Wearable audio device with improved output

Abstract

A wearable audio device with improved output, such as a wireless headset, is disclosed, which generates a synthetic sound signal based on a low-band signal and a high-band signal. The low-band signal includes a component of a user's voice obtained from an acoustic vibration sensor for detecting body-conducted sound, and the high-band signal includes a component of the user's voice obtained from a microphone for detecting atmospheric sound, wherein the low-band signal is mainly obtained from the acoustic vibration sensor and the high-band signal is mainly obtained from the microphone. The low-band signal and the high-band signal are based on one or more characteristics of the vibration sensor signal.

Description

Technical Field

[0001] The present disclosure relates generally to wearable audio devices, such as wireless earbuds, having improved audio output and circuitry therefor. Background Art

[0002] Wearable audio devices such as earbuds now typically include a microphone and circuitry to capture the user's voice and generate a corresponding audio signal for transmission to a host device, such as a mobile phone or other device that is paired with or otherwise connected to the wearable device. However, the audio signal generated by the wearable device may not be an accurate representation of the user's voice because the microphone is not directly in front of the user's mouth, there is ambient noise, and variability (e.g., ear canal seal) coupled to the user's body, as well as various other factors. The sound signal generated by such an audio signal may be characterized by poor tonal quality or sound color (referred to as timbre), and may sound too "tubby" from excessive low frequencies, or too "nasally" from inadequate low frequencies, resulting in poor intelligibility. Therefore, audio devices worn on the user's body (e.g., in the ear, around the neck, etc.) typically require compensation to more accurately reproduce the user's voice.

[0003] The objects, features and advantages of the present disclosure will become more fully apparent to those of ordinary skill in the art after carefully considering the following detailed description and the appended claims in conjunction with the accompanying drawings described below. Summary of the invention

[0004] According to an aspect of the present disclosure, there is provided a wearable audio device, the wearable audio device comprising: a microphone positioned to detect atmospheric sounds including the user's voice when the wearable audio device is worn by a user; an acoustic vibration sensor positioned to detect sounds including the user's voice conducted through the user's body when the wearable audio device is worn by the user; a body acoustic filter coupled to the acoustic vibration sensor; a high-pass filter coupled to the microphone; a filter parameter generator coupled to the acoustic vibration sensor, the body acoustic filter and the high-pass filter, the filter parameter generator being configured to generate parameters for the body acoustic filter and the high-pass filter based on frequency characteristics of a signal obtained from the acoustic vibration sensor; and a synthetic signal generator coupled to the body acoustic filter and the high-pass filter and configured to generate a synthetic sound signal based on a low-frequency band signal mainly obtained from the body acoustic filter and based on a high-frequency band signal mainly obtained from the high-pass filter.

[0005] According to another aspect of the present disclosure, a wearable audio device is provided, comprising: a microphone positioned to detect sounds including the user's voice when the wearable audio device is worn by a user; an acoustic vibration sensor positioned to detect sounds including the user's voice conducted through the user's body when the wearable audio device is worn by the user; and a synthetic signal generator connected to the microphone and the acoustic vibration sensor, the synthetic signal generator being configured to generate a synthetic sound signal based on a low-frequency band signal and a high-frequency band signal, wherein the low-frequency band signal is mainly obtained from the acoustic vibration sensor, and the high-frequency band signal is mainly obtained from the microphone. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic diagram of a wearable audio device implemented as a hearable device wearable in or on a user's ear.

[0007] Figure 2 yes Figure 1 A more detailed view of your hearable devices.

[0008] Figure 3 It is a wearable audio device implemented as a neckband.

[0009] Figure 4 is a graph of gain versus frequency of a composite signal including a low-band signal based on a vibration sensor signal and a high-band signal based on a microphone signal.

[0010] Figure 5 is a more detailed block diagram of a wearable audio device according to one embodiment. DETAILED DESCRIPTION

[0011] The present disclosure relates to a wearable audio device that detects acoustic signals of a user wearing the device and generates corresponding electrical audio signals for transmission to a host device, such as a mobile phone or other device that is paired with or otherwise connected to the wearable device. A microphone is integrated with the wearable device and is positioned to detect acoustic signals including noise and sound propagated through the atmosphere when the wearable device is worn by the user. A vibration sensor is integrated with the device and is positioned to capture sound and body noise conducted through the user's body when the wearable device is worn by the user.

[0012] Wearable audio devices can be wired earbuds, headphones, on-ear headphones, True Wireless Stereo (TWS) headphones, neckbands and other wearable audio devices, which include: one or more outward-facing microphones that can detect atmospheric acoustic signals or sounds; and one or more vibration sensors that can detect sounds conducted through the user's body.

[0013] exist Figure 1 In the embodiment, the wearable audio device is configured with a microphone 102 and a vibration sensor 104, which are close to the user's ear when the user wears the device. In this embodiment, the microphone is oriented outward to detect sounds propagating through the atmosphere. The vibration sensor is located in a position to detect sounds conducted through the user's body. Figure 2 In the embodiment of the present invention, the hearing device 200 includes a housing 202 having a stem portion 204 that partially fits in the ear canal of a user and an exterior portion 206 that is exposed to the atmosphere when worn by the user. The microphone 102 is integrated with the exterior portion 206 of the housing, where it can detect atmospheric noise and sound signals, and the vibration sensor 104 is integrated with a portion of the housing (such as the stem 204), where it can detect sound and other sounds conducted through the user's body. When the device is worn by the user, the seal between the exterior portion of the housing where the microphone is located and the stem portion where the vibration sensor is located can improve the isolation of the vibration sensor from sounds propagated through the atmosphere.

[0014] exist Figure 3In the embodiment, the wearable audio device is configured as a neckband having a neck loop portion 300, with one or more earphones electrically coupled to the circuit in the neckband. As shown, the microphone 102 faces outward from one or both earphones. In an alternative embodiment, the neckband has no earphones, and the microphone is integrated into a portion of the neck loop 300 where the user's voice and other atmospheric sounds can be detected. In either embodiment, the vibration sensor 104 is arranged on a portion of the collar 300 or close enough to a portion of the collar 300 where it can detect acoustic vibrations conducted through the user's body.

[0015] According to one aspect of the present disclosure, a wearable device generates a composite voice signal based on a low-band signal and a high-band signal. The composite voice signal is in an audio frequency band, and the "low" frequency band characteristics and the "high" frequency band characteristics are relative terms. Figure 4 , the synthesized signal includes a low-band signal 400 and a high-band signal 402. The low-band signal includes a component of the user's voice obtained from the acoustic vibration sensor, and the high-band signal includes a component of the user's voice obtained from the microphone. The low-band signal is mainly obtained from the acoustic vibration sensor, and the high-band signal is mainly obtained from the microphone. The synthesized signal can be personalized for the user of the wearable audio device by selecting the characteristics (e.g., bandwidth, cutoff frequency, slope, gain, etc.) of the low-band signal and the high-band signal based on one or more characteristics of the signal from the acoustic vibration sensor. The synthesized sound signal can be generated when a specific event occurs, and can also be adjusted by updating the low-band and high-band signals from time to time based on changes in the characteristics of the acoustic vibration sensor signal.

[0016] Typically, the characteristics of low-band signals are based on the characteristics of signals generated by acoustic vibration sensors. The characteristics of low-band signals (e.g., low cutoff frequency, slope ...) can be set to capture the first sound (i.e., fundamental frequency) frequency of the user. The first sound frequency of an adult is between about 60Hz and about 220Hz. For adult males, the first sound frequency is generally about 80Hz, and for adult females, it is about 165Hz. However, these ranges are only approximate, because there is significant variability in the sound frequency of people. Moreover, the first sound frequency of children can also be located outside these ranges. The low frequency f0 of the low-band signal can also be set to be higher than the low-frequency noise conducted by the body. The low-frequency noise conducted by the body can be determined based on the spectrum analysis of the vibration sensor signal, and the filter frequency f0 can be set or selected based on the noise level (e.g., energy or power) threshold. The high frequency f1 of the low-band signal and the filter roll-off slope (roll-off slope) can be determined based on the high frequency or upper frequency edge (high or upper frequency edge) and slope of the bandwidth of the signal output by the vibration sensor. The upper frequency edge and slope of the vibration sensor signal can be determined by spectrum analysis, and the high frequency f1 can be set or selected based on a signal level (e.g., energy or power) threshold. Figure 4 The low band signal has a low filter frequency f0 of 60 Hz and a high filter frequency f1 of 700 Hz, but these filter frequencies will be different for each proposed user.

[0017] The characteristics of the high-frequency band signal are also based on the characteristics of the signal generated by the acoustic vibration sensor. The characteristics of the high-frequency band signal (e.g., low cut-off frequency, slope ...) can be set or selected based on the characteristics of the low-frequency band signal, and a synthetic signal is provided, which has no significant ripples and other gain anomalies (gain anomaly or processing artifacts) that may adversely affect the audio quality. Typically, when the roll-off slope is high, such as 24dB / octave instead of 12dB / octave, the high filter frequency f1 of the low-frequency band signal and the low filter frequency f0 of the high-frequency band signal will converge. On the contrary, the filter frequencies of the low-frequency band and high-frequency band signals will diverge as the slope decreases. In one embodiment, the low filter frequency f0 of the high-frequency band signal is the same as the high filter frequency f1 of the low-frequency band signal. In Figure 4In the embodiment of the present invention, high frequency band signal 402 has a low filter frequency f0 of 700Hz, which is identical with the high filter frequency f1 of low frequency band signal 400. However, as suggested, the signal characteristics of low frequency band signal and high frequency band signal can be different. In other embodiments, the high filter frequency f1 of low frequency band signal and the low filter frequency f0 of high frequency band signal are different. Crossover frequency is the frequency that low frequency band and high frequency band signal cross.

[0018] exist Figure 5 In the embodiment of the present invention, the wearable audio device includes: a synthetic signal generator 106 connected to a microphone 102 and a vibration sensor 104. These and other connections described herein are electrical signal connections that enable the signal communication and processing described herein. The synthetic signal generator is configured to generate a synthetic sound signal based on a low-frequency band signal obtained primarily from the acoustic vibration sensor and based on a high-frequency band signal obtained primarily from the microphone.

[0019] exist Figure 5 In the embodiment, a body voice filter (BVF) 108 is provided in a signal path between an acoustic vibration sensor 104 and a synthetic signal generator 106. A high pass filter 112 is provided in a signal path between a microphone 102 and a synthetic signal generator. A filter parameter generator 110 is coupled to the acoustic vibration sensor 104, the body voice filter 108 and the high pass filter 112. In one embodiment, the low frequency band and the high frequency band are defined by a fourth order filter.

[0020] The filter parameter generator is configured to generate parameters of a body acoustic filter and a high pass filter based on a signal from an acoustic vibration sensor as described herein. The filter parameters include a cutoff frequency, an order / slope, a quality factor Q, and a gain. The filter parameter generator can be implemented as a code executed by a processor, which dynamically generates filter coefficients using an algorithm, or obtains filter parameters by referring to a lookup table storing pre-calculated coefficients. The filter parameter generator generates low cutoff frequency and high cutoff frequency, slope, and gain for the body acoustic filter 108. The filter parameter generator also generates parameters for the high pass filter 112. The filter parameters further indicate the crossover frequency between the low frequency band signal and the high frequency band signal. When configured with parameters from the filter parameter generator, the body acoustic filter outputs a low frequency band signal based on a signal including a user voice component obtained from a vibration sensor, and the high pass filter outputs a high frequency band signal based on a signal including a user voice component from a microphone. The low frequency band signal is effectively replaced by a low frequency microphone signal attenuated by a high pass filter, thereby eliminating the low frequency atmospheric noise detected by the microphone. Thus configured, the synthesized sound signal is based on the low-frequency band signal mainly obtained from the body acoustic filter and on the high-frequency band signal mainly obtained from the high-pass filter.

[0021] The wearable audio device can be configured to generate or update the characteristics of the low-band signal and the high-band signal from time to time by updating the parameters of the body sound filter and the high-pass filter. The filter parameters can be continuously or intermittently updated based on changes in one or more characteristics of the vibration sensor signal. Such changes in the acoustic vibration sensor signal can be changes in the user's voice due to fatigue or changes in mood, humidity, temperature, etc. The occurrence of other events can also prompt the generation or update of filter parameters. Such other events include: power on, the insertion of the hearable device into the user's ear, changes in the position or fit of the wearable audio device (e.g., sealing with the user's ear canal), environmental conditions, etc. In contrast, the generation or update of parameters can be paused when certain other events occur (e.g., ambient noise exceeding a predetermined threshold, etc.).

[0022] According to another aspect of the present disclosure, the wearable audio device includes a voice activity detection (VAD) function, and the wearable audio device is configured to generate or update the low-band signal and the high-band signal only when it is determined that the user wearing the wearable audio device is speaking. In this way, the filter parameter generator generates parameters based on one or more characteristics of the vibration sensor signal obtained when the user is speaking. Figure 5 In the embodiment of the present invention, a voice activity detector 118 is connected to the filter parameter generator 110, or for this purpose. It can be determined that the user is speaking based on the correlation between the signals from the voice activity detector, the acoustic vibration sensor or the microphone. For example, simultaneously detecting the signals from one or both of the microphone and the vibration sensor and the VAD can support the conclusion that the user is speaking. Greater certainty can be obtained by further processing such as spectral analysis of the signal before the correlation operation. Such further processing can include noise versus speech discrimination, word or voice detection, authentication, etc. These analyses and correlations can be performed by a processor that performs the filter parameter generation. Figure 2 A voice activity detector 208 is shown integrated with the hearable device 200. Using a VAD can reduce the collection of data to time periods when the likelihood of the user speaking is high or at least greater, and can eliminate or reduce unnecessary power consumption.

[0023] According to another aspect of the present disclosure, the wearable audio device is configured to adjust the synthesized signal by controlling the gain of the low-band signal or the high-band signal. For example, the gain of the low-band signal and the high-band signal can be equalized. The filter parameter generator can be configured to generate a time-variant gain of the low-band signal or the high-band signal based on the signal from the microphone. Figure 5 In, the low-band gain parameters may be provided to the body acoustic filter 108. Alternatively, the filter parameter generator may be coupled to the high-band gain amplifier 114 or the low-band gain amplifier 116 and configured to generate a gain control signal for the high-band gain amplifier 114 or the low-band gain amplifier 116. In one embodiment, the filter parameter generator is coupled to a microphone and configured to generate a gain for the low-band signal based on an energy ratio in a low-band portion to a high-band portion of the microphone signal, wherein a portion of the low microphone signal corresponds to a bandwidth of the low-band signal of the body acoustic filter. Figure 4 In order to be consistent with high gain signal 402, the gain of low frequency band signal 400 increases from lower level 401.More generally, filter parameters can be generated to generate any desired output response with the corresponding passband across low frequency band and high frequency band signal.So configured, low frequency band or high frequency band signal can be adjusted or balanced, with the contribution to composite signal of balance.Gain control can be realized at any time when updating filter parameters.

[0024] In some embodiments, the wearable audio device further comprises a sensor configured to sense when the wearable audio device is worn on or by a user. According to another aspect of the present disclosure, the wearable audio device is configured to generate or update the low-frequency band signal and the high-frequency band signal only when the wearable audio device is worn by the user. Figure 5 For this purpose, a sensor 120 is coupled to a filter parameter generator 110 . Figure 2 A sensor 210 is shown integrated with the stem portion 204 of the hearable device, where it can detect when the hearable device is inserted into or placed on the user's ear. The sensor can be an LED, infrared, or other sensor capable of detecting proximity, temperature, heat rate, or some other biological condition that indicates that the wearable audio device is being worn by the user. A filter parameter generator can be coupled to the sensor, and the filter parameter generator can be configured to generate or update parameters based on whether the wearable audio device is being worn as indicated by the sensor. Thus, for example, when the hearable device is inserted into the user's ear, low-band and high-band signals can be initially generated. Thereafter, the low-band and high-band signals can be updated from time to time based on changes in the characteristics of the signal from the vibration sensor.

[0025] Although the present disclosure and what is presently considered to be the best mode thereof have been described in a manner to establish the applicant's ownership and enable one of ordinary skill in the art to make and use the content, it should be understood and appreciated that within the scope and spirit of the present disclosure, there are equivalents to the exemplary embodiments disclosed herein, and that various modifications and variations may be made thereto, and the scope and spirit of the present disclosure is not limited by the exemplary embodiments, but rather by the appended claims.

Claims

1. A wearable audio device, comprising: a microphone positioned to detect atmospheric sounds including the user's voice when the wearable audio device is worn by the user; an acoustic vibration sensor positioned to detect sounds including the user's voice conducted through the user's body when the wearable audio device is worn by the user; a bulk acoustic filter coupled to the acoustic vibration sensor; a high pass filter coupled to the microphone; a filter parameter generator coupled to the acoustic vibration sensor, the body acoustic filter, and the high pass filter, the filter parameter generator being configured to generate parameters for the body acoustic filter and the high pass filter based on frequency characteristics of a signal obtained from the acoustic vibration sensor; and a synthetic signal generator coupled to the bulk acoustic filter and the high pass filter and configured to generate a synthetic sound signal based on a low frequency band signal obtained from the bulk acoustic filter and based on a high frequency band signal obtained from the high pass filter, and The filter parameter generator is configured to generate a crossover frequency between the low-frequency band signal and the high-frequency band signal from time to time based on a change in a frequency characteristic of a signal obtained from the acoustic vibration sensor.

2. The wearable audio device according to claim 1, wherein: The high filter frequency of the low frequency band signal is at the high frequency edge of the signal bandwidth of the acoustic vibration sensor.

3. The wearable audio device according to claim 2, wherein: The low filter frequency of the low frequency band signal is at the first sound frequency of the user.

4. The wearable audio device according to claim 2, wherein: The high filter frequency of the low frequency band signal is the same as the low filter frequency of the high frequency band signal.

5. The wearable audio device according to claim 1, wherein: The filter parameter generator is connected to the microphone and is configured to generate a gain for the low-band signal based on a ratio of energy in a low-band portion and a high-band portion of the signal from the microphone, wherein a bandwidth of the low-band portion of the signal from the microphone corresponds to a bandwidth of the low-band signal.

6. The wearable audio device of claim 1, further comprising a voice activity detector, wherein: The filter parameter generator is configured to generate parameters for the body sound filter and the high pass filter only when it is determined that the user wearing the wearable audio device is speaking based on the correlation between the signals from the microphone, the acoustic vibration sensor, and the voice activity detector.

7. The wearable audio device according to claim 1, wherein: The wearable audio device is a hearable device comprising a portion configured to be at least partially inserted into the ear of the user and another portion exposed to the atmosphere when the hearable device is worn by the user, wherein the acoustic vibration sensor is integrated with the portion of the hearable device configured to be at least partially inserted into the ear of the user, and the microphone is integrated with the other portion of the hearable device exposed to the atmosphere.

8. The wearable audio device of claim 7, further comprising a sensor integrated with the hearable device and configured to sense when the hearable device is worn by the user, wherein: The filter parameter generator is configured to generate or update parameters for the body sound filter and the high pass filter upon detecting that the hearable device is worn by the user.

9. A wearable audio device, comprising: a microphone positioned to detect sounds including the user's voice when the wearable audio device is worn by the user; an acoustic vibration sensor positioned to detect sounds including the user's voice conducted through the user's body when the wearable audio device is worn by the user; as well as a synthetic signal generator coupled to the microphone and the acoustic vibration sensor, the synthetic signal generator being configured to generate a synthetic sound signal based on the low-band signal and the high-band signal, wherein the low frequency band signal is obtained from the acoustic vibration sensor, and the high frequency band signal is obtained from the microphone, and Wherein, the wearable audio device is configured to adjust the crossover frequency of the low frequency band signal and the high frequency band signal from time to time based on changes in the characteristics of the signal from the acoustic vibration sensor.

10. The wearable audio device according to claim 9, wherein: The low-band signal and the high-band signal are based on characteristics of a signal from the acoustic vibration sensor.

11. The wearable audio device according to claim 10, wherein: The high filter frequency of the low frequency band signal is at the high frequency edge of the signal bandwidth of the acoustic vibration sensor, and the low filter frequency of the low frequency band signal captures the first voice frequency of the user.

12. The wearable audio device according to claim 11, wherein: The high filter frequency of the low frequency band signal is the same as the low filter frequency of the high frequency band signal.

13. The wearable audio device of claim 10, further comprising a voice activity detector, wherein: The wearable audio device is configured to select the characteristics of the low frequency band signal and the high frequency band signal only when it is determined that a user wearing the wearable audio device is speaking based on a correlation between signals from the voice activity detector and the acoustic vibration sensor.

14. The wearable audio device of claim 10, further comprising a sensor configured to sense when the wearable audio device is worn on the user, wherein: The wearable audio device is configured to generate or update the low frequency band signal and the high frequency band signal only when the wearable audio device is worn by the user.

15. The wearable audio device according to claim 9, wherein: The gain of the low-band signal and the gain of the high-band signal are equalized.

16. The wearable audio device according to claim 9, further comprising: a bulk acoustic filter in a signal path between the acoustic vibration sensor and the composite signal generator; a high pass filter in the signal path between the microphone and the synthesized signal generator; as well as a filter parameter generator coupled to the acoustic vibration sensor, the body acoustic filter and the high pass filter, the filter parameter generator being configured to generate parameters for the body acoustic filter and the high pass filter based on frequency characteristics of a signal output by the acoustic vibration sensor, wherein the body acoustic filter configured with the parameters from the filter parameter generator generates the low frequency band signal based on a signal obtained from the vibration sensor, and wherein the high pass filter configured with the parameters from the filter parameter generator generates the high frequency band signal based on a signal obtained from the microphone.

17. The wearable audio device of claim 16, the filter parameter generator being coupled to the microphone, wherein: The filter parameter generator is configured to generate a time-varying gain of the low-band signal or the high-band signal based on a signal from the microphone.

18. The wearable audio device of claim 9, further comprising a housing comprising a portion configured to be at least partially inserted into an ear of the user and another portion exposed to atmosphere when the wearable audio device is worn by the user, wherein The acoustic vibration sensor is integrated with the portion of the housing configured to be at least partially inserted into an ear of the user, and the microphone is integrated with the other portion of the housing exposed to atmosphere.

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