Wearable audio device placement detection

Abstract

An earphone, comprising: an electroacoustic transducer for generating sound; a proximity sensor configured to detect when the earphone is close to the user's skin; an orientation sensor configured to detect the orientation of the earphone; and a processor configured to estimate whether the earphone is inserted into the user's external auditory canal based on the proximity sensor and the orientation sensor.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application is a partial continuation application claiming priority from International Patent Application No. PCT / US2021 / 034049, filed on May 25, 2021, which in turn claims priority from U.S. Patent Application No. 16 / 882,673, filed on May 25, 2020, and is currently issued as U.S. Patent No. 11,202,137, issued on December 14, 2021. The entire disclosures of both prior applications are hereby incorporated by reference in their entirety for all purposes.

Background Art

[0002] This disclosure relates to wearable audio devices.

[0003] Wearable audio devices are designed to function optimally when they are in proper use positions on the body and when the user stops operating the device.

Summary of the Invention

[0004] All examples and features mentioned below can be combined in any technically possible way.

[0005] In one embodiment, the wearable audio device includes an electroacoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in close proximity to a user; an orientation sensor configured to detect the orientation of the wearable audio device; an internal microphone positioned within the housing of the wearable audio device and configured to detect sound within a cavity at least partially formed by a portion of the housing; and a processor configured to estimate (i) whether the wearable audio device is in proper place on the user's body based on the proximity sensor and the orientation sensor, and (ii) whether the user has completed operation of the wearable audio device based on the internal microphone.

[0006] Some embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, the proximity sensor includes an infrared sensor. In one embodiment, the orientation sensor includes an inertial measurement unit (IMU). In one embodiment, the IMU comprises an accelerometer used to detect the orientation of the wearable audio device. In one embodiment, the proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in place on the user's body is based in part on the level of the proximity sensor output. In one embodiment, after the processor has estimated whether the wearable audio device is in place on the user's body, the processor is configured to activate a predetermined wearable audio device function. In one embodiment, the predetermined wearable audio device function includes at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of a microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

[0007] Some embodiments include one of the features described above and / or below, or any combination thereof. In some embodiments, the wearable audio device further comprises an external microphone configured to sense sounds outside the housing, and the processor's estimation of whether the wearable audio device is in place on the user's body is further based on a transfer function between the external microphone and the internal microphone. In one embodiment, the processor is further configured to cause an electroacoustic transducer to generate a sound on which the transfer function is based. In one embodiment, the transfer function is determined at a frequency of up to 1,000 Hz. In one embodiment, the processor is further configured to cause an electroacoustic transducer to generate a sound at two different frequencies, the first frequency being at least 1,500 Hz, and the processor is configured to determine whether the wearable audio device nozzle is blocked based at least in part on the first frequency, and the second frequency being 1,000 Hz or less, and the processor is configured to determine whether the wearable audio device is in place on the user's body based at least in part on the second frequency.

[0008] Some embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, the generated sound is part of a wearable audio device activation tone sequence. In one embodiment, the processor's estimation of whether the wearable audio device is in place on the user's body includes a set of two steps: a first step based on at least a proximity sensor, an orientation sensor, and an internal microphone; and a second step based on at least an internal microphone and an external microphone. In some embodiments, the processor is configured to initiate a first group of wearable audio device functions based on the first step, and a second group of wearable audio device functions based on the second step, wherein the functions of the second group are different from those of the first group. In one embodiment, the functions of the first and second groups include at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of the microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system. In one embodiment, during at least the first step, the internal microphone is monitored at a frequency in the range of 0 to 20 Hz.

[0009] In another embodiment, a method for detecting when a wearable audio device is in place on a user's body, the wearable audio device comprising: an electroacoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in close proximity to a user; an orientation sensor configured to detect the orientation of the wearable audio device; an internal microphone positioned within the housing of the wearable audio device and configured to detect sound within a cavity at least partially formed by a portion of the housing; and an external microphone configured to sense sound outside the housing, the method comprising: estimating whether the wearable audio device is in place on a user's body based on the proximity sensor, the orientation sensor, and the internal microphone; and estimating whether the user has completed operation of the wearable audio device based on the internal microphone.

[0010] Some embodiments include one of the features described above and / or below, or any combination thereof. In one embodiment, the processor is further configured to cause an electroacoustic transducer to generate sound after the processor has estimated that a wearable audio device is in place on the user's body, and the processor is further configured to calculate a transfer function between an external microphone and an internal microphone over a specified frequency or frequency range of the generated sound. In one embodiment, the processor's estimation of whether a wearable audio device is in place on the user's body includes a set of two steps: a first step based on at least a proximity sensor, an orientation sensor, and an internal microphone; and a second step based on at least an internal microphone and an external microphone, and the processor is configured to initiate a first group of wearable audio device functions based on the first step, and a second group of wearable audio device functions based on the second step, wherein the functions of the second group are different from those of the first group.

[0011] In another embodiment, a wearable audio device (e.g., headphones) includes an electroacoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in close proximity to a user; an internal microphone positioned within the housing of the wearable audio device (e.g., within the earcup of headphones) and configured to detect sound within a cavity at least partially formed by a portion of the housing; and a processor configured to estimate, at least based on the proximity sensor, whether the wearable audio device is in proper place on the user's body, and based on the internal microphone, whether the user has completed operation of the wearable audio device.

[0012] Some embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, the wearable audio device further includes at least one earcup configured to be positioned over or over the wearer's ears when the wearable audio device is placed on the head, and both a proximity sensor and an internal microphone are positioned within the earcup. In some embodiments, the proximity sensor comprises a capacitive proximity sensor. In one embodiment, the capacitive proximity sensor comprises a conductive member inside the earcup of the wearable audio device. In one embodiment, the conductive member has a curved outer circumference that mimics the curvature of the human auricle. In one embodiment, the wearable audio device further includes two earcups configured to be positioned over or over the wearer's ears when the wearable audio device is placed on the head, and each earcup has an internal microphone positioned within it, and the estimation of whether the user has completed operation of the wearable audio device is based on the internal microphones positioned within each earcup.

[0013] Some embodiments include one of the features described above and / or below, or any combination thereof. In some embodiments, the processor is configured to initiate a first group of wearable audio device functions based on an estimation of whether the wearable audio device is in proper place on the user's body. In one embodiment, the processor is configured to initiate a second group of wearable audio device functions based on an estimation of whether the user has completed operation of the wearable audio device, the functions of the second group being different from those of the first group. In one embodiment, the functions of the first and second groups include at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of a microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

[0014] Several embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, an internal microphone is monitored at a frequency in the range of 0 to 20 Hz, at least during the estimation of whether the user has completed operation of the wearable audio device. In one embodiment, a proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in place on the user's body is based in part on the level of the proximity sensor output. In some embodiments, after the processor has estimated whether the wearable audio device is in place on the user's body, the processor is configured to activate a predetermined wearable audio device function. In one embodiment, the predetermined wearable audio device function includes at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of the microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system. In one embodiment, the processor is further configured to initiate an active noise reduction (ANR) filter determination procedure after the estimation that the user has completed operation of the wearable audio device.

[0015] Some embodiments include one of the features described above and / or below, or any combination thereof. In some embodiments, the wearable audio device further includes an orientation sensor configured to detect the orientation of the wearable audio device. In one embodiment, the processor is further configured to estimate, based at least on the orientation sensor, whether the user has removed the wearable audio device from the user's body. In one embodiment, the processor is configured to reduce power consumption based on the estimation of whether the user has removed the wearable audio device from the user's body. In one embodiment, the estimation of whether the user has removed the wearable audio device from the user's body is further based on a proximity sensor. In one embodiment, the processor's estimation of whether the wearable audio device is in proper place on the user's body is based on the proximity sensor and the orientation sensor. In one embodiment, the orientation sensor includes an accelerometer. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of wearable audio devices. [Figure 2] This is a partial cross-sectional view of a wearable audio device. [Figure 3] This is a flowchart illustrating the operation of the earphone placement detection method. [Figure 4] This shows the transfer function between the external microphone and the internal microphone of the earphone when the earphone is located in free space and when it is located inside the ear. [Figure 5] This is a schematic cross-sectional view of an over-ear headphone positioned appropriately on the user's head. [Figure 6] This is an internal diagram of the earcup section for over-ear headphones. [Figure 7] This is a flowchart illustrating the operation of the headphone insertion / removal detection method. [Modes for carrying out the invention]

[0017] This disclosure relates to wearable audio devices. Some non-limiting embodiments of this disclosure describe a type of wearable audio device known as earphones. Earphones generally include an electroacoustic transducer for generating sound and are configured to deliver sound directly to the user's ear canal. Earphones can be wireless or wired. In the embodiments described herein, the earphones are wireless and therefore carry a power source (generally a rechargeable battery), a wireless communication system (in one embodiment, a Bluetooth-based communication system), and any necessary processing. Other embodiments of earphones not included in this disclosure are not illustrated or described.

[0018] Furthermore, some embodiments of this disclosure describe a type of wearable audio device known as an open-type audio device. An open-type audio device has one or more electroacoustic transducers (i.e., audio drivers) located away from the opening of the ear canal. In some embodiments, the open-type audio device also includes one or more microphones, which may be used to pick up the user's voice and / or for noise cancellation. Open-type audio devices are further described in U.S. Patent No. 10,397,681, the entire disclosure of which is incorporated herein by reference for any purpose.

[0019] Headphones generally refer to a device that is worn around the ear, over the ear, or in the ear and radiates acoustic energy directly or indirectly into the external auditory canal. Headphones are sometimes referred to as earphones, earpieces, headsets, in-ear headphones, or sports headphones and can be wired or wireless. Headphones include an electroacoustic transducer (driver) that converts an audio signal into acoustic energy. The acoustic driver may or may not be housed in an earcup or housing configured to be located on the head or ear or inserted directly into the user's external auditory canal. Headphones may be one per ear, a single standalone unit, or one of a pair of headphones (each including at least one acoustic driver). One side of the headphones can be mechanically connected to the other side of the headphones, for example, by a headband and / or by a lead wire that transmits an audio signal to the acoustic driver within the headphones. Headphones may include components for receiving an audio signal wirelessly. Headphones may include components of an active noise reduction (ANR) system that includes an internal microphone within the housing of the headphones. Headphones can also include other functions, such as an additional microphone for the ANR system or one or more microphones used to pick up the user's voice.

[0020] In around-ear headphones or on-ear headphones or off-ear headphones, the headphones may include a headband or other support structure and / or at least one housing or other structure that houses the transducer and is arranged to rest above or over or near the user's ear. The headband can be foldable or collapsible and can be made of multiple parts. Some headbands include a slider that can be located inside the headband and provides any desired translation of the housing. Some headphones include a yoke pivotally attached to the headband, and the housing is pivotally attached to the yoke to provide any desired rotation of the housing.

[0021] An open - type audio device includes, but is not limited to, an off - ear headset, i.e., a device having one or more electro - acoustic transducers that are coupled (typically by a support structure) to the head or ear but do not occlude the external auditory meatus opening. In some embodiments, the open - type audio device is an off - ear headset with audio glasses, but this does not limit the present disclosure. Because in an open - type audio device, the device is typically configured to deliver sound to one or both ears of a wearer without an ear cup or an ear bud. Wearable audio systems contemplated herein may include various devices such as wireless headsets, hearing aids, glasses, protective helmets, and other open - type ear audio devices including over - ear hooks.

[0022] One or more of the devices, systems, and methods described herein can be used in various embodiments and combinations in a wide variety of wearable audio devices or systems, including wearable audio devices of various form factors. Unless otherwise specified, the term active part of a wearable audio system as used in this document includes headsets and various other types of wearable audio devices such as acoustic devices mounted on the head, shoulders, or body (e.g., audio glasses or other head - mounted audio devices), which include another electro - acoustic transducer for receiving and / or generating sound in contact with or without contact with the user's ear.

[0023] Specific implementations of wearable audio devices that primarily serve the purpose of acoustically outputting audio are presented with some degree of 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 covered by the claims.

[0024] In some embodiments, the wearable audio device includes a proximity sensor configured to detect when the earphone is close to the user. In one embodiment, the proximity sensor detects the user's skin. In one embodiment, the proximity sensor is an infrared (IR) sensor capable of detecting when the wearable audio device is close to or in contact with the skin of the ear. In one embodiment, the IR sensor output is within a predetermined range or at least at a predetermined threshold level for use position determination to be performed. In some embodiments, the wearable audio device also includes an orientation sensor configured to detect the orientation of the wearable audio device. In one embodiment, the orientation is determined along three mutually orthogonal axes in space. Since the wearable audio device is designed to be worn in a specific orientation, knowing the orientation via the orientation sensor can indicate whether the device is in place. For example, when the earphone is held in the ear of an upright head, the internal orientation sensor has a known orientation in three-dimensional space. The resulting value of the orientation sensor may be within a nominal predetermined range for use position determination to be performed. The wearable audio device further includes a processor configured to estimate, based on proximity and orientation sensors, whether the wearable audio device is in the appropriate place on the user's body. In some embodiments where the wearable audio device is an earphone, the appropriate place is within the user's ear canal.

[0025] In some embodiments, the wearable audio device also includes an internal microphone. In one embodiment, the internal microphone is positioned within the housing of the wearable audio device. In one embodiment, the microphone is positioned to detect sound within a cavity at least partially formed by a portion of the housing. When the internal microphone is used within the wearable audio device, the processor may also be configured to estimate whether the user has completed an operation of the wearable audio device. In some embodiments, the operation includes placing the wearable audio device in place on the body or removing it from the body. In some embodiments, the wearable audio device also includes an external microphone. In one embodiment, the external microphone is positioned to detect sound outside the housing of the wearable audio device. When the external microphone is used within the wearable audio device, the processor may also be configured to calculate an audio transfer function between the internal and external microphones and, based on the transfer function, estimate whether the wearable audio device is in its proper use location (e.g., inside the ear).

[0026] Figure 1 is a perspective view of a wireless in-ear earphone 10. An earphone is a non-limiting example of a wearable audio device. The earphone 10 includes a body or housing 12 that houses the active components of the earphone. Part 14 is coupled to the body 12 and is flexible so that it can be inserted into the entrance of the ear canal. Sound is delivered through an opening 15. A retaining loop 16 is configured and positioned to be located in the outer ear, for example, in the antihelix, to help hold the earphone in the ear. Earphones are well known in the art (for example, disclosed in U.S. Patent No. 9,854,345, the disclosure of which is incorporated herein by reference in its entirety for any purpose), and therefore specific details of earphones are not further described herein.

[0027] Figure 2 is a partial cross-sectional view of only specific elements of the earphone 20, which is useful for better understanding this disclosure. The earphone 20 comprises a housing 21 surrounding an electroacoustic transducer (audio driver) 30. The housing 21 includes a front housing portion 50 and rear housing portions 60 and 62. The transducer 30 has a diaphragm 32 that is driven to create sound pressure in the front cavity 52. ​​The sound pressure is directed outward from the front housing portion 50 through a sound outlet 54. An internal microphone 80 is located inside the housing 21. An exemplary microphone 80 is located inside the sound outlet 54, as shown in Figure 2. An external microphone 81 is configured to sense sound from outside the housing 21. In one embodiment, the internal microphone 80 is used as a feedback microphone for active noise reduction, and the external microphone 81 is used as a feedforward microphone for active noise reduction. An earphone, such as the earphone 10 shown in Figure 1, typically includes a flexible tip (not shown) that engages with the neck 51 of the housing portion 50 to help direct sound into the ear canal. The earphone housing 21 further includes a rear enclosure made from rear housing portions 60 and 62 and a grille 64. Note that the details of the earphone 20 are illustrative embodiments of the earphone and do not limit the scope of this disclosure, because the in-ear detection can be used in various types and designs of earbuds and earphones and other wearable audio devices.

[0028] The transducer 30 further comprises a magnetic structure 34. The magnetic structure 34 includes a transducer magnet 38 and a magnetic material that functions to confine and guide the magnetic field from the magnet 38, so that, as is well known in the field of electroacoustic transducers, the magnetic field interacts appropriately with the coil 33 to drive the diaphragm 32. The magnetic material includes a cup 36 and a front plate 35, which, as is also known in the art, are preferably made from a material having a relatively high magnetic susceptibility. The transducer printed circuit board (PCB) 40 carries electrical and electronic components (not shown) involved in driving the transducer. Pads 41 and 42 are locations on the PCB 40 where wires (not shown) can be coupled.

[0029] In one embodiment, an inertial measuring unit (IMU) 72 is used to detect the orientation of the earphone in three-dimensional space. The IMU may include a three-axis accelerometer that can be used to determine the orientation. The use of an accelerometer to determine the orientation of a device that includes or supports an accelerometer is known in the art and is therefore not further described herein. The IMU may also include one gyroscope, or three gyroscopes configured to determine rotational speeds around three mutually orthogonal axes. The orientation of the earphone may be determined by additional or alternative use of gyroscopes. The use of a gyroscope to determine the orientation of a device that includes or supports a gyroscope is known in the art and is therefore not further described herein. In one embodiment, the IMU 72 is mounted on a PCB 70, but the IMU may be located inside or elsewhere on the earphone.

[0030] In some embodiments, the proximity sensor 76 is used to detect when the earphone 20 is in close proximity to the user's skin. In one embodiment, the proximity sensor 76 may be an infrared (IR) sensor or a capacitive sensor. An IR sensor can be used to detect proximity to skin, while a capacitive sensor can detect when the device is touching skin. An IR sensor can be used to detect when the earphone is in close proximity to skin. Since the earphone needs to be inside the ear when in the proper use position, parts of the earphone are in contact with or near the skin. Therefore, by positioning the IR sensor on the part of the earphone that is in contact with or near the skin, it becomes possible to use the IR sensor as a proximity sensor. In one embodiment, the IR sensor is positioned to detect the tragus. In another example, a distance sensor, such as a time-of-flight sensor, can be used to detect the distance between the wearable audio device and a desired location on the body (e.g., inside the ear). When the wearable audio device is in place, the device is properly positioned at a known location on the body (e.g., inside the ear, above the ear, or other location on the head), so the distance from the device to the proper location should be 0 or close to 0.

[0031] The earphone 20 also includes a processor 74. In some embodiments, the processor 74 is configured to process the outputs of the IMU 72, proximity sensor 76, internal microphone 80, and external microphone 81. As will be apparent to those skilled in the art, the processor naturally also engages in other processing necessary for the earphone functionality, such as processing the digital sound files played by the earphone. In one embodiment, the processor is configured to estimate whether the wearable audio device is in proper place on the user's body based on both the proximity sensor and the orientation sensor. In some examples, the processor's estimation of whether the wearable audio device is in proper place on the user's body is further based on the transfer function between the external microphone and the internal microphone. In one embodiment, the processor is configured to estimate whether the user has completed operation of the wearable audio device based on the internal microphone. In some embodiments, the proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in proper place on the user's body is partially based on the level of the proximity sensor output. In one embodiment, the processor's estimation of whether a wearable audio device is in proper place on the user's body is partially based on whether the proximity sensor output has reached a threshold level. For example, as the wearable audio device moves closer to the skin, the IR sensor output increases. For any particular IR sensor, the output reaching a predetermined level can be considered equivalent to the sensor being within a predetermined distance from the skin.

[0032] In some embodiments, the processor's estimation of whether a wearable audio device is in the correct position on the user's body involves a series of steps. In one embodiment, a first step is based on proximity and orientation sensors, a second step is based on an internal microphone, and a third second step is based on internal and external microphones. In one embodiment, the processor is configured to initiate a first group of wearable audio device functions based on the first and second steps, and a second group of wearable audio device functions based on the third step. In one embodiment, the functions of the second group are different from those of the first group. In some embodiments, the functions of the first and second groups include at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of microphones carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

[0033] In some embodiments, the processor is configured to cause an electroacoustic transducer to generate a sound used in a high-confidence determination of whether a wearable audio device is in place. In one embodiment, this high-confidence determination is performed only after the processor has made a first-level low-confidence determination that the wearable audio device is in place on the user's body and the user has stopped operating the device. In one embodiment, the processor is configured to calculate a transfer function between an external microphone and an internal microphone over a specified frequency range. In one embodiment, the generated sound is part of a wearable audio device activation tone sequence.

[0034] In one embodiment, the processor is configured to cause an electroacoustic transducer to generate sounds at two (or more) different frequencies for determining appropriate / inappropriate locations. In one embodiment, the first frequency is at least 1,500 Hz (e.g., 1,500–3,000 Hz), and the processor is configured to determine, at least partially, whether the wearable audio device nozzle is blocked. In one embodiment, the second frequency is less than 1,000 Hz, and the processor is configured to determine, at least partially, whether the wearable audio device is in appropriate location on the user's body. When frequencies or frequency ranges are described herein, it should be understood that frequencies or ranges are often approximations. If a particular frequency is specified, it should be understood that the actual frequency may be approximately or nearly the specified frequency. One reason for this is that even if the actual frequency differs from the stated frequency, the results may not differ dramatically.

[0035] Internal and external microphones can be used to detect sounds that are analyzed in different ways and for different purposes. There can be multiple functions for which microphones are used. One is to determine that a user is adjusting a wearable audio device. An internal microphone may be monitored for this function. In one embodiment, monitoring can be performed at frequencies up to 20 Hz, and the monitoring is passive, meaning the microphone is used to monitor sounds inside the wearable audio device without using a driver to reproduce sound. If the wearable audio device is an earphone, the internal microphone may be a feedback microphone located within the earphone nozzle. When the earphone is being operated (i.e., when it is inserted into or removed from the ear), that operation produces sounds in the range up to 20 Hz. Therefore, detecting sounds in this range can be considered equivalent to detecting the operation of the earphone. Also, when the earphone is inserted into the ear, the cavity bounded by the driver, earphone nozzle, ear canal, and eardrum is sealed, causing a DC pressure spike. The DC pressure spike occurs at 0 Hz but spreads slightly within the frequency range. Therefore, monitoring the internal microphone in the 0-20Hz range is useful for estimating whether the earphone is inserted into the ear, or whether the earphone is no longer being operated, or both.

[0036] A second function for which microphones may be used is to provide a more reliable determination of whether a wearable audio device is in the correct location on the user's body. Internal and external microphones may be used for this purpose. In one embodiment, the audio transfer function between the external and internal microphones is determined. This determination can be made at a frequency or frequency range where there is good separation of the magnitude of the transfer function between the correct and incorrect locations (e.g., inside and outside the ear of the earphone). In the earphone embodiment, the magnitude of the transfer function differs between the inside and outside of the ear in the frequency range of 0 to 1,000 Hz. Therefore, by determining the transfer function in this frequency range, it is possible to reliably indicate whether the earphone is inside the ear or not. The same principle can be used for other types of earphones, headphones, and other types of wearable audio devices. The specific frequency or frequency range where there is good separation of the magnitude of the transfer function between the correct and incorrect locations is unique for any given product. The determination of the "correct location" can then be made at a frequency or frequency range where good amplitude separation exists.

[0037] Another function that a microphone may be used for is determining whether the earphone nozzle is blocked. The earphone nozzle may be blocked by a finger when the earphone is being manipulated (e.g., when the earphone is in the proper position inside the ear or when it is removed from the ear). Therefore, the determination that the nozzle is blocked can be used as a less reliable indicator that the earphone is being manipulated and is therefore not in the proper position for use. In one embodiment, within one frequency range, the audio transfer function between an external microphone and an internal microphone has a certain value when the nozzle is blocked by a finger and a different value when the wearable audio device is in free air or in the proper position for use. For example, in the range of 1,500 to 3,000 Hz, there is a different response when the earphone nozzle is blocked by a thumb compared to when the earphone is inside or outside the ear (which have similar responses). In another embodiment, the transfer function of an earphone in the frequency range of 0 to 1,000 Hz may be low when the earphone is in free air and high when the nozzle is blocked (either by a finger or by the earphone being sealed within the ear canal). Thus, the transfer function can serve as an indicator of whether the earphone is being manipulated and whether it is inside the ear. This determination can be used in conjunction with other determinations described herein to make a final determination of whether a wearable audio device is in its proper use position.

[0038] Figure 3 shows the steps of method 100 for detecting whether a wearable audio device, as described above, is in proper place on the user's body. In step 102, a proximity sensor is monitored for proximity detection events. In step 104, an orientation sensor is monitored for proper orientation of the wearable audio device. In one embodiment, both sensors are monitored simultaneously. When the proximity sensor and the orientation sensor reach thresholds indicating a possible in-ear event, in step 105, an internal microphone is monitored. In one embodiment, the microphone is monitored in the range of 0 to 20 Hz to detect that the wearable audio device is being operated by the user and that the earphone is inserted into the ear, as described elsewhere in this specification. Based on the monitoring of the proximity sensor, orientation sensor, and internal microphone, in step 106, a low-confidence determination is made regarding whether the device is in proper place (i.e., in proper place on the user's body). In this non-limiting embodiment, the device is an earphone, and therefore the determination is whether the device is in proper place in the ear. If a low-confidence in-ear determination is made, a first group of earphone functions is activated in step 108. In some embodiments, earphone functions that may be activated based on this low-confidence determination include some or all of the following: automatic power on / off, automatic audio pause / play, automatic call answering function, Bluetooth connection / reconnection, beamforming of microphones carried by the wearable audio device, activation of user interface functions, and tuning of the active noise reduction system. More specifically, in one embodiment, the functions activated after the low-confidence determination are background functions such as turning on the processor, sensors, and Bluetooth. As a result, the chips, sensors, and other aspects of the power-consuming audio device remain off until the first level determination is made, thus saving battery power.

[0039] Next, method 100 proceeds to a second level of high-confidence determination that the earphone is in the correct position within the ear. In step 110, internal and external microphones are monitored. Next, in step 112, the driver is made capable of playing one or more tones. The purpose of playing tones is to receive tones in the microphones and determine whether there is a tone reception, as would be expected if the wearable audio device is in the correct position for use and the user stops operating the wearable audio device. In embodiments of earphones, microphones used for this purpose include internal microphones used for feedback-based active noise reduction and external microphones used for feedforward-based active noise reduction. Both types of microphones are known in the field of active noise reduction for wearable audio devices and are therefore not further described herein. Internal microphones are typically positioned to be able to sense sound within the cavity formed by the driver, earphone nozzle, and ear canal. One example is microphone 80 in Figure 2. External microphones are capable of sensing sound outside the housing of the earphone. One example is microphone 81 in Figure 2. In method 100, in step 114, the transfer function (G) between the two microphones is determined. sd ) is determined. G sdThe decision is described in U.S. Patent No. 10,462,551, entitled “Wearable Audio Device with Head On / Off State Detection,” issued on 29 October 2019, and the entire disclosure is incorporated herein by reference for all purposes. The acoustic coupling from the driver to the microphone (exemplified by the transfer function) changes (at least at one frequency) when the earphone is inside the ear and when it is outside the ear. In one embodiment, the processor of the wearable audio device is configured to both cause the electroacoustic transducer to generate sound and calculate the transfer function after the processor has made a first level estimate that the wearable audio device is in place on the user’s body. In one embodiment, the transfer function is calculated over a specified frequency range which may be in the range of 0 to 1,000 Hz. In some embodiments, the sound to be reproduced is part of a series of tones of a type common in electronic devices for device activation.

[0040] If the transfer function is as expected, a highly reliable intra-ear determination is made in step 116. In one embodiment, this highly reliable second-stage determination is also involved in the first-stage determination (a microphone-based determination of proximity to the user, proper orientation, and whether the user has stopped operating the wearable audio device). In other words, the device is considered (with low confidence) to be in the proper use position both when it is in the correct physical location and when the user is not operating the device (which is expected to occur when the user is satisfied that the device is in place). In one embodiment, as part of the second-stage highly reliable determination, the indicator for a blocked nozzle is G in the range of 0 to 1,000 Hz. sdThis is calculated simultaneously. If the calculation for a blocked nozzle indicates that the nozzle is blocked, the high-confidence determination can be delayed for a short time to ensure that the user has stopped operating the earphones. If the in-ear condition is still indicated after that time, the high-confidence determination is made. After the second-stage high-confidence determination is made, in step 118, a second group of earphone functions is activated. In some embodiments, the functions of the second group differ from those of the first group. In one embodiment, the functions of the second group include both functions involved in user interaction (such as switches, capacitive touch sensors, and microphone beamforming) and tuning of the active noise reduction system. In some embodiments, multiple stages can be performed on different subsystems. For example, there may be a sensor subsystem used in the first low-confidence stage (using proximity sensors, orientation sensors, and internal microphones) and a microphone subsystem used in the second-stage high-confidence determination (using internal and external microphones). This would allow the microphone subsystem to be turned on only when needed to save power. This design would require some message exchange between subsystems.

[0041] In some embodiments, monitoring of proximity and orientation sensors continues during the process of making a second-stage determination. One reason for this is that it is possible to determine whether the wearable audio device has been removed from its place of use. For example, an earphone may be placed in the ear and then quickly removed. Or perhaps the user may continue to adjust the earphone for a short time after it has been placed in the ear. Monitoring the proximity and / or orientation sensors throughout the entire startup sequence can provide greater confidence in determining that the device is in place and that the user has completed operating the device. Additionally, continuous or periodic monitoring of the microphone and calculation of its transfer function can be used to confirm that the device has been moved from its place of use (e.g., removed from the ear). In some embodiments, the processor may enable a timer that can be used as part of the proper / inappropriate place determination. For example, if the determination remains high confidence for at least a short time (perhaps 1-2 seconds), there may be a higher confidence that the user has stopped adjusting the device's position. Additionally, a timer can be used to turn off the earphone function only after a short period of time if the proximity sensor stops sensing proximity (which happens when the earphones are removed from the ears). This can help prevent potentially annoying false location detections. For example, if the driver and external microphone are disabled when the device is removed from its intended use location, a false detection could interrupt phone calls, music, or podcasts against the user's wishes.

[0042] Figure 4 shows the transfer function (G) between the external microphone and internal microphone of the earphone (as described above) over a frequency range of up to approximately 10,000 Hz. sd Graph 130 shows the transfer function when the earphone is inside the ear canal, and the dotted line 132 shows the transfer function when the earphone is in free space. As can be seen, the magnitude of the transfer function differs at frequencies up to 1,000 Hz. Therefore, determining the transfer function in the range of 0 to 1,000 Hz indicates whether the earphone is inside the ear canal or not.

[0043] Some embodiments of the present disclosure relate to detecting the placement of around-ear or on-ear headphones having earcups configured to cover or sit on the ears, respectively. Placement detection can be based on proximity sensors, such as capacitive proximity sensors, microphones that sense sound inside the earcups (as opposed to external ambient noise), and accelerometers, which may but may not be functions of an IMU. As described below, in some embodiments, these sensors are used to make a first level determination that the headphones are on the head, a second level determination that the headphones are in place on the head and ready to use, and a third level determination that the headphones have been removed from the head.

[0044] In some embodiments, placement detection of a wearable audio device (e.g., on-ear or over-ear headphones) relies on three types of sensors: capacitive, microphone, and IMU / accelerometer. The placement detection algorithm can be thought of as having several different stages. In the first stage, a capacitive sensor is used to detect whether one or both of the earcups are covering or around the user's ears (i.e., the headphones are being worn). In some embodiments, there is a single capacitive sensor in / on one of the earcups. In other embodiments, there is a capacitive sensor in each of the two earcups. The capacitive sensor (e.g., the sensor's electrodes or conductive material) is molded to use its own capacitance to pick up the most definitive part of the ear. The input from the capacitive sensor is monitored to determine whether / when a threshold indicating an on-head event has been met. This can be considered a low-confidence determination that the user has placed the headphones on their head. When an on-head event is detected, a first group of one or more headphone functions is activated. The first group of headphone functions may include one or more of the following: power on, automatic audio playback, automatic call answering, Bluetooth connection, beamforming of an external microphone carried by the headphones, and activation of user interface (UI) functions. In one embodiment, the functions activated after a low confidence determination are background functions such as turning on the processor, sensors, and Bluetooth. As a result, the audio device chips, sensors, and other components that use power remain off until the first level determination is made, thus saving battery power.

[0045] Next, when the input from the capacitive sensor reaches a threshold indicating an on-head event, a second stage is performed in which input from one or more internal microphones (e.g., feedback microphones used in active noise reduction or ANR systems) is monitored to detect "end-of-wearing," which is when the user has finished adjusting the headphones (i.e., the headphone cups are fully in place or "worn"). In one embodiment, microphone monitoring is performed in the range of 0-20Hz to detect that the wearable audio device is being operated by the user. After the second stage determination that the user has stopped operating the headphones is made, a second group of earphone functions is activated. In some embodiments, the functions of the second group differ from those of the first group. In one embodiment, the functions of the second group include both functions involved in user interaction (such as switches, capacitive touch sensors, and microphone beamforming) and tuning of the ANR system. In this regard, measurements to provide customized ANR are delayed until the "end-of-wearing" state is detected. These measurements generally consist of reproducing a tone and measuring the response with a feedback microphone to measure the unique response of the user's ear canal. Customized ANRs in headphones are described in U.S. Patent No. 10,937,410, the entire disclosure of which is incorporated herein by reference for all purposes.

[0046] In some embodiments, an inertial monitoring unit (IMU) or accelerometer is used to detect when the headphones are lying flat / horizontally and indicate an off-head state (i.e., the headphones are removed or "undressed"). In response, the headphones power off. In some embodiments, input from a capacitive sensor is used in combination with input from the IMU / accelerometer to determine that the headphones are in an off-head state. That is, by monitoring input from the capacitive sensor, it may be possible to detect that the user has removed the headphones, but the headphones will delay powering off until input from the IMU / accelerometer indicates that the headphones are lying horizontally. This can help prevent false off-head detection. Therefore, for example, if the user removes the headphones briefly to readjust them, the headphones may not change any function until the IMU / accelerometer exceeds some threshold. This helps avoid interruptions in headphone function, such as when the user lifts one or both earcups, or when the headphones are adjusted after being worn.

[0047] In embodiments of this specification, a wearable audio device includes an electroacoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in close proximity to a user; an internal microphone positioned within the housing of the wearable audio device and configured to detect sound within a cavity at least partially formed by a portion of the housing; and a processor configured to estimate, at least based on the proximity sensor, whether the wearable audio device is in proper place on the user's body, and based on the internal microphone, whether the user has completed operation of the wearable audio device.

[0048] In one embodiment, the wearable audio device further includes at least one earcup configured to be positioned over or covering the wearer's ears when the wearable audio device is placed on the head, and both a proximity sensor and an internal microphone are positioned within the earcup. In some embodiments, the proximity sensor comprises a capacitive proximity sensor. In one embodiment, the capacitive proximity sensor comprises a conductive member inside the earcup of the wearable audio device. In one embodiment, the conductive member has a curved outer circumference that mimics the curvature of the human auricle. In one embodiment, the wearable audio device further includes two earcups configured to be positioned over or covering the wearer's ears when the wearable audio device is placed on the head, and each earcup has an internal microphone positioned within it, and the estimation of whether the user has completed operation of the wearable audio device is based on the internal microphone positioned within each earcup.

[0049] In some embodiments, the processor is configured to initiate a first group of wearable audio device functions based on an estimation of whether the wearable audio device is in proper place on the user's body. In one embodiment, the processor is configured to initiate a second group of wearable audio device functions based on an estimation of whether the user has completed operation of the wearable audio device, the functions of the second group being different from those of the first group. In one embodiment, the functions of the first and second groups include at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of a microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

[0050] In one embodiment, an internal microphone is monitored at a frequency in the range of 0 to 20 Hz, at least while estimating whether the user has completed operation of the wearable audio device. In one embodiment, a proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in place on the user's body is partially based on the level of the proximity sensor output. In some embodiments, after the processor has estimated whether the wearable audio device is in place on the user's body, the processor is configured to activate a predetermined wearable audio device function. In one embodiment, the predetermined wearable audio device function includes at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of the microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system. In one embodiment, the processor is further configured to initiate an active noise reduction (ANR) filter determination procedure after estimating that the user has completed operation of the wearable audio device.

[0051] In some embodiments, the wearable audio device further includes an orientation sensor configured to detect the orientation of the wearable audio device. In one embodiment, the processor is further configured to estimate, based at least on the orientation sensor, whether the user has removed the wearable audio device from the user's body. In one embodiment, the processor is configured to reduce power consumption based on the estimation of whether the user has removed the wearable audio device from the user's body. In one embodiment, the estimation of whether the user has removed the wearable audio device from the user's body is further based on a proximity sensor. In one embodiment, the processor's estimation of whether the wearable audio device is in proper place on the user's body is based on the proximity sensor and the orientation sensor. In one embodiment, the orientation sensor includes an accelerometer.

[0052] Figure 5 is a schematic cross-sectional view of an over-ear headphone 150 positioned on the user's head 152. Only one earcup 160 is shown positioned to cover the ear 154, defining an internal cavity 161 between the earcup 160 and the head 152 / ear 154. In most, though not all, headphones include two essentially identical earcups, one on each ear, mechanically connected by a headband 162. In the case of on-ear headphones, the earcups are designed to cover, rather than be on, the outer ear or auricle. The headphones 150 include an electroacoustic transducer 170 and an internal microphone 164, where the transducer 170 generates sound pressure within the cavity 161, and the microphone 164 is positioned to sense the sound pressure within the cavity 161. An external microphone 166 is positioned to sense external sounds to the earcup 160. The processor 168 is operably connected to the microphones 164 and 168 and the transducer 170. The headphones 150 also include a proximity sensor (not shown) configured to detect when the headphones are close to use. An exemplary proximity sensor is described further below with reference to Figure 6. Other typical headphone hardware and features are not shown or described.

[0053] Figure 6 is an internal view of the frame 180 of an earcup for over-ear headphones. The frame rim 182 carries a cushion (not shown). Region 184 is where an electroacoustic transducer (not shown) is located. A conductive member 186 is located on the inner surface of the frame 180. The conductive member 186 is configured as a capacitive proximity sensor used to detect the proximity of the earcup to the user's skin (e.g., ear or auricle). When the conductive member 186 approaches the skin, its capacitance changes. In some cases, the capacitance level indicates the degree of proximity of the conductive member 186 to the skin. Thus, the capacitance level can be used as a threshold indicator for the placement of the earcup over or over the ear. A processor (not shown) is configured to measure this capacitance change via a trace 188 connected to the processor. The conductive member 186 has a position and shape within the earcup such that it overlaps at least a portion of the human outer ear or auricle when the earcup is worn. Thus, the size, position, and shape of the conductive member 186 increase the likelihood of ear detection. In some embodiments, ear detection is used as a first low-level indication that the user has placed the headphones on their head. As will be described in more detail elsewhere in this specification, in some embodiments, the processor is configured to enable one or more functions of the headphones based at least in part on the proximity sensor. The proximity sensor may be located in one or both ear cups.

[0054] Figure 7 shows method 190 of the headphone attachment / detachment detection method. This method includes a first determination of whether the headphones are placed on the head, a second determination of whether the headphones are fully attached (in other words, whether the headphones are properly positioned over or covering the ears and are usable), and a third determination of whether the headphones have been removed from the head.

[0055] In step 192, the processor monitors proximity sensors to detect proximity to the head. In some embodiments, there is a proximity sensor that is part of only one of the two earcups. In other embodiments, there are two proximity sensors, one of each of the two earcups. When the head is detected, in step 194, an on-head determination is made, and then in step 196, a first group of headphone functions is activated. The on-head determination may be considered a low-reliability determination because it is based on only a single sensor. In some embodiments, this first group of headphone functions includes one or more of the following: power on, automatic playback of activated audio, automatic call answering of activated calls, Bluetooth connection, beamforming of microphones carried by the headphones, and activation of UI functions. In one embodiment, the functions to be activated are background functions such as turning on the processor, sensors, and Bluetooth. As a result, the chip, sensors, and other aspects of the headphones that use power may remain off until the on-head determination is made. This saves power.

[0056] A second level of determination that the headphones are fully worn and ready for use is based in step 198 on monitoring one or more internal microphones in one or both earcups. The microphones may be feedback microphones in the headphone ANR system. In one embodiment, at least one microphone in each earcup is monitored to detect when the user stops touching or moving both earcups, which typically occurs briefly after the headphones have been placed on the head while the user adjusts the position of the earcups for a more comfortable and better audio result. In one embodiment, the microphone output is monitored in the range of approximately 0–20Hz. This range is selected in part because sound / vibration in this range is generally unaffected by the ANR system, and therefore the response is expected to be the same regardless of which ANR is enabled. When a low threshold of sound monitored in the 0–20Hz range is reached, a determination of completion of wearing is made in step 200, and a second group of headphone functions is enabled in step 202. In some embodiments, the functions of the second group are different from those of the first group. In one embodiment, the second group of functions includes both functions involved in user interaction (such as switches, capacitive touch sensors, and microphone beamforming) and tuning of the ANR system. In some embodiments, measurements to provide a customized ANR are delayed until a "wearing complete" state is detected. These measurements generally consist of playing a tone and measuring the response with a feedback microphone to measure the unique response of the user's ear canal.

[0057] A third sensing state is when the user removes or takes off the headphones. In some embodiments, in step 204, one or both of the proximity sensor and / or inertial monitoring unit (IMU), or an accelerometer, are monitored, and in step 206, it is detected that the headphones are lying flat / horizontally, and the processor indicates an off-head state (i.e., the headphones are removed or "taken off"). In response, in step 208, the processor is activated and one or more headphone functions are disabled. In some embodiments, the headphones are powered off in response to off-head detection. In embodiments that use an accelerometer to detect orientation, when the headphones are worn on the head in a normal upright position, there is a steady-state acceleration due to gravity in one direction which may be called the "vertical" direction, and no acceleration in two orthogonal directions. When the headphones are removed and placed nearly flat, the steady-state acceleration is not on the original axis. Therefore, the processor can use the accelerometer to determine whether the headphones are lying flat.

[0058] In some embodiments, input from a proximity sensor (e.g., a capacitive proximity sensor) is used in combination with input from an IMU / accelerometer to determine if the headphones are in an off-head state. In some embodiments, input from the proximity sensor is monitored to detect when the user removes the headphones, but the headphones delay powering off until input from the IMU / accelerometer indicates that the headphones are placed horizontally. This can help prevent false off-head detection. For example, if the user briefly removes the headphones or earcups and readjusts them, the headphones may not change their function until the proximity sensor exceeds some threshold. This helps avoid interruptions to headphone function, such as when the user lifts one or both earcups, or when the headphones are adjusted after being put on, or when the head is briefly tilted to the side.

[0059] When a process is represented or suggested in a block diagram, the steps may be performed by one or more elements. These steps may be performed collectively or at different points in time. The elements performing the activities may be physically the same, in close proximity to each other, or physically separate. One element may perform the activities of two or more blocks. Audio signals may be encoded or unencoded, and may be transmitted in either digital or analog form. Conventional audio signal processing devices and their operation may be omitted from the drawings.

[0060] Examples of systems and methods described herein include computer components and computer implementation steps that would be obvious to those skilled in the art. For example, it should be understood by those skilled in the art that computer implementation steps may be stored as computer executable instructions on computer-readable media such as floppy disks, hard disks, optical disks, flash ROMs, non-volatile ROMs, and RAMs. Furthermore, it should be understood by those skilled in the art that computer executable instructions may be executed on various processors such as microprocessors, digital signal processors, and gate arrays. For the sake of ease of explanation, not all steps or elements of systems and methods are described herein as part of a computer system, but it will be recognized by those skilled in the art that each step or element may have a corresponding computer system or software component. Thus, such computer systems and / or software components are made possible by describing their corresponding steps or elements (i.e., their functionality) and are within the scope of this disclosure.

[0061] Several implementations have been described. Nevertheless, additional modifications can be made without departing from the scope of the concept of the present invention as described herein, and it is understood that other examples also fall within the scope of the following claims.

Claims

1. It is a wearable audio device, An electroacoustic transducer for generating sound, A proximity sensor configured to detect when the wearable audio device is in close proximity to the user, An internal microphone positioned within the housing of the wearable audio device and configured to detect sound in a cavity at least partially formed by a portion of the housing, An orientation sensor configured to detect the orientation of the wearable audio device, wherein the orientation sensor includes an inertial measuring unit (IMU), A processor configured to estimate, at least based on the proximity sensor, whether the wearable audio device is in the correct position on the user's body, and based on the internal microphone, whether the user has completed operation of the wearable audio device; Equipped with, The processor is further configured to determine that the wearable audio device is in an off-head state, and the determination is made based on input from the proximity sensor and input from the IMU of the wearable audio device.

2. The wearable audio device according to claim 1, further comprising at least one earcup configured to be positioned over or covering the wearer's ear when the wearable audio device is placed on the head, wherein both the proximity sensor and the internal microphone are positioned within the earcup.

3. The wearable audio device according to claim 1, wherein the proximity sensor includes a capacitive proximity sensor.

4. The wearable audio device according to claim 3, wherein the capacitance proximity sensor includes a conductive member inside the ear cup of the wearable audio device.

5. The wearable audio device according to claim 4, wherein the conductive member is configured to overlap at least a portion of the human auricle.

6. The wearable audio device according to claim 1, further comprising two earcups configured to be positioned over or covering the wearer's ears when the wearable audio device is placed on the head, each having an internal microphone positioned within the earcup, and the estimation of whether the user has completed operation of the wearable audio device is based on the internal microphone positioned within each of the earcups.

7. The wearable audio device according to claim 1, wherein the processor is configured to initiate a first group of wearable audio device functions based on the estimation of whether the wearable audio device is in the right place on the user's body.

8. The wearable audio device according to claim 7, wherein the processor is configured to initiate a second group of wearable audio device functions based on the estimation of whether the user has completed the operation of the wearable audio device, and the functions of the second group are different from the functions of the first group.

9. The wearable audio device according to claim 8, wherein the first and second groups of functions include at least one of: telephone answering capability, Bluetooth connectivity, beamforming of a microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

10. The wearable audio device according to claim 1, wherein, at least during the estimation of whether the user has completed operation of the wearable audio device, the internal microphone is monitored at a frequency in the range of 0 to 20 Hz.

11. The wearable audio device according to claim 1, wherein the proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in the right place on the user's body is based in part on the level of the proximity sensor's output.

12. The wearable audio device according to claim 1, wherein the processor is configured to enable a predetermined wearable audio device function after estimating whether the wearable audio device is in the appropriate place on the user's body.

13. The wearable audio device according to claim 12, wherein the predetermined wearable audio device function includes at least one of the following: telephone answering capability, Bluetooth connectivity, beamforming of a microphone carried by the wearable audio device, playback of audio received from an external audio source, activation of a user interface function, and tuning of an active noise reduction system.

14. The wearable audio device according to claim 1, wherein the processor is further configured to initiate an active noise reduction (ANR) filter determination procedure after it is assumed that the user has completed operation of the wearable audio device.

15. The wearable audio device according to claim 1, wherein the processor is further configured to estimate, at least based on the orientation sensor, whether the user has removed the wearable audio device from the user's body.

16. The wearable audio device according to claim 15, wherein the processor is configured to reduce power consumption based on the estimation of whether the user has removed the wearable audio device from the user's body.

17. The wearable audio device according to claim 15, wherein the estimation of whether the user has removed the wearable audio device from the user's body is further based on the proximity sensor.

18. The wearable audio device according to claim 1, wherein the processor estimates whether the wearable audio device is in the correct position on the user's body based on the proximity sensor and the orientation sensor.

19. The wearable audio device according to claim 1, wherein the orientation sensor includes an accelerometer.

20. The wearable audio device according to claim 1, further comprising two earcups configured to be positioned over or covering the wearer's ears when the wearable audio device is placed on the head, with proximity sensors located within each earcup.

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