Audio device with recognition mode auto-leveler

Abstract

Various implementations include a system for providing enhanced recognition mode functionality in an ANR audio device. In a particular implementation, a method includes receiving an ambient noise signal from a microphone associated with a wearable audio device, determining a gain value based on a sound pressure level (SPL) of the ambient noise signal, generating a gain-adjusted ambient noise signal by applying the gain value to the ambient noise signal, generating a total external microphone signal by adding the gain-adjusted ambient noise signal to a noise-reduced ambient signal, generating an augmented audio signal by selectively adjusting a source audio signal based on the gain-adjusted ambient noise signal, and combining the augmented audio signal with the total external microphone signal and outputting it to an acoustic transducer.

Description

[Technical Field]

[0001] Priority claims This application claims priority to U.S. Provisional Patent Application No. 63 / 286,659, filed December 7, 2021, and U.S. Patent Application No. 18 / 062,108, filed December 6, 2022, each of which is incorporated by reference herein in its entirety.

[0002] The present disclosure relates generally to active noise reduction (ANR) devices that provide enhanced awareness mode functionality. [Background technology]

[0003] Acoustic devices such as headphones may include active noise reduction (ANR) functionality that blocks at least a portion of ambient noise from reaching a user's ears. Thus, the ANR device creates an acoustic isolation effect that at least partially isolates the user from the environment. To mitigate the effects of such isolation, some acoustic devices with ANR functionality may include a "awareness mode" that transmits ambient sounds to the user's ears along with the source audio being played on the acoustic device. Summary of the Invention

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

[0005]

[0006] Systems and approaches directed to an active noise reduction device with enhanced awareness mode functionality are disclosed. Some implementations provide a method that includes receiving an ambient noise signal from a microphone associated with a wearable audio device, determining a gain value based on a sound pressure level (SPL) of the ambient noise signal, generating a gain-adjusted ambient noise signal by applying the gain value to the ambient noise signal, generating a total external microphone signal by adding the gain-adjusted ambient noise signal to a noise-reduced ambient signal, generating an augmented audio signal by selectively adjusting a source audio signal based on the gain-adjusted ambient noise signal, and outputting the augmented audio signal to an acoustic transducer.

[0006] In an additional specific implementation, a wearable audio device is provided that includes an acoustic transducer and a microphone, and a signal processing system that performs the following operations: receiving an ambient noise signal from the microphone associated with the wearable audio device; determining a gain value based on a sound pressure level of the ambient noise signal; generating a gain-adjusted ambient noise signal by applying the gain value to the ambient noise signal; generating a total external microphone signal by adding the gain-adjusted ambient noise signal to a noise-reduced ambient signal; generating an augmented audio signal by selectively adjusting a source audio signal based on the gain-adjusted ambient noise signal; and outputting the augmented audio signal with the total external microphone signal to the acoustic transducer.

[0007] In a further implementation, a method includes obtaining a source audio signal and an ambient noise signal, comparing the ambient noise signal to a predefined hearing threshold, generating an effective noise signal in response to the comparison, generating an enhanced audio signal by selectively adjusting a sound pressure level of the source audio signal based on the effective noise signal, and driving an acoustic transducer of headphones using the enhanced audio signal.

[0008] In yet another approach, a method includes receiving an ambient noise signal from a microphone associated with a wearable audio device, determining a gain value based on a sound pressure level of the ambient noise signal, generating a gain-adjusted ambient noise signal by applying the gain value to the ambient noise signal, generating a total external microphone signal by adding the gain-adjusted ambient noise signal to a noise-reduced ambient signal, generating an augmented audio signal by selectively adjusting a source audio signal based on a noise control signal, and outputting the augmented audio signal with the total external microphone signal to an acoustic transducer.

[0009] Implementations may include one or any combination of the following features.

[0010] In various implementations, a signal-to-noise ratio (SNR) is determined from the source audio signal and the gain-adjusted ambient noise signal, and generating the enhanced audio signal includes selectively adjusting the source audio signal based on the SNR.

[0011] In some cases, generating the noise control signal includes generating a residual sound component based on the SPL of the ambient noise signal, and adding the residual sound component to the gain adjusted ambient noise signal.

[0012] In certain cases, the gain value is determined using a lookup table having a correspondence between SPL and gain value, the lookup table including a first SPL threshold below which the gain value is set to 1, a second SPL threshold above which the gain value is set to 0, and an SPL range between the first and second SPL thresholds within which the gain value varies between 1 and 0.

[0013] In some examples, generating the enhanced audio signal includes selectively adjusting the SPL for each of a plurality of different frequency bands of the source audio signal.

[0014] In another example, the method further includes determining a signal-to-noise ratio (SNR) from the source audio signal and the gain-adjusted ambient noise signal, where determining the SNR includes determining a sub-SNR for each of the different frequency bands, selectively adjusting the SPL of each different frequency band of the source audio signal based on the associated sub-SNR, and generating the enhanced audio signal includes selectively adjusting the source audio signal based on the SNR or according to a model of perceptual masking. In some aspects, selectively adjusting the SPL of each different frequency band of the source audio signal is based on the associated sub-SNR combined in a weighted manner with the sub-SNR for the lower frequency band.

[0015] In some examples, the different frequency bands of the audio signal include a low frequency band, a mid frequency band, and a high frequency band.

[0016] In some aspects, the SPL of the low frequency band is increased in response to the SNR meeting a first threshold, the SPL of the low and mid frequency bands is increased in response to the SNR meeting a second threshold, the SPL of the low, mid, and high frequency bands is increased in response to the SNR meeting a third threshold, and so on. 1 The first threshold is greater than the second threshold, and the second threshold is 3 is greater than the threshold.

[0017] In certain aspects, comparing the ambient noise signal to the hearing threshold includes comparing the energy level from each of a predefined set of frequency bands between the ambient noise signal and the hearing threshold.

[0018] In other cases, generating the effective noise signal includes determining a maximum value between the ambient noise signal and the hearing threshold for each of different frequency bands of a predefined set of frequency bands, and providing the effective noise signal using the maximum value for each of the frequency bands of the predefined set.

[0019] Two or more features described in this disclosure, including features described in this Summary section, may be combined to form implementations not specifically described herein.

[0020] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a block diagram of a wearable audio device having a recognition mode and audio leveling feature that provides audio leveling, according to various implementations. [Figure 2] 1 is a block diagram of a recognition mode audio device according to various implementations. [Figure 3] 10 illustrates hear-through characteristic graphs according to various implementations. [Figure 4] FIG. 1 is a block diagram of an expander utilized in a wearable audio device, according to various implementations. [Figure 5] 1 is a block diagram of an enhancement expander utilized in a recognition mode audio device, according to various implementations. [Figure 6] 1 illustrates an exemplary form factor of a recognition mode audio device, according to various implementations.

[0022] It should be noted that the drawings of the various implementations are not necessarily to scale. The drawings are intended to depict only typical aspects of the disclosure and therefore should not be considered limiting of the scope of the implementations. In the drawings, like numbering represents like elements between the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0023] Various implementations describe a solution that enables the use of active noise reduction (ANR) in acoustic devices while allowing users to be aware of surrounding sounds, referred to herein as an "awareness mode." Wearable ANR devices, such as ANR headphones, are used to potentially provide an immersive listening experience by reducing the impact of environmental noises and sounds near the user (referred to herein as "ambient noise"). However, by blocking the impact of ambient noise, ANR devices can create acoustic isolation from the environment, which may be undesirable in some conditions. For example, a user waiting at an airport may want to be aware of flight announcements while using ANR headphones. In another example, a user may want to use ANR headphones to cancel out cabin noise during a flight, while still being able to communicate with flight attendants without having to remove the headphones.

[0024] Various technical challenges exist with awareness mode audio devices, including the fact that the type and amount of ambient noise can change while the device is in use. To provide a balanced user experience, the amount of noise reduction may need to be increased or decreased to keep the ambient noise at a desired level. Additionally, as the ambient noise level increases, the source audio content may need to be boosted to compensate for the excess ambient noise reaching the user's ears. The approach described herein addresses these and other technical challenges by providing a awareness mode auto-leveler that automatically adjusts both the amount of noise cancellation and the amount of boost to provide a balanced user experience.

[0025] It is understood that the solutions disclosed herein are intended to be applicable to a wide variety of ANR-based wearable audio devices, i.e., devices structured to be at least partially worn by a user near at least one of the user's ears and to provide ANR functionality for at least one ear. The ANR processing may include either or both of feedback-based ANR and feedforward-based ANR. Exemplary wearable audio devices may include headphones, two-way communication headsets, earphones, earbuds, hearing aids, audio glasses, wireless headsets (also known as "earsets"), and ear protectors.

[0026] Additionally, the solutions disclosed herein are applicable to wearable audio devices that provide two-way audio communication, one-way audio communication (i.e., acoustic output of audio provided electronically by another device), or no communication. Furthermore, what is disclosed herein is applicable to wearable audio devices that connect to other devices wirelessly, via electrically and / or optically conductive cables, or are not connected to any other devices. These teachings are applicable to wearable audio devices having a physical structure configured to be worn near either one or both of a user's ears, including, but not limited to, headphones with one or two earpieces, over-the-head headphones, behind-the-neck headphones, headsets with a communication microphone (e.g., a boom microphone), in-ear or behind-ear hearing aids, wireless headsets (i.e., earsets), audio glasses, a single earphone or a pair of earphones, as well as hats, helmets, clothing, or any physical structure incorporating one or two earpieces to enable audio communication and / or ear protection. The presentation of specific implementations is intended to facilitate understanding through the use of examples and should not be construed as limiting either the scope of the disclosure or the applicability of the claims.

[0027] FIG. 1 illustrates an exemplary implementation of an ANR-based audio device ("audio device") 10 that provides an automatic leveler for adaptively managing recognition mode functionality. As illustrated, audio device 10 receives and processes a source audio signal 18 and an ambient noise signal 16. Source audio signal 18 may include any type of audio content, such as streaming music, telephone communications, an audio feed from an audiovisual source, a streaming podcast, an audio recording, etc. Ambient noise signal 16 may include any type of environmental noise captured by, for example, an ANR feedforward (i.e., external) microphone or any other microphone or array of microphones adapted to capture ambient noise near a user. In some implementations, audio device 10 includes (1) a first processing system 12 that adaptively routes some or all of the ambient noise signal 16, the resulting signal referred to herein as a "total external microphone signal" 34, and (2) a second processing system 14 that adaptively boosts source audio signal 18 to generate an enhanced noise signal 36. The first processing system 12 and the second processing system 14 work together to adaptively implement an auto-leveler that provides a balanced user experience under varying ambient noise conditions. In the example device 10 shown in FIG. 1, the generated total external microphone signal 34, the extended noise signal 36, and the feedback signal 33 (ANR feedback filter K fb 32 and the associated ANR feedback (generated by microphone 31) are combined and output to acoustic transducer 20. As a result, audio device 10 enables the user to achieve a desired balance of ambient awareness, auditory comfort, and media enjoyment.

[0028] In some exemplary approaches, the first processing system 12 may include an ANR filter (K nc) 22 and a modulator 24 that generates a gain-adjusted ambient noise signal 25 via a pass-through signal path 23. In some approaches, the amount of gain applied to the ambient noise signal 16 via the pass-through signal path 23 is based on the sound pressure level (SPL) of the ambient noise signal 16. In the illustrated example, the gain-adjusted ambient noise signal 25 is filtered by a filter K fb A pass-through filter (K) that shapes the external microphone signal to work in concert with the feedback-based ANR provided by aw ) 26. In some embodiments, K aw 26, for example, equalizes the spectrum of the ambient noise signal 16 so that the signal 16 sounds natural, as if it were unobstructed and the user were not wearing a headset. aw 26 also ensures that stability criteria are met for any acoustic path from the driver 20 to the external microphone that receives the ambient noise signal 16 .

[0029] The resulting noise-reduced ambient signal 17 and gain-adjusted ambient noise signal 25 are combined to produce a total external microphone signal 34 .

[0030] 2 illustrates an exemplary modulator 24 for generating a gain-adjusted ambient noise signal 25, which includes a variable gain amplifier 48 that adjusts the ambient noise signal 16 based on a calculated gain value 46. In some approaches, the gain value 46 is determined using (1) an energy calculator 40 that measures the SPL of the ambient noise signal 16, e.g., using A-weighting; (2) a gain lookup table 42 that determines a gain level based on the corresponding SPL; and (3) a filter 44 that generates the gain value 46 by, e.g., smoothing the gain level obtained from the lookup table. The filter 44 controls the trajectory of the gain signal to ensure that the recognition-mode signal does not jump up or down rapidly, allowing for smooth changes with a long time constant.

[0031] In some implementations, the modulator 24 can be configured to control the amplifier 48 according to one or more threshold conditions. The threshold conditions can be preset or set in response to user input. In some implementations, if the modulator 24 determines that the ambient noise signal 16 is below a certain threshold, the gain value 46 controls the amplifier 48 so that the gain of the pass-through signal path 23 is substantially equal to one. This allows the user to hear the ambient sounds with little or no attenuation. In some implementations, if the modulator 24 determines that the ambient noise signal 16 is equal to or greater than a certain threshold, the gain value 46 can be configured to control the amplifier 48 so that the overall gain of the pass-through signal path 23 is less than one and the output of the ANR filter 22 ( FIG. 1 ) results in attenuation of the ambient noise signal 16 at the ear. This allows the user to recognize environmental noises and sounds when the noise is below the threshold, but can utilize the ANR functionality of the device 10 to prevent loud sounds, such as vehicle sounds, sirens, or machinery sounds, from becoming uncomfortably loud when the noise exceeds the threshold.

[0032] 3 shows an exemplary graph illustrating the level of the gain-adjusted ambient signal 25 as a function of the ambient noise signal 16. In this case, the gain-adjusted ambient signal 25 is controlled by a modulator 24, which varies the amount of the gain-adjusted ambient signal 25 based on two threshold levels 64, 66 of the ambient noise signal 16. When the ambient noise signal 16 is below the first threshold 64, the gain-adjusted ambient signal 25 is passed through with substantially no reduction applied to the ambient noise signal 16 (e.g., the gain value is set to 1). When the ambient noise signal 16 is above the first threshold 64 but below the second threshold 66, the gain-adjusted ambient signal 25 is held at a substantially constant level, i.e., as the ambient noise signal 16 is increased, the gain is reduced to maintain a substantially constant sound pressure level at the ear (e.g., the gain value fluctuates between 1 and 0). When the ambient noise signal 16 is above the second threshold 66, the gain-adjusted ambient signal 25 is set to a minimum (e.g., the gain value is set to 0). It should be noted that in an alternative approach, curve 62 may be achieved with a compressor in which the slope between first threshold 64 and second threshold 66 may be greater than zero.

[0033] Aspects relating to the first processing system 12 are further described in U.S. Patent Application Publication No. 2019 / 0130928, entitled "Compressive Hear-Through In Personal Acoustic Devices," published May 2, 2019, which is incorporated herein by reference in its entirety.

[0034] As noted herein, in certain implementations, one purpose of first processing system 12 is to determine the amount of ambient noise that should be transmitted to the listener. In an alternative approach to that described in FIGS. 1 and 2, rather than (or in addition to) controlling gain value 46 in pass-through path 23, feed-forward filter K nc 22 and / or feedback filter K fb 32. By reducing the noise cancellation signal in this way, the amount of noise reduction can be controlled by varying K aw26 does not need to overcome all active noise reduction components, only small passive noise reduction components(s).

[0035] 1 and 2 , in addition to generating the total external microphone signal 34, the first processing system 12 also outputs a noise control signal 27 to the second processing system 14. In certain approaches, the second processing system 14 automatically adjusts the SPL of the source audio signal 18 to generate the expanded audio signal 36 based at least in part on a comparison of the SPL of the source audio signal 18 and the ambient noise signal 16 (or a signal derived therefrom). In this way, as the ambient noise becomes louder, the audio output of the audio device 10 is automatically adjusted to be louder. If the ambient noise changes, for example, to a quieter environment with a lower SPL, the volume of the audio output is reduced. In various approaches, the noise control signal 27 reflects how much ambient noise is present in the environment and is utilized to determine how much SPL expansion should be applied to the source audio signal 18. In some cases, the second processing system 14 also includes an equalizer (Keq) 28 that initially processes the source audio signal 18, e.g., adjusts the frequency response to target some aspect of the ear after processing by the system.

[0036] In some examples, the noise control signal 27 is based on the gain adjusted ambient noise signal 25 generated by the modulator 24. In the exemplary modulator 24 shown in FIG. 2, the noise control signal 27 is a combination of the gain adjusted ambient noise signal 25 and K TIG 50 and the residual sound component (RSC) 52 generated by K TIG50 is a filter that attenuates external sounds to model the residual sound that reaches the ear even with full ANR. In this case, the gain adjusted ambient noise signal 25 is zero and the noise reduced ambient signal 17 is non-zero. Therefore, the sum, or total external microphone signal 34, is not zero. Thus, RSC 52 provides the SPL received at the ear when the sound is actually loud outside and the total external microphone signal 34 is essentially blocked. Other approaches use K instead of being implemented as a filter. TIG 50 can simply be implemented as a scalar gain to provide RSC52.

[0037] FIG. 4 illustrates an exemplary embodiment of the expander 30 in which a signal-to-noise ratio (SNR) calculator 70 is utilized to generate a side-chain input 74 for controlling the adaptive audio expander 72. In certain cases, the SNR calculator 70 receives both the source audio signal 18 and the noise control signal 27 (possibly including, at least in part, the gain-adjusted ambient noise signal 25), calculates an SNR value, and outputs a side-chain input 74. The side-chain input 74 may consist of the calculated SNR value itself or a value derived from the SNR value. The SNR calculator 70 may include any system for evaluating the source audio signal against the noise signal and outputting a side-chain value 74, which may include, for example, a ratio, a difference, one or more derived values, etc. Nevertheless, the adaptive audio expander 72 uses the side-chain input 74 to control the expansion of the source audio signal 18, i.e., in generating the expanded audio signal 36. In certain cases, the higher the SNR value, the more SPL boost is provided by the adaptive audio expander 72.

[0038] In the above implementation, the noise control signal 27 includes, at least in part, the gain-adjusted ambient noise signal 25. In an alternative approach, rather than calculating an SNR value ( FIG. 1 ) using the gain-adjusted ambient noise signal 25, the noise control signal 27 may include calculated values ​​that capture or predict one or more spectral characteristics of the ambient noise signal 16. In certain cases, the SPL or other information derived from the ambient noise signal 16 and / or the total external microphone signal 34 may be analyzed, for example, by a signal processor using a table of pre-calculated metrics, a machine learning system that evaluates the acoustic environment, or the like, to generate one or more spectral characteristic values. The resulting value(s) may then be sent directly to the adaptive audio expander 72, which may utilize the value(s) to adaptively boost the source audio signal 18. Thus, the noise control signal 27 may include any type of information or signal that captures, predicts, forecasts, or the like the amount of ambient noise in an environment.

[0039] According to various implementations, the amount or type of SPL expansion provided by the expander 30 may be based on several factors. In some cases, the expansion is based on a threshold level of the sidechain input 74. In certain cases, different amounts of boost in SPL are applied to any number of different frequency bands. In one example, different boosts are applied to the low (i.e., low frequencies), mid (i.e., mid frequencies), and / or high (i.e., high frequencies) bands. In one example, the low frequency band refers to lower frequencies below 100 Hz, the mid frequency band refers to frequencies between 100 Hz and 4 kHz, and the high frequency band refers to higher frequencies above 4 kHz. According to various implementations, the SPL boost applied to the low frequency bands is greater than the SPL boost applied to the mid frequency bands, which is greater than the SPL boost applied to the high frequency bands.

[0040] In some cases, the SPL of the low frequency band is increased in response to the SNR meeting a first threshold, the SPL of the low and mid frequency bands is increased in response to the SNR meeting a second threshold, the SPL of the low, mid, and high frequency bands is increased in response to the SNR meeting a third threshold, and so on. 1 The first threshold is greater than the second threshold, and the second threshold is 3 is greater than the threshold.

[0041] Table 1 provides exemplary SPL boost values ​​in dB applied to music audio based on frequency range. The music has a constant SPL of 70 dB estimated at the user's ear. The ambient noise (derived from noise control signal 27) increases from 50 dB to 65 dB in 5 dB increments. Because there is no or substantially no feedback path, the SPL boost applied for each frequency range does not result in an increase (or substantial increase) in the estimated music SPL at the user's ear. The SPL increase or decrease is controlled independently for each frequency range. As shown in Table 1, the SPL of low-band frequencies is boosted more than the SPL of mid-band frequencies, which are boosted more than the SPL of high-band frequencies. Correspondingly, when the ambient noise decreases (i.e., the SNR increases), for example, from 65 dB to 50 dB, the SPL of low-band frequencies decreases more than the SPL of mid-band frequencies, which in turn decrease more than the SPL of high-band frequencies. Additionally, some limits can be placed on the maximum allowable gain in each band.

[0042] [Table 1]

[0043] In some approaches, sub-SNRs are determined for different frequency bands from the ambient noise signal and the gain-adjusted ambient noise signal by SNR calculator 70. Thus, for example, sub-SNRs may be determined for a low band, a mid band, and a high band to generate three sidechain input values ​​74. The SPL of each different frequency band of source audio signal 18 is then selectively adjusted by adaptive audio expander 72 based on the associated sub-SNR.

[0044] Related aspects for implementing an expander are described in U.S. Patent Application Publication No. 2020 / 0143790, entitled "Ambient Volume Control in Open Audio Devices," published May 7, 2020, the contents of which are incorporated herein by reference in their entirety.

[0045] Referring to FIG. 5, an enhancement expander 80 for generating an enhanced audio signal 38 from a source audio signal 18 is shown. In this approach, an SNR calculator 70 utilizes an effective noise signal 86 generated by a comparator 82 to determine the sidechain input 74 to the audio expander 72. In a particular approach, the comparator 82 compares the energy level of the ambient noise signal 16 with an audiogram of a user's predefined hearing threshold 84, and uses the maximum of the two as the effective noise signal 86. By using the predefined hearing threshold 84, the user hears content only if it is sufficiently loud (i.e., frequency-dependent), and the sound is not masked by the noise (again frequency-dependent). Therefore, hearing loss or masking by ambient sounds are equivalent, and the same method can be used to ensure that the listener perceives the full spectrum of sound.

[0046] In some cases, comparator 82 compares energy levels across a predefined set of frequency bands or ranges. In certain cases where predefined frequency bands are compared, the maximum value of each comparison of the predefined set of frequency bands is combined to provide effective noise signal 86. In other cases where predefined frequency bands are compared, the maximum value of each comparison of the predefined set of frequency bands can be used to determine a sub-SNR by SNR calculator 70. The resulting sub-SNR can be used by audio expander 72 to control the expansion of individual frequency bands. (In various cases, the maximum value is the maximum value of the signal either within a given range or across the entire domain.)

[0047] It will be appreciated that the reinforcement expander 80 may be implemented separately from the first processing system 12 (FIG. 1) or may be integrated with the first processing system 12. When the expander 80 is integrated with the first processing system 12, the ambient noise signal 16 may include a gain adjusted ambient noise signal 25 or other noise control signal 27 derived from the ambient noise signal 16. When implemented separately, the ambient noise signal 16 may be obtained, for example, from any external microphone.

[0048] It should be understood that device 10, as shown and described according to various implementations, may be structured to be worn by a user to provide audio output proximate at least one of the user's ears. Device 10 may have any of several form factors, such as configurations incorporating a single earpiece to provide audio to only one of the user's ears, other configurations incorporating a pair of earpieces to provide audio to both of the user's ears, and other configurations incorporating one or more standalone speakers to provide audio to the user's surrounding environment.

[0049] FIG. 6 is a block diagram of an embodiment of an in-ear wearable audio device 100 having two earphones 112A and 112B, each configured to transmit sound toward a user's ear. (Reference numerals labeled "A" or "B" indicate a specific one of the two earphones and a corresponding identified function. However, for simplicity, lettering is omitted from the following description; for example, earpiece 112 refers to either or both earpieces 112A and 112B.) Each earpiece 112 includes a case 114 defining a cavity 116 that houses an electroacoustic transducer 128 for outputting audio signals to the user. Additionally, at least one internal microphone 118 is also disposed within cavity 116. In an implementation in which wearable audio device 100 is wearable on the ear, an ear coupling 120 (e.g., an ear tip or ear cushion) attached to case 114 surrounds an opening to cavity 116. A passageway 122 is formed through the ear coupling 120 and communicates with the cavity 116 at an opening. In various implementations, one or more external microphones 124 are positioned on the case 112 in a manner that allows acoustic coupling to the environment external to the case.

[0050] Audio output by transducer 128, including both the source audio signal and the aggregate external microphone signal, is implemented by audio processing system 130, which incorporates first and second processing systems 12, 14 described herein. Audio processing system 130 may be integrated into one or both earpieces 112 or may be implemented by an external system. If audio processing system 130 is implemented by an external system, each earpiece 112 may be coupled to audio processing system 130 in either a wired or wireless configuration. In various implementations, audio processing system 130 may include hardware, firmware, and / or software for providing various features to support operation of wearable audio device 100, including providing, for example, power, amplification, input / output, network interface, user controls, ANR, signal processing, data storage, data processing, voice detection, etc.

[0051] In implementations that include ANR to enhance the audio signal, the inner microphone 118 may function as a feedback microphone, and the outer microphone 124 may function as a feedforward microphone. In such implementations, each earphone 112 may utilize ANR circuitry in communication with the inner microphone 118 and the outer microphone 124. The ANR circuitry receives the internal signal generated by the inner microphone 118 and the external signal generated by the outer microphone 124 and performs ANR processing on the corresponding earphone 112. This process includes providing a signal to an electroacoustic transducer (e.g., a speaker) 128 located within the cavity 116 to generate an anti-noise acoustic signal that reduces or substantially prevents sound from one or more acoustic noise sources external to the earphone 112 from being heard by the user.

[0052] It will be understood that one or more of the functions of the described systems may be implemented as hardware and / or software, and that the various components may include communication paths connecting the components by any conventional means (e.g., wired and / or wireless connections). For example, one or more non-volatile devices (e.g., centralized or distributed devices such as flash memory devices) may store and / or execute programs, algorithms, and / or parameters of one or more of the described systems of devices. Also, the functionality described herein, or portions thereof, and various modifications thereof (hereinafter "functions"), may be implemented, at least in part, via a computer program product (e.g., a computer program tangibly embodied in an information carrier, such as one or more non-transitory machine-readable media, for execution by or to control the operation of one or more data processing devices (e.g., programmable processors, computers, multiple computers, and / or programmable logic components, etc.)).

[0053] The computer program may be written in any form of programming language, including compiled or interpreted languages, and may be arranged in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may be arranged to be executed on one computer, on multiple computers at one site, or distributed across multiple sites and interconnected by a network.

[0054] Actions associated with carrying out all or a portion of the functions may be performed by one or more programmable processors executing one or more computer programs to perform the functions. All or a portion of the functions may be implemented as special purpose logic circuitry, such as a field programmable gate array (FPGA) and / or an application-specific integrated circuit (ASIC). Processors suitable for executing computer programs include, by way of example, both general-purpose and special-purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor may receive instructions and data from a read-only memory, a random-access memory, or both. Elements of a computer include a processor for executing instructions and one or more memory devices for storing instructions and data.

[0055] It should be noted that while the implementations described herein utilize a microphone system to collect input signals, it is understood that any type of sensor, e.g., accelerometer, thermometer, optical sensor, camera, etc., may be utilized separately or in addition to a microphone system to collect input signals.

[0056] Additionally, actions associated with implementing all or a portion of the functionality described herein may be performed by one or more networked computing devices that may be connected via a network, e.g., one or more wired and / or wireless networks, such as a local area network (LAN), a wide area network (WAN), a personal area network (PAN), an internet-connected device and / or network, and / or cloud-based computing (e.g., cloud-based servers).

[0057] In various implementations, electronic components described as "coupled" may be linked via conventional wired and / or wireless means such that the electronic components can communicate data with one another. Furthermore, subcomponents within a given component may be considered to be linked via conventional paths, although not necessarily shown.

[0058] Although multiple implementations have been described, it is nevertheless understood that additional modifications may be made without departing from the scope of the inventive concepts described herein, and, accordingly, other implementations are within the scope of the following claims. [Explanation of symbols]

[0059] 10 devices 12 First Processing System 14 Second Processing System 16 Ambient noise signal 17 Noise reduction ambient signals 18 source audio signals 20 Acoustic Transducer 20 Drivers 21 Noise reduction route 22 ANR filter 23 Pass-Through Signal Path 24 Modulator 25 Ambient noise signal 26 Pass-through filter (Kaw) 27 Noise Control Signal 28 Equalizer (Keq) 30 Expander 31 ANR Feedback Microphones 33 Feedback back signal 34 total external microphone signals 36 Extended Audio Signals 38 Extended Audio Signals 40 Energy Calculator 42 Gain Lookup Table 44 filters 46 Gain Value 48 Amplifier 52 Residual sound component (RSC) 62 curve 64 First Threshold 66 Second Threshold 70 SNR Calculator 72 Adaptable Audio Expander 74 Sidechain Inputs 80 Expander 82 Comparator 84 Hearing Threshold 86 Effective noise signal 100 In-Ear Wearable Audio Devices 112 earpiece 114 cases 116 Cavity 118 Internal Microphone 120 Ear Coupling 122 Passage 124 Outside Microphone 128 Electroacoustic Transducer 130 Audio Processing System

Claims

1. 1. A method comprising: receiving an ambient noise signal from a microphone associated with a wearable audio device; determining a gain value based on a sound pressure level (SPL) of the ambient noise signal; applying the gain value to the ambient noise signal to generate a gain adjusted ambient noise signal; generating a total external microphone signal by adding the gain adjusted ambient noise signal to a noise-reduced ambient signal; generating an enhanced audio signal by selectively adjusting a source audio signal based on the gain adjusted ambient noise signal; combining the extended audio signal with the total external microphone signal and outputting the combined signal to an acoustic transducer; 10. The method of claim 9, wherein adjusting the source audio signal to generate the enhanced audio signal is based on combining the gain adjusted ambient noise signal with a residual sound component, the residual sound component being based on the SPL of the ambient noise signal.

2. determining a signal-to-noise ratio (SNR) from the source audio signal and the gain adjusted ambient noise signal; The method of claim 1 , wherein generating the enhanced audio signal comprises selectively adjusting the source audio signal based on the SNR.

3. The gain value is determined using a lookup table having a correspondence between SPL and gain value, the lookup table comprising: a first SPL threshold below which the gain value is set to 1; a second SPL threshold above which the gain value is set to zero; The method of claim 1 , further comprising an SPL range between the first SPL threshold and the second SPL threshold, the gain value varying between 1 and 0.

4. The method of claim 1 , wherein generating the enhanced audio signal comprises selectively adjusting an SPL for each of a plurality of different frequency bands of the source audio signal.

5. determining a signal-to-noise ratio (SNR) from the source audio signal and the gain adjusted ambient noise signal; determining the SNR includes determining a sub-SNR for each of the different frequency bands; The method of claim 4 , wherein selectively adjusting the SPL of each of the different frequency bands of the source audio signal is based on an associated sub-SNR.

6. The method of claim 4 , wherein the different frequency bands of the source audio signal include a low frequency band, a mid frequency band, and a high frequency band.

7. the SPL of the low frequency band is increased in response to a signal-to-noise ratio (SNR) satisfying a first threshold; the SPL for the low frequency band and the mid frequency band is increased in response to the SNR meeting a second threshold; the SPL for the low frequency band, the mid frequency band, and the high frequency band is increased in response to the SNR meeting a third threshold; the first threshold is greater than the second threshold, and the second threshold is greater than the third threshold; The method of claim 6.

8. A wearable audio device, comprising: an acoustic transducer; A microphone and 1. A signal processing system that performs the following operations: receiving an ambient noise signal from a microphone associated with a wearable audio device; determining a gain value based on a sound pressure level (SPL) of the ambient noise signal; applying the gain value to the ambient noise signal to generate a gain adjusted ambient noise signal; generating a total external microphone signal by adding the gain adjusted ambient noise signal to a noise-reduced ambient signal; generating an enhanced audio signal by selectively adjusting a source audio signal based on the gain adjusted ambient noise signal; and a signal processing system including: combining the extended audio signal with the total external microphone signal and outputting the combined signal to an acoustic transducer; 10. A wearable audio device, wherein adjusting the source audio signal to generate the enhanced audio signal is based on combining the gain-adjusted ambient noise signal with a residual sound component, the residual sound component being based on the SPL of the ambient noise signal.

9. determining a signal-to-noise ratio (SNR) from the source audio signal and the gain adjusted ambient noise signal; The device of claim 8 , wherein generating the enhanced audio signal comprises selectively adjusting the source audio signal based on the SNR.

10. The gain value is determined using a lookup table having a correspondence between SPL and gain value, the lookup table comprising: a first SPL threshold below which the gain value is set to 1; a second SPL threshold above which the gain value is set to zero; 9. The device of claim 8, further comprising an SPL range between the first SPL threshold and the second SPL threshold, wherein the gain value varies between 1 and 0.

11. determining a signal-to-noise ratio (SNR) from the source audio signal and the gain adjusted ambient noise signal; determining the SNR includes determining a sub-SNR for each of a plurality of different frequency bands of the source audio signal; The device of claim 8 , wherein selectively adjusting the SPL of each of the different frequency bands of the source audio signal is based on an associated sub-SNR.

12. the different frequency bands of the source audio signal include a low frequency band, a mid frequency band, and a high frequency band; the SPL of the low frequency band is increased in response to the SNR meeting a first threshold; the SPL for the low frequency band and the mid frequency band is increased in response to the SNR meeting a second threshold; the SPL for the low frequency band, the mid frequency band, and the high frequency band is increased in response to the SNR meeting a third threshold; The device of claim 11 , wherein the first threshold is greater than the second threshold, and the second threshold is greater than the third threshold.

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