Headphone Audio Controller

Abstract

A method and related computer program product and system for determining an audio controller for headphones configured to use an acoustic transducer to generate sound delivered to a user's ear and including a feedback microphone configured to sense the sound generated by the acoustic transducer. A first audio transfer function between the acoustic transducer and the feedback microphone is measured. With the feedback controller applied, a second audio transfer function between the acoustic transducer and the feedback microphone is determined. The audio controller is calculated based on both the first audio transfer function and the second audio transfer function.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims priority to U.S. Patent Application No. 17 / 562,142, filed December 27, 2021.

[0002] The present invention relates to a headphone audio controller.

Background Art

[0003] This disclosure relates to the control of audio headphones.

[0004] Headphones can be controlled, particularly for the purpose of providing an equalized sound. Headphones with active noise reduction (ANR) may include a transparency or awareness mode in which external sound is sensed by an external microphone and reproduced to the user. Such headphones can also be controlled to provide a desired transparency sound profile.

Summary of the Invention

Means for Solving the Problems

[0005] Aspects and examples are directed to determining an audio controller for one or both of a headphone equalization (EQ) mode and a headphone awareness mode. The controller is calculated in - use (on - the - fly) based at least in part on an audio transfer function measured between an acoustic transducer of the headphones and a microphone that senses the transducer output (e.g., a feedback microphone in ANR headphones), and further based on the same transfer function, but determined with a feedback controller turned on. As a result, the EQ and awareness mode controllers are customized for a particular user, and no action needs to be taken by the user or another user. This provides a more consistent listening experience across a large population of users.

[0006] All of the examples and features mentioned below can be combined in any technically possible way.

[0007] In one aspect, a method for determining an audio controller for headphones configured to use an acoustic transducer to generate sound delivered to a user's ear and comprising a feedback microphone configured to sense the sound generated by the acoustic transducer includes measuring a first audio transfer function between the acoustic transducer and the feedback microphone, determining a second audio transfer function between the acoustic transducer and the feedback microphone with a feedback controller applied, and calculating the audio controller based on both the first audio transfer function and the second audio transfer function.

[0008] Some examples include one of the features above and / or below, or any combination thereof. In one example, measuring the first audio transfer function includes providing an audio signal configured to operate the acoustic transducer to generate sound, sensing the sound using the feedback microphone, and calculating the first audio transfer function based on the audio signal and the sensed sound. In some examples, determining the second audio transfer function includes measuring the audio transfer function between the acoustic transducer and the feedback microphone with the feedback controller applied. In one example, measuring the audio transfer function between the acoustic transducer and the feedback microphone with the feedback controller applied includes providing an audio signal configured to operate the acoustic transducer to generate sound, sensing the sound using the feedback microphone, and calculating the second audio transfer function based on the audio signal, the sensed sound, and the feedback controller.

[0009] Some examples include one or more of the above and / or below features, or any combination thereof. In some examples, determining the second audio transfer function includes calculating the second audio transfer function based on both the first audio transfer function and the feedback controller. In one example, the audio controller includes an equalization (EQ) controller. In one example, the audio controller includes a controller for a headphone usage recognition mode in which external sound of the headphone is reproduced by the acoustic transducer.

[0010] Some examples include one or more of the above and / or below features, or any combination thereof. In some examples, the method further includes providing a power spectrum measured for a microphone disposed within a person's ear canal and providing a power spectrum measured for a microphone disposed on a person's head. In some examples, the power spectra are measured for a plurality of different people. Next, an edit or sort of the average of the values from this dataset can be used with the headphones. In one example, the calculation of the audio controller is further based on both the measured power spectrum for a microphone disposed within a person's ear canal and the measured power spectrum for a microphone disposed on a person's head. In one example, the calculation of the audio controller is further based on a third audio transfer function between the acoustic transducer and a microphone disposed within a person's ear canal.

[0011] Some examples include one or more of the above and / or the following features, or any combination thereof. In some examples, the method further includes providing a third audio transfer function between a first position of a feedback microphone within a person's ear canal and a second position on the person's head. In one example, the method further includes providing a fourth audio transfer function between an acoustic transducer and the first position of the feedback microphone within the person's ear canal. In one example, the second, third, and fourth audio transfer functions are each calculated by providing an audio signal to the acoustic transducer, sensing the converted sound with the microphone, and calculating the transfer function based on the audio signal and the sensed sound. In some examples, the audio transfer function is measured in real time for a user. As further described below, in some examples, data derived from measurements made on a plurality of people in a controlled environment is used with the measured transfer function to calculate one or both of a recognition mode and an EQ audio controller.

[0012] Some examples include one or more of the above and / or the following features, or any combination thereof. In one example, the method further includes providing first and second constant values. In one example, the first and second constant values are calculated based on both the third and fourth audio transfer functions. In one example, the first and second constant values are calculated based on both the third and fourth audio transfer functions for a plurality of different fittings of headphones to a plurality of different people. In one example, the first and second constant values represent frequency-dependent complex quantities.

[0013] In another aspect, a computer program product having a non-transitory computer-readable medium including encoded computer program logic, which is configured to use an acoustic transducer to generate sound delivered to a user's ear and includes a feedback microphone configured to sense sound generated by the acoustic transducer, when executed on headphones, the computer program logic causes the headphones to measure a first audio transfer function between the acoustic transducer and the feedback microphone, determine a second audio transfer function between the acoustic transducer and the feedback microphone with a feedback controller applied, and calculate an audio controller based on both the first audio transfer function and the second audio transfer function.

[0014] Some examples include one or more of the above and / or the following features, or any combination thereof. In one example, the audio controller includes at least one of an equalization (EQ) controller and a controller for a headphone recognition usage mode in which external sound of the headphones is reproduced by the acoustic transducer. In one example, the first audio transfer function is measured by providing an audio signal configured to operate the acoustic transducer to generate sound, sensing the sound with the feedback microphone, and calculating the first audio transfer function based on the audio signal and the sensed sound. Further, the second audio transfer function is calculated based on both the first audio transfer function and the feedback controller. In one example, the computer program product further includes providing a power spectrum measured for a microphone disposed in a human ear canal and providing a power spectrum measured for a microphone disposed on a human head, and the calculation of the audio controller is further based on the power spectrum measured for the microphone disposed in the human ear canal, the power spectrum measured for the microphone disposed on the human head, and a third audio transfer function between the acoustic transducer and the microphone disposed in the human ear canal.

[0015] Various aspects of at least one example will be considered below with reference to the accompanying drawings, which are not intended to be drawn to scale. These drawings are included to provide illustration of various aspects and examples and further understanding, and are incorporated herein and constitute a part of this specification, but are not intended as a definition of the limitations of the present invention. In the figures, the same or almost the same components illustrated in the various figures may be denoted by like letters or numbers. For clarity, in all the figures, not all components may necessarily be labeled. In the figures, it is as follows.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0017] Examples of systems, methods, and apparatus described herein are not limited to the details of construction and arrangement of components set forth in the following description or illustrated in the accompanying drawings. The systems, methods, and apparatus are implementable in other examples and are executable in various ways. Specific examples are provided herein for illustrative purposes only and are not intended to be limiting. Specifically, the functions, components, elements, and features contemplated in connection with any one or more examples are not intended to be excluded from similar roles in any other example.

[0018] Examples disclosed herein can be combined with other examples in any manner consistent with at least one of the principles disclosed herein. Further, references to "an example", "some examples", "an alternate example", "various examples", "one example", etc. are not necessarily mutually exclusive, and are intended to indicate that a particular feature, structure, or characteristic described may be included in at least one example. The appearance of such terms in this specification is not necessarily indicative of all being the same example.

[0019] Also, the expressions and terms used in this specification are for illustrative purposes only and should not be regarded as limiting. Any reference in this specification to an embodiment, component, element, act, or function of a computer program product, system, and method in the singular may also include embodiments that include a plurality, and any reference in the plural to any embodiment, component, element, act, or function in this specification may also include embodiments that include only the singular. Thus, a reference to the singular or plural is not intended to limit the system or method of the present disclosure, their components, acts, or elements. The use of "including", "comprising", "having", "containing", "involving", and variations thereof in this specification means including the items listed below and their equivalents, as well as other items. A reference to "or" can be construed as inclusive such that all terms described by "or" can indicate any of the singular, plural, and all of the terms described.

[0020] This disclosure is directed, in part, to determining an audio controller for headphones such as on-ear, over-ear, or in-ear headphones. The audio controller can be one or both of a headphone equalization (EQ) and a headphone recognition mode controller. The controller is calculated during use of the headphones using existing headphone components and processing. The calculation is based at least in part on an audio transfer function measured between an acoustic transducer of the headphones and a microphone that senses the transducer output (e.g., a feedback microphone in ANR headphones, which is typically located between the transducer and the user's eardrum). The calculation is further based on this same transfer function but with the feedback controller turned on. This determination can be calculated based on the measured transfer function. The result of this real-time controller calculation is that the EQ and recognition mode controllers are customized for a particular user based on a single measured audio transfer function during use of the headphones. This provides a more consistent listening experience across a large population of users of the subject headphones.

[0021] In one example, a first audio transfer function is determined by operating an acoustic transducer of the headphones and sensing sound with a feedback microphone. The first audio transfer function is calculated based on the audio signal provided to the transducer and on the sensed sound. A second audio transfer function is determined by measuring the audio transfer function between the acoustic transducer and the feedback microphone, but now with the headphone feedback controller applied. In one example, the second transfer function is calculated based on the audio signal, the sensed sound, and the feedback controller. In one example, the second audio transfer function is determined by calculating based on both the first audio transfer function and the feedback controller.

[0022] In a more specific example, the calculations of the audio controller are based on data obtained during the design of the controller calculation method. Such data can be measured over multiple different people and multiple fittings of headphone use on both ears of each person in a laboratory or another controlled environment. By measuring different people, data regarding many different ear shapes is provided. In one example, this data includes the measured power spectrum of a microphone placed in the ear canal (close to the eardrum) and a separate measured power spectrum of a microphone placed on a person's head at a position where it does not interfere with the headphones. The dataset can be created by placing a microphone in a human subject's ear and placing a microphone on the subject's head. The measurements are made with and without using headphones.

[0023] In one example, there are three measurements conducted in a laboratory and two sound sources for the measurements. In one measurement, the transfer function from the driver in the headphones to the feedback microphone and the canal microphone is measured while wearing the headset using the driver in the headphones. The other two measurements are conducted by playing sound from a speaker in the measurement room. This is done both with and without wearing the headset. For EQ, only the driver measurement and the open room noise measurement are used. In the recognition mode, all three are used because the response of the external (feedforward) microphone when the headset is worn is required.

[0024] In one example, the inspection data is represented by two constant values. These constant values can be derived as further explained below.

[0025] The present disclosure relates to a headphone audio device. Some non-limiting examples of the present disclosure describe headphones of the type known as earphones. Earphones generally include an electroacoustic transducer for generating sound and are configured to deliver the sound directly to the user's external ear canal. Earphones can be wireless or wired. In the non-limiting examples described herein, the earphones include one or more feedback microphones that sense the sound generated by the transducer. The examples also include a feedforward (external) microphone that senses external sound outside the housing. The feedback and feedforward microphones can be used for functions such as active noise reduction (ANR) where external sound is canceled so that it cannot be heard, and a transparency mode operation where external sound is reproduced for the user. Other types of aspects of earphones and headphones not included in the present disclosure are not illustrated or described.

[0026] Headphones generally refer to devices that are worn around the ear, over the ear, or in the ear and radiate acoustic energy directly or indirectly into the ear canal. Headphones are sometimes referred to as earphones, earpieces, headsets, in-ear headphones, or sports headphones, and can be wired or wireless. Headphones include a driver (acoustic transducer) that converts an electronic audio signal into acoustic energy. The driver may or may not be housed in an earcup or housing configured to be located on the head or over the ear, or to be inserted directly into the user's ear canal. Headphones may be one for each ear, a single standalone unit, or one of a pair of headphones (each including at least one acoustic driver). One headphone can be mechanically connected to the other headphone, for example, by a headband and / or by a lead wire that transmits an audio signal to the acoustic driver within the headphone. Headphones may include components for receiving an audio signal wirelessly. Headphones can include components of an ANR system, which can include an internal microphone within the headphone housing and an external microphone that picks up sounds outside the housing. Headphones can also include other functions, such as additional microphones for the ANR system or one or more microphones used to pick up the user's voice.

[0027] One or more of the systems and methods described herein can be used in various embodiments and combinations in a wide variety of headphones of various form factors. One such form factor is in-ear headphones. Another is on-ear or over-ear headphones.

[0028] Specific implementations of headphones that primarily serve the purpose of acoustically outputting audio are presented in some detail, but it should be noted that the presentation of such specific implementations is intended to facilitate understanding through the provision of examples and should not be construed as limiting either the scope of the disclosure or the scope of the claims.

[0029] In some embodiments, the headphones include an electroacoustic transducer configured to generate sound for a user, a housing that holds the transducer, and a feedback microphone configured to detect sound within the housing before the sound reaches the eardrum. The processor system of the headphones is programmed to achieve a method for determining audio controllers such as an equalization (EQ) controller and a recognition mode controller.

[0030] FIG. 1 is a perspective view of a wireless in-ear earphone 10. The earphone is a non-limiting example of a headphone device. Earphone 10 includes a body or housing 12 that houses the active components of the earphone. Housing 12 houses an electroacoustic transducer (audio driver) 14 that generates sound via a movable diaphragm 16. Housing 12 includes a front housing portion 22 and a rear housing portion 23. Diaphragm 16 is driven to create sound pressure within front housing cavity 18. Sound is also generated within rear housing cavity 20. The sound pressure exits front housing portion 22 and is directed out of cavity 18 through sound outlet 24. An internal microphone 32 is located inside housing 12. An exemplary microphone 32 is within housing portion 12 as shown in FIG. 1. An external microphone 34 is configured to sense sound outside of housing 12. An exemplary external microphone 34 is disposed inside the housing and is acoustically coupled to the external environment through a housing opening 36 that allows ambient sound to reach microphone 34. An exemplary internal microphone 32 is used as a feedback microphone for active noise reduction (ANR), and external microphone 34 is used as a feedforward microphone for ANR and / or for transparent mode operation, in which ambient sound is sensed and reproduced to the user so that the user can hear other people speaking and be more aware of the external environment. The earphone also typically includes a flexible tip (not shown) that engages with neck 25 of housing portion 22 to help direct sound into the ear canal. Note that the details of earphone 10 and its operation are well known in the art and will not be described further herein. Also note that the details of earphone 10 are an exemplary aspect of a headphone and do not limit the scope of the present disclosure, because the present audio controller can be used in various types and designs of small earphones and earbuds, as well as other headphones.

[0031] The earphone 10 also includes a processor 30. In some examples, the processor 30 is configured to process the outputs of microphones 32 and 34. As will be apparent to those skilled in the art, in some examples, the processor is used to perform other processes necessary for earphone functions, such as processing digital sound files played back by the earphone. In one example, the processor is configured to calculate and then apply the audio controllers disclosed herein. The use of EQ and recognition mode audio controllers is known in the art.

[0032] In some examples, the processor is programmed to calculate an EQ controller and / or a recognition mode controller based on the audio transfer function between the transducer 14 and the feedback microphone 32. The transfer function is determined both when the ANR feedback controller is applied and when it is not applied.

[0033] FIG. 2 is a block diagram of an embodiment of a headphone device 60. In one example, the device 60 is an earphone, but this is not a limitation of the present disclosure as the present disclosure applies to other types of headphones as described herein. The device 60 includes a processor 66 that receives audio data from an external source via a wireless transceiver 68. The processor 66 also receives the outputs of feedback microphone(s) 70 and feedforward microphone(s) 72. The processor 66 outputs audio data that is converted into an analog signal supplied to an audio driver 64. An exemplary device 60 includes memory that, when executed by a processor, comprises instructions to accomplish the calculations and application of an audio controller and other processes described herein. In some examples, the device 60 is configured to store a computer program product using a non-transitory computer-readable medium, the medium including computer program logic encoded thereon that, when executed (e.g., by a processor) on the headphone device, causes the headphone device to determine an audio controller as described herein. Note that the details of the wearable audio device 60 are an exemplary aspect of headphones and are not intended to limit the scope of the present disclosure, because the present audio controller techniques can be used in various types and designs of earphones and headphones. Also note that aspects of the headphone device 60 that are not involved in the present audio controller techniques are not shown in FIG. 2 for simplicity.

[0034] Headphones are typically designed with a control scheme aimed at providing a pre-set manufacturer-designed audio response both when music is being played and during the use of recognition or transparency modes. An equalization audio controller is designed, at least ideally, to help achieve a desired target curve equalization (EQ) such that the reproduced sound has a desired spectral response. A transparency mode controller is used to help achieve the desired transparent sound reproduction. The controller is typically designed to accurately reproduce the perceived external sound. In some examples, one or both of these audio controllers are stored in the device memory and applied by the device controller. Their use in audio controllers and headphones is well known in the field of audio engineering.

[0035] However, when headphones are actually used, the user's anatomical structure (such as the anatomy of the ear) and the way the headphones are worn introduce a high degree of variability in the sound actually delivered to the person. Thus, few, if any, people actually receive the target sound profile intended by the designed and installed EQ and recognition (transparency) mode audio controllers.

[0036] In this audio control system and method, one or both of an EQ audio controller and a transparency audio controller are calculated and applied in real time during the use of the headphones. As a result, the user experience becomes closer to what is intended by the headphone manufacturer, even considering user-to-user variations. In some examples, the calculation of the audio controller is based on an audio transfer function measured while the headphones are being used by the user. This transfer function is between a headphone acoustic transducer or driver and one or more headphone microphones that receive the driver output. In ANR headphones, this microphone can be a feedback microphone disposed between the driver and the user's eardrum. In one example, in earphones, this feedback microphone is typically located within a nozzle through which sound is directly delivered into the ear canal. The audio transfer functions and their calculations are well known in the audio art and will not be described in detail. Also, the application of the audio controller by the headphone processor is commonly used in headphones and will not be described in detail.

[0037] Figure 3 is a schematic diagram of a user's head 80 useful for understanding headphone audio controllers. The right headphone 86 is disposed over, above, or in the middle of the right ear 82 having an ear canal 83. The left headphone 88 is disposed over, above, or in the middle of the left ear 84 having an ear canal 85. Also, a microphone 90 is shown disposed on the user's head 80 in a position that does not interfere with the headphones. The placement of the headphones and the microphone(s) is useful for aspects of the audio controller, as will be further described below.

[0038] In the example shown in FIG. 4, a method 100 for determining an audio controller for a headset device is achieved using an existing headset control and sound delivery system such as the processor 66, feedback (or other) microphone 70, and driver 64 of FIG. 2. At step 102, an audio transfer function between the acoustic transducer 64 and the microphone 70 is measured. As is known in the art, audio transfer function measurements in some examples are based on a known audio signal used to drive the transducer, reception of the resulting sound by the microphone, and calculation of the transfer function between the driver and the microphone. In method 100, at step 104, a second audio transfer function is determined, and this time, a feedback controller for an existing headset ANR system is applied. At least one measurement is required, and other measurements can be calculated using knowledge of the feedback controller. The feedback controller is used in headsets with ANR and is well-known in the art, so it will not be described further herein. At step 106, the relevant audio controller(s) (one or both of the EQ controller and the transparency mode controller) are calculated based on both the first and second transfer functions.

[0039] In an exemplary recognition mode controller Kaw, assuming a negligible direct sound path due to passive insertion gain and effective ANR, and when the power spectrum Scc of a microphone placed in the ear canal is equal to the power spectrum Scc,open (where "open" means the headset is not worn during measurement), the recognition mode controller (referred to as the "semicustom" or "sc" controller) can be represented by the following equation (1).

[0040]

Equation

[0041] The transfer function subscript annotation standard is from the second subscript to the first subscript. Thus, Gsd is the transfer function from the driver to the feedback microphone. Regarding the power spectrum, they generally refer to the measured values when the headset is worn, unless the subscript includes "open" which means the measured value when the headset is not worn. Srr is the measured value of the reference microphone when the headset is worn. Regarding the controller, Kaw is the recognition mode controller and Keq is the audio controller. In some cases, the absolute value of the controller is defined. This is because their phases generally do not matter as long as no unwanted phase is added. In other words, they should be minimum phase. This is well-known in the case of music. However, for the recognition mode controller, this fact depends on the total noise reduction (passive + feedback + feedforward) being sufficient such that the direct noise reaching the ear is very low and what is heard in the ear when the recognition mode controller is turned on is completely dominated by the signal from Kaw. This is generally the case for many ANR headsets.

[0042] An exemplary semi-custom EQ controller can be represented by the following equation (2).

[0043]

Equation

[0044] Thus, by measuring the transfer function between the transducer and one or more microphones of the headphones (both when the ANR feedback controller is applied and when it is not applied), the recognition mode and the EQ controller can be calculated and applied on-the-fly while the headphones are in use.

[0045] The recognition mode and the EQ controller may operate more uniformly across multiple users if they are modified to take into account data measured from multiple subjects in multiple fittings of the headphones, as described above in relation to laboratory data. Since there is no way to obtain open-ear information from users in the field, appropriate test data can be used instead of open-ear information. In some examples, Gsd is used to estimate the relationship Sss,open / Srr,open (where Sss,open is the power spectrum expected at the feedback microphone if the feedback microphone remains at the same position in the ear canal when the earphone is removed. Since the feedback microphone is removed with the headset, Sss,open is an estimate of what it would be in such an imagined situation). In one example, Sss,open is estimated from Gsd based on the average transfer matrix of the part of the ear blocked by the earphone, and the matrix is estimated from laboratory data. In one example, the constants α and β are used to represent frequency-dependent complex quantities derived from laboratory data. These constants are determined based on Gsd and the transfer function (Gp1p2) between an external reference microphone (on the user's head) and a microphone in the ear canal at the position of the feedback microphone of the inserted earphone. In one example, Gsd, Gcd, and Scc,open are measured and Gp1p2 is estimated based on these three measurements.

[0046] In one example, the constant values can be derived as follows.

[0047] When the reference microphone is called #1 and the feedback microphone is called #2, the transfer function from 1 to 2 with respect to external noise is G p1p2 which is called, that is, (a):

[0048]

Number

[0049] From a simple modeling, the following (b) can be claimed.

[0050]

Number

[0051] Also, from the laboratory data, the following (c) can be estimated.

[0052]

Number

[0053] Next, in order to solve for the best α and β, combine a and c to derive (d).

[0054]

Number

[0055] G p1p2 To remove the absolute value of the periphery, some phase is added to the right - hand side of the equation of (d). Possible examples are to give a 0 - phase at all frequencies, or to calculate the minimum - phase that matches the magnitude. The result is G for all fittings in the laboratory data p1p2 is.

[0056] Ideally, all fittings should have different α and β, each selected for use with headphones, which can be achieved by developing the best fit to the data on average.

[0057] Here, rearrange (b) to get (e).

[0058]

Number

[0059] Using this equation (e) for all fittings, a matrix equation of the following type Ax = b

[0060] can be set up. Next, solve for the best least squares fit using the pseudo-inverse of A. x = A † b

[0061] Alternatively, for the above equation, using all fittings in the laboratory data, it is as follows.

[0062]

Number

[0063] This gives an optimized solution that functions best on average across the entire population.

[0064] Taking the laboratory data into account in this way leads to the modified or "enhanced" recognition modes and EQ controllers described in equations (3) and (4) respectively. Note that the desired controller shape is calculated for each frequency based on the controller design.

[0065]

Number

[0066] The theoretical "optimal" or "opt" controller includes a microphone in the ear canal and thus cannot be implemented for a headphone user. The optimal controller is useful for understanding the semi-custom and enhanced controllers disclosed herein. The optimal recognition mode and EQ controller equations are set forth in equations (5) and (6), respectively.

[0067]

Number

[0068]

Number

[0069] FIG. 5 shows the standard deviation of the total insertion gain (in dB) of earphones with and without the exemplary semi-custom and enhanced recognition mode controllers described in equations (1) and (2) (referred to as the "ensemble mode"). This demonstrates that performance is improved using any of these recognition mode controllers from approximately 700 Hz to approximately 7 kHz.

[0070] FIG. 6 shows the standard deviation of the total insertion gain (in dB) of earphones with and without the exemplary semi-custom and enhanced EQ mode controllers described in equations (3) and (4) (referred to as the "ensemble mode"). This demonstrates that performance is improved using any of these EQ mode controllers from approximately 300 Hz to approximately 5 kHz.

[0071] By determining and applying the subject audio controller, it is possible to improve both the EQ of the headphones and the use of the recognition mode. The calculation of the controller(s) is based on real-time measurement of the audio transfer function between the audio transducer of the headphones and one or more microphones of the headphones configured to receive the transducer output. Thus, the controller(s) is at least partially customized for a particular user of the headphones and for the current use of the headphones. As a result, the recognition mode and / or EQ performance of the headphones is clearly closer to the desired design target performance. Thus, the headphones provide performance closer to the standard across different users as compared to headphones having preset recognition modes and EQ controllers.

[0072] Note that this method of determining the audio controller is not limited to the presence of a feedback loop for the EQ mode as long as there are suitable microphones within the headset. In the case of the recognition mode, the need to remove all direct external noise might seem like it would require a feedback loop, but only a feedforward loop with passive sound attenuation might potentially be sufficient.

[0073] Also note that the present disclosure can use multiple microphones including outside the headset (for the recognition mode), which can be simply added or used in an array fashion to have a directional recognition mode / listening, and can include multiple feedback microphones.

[0074] Furthermore, this EQ and recognition mode controller can be injected in two places, namely, at the driver (disturbance injection) or before the feedback controller (command injection). Both can be used with complementary filters in place.

[0075] The elements of the drawings are illustrated and described as individual elements of a block diagram. These elements may be implemented as one or more of analog circuits or digital circuits. Alternatively, or in addition, these elements may be implemented by one or more microprocessors executing software instructions. The software instructions can include digital signal processing instructions. Operations can be performed by an analog circuit or by a microprocessor executing software that performs an operation equivalent to an analog operation. Signal lines can be implemented as individual analog signal lines or digital signal lines, as individual digital signal lines that perform appropriate signal processing for processing separate signals, and / or as elements of a wireless communication system.

[0076] When a process is represented or suggested in a block diagram, steps may be performed by one element or a plurality of elements. These steps may be performed together or at different times. The elements performing the activities may be physically the same, or may be in proximity to each other, or may be physically separate. One element may perform more activities than one block. An audio signal may or may not be encoded and may be transmitted in either digital or analog form. Conventional audio signal processing devices and operations may be omitted from the drawings.

[0077] Examples of the systems and methods described herein include computer components and computer-implemented steps that would be apparent to one of ordinary skill in the art. For example, it should be understood by one of ordinary skill in the art that computer-implemented steps can be stored as computer-executable instructions on a computer-readable medium such as, for example, a hard disk, optical disk, flash ROM, non-volatile ROM, and RAM. Further, it should be understood by one of ordinary skill in the art that computer-executable instructions can be executed on various processors such as, for example, a microprocessor, digital signal processor, gate array, etc. For ease of explanation, not all steps or elements of the systems and methods are described herein as part of a computer system, but one of ordinary skill in the art will recognize that each step or element can have a corresponding computer system or software component. Thus, such computer systems and / or software components are enabled by, and within the scope of, the disclosure by virtue of their corresponding steps or elements (i.e., their functionality).

[0078] The functions, methods, and / or components of the methods and systems disclosed herein according to various aspects and embodiments may be implemented or executed in digital signal processors (DSPs) and / or other circuitry suitable for performing signal processing and other functions, analog or digital, according to the aspects and embodiments disclosed herein. Additionally or alternatively, a microprocessor, logic controller, logic circuit, field programmable gate array(s) (FPGA), application specific integrated circuit(s) (ASIC), general purpose computing processor(s), microcontroller(s), etc., or any combination thereof may be suitable and may include analog or digital circuit components and / or other components for any particular implementation.

[0079] The functions and components disclosed herein can operate in the digital domain, analog domain, or a combination of the two. Specific embodiments include, where appropriate, an analog-to-digital converter (ADC) and / or a digital-to-analog converter(s) (DAC), despite the lack of description of an ADC or DAC in various figures. Further, the functions and components disclosed herein can operate in the time domain, frequency domain, or a combination of the two, and specific embodiments include various forms of Fourier or similar analysis, synthesis, and / or transformation to adapt to processing in various domains.

[0080] Any suitable hardware and / or software, including firmware, etc., may be configured to execute or implement the components of the aspects and embodiments disclosed herein, and various implementations of the aspects and embodiments may include components and / or functions in addition to those disclosed. Various implementations may include stored instructions of a digital signal processor and / or other circuitry to enable the circuitry to execute, at least in part, the functions described herein.

[0081] Although some aspects regarding at least one embodiment have been described, it will be understood by those skilled in the art that various changes, modifications, and improvements will readily occur to them. Such changes, modifications, and improvements are part of this disclosure and are intended to be within the scope of the invention. Accordingly, the foregoing description and drawings are by way of example only, and the scope of the invention should be determined from the appropriate construction of the appended claims and their equivalents.

Description of Reference Numerals

[0082] 10 Wireless in-ear earphone 12 Housing 14 Electroacoustic transducer 16 Movable diaphragm 18 Front housing cavity 20 Rear housing cavity 22 Front housing portion 23 Rear housing part 24 Sound outlet 25 Neck 30 Processor 32 Internal microphone 34 External microphone 36 Housing opening 60 Headphone device 64 Audio driver 66 Processor 68 Wireless transceiver 70 Feedback microphone 72 Feedforward microphone 80 Head 82 Right ear 83 External auditory canal 84 Left ear 85 External auditory canal 86 Right headphone 88 Left headphone 90 Microphone

Claims

**Claim 1** A method for determining an audio controller for a headset comprising a feedback microphone configured to use an acoustic transducer to generate sound delivered to a user's ear and configured to sense the sound generated by the acoustic transducer, comprising: measuring a first audio transfer function between the acoustic transducer and the feedback microphone; determining a second audio transfer function between the acoustic transducer and the feedback microphone with a feedback controller applied; calculating the audio controller based on both the first audio transfer function and the second audio transfer function; A method comprising the steps of: **Claim 2** The step of measuring the first audio transfer function includes providing an audio signal configured to operate the acoustic transducer to generate sound, sensing the sound using the feedback microphone, and calculating the first audio transfer function based on the audio signal and the sensed sound. The method according to claim 1. **Claim 3** The step of determining the second audio transfer function includes measuring the audio transfer function between the acoustic transducer and the feedback microphone with a feedback controller applied. The method according to claim 1. **Claim 4** The step of measuring the audio transfer function between the acoustic transducer and the feedback microphone with a feedback controller applied includes providing an audio signal configured to operate the acoustic transducer to generate sound, sensing the sound using the feedback microphone, and calculating the second audio transfer function based on the audio signal, the sensed sound, and the feedback controller. The method according to claim 3. **Claim 5** The step of determining the second audio transfer function includes calculating the second audio transfer function based on both the first audio transfer function and the feedback controller. The method according to claim 1. **Claim 6** The audio controller includes an equalization (EQ) controller. The method according to claim 5. **Claim 7** The method according to claim 5, wherein the audio controller includes a controller for a headphone use mode in which sound outside the headphones is reproduced by the acoustic transducer.

8. The method according to claim 1, further comprising providing a power spectrum measured for a microphone disposed in a human external auditory canal and providing a power spectrum measured for a microphone disposed on the human head.

9. The method according to claim 8, wherein the calculation by the audio controller is further based on both the measured power spectrum for a microphone disposed in a human external auditory canal and the measured power spectrum for a microphone disposed on the human head.

10. The method according to claim 9, wherein the calculation by the audio controller is further based on a third audio transfer function between the acoustic transducer and a microphone disposed in a human external auditory canal.

11. The method according to claim 1, further comprising providing a third audio transfer function between a first position of a feedback microphone in a human external auditory canal and a second position on the human head.

12. The method according to claim 11, further comprising providing a fourth audio transfer function between the acoustic transducer and the first position of the feedback microphone in the human external auditory canal.

13. The method according to claim 12, further comprising providing first and second constant values.

14. The method according to claim 13, wherein the first and second constant values are calculated based on both the third and fourth audio transfer functions.

15. The method according to claim 14, wherein the first and second constant values are calculated based on both the third and fourth audio transfer functions for a plurality of different fittings of the headphones to a plurality of different people.

16. The method according to claim 13, wherein the first and second constant values represent frequency-dependent complex quantities.

17. A computer program product having a non - transitory computer - readable medium including symbolized computer program logic, configured to use an acoustic transducer to generate sound delivered to a user's ear, and comprising a feedback microphone configured to sense the sound generated by the acoustic transducer, when executed on headphones, the computer program logic causes the headphones to, measure a first audio transfer function between the acoustic transducer and the feedback microphone, determine a second audio transfer function between the acoustic transducer and the feedback microphone with a feedback controller applied, calculate an audio controller based on both the first audio transfer function and the second audio transfer function, A computer program product. **Claim 18** The computer program product according to claim 17, wherein the audio controller comprises at least one of an equalization (EQ) controller and a controller for a headphone usage mode in which external sound of the headphones is reproduced by the acoustic transducer. **Claim 19** The first audio transfer function is measured by providing an audio signal configured to operate the acoustic transducer to generate sound, sensing the sound with the feedback microphone, and calculating the first audio transfer function based on the audio signal and the sensed sound. Further, the second audio transfer function is calculated based on both the first audio transfer function and the feedback controller. The computer program product according to claim 18. **Claim 20** Further comprising providing a power spectrum measured for a microphone disposed in a human external auditory canal and providing a power spectrum measured for a microphone disposed on the human head, and the calculation of the audio controller is further based on the measured power spectrum for the microphone disposed in the human external auditory canal, the measured power spectrum for the microphone disposed on the human head, and a third audio transfer function between the acoustic transducer and the microphone disposed in the human external auditory canal. The computer program product according to claim 19.

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