible signal based on the processed right sound signal  1110 R and transmits the right audible signal to the right ear canal of the wearer. In one embodiment, the sound processor  1108 R produces the processed right sound signal  1110 R based on the first right microphone signal. In another embodiment, the sound processor  1108 R produces the processed right sound signal  1110 R based on the first right microphone signal and the second right microphone signal. 
     The right voice detector  1109 R detects the voice of the wearer using the first right microphone signal and the second right microphone signal. In one embodiment, in response to the voice of the wearer being detected based on the first right microphone signal and the second right microphone signal, the right voice detector  1109 R produces a right detection signal indicative of detection of the voice of the wearer. In one embodiment, the right voice detector  1109 R includes a right adaptive filter configured to output right information and identifies the voice of the wearer from the output right information. In various embodiments, the output right information includes coefficients of the right adaptive filter and/or a right error signal. In various embodiments, the right voice detector  1109 R includes the voice detector  309  or the voice detector  409  as discussed above. The right communication circuit  1130 R receives information from, and transmits information to, the right hearing assistance device  1105 R via a wireless communication link  1132 . 
     In various embodiments, at least one of the left voice detector  1109 L and the right voice detector  1109 R is configured to detect the voice of wearer using the first left microphone signal, the second left microphone signal, the first right microphone signal, and the second right microphone signal. In other words, signals produced by all of the microphones MIC  1 L, MIC  2 L, MIC  1 R, and MIC  2 R are used for determining whether the voice of the wearer is present. In one embodiment, the left voice detector  1109 L and/or the right voice detector  1109 R declares a detection of the voice of the wearer in response to at least one of the left detection signal and the second detection signal being present. In another embodiment, the left voice detector  1109 L and/or the right voice detector  1109 R declares a detection of the voice of the wearer in response to the left detection signal and the second detection signal both being present. In one embodiment, the left voice detector  1109 L and/or the right voice detector  1109 R determines whether to declare a detection of the voice of the wearer using the output left information and output right information. The output left information and output right information are each indicative of one or more detection strength parameters each being a measure of likeliness of actual existence of the voice of wearer. Examples of the one or more detection strength parameters include the difference between the power of the error signal and the power of the first microphone signal and the largest normalized coefficient of the adaptive filter. In one embodiment, the left voice detector  1109 L and/or the right voice detector  1109 R determines whether to declare a detection of the voice of the wearer using a weighted combination of the output left information and the output eight information. For example, the weighted combination of the output left information and the output right information can include a weighted sum of the detection strength parameters. The one or more detection strength parameters produced by each of the left and right voice detectors can be multiplied by one or more corresponding weighting factors before being added to produce the weighted sum. In various embodiments, the weighting factors may be determined using a priori information such as estimates of the background noise and/or position(s) of other sound sources in a room. 
     In various embodiments when a pair of left and right hearing assistance device is worn by the wearer, the detection of the voice of the wearer is performed using both the left and the right voice detectors such as detectors  1109 L and  1109 R. In various embodiments, whether to declare a detection of the voice of the wearer may be determined by each of the left voice detector  1109 L and the right voice detector  1109 R, determined by the left voice detector  1109 L and communicated to the right voice detector  1109 R via wireless link  1132 , or determined by the right voice detector  1109 R and communicated to the left voice detector  1109 L via wireless link  1132 . Upon declaration of the detection of the voice of the wearer, the left voice detector  1109 L transmits an indication  1111 L to the sound processor  1108 L, and the right voice detector  1109 R transmits an indication  1111 R to the sound processor  1108 R. The sound processors  1108 L and  1108 R produce the processed sound signals  1110 L and  1110 R, respectively, using the indication that the voice of the wearer is detected. 
       FIG. 12  illustrates a process for detecting voice using a pair of hearing assistance devices including a left hearing assistance device and a right hearing assistance device, such as the left and right hearing assistance devices  1105 L and  1105 R. At  1241 , voice of a wearer is detected using the left hearing assistance device. At  1242 , voice of a wearer is detected using the right hearing assistance device. In various embodiments, steps  1241  and  1242  are performed concurrently or simultaneously. Examples for each of steps  1241  and  1242  include the processes illustrated in each of  FIGS. 5-7 . At  1243 , whether to declare a detection of the voice of the wearer is determining using an outcome of both of the detections at  1241  and  1242 . 
     In one embodiment, the left and right hearing assistance devices each include first and second microphones. Electrical signals produced by the first and second microphones of the left hearing assistance device are used as inputs to a voice detector of the left hearing assistance device at  1241 . The voice detector of the left hearing assistance device includes a left adaptive filter. Electrical signals produced by the first and second microphones of the right hearing assistance device are used as inputs to a voice detector of the right hearing assistance device at  1242 . The voice detector of the right hearing assistance device includes a right adaptive filter. The voice of the wearer is detected using information output from the left adaptive filter and information output from the right adaptive filter at  1243 . In one embodiment, the voice of the wearer is detected using left coefficients of the left adaptive filter and right coefficients of the right adaptive filter. In one embodiment, the voice of the wearer is detected using a left error signal produced by the left adaptive filter and a right error signal produced by the right adaptive filter. In one embodiment, the voice of the wearer is detected using a left detection strength parameter of the information output from the left adaptive filter and a right detection strength parameter of the information output from the right adaptive filter. The left and right detection strength parameters are each a measure of likeliness of actual existence of the voice of wearer. Examples of the left detection strength parameter include the difference between the power of a left error signal produced by the left adaptive filter and the power of the electrical signal produced by the first microphone of the left hearing assistance device and the largest normalized coefficient of the left adaptive filter. Examples of the right detection strength parameter include the difference between the power of a right error signal produced by the right adaptive filter and the power of the electrical signal produced by the first microphone of the right hearing assistance device and the largest normalized coefficient of the right adaptive filter. In one embodiment, the voice of the wearer is detected using a weighted combination of the information output from the left adaptive filter and the information output from the right adaptive filter. 
     In one embodiment, the voice of the wearer is detected using the left hearing assistance device based on the electrical signals produced by the first and second microphones of the left hearing assistance device, and a left detection signal indicative of whether the voice of the wearer is detected by the left hearing assistance device is produced, at  1241 . The voice of the wearer is detected using the right hearing assistance device based on the electrical signals produced by the first and second microphones of the right hearing assistance device, and a right detection signal indicative of whether the voice of the wearer is detected by the right hearing assistance device is produced, at  1242 . Whether to declare the detection of the voice of the wearer is determined using the left detection signal and the right detection signal at  1243 . In one embodiment, the detection of the voice of the wearer is declared in response to both of the left detection signal and the right detection signal being present. In another embodiment, the detection of the voice of the wearer is declared in response to at least one of the left detection signal and the right detection signal being present. In one embodiment, whether to declare the detection of the voice of the wearer is determined using the left detection signal, the right detection signal, and weighting factors applied to the left and right detection signals. 
     The various embodiments of the present subject matter discussed with reference to  FIGS. 1-10  can be applied to each device of a pair of hearing assistance devices, with the declaration of the detection of the voice of the wearer being a result of detection using both devices of the pair of hearing assistance devices, as discussed with reference to  FIGS. 11 and 12 . Such binaural voice detection will likely improve the acoustic perception of the wearer because both hearing assistance devices worn by the wearer are acting similarly when the wearer speaks. In various embodiments in which a pair of hearing assistance devices is worn by the wearer, whether to declare a detection of the voice of the wearer may be determined based on the detection performed by either one device of the pair of hearing assistance devices or based on the detection performed by both devices of the pair of hearing assistance devices. An example of the pair of hearing assistance devices includes a pair of hearing aids. 
     The present subject matter includes hearing assistance devices, and was demonstrated with respect to BTE, OTE, and RIC type devices, but it is understood that it may also be employed in cochlear implant type hearing devices. It is understood that other hearing assistance devices not expressly stated herein may fall within the scope of the present subject matter. 
     This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. The scope of the present subject matter should be determined with reference to the appended claims, along with the full scope of legal equivalents to which such claims are entitled.