Over-the-ear (OTE) hearing protection device with compensation

Abstract

A hearing protection device (HPD) (110) and method include over-the-ear (OTE) earcups (114, 116) combining built-in ITE occlusion testing with compensated audio signals using previously stored hearing frequency profiles associated with a user / use or type / brand of earplugs used with the HPD. Audio signals are frequency adjusted to enhance desired content for intelligibility and user safety. Audio and / or volume compensation may be applied to wired or wirelessly received communications received by the HPD and / or to ambient sounds to adjust frequency-specific audio energy based on the earplug occlusion to enhance desired sounds such as speech and diminish undesired noise to improve situational awareness for users. The HPD may generate the hearing frequency profiles and / or remotely-generated profiles may be transferred to the HPD. Noise dosing information associated with sound level exposure over time may be used to adjust the ambient pass-thru cutoff threshold. Active noise cancellation (ANC) with feedback and / or feedforward control may also be performed.

Description

OVER-THE-EAR (OTE) HEARING PROTECTION DEVICE WITH COMPENSATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63 / 607,560 filed December 7, 2023, the disclosure of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] This application relates to an over-the ear (OTE) hearing protection device with audio and volume compensation for individual users, in-the-ear (ITE) hearing protection devices including various types of earplugs, and / or particular applications.BACKGROUND

[0003] Intra-aural or in-the-ear (ITE) hearing protection devices (HPD’s) and circumaural or over-the-hear (OTE) (muff style) HPD’s are often used in elevated noise environments to provide hearing protection, either alone or in combination. In an increasingly noisy world, hearing protection has become a matter of paramount importance. ITE HPDs, including various types of earplugs, have been relied upon as indispensable tools for safeguarding auditory well-being in a wide variety of noisy occupational environments. These unassuming, yet highly effective, devices serve as a shield against the harmful effects of exposure to excessive noise, making them a vital accessory for a wide range of recreational as well as occupational scenarios, such as attending a loud concert, working in a noisy industrial, aerospace, military, entertainment, or tactical environment, etc.

[0004] Earplugs and similar ITE HPDs come in various types, each designed to cater to specific needs and preferences. Some examples include foam earplugs made of soft, compressible foam that expands in the ear canal to provide a snug fit provide noise reduction and are often disposable, making them suitable for occasional use. Silicone earplugs are reusable and can be moldable for a customized fit to an individual's ear canal providing a comfortable and effective seal. Flanged earplugs have multiple soft, flexible flanges that create a seal in the ear canal and arecommonly used by industrial workers, motorcyclists, and musicians as they offer a balance between comfort and protection. Custom-molded earplugs are individually molded to fit the user's ear canal and may be made by taking an impression of the ear. While custom molded earplugs provide superior comfort and noise reduction, they are more costly to produce and may require trained technicians to for making the impressions and molding the earplugs. High-fidelity earplugs may be designed to reduce noise without distorting sound quality and are often used by musicians and concertgoers to protect their hearing with better sound fidelity. Electronic earplugs with active noise reduction (ANR) or active noise cancellation (ANC) may use a processor to generate a phase-shifted audio signal based on detected ambient noise that combines with noise to reduce or cancel the noise reaching the eardrum or tympanic membrane. Some of these devices can also amplify ambient sounds, making them valuable for shooting sports, hunting, and professional settings where situational awareness is desired.10005] Regardless of the type of ITE HPD, proper fit is needed for effective hearing protection, and an improper fit can significantly compromise the ability to reduce noise. When earplugs do not fit correctly, noise leak paths allow sound to bypass the earplugs and reach the ear canal. Proper fit may be influenced by how the user places the earplug in the ear canal in addition to the physical shape and size of the earplugs, which may change after repeated use or with each placement or adjustment by the user. The ear canal shape and dimensions (size, depth, configuration) on an individual also affects the fit of a given style of ITE HPD in a specific user. While earplugs are typically designed to provide a specific Noise Reduction Rating (NRR) that indicates the level of noise reduction when properly inserted, improper fitment can significantly reduce the NRR and may lead to unknowing and unintended exposure to harmful noise levels for the user resulting in temporary or permanent noise- induced hearing loss (NIHL). Various strategies for fit testing of ITE HPD are described in commonly owned and co-pending US2024 / 0148557A1, the disclosure of which is hereby incorporated by reference in its entirety.(0006) On the other hand, it is well understood that individuals are accustomed to operating with full environmental auditory information in various situations, and properly worn HPD’s can dramatically reduce the availability and intelligibility of “wanted” sound content, which may include speech, alarms, approaching vehicles, animals, or people, etc. As such, users will prioritize personal safety and communication effectiveness over hearing protection with the actual protection providedby well-performing HPD’s eroded by user’s intentionally compromising performance to hear desired or needed sounds to provide situational awareness and / or to facilitate communication.SUMMARY100071 The present inventors have recognized that alternative HPD technologies can be applied to enhance the user’s mission effectiveness for various applications such that users want to wear HPD’s that provide appropriate protection. By providing audio compensation, volume level compensation, and / or adaptive threshold shutoff levels for talk-thru applications in an OTE HPD or headset, the HPD or headset may enhance user compliance and attention to recommended use and fitment for optimal mission effectiveness. Various embodiments provide normal passive attenuation or can add ANC using feedback and / or feedforward control. Embodiments may include active / personalized audio compensation with adjustments to communication signals and talk-thru audio to compensate for user auditory losses and provide situational awareness, and noise dosing information that may be used to monitor and / or respond to accumulated noise exposure to provide adaptive shutoff thresholds for talk-thru applications.

[0008] In one or more embodiments, an OTE hearing protection device includes a headband configured to extend around the head of a user, left and right OTE earcups each connected to a respective end portion of the headband and configured for positioning over respective ears of the user, left and right ambient microphones each associated with a respective one of the earcups and configured to generate signals responsive to ambient sound, left and right internal microphones each positioned within a respective one of the earcups and configured to generate signals responsive to sound within the earcups, left and right speakers each positioned within a respective one of the earcups and configured to generate sound responsive to at least one of a communication signal and the signal from a respective one of the ambient microphones, and at least one processor in communication with the ambient microphones, the internal microphones, and the speakers. The at least one processor programmed to retrieve left and right hearing frequency profiles previously stored in memory accessible by the at least one processor, apply a speech isolation filter to signals from the ambient microphones to generate respective left and right filtered speech signals, apply the retrieved left and right hearing frequency profiles to the left and right filtered speech signals to generate respective leftand right audio signals, and output the left and right audio signals to the left and right speakers, respectively. The at least one processor may be further programmed to generate the left and right hearing frequency profiles.

[0009] In various embodiments, the hearing protection device includes at least one processor programmed to: control the left and right speakers to sequentially generate sound at each of a plurality of frequencies, the sound increasing in sound pressure level (SPL) at each of the plurality of frequencies for each speaker until receiving a signal responsive to user input; store an SPL value in the memory accessible by the at least one processor for each of the plurality of frequencies in response to the user input; compare each stored SPL value to a corresponding reference value to determine associated difference values; and store the difference values in the memory as the left and right hearing frequency profiles. In some embodiments the hearing frequency profiles are remotely generated by a third-party and associated with a particular type, model, brand, size, etc. of earplugs. In one embodiment, the left and right hearing frequency profiles are associated with one of a plurality of commercially available ear plugs. In other embodiments, the hearing frequency profiles are generated by the hearing protection device or a similar device for a particular user and stored for subsequent use. Embodiments may also use generalized hearing frequency profiles generated by a third-party for common applications, such as airport support, shooting range, etc. or generated for a particular location, such as a manufacturing plant. In embodiments where the hearing protection device is used to generate the hearing frequency profiles, the user input may be provided by a signal from a volume control positioned on one of the OTE earcups, or by a signal from a wirelessly connected smartphone.

[0010] In one or more embodiments, the hearing protection device includes at least one processor programmed to adjust volume of the left and right audio signals in response to amplitudes of respective signals from left and right ambient microphones. The at least one processor may also be programmed to determine a continuous noise dosing level based on amplitudes of signals from the left and right internal microphones over a measurement period and to adjust volume of the left and right audio signals in response to the noise dosing level. The at least one processor may be further programmed to increase volume of the left and right audio signals in response to increasing ambient noise if the noise dosing level is less than an associated threshold, and to reduce volume of the left and right audio signals if the noise dosing level is not less than the associated threshold.(0011] In various embodiments, the hearing protection device includes a transceiver in communication with the at least one processor and configured to transmit and receive communication signals. The at least one processor is programmed to apply retrieved left and right hearing frequency profiles to received communication signals to generate respective left and right audio compensated communication signals and output the left and right audio-compensated communication signals to the left and right speakers, respectively. The left and right audio-compensated signals may also be volume compensated based on ambient noise level until a noise dosing level reaches a threshold, and not volume compensated otherwise. The hearing protection device may also include a communications microphone configured to generate signals in response to user speech, the communications microphone being in communication with the at least one processor. The communications microphone may be implemented by a boom microphone extending from one of the left and right OTE earcups.(0012] In one or more embodiments, the hearing protection device may include at least one processor programmed to perform active noise cancellation (ANC) using input signals from the left and right internal microphones to generate respective left and right feedback ANC signals, and signals from the left and right ambient microphones to generate respective left and right feedforward ANC signals, the at least one processor combining the left and right feedforward ANC signals with the left and right feedback ANC signals to generate respective left and right combined ANC signals, and applying the left and right combined ANC signals to the left and right speakers, respectively.

[0013] Embodiments may also include a method for compensating audio signals provided by an OTE hearing protection device, the method performed by at least one processor executing instructions to retrieve left and right hearing frequency profiles previously stored in memory accessible by the at least one processor, apply a speech isolation filter to signals from left and right ambient microphones positioned to receive ambient sound to generate respective left and right filtered speech signals, apply the retrieved left and right hearing frequency profiles to the left and right filtered speech signals to generate respective left and right audio signals, and output the left and right audio signals to left and right speakers, respectively, of the hearing protection device. The method may also include generating the left and right hearing frequency profiles and storing the left and right hearing frequency profiles in the memory accessible by the at least one processor.(0014] In one or more embodiments, the method includes generating the left and right hearing frequency profiles by controlling the left and right speakers to sequentially generate sound at each of a plurality of frequencies, the sound increasing in sound pressure level (SPL) at each of the plurality of frequencies for each speaker until receiving a signal responsive to user input, storing an SPL value in the memory accessible by the at least one processor for each of the plurality of frequencies in response to a signal from a user operable input, comparing each stored SPL value to a corresponding reference value to determine associated difference values, and storing the difference values in the memory as the left and right hearing frequency profiles.

[0015] Various embodiments may include determining a noise dosing level based on amplitudes of signals from the left and right internal microphones over a measurement period. The method may include adjusting volume of the left and right audio signals in response to the noise dosing level. The method may include increasing volume of the left and right audio signals in response to increasing ambient noise when the noise dosing level is less than an associated threshold and not increasing volume of the left and right audio signals otherwise.[0016| In one or more embodiments, the at least one processor may also be programmed to determine a noise dosing level based on an accumulated length of time that amplitudes of signals from the left and right internal microphones exceed a threshold. The data can be used to establish the accumulated exposure level of the wearer during an associated wearing time period. When compared to an established noise exposure / time table, the device can adjust the talk-thru threshold levels to optimize the availability of ambient sounds while insuring the user does not exceed allowable exposure levels.(0017] In one or more embodiments, the method includes applying retrieved left and right hearing frequency profiles to received communication signals to generate respective left and right compensated communication signals and outputting the left and right compensated communication signals to left and right speakers, respectively.

[0018] Embodiments may also include performing active noise cancellation (ANC) using input signals from left and right internal microphones to generate respective left and right feedback ANC signals, and signals from left and right ambient microphones to generate respective left and rightfeedforward ANC signals. The method may also include combining the left and right feedforward ANC signals with the left and right feedback ANC signals to generate respective left and right combined ANC signals, and applying the left and right combined ANC signals to the left and right speakers, respectively.

[0019] Systems and methods according to the present disclosure may provide one or more associated advantages. For example, embodiments according to the disclosure manage audio energy to improve user performance by reducing unwanted sounds and enhancing wanted or desired sounds. Unwanted sounds may include distracting and / or damaging audio energy, which may include ambient energy content that masks wanted sounds, transmitted (communication or talk-thru) energy with degraded signal-to-noise ratios, and external audio energy levels that create hazardous exposure (dB and time). The systems and methods also enhance wanted sounds by improving signal-to-noise ratios while managing external audio energy affecting hearing loss by reducing hazardous dosing (dB and time). Wanted sounds may include ambient audio energy that assists with situational awareness or intelligibility as well as transmitted / received communication energy. Compensated audio signals provided by HPDs according to one or more embodiments substantially reduce mental fatigue, particularly for users with asymmetric hearing loss. Automatic adjustment of the cutoff thresholds allows more user availability of ambient / situational sound content while still providing the needed noise protection.

[0020] The above advantages and other advantages and features will be readily apparent from the following detailed description when taken in connection with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIGURE 1 illustrates a representative hearing protection device with compensation having OTE earcups that may be used alone or in combination with ITE hearing protection devices such as earplugs after insertion into ear canals of a user.|0022| FIGURE 2 is a flowchart illustrating operation of an HPD or similar device for generating hearing frequency profiles for use in an HPD with compensation according to one or more embodiments.

[0023] FIGURE 3 is a representative user interface for a smartphone app displaying hearing frequency profdes for use in an HPD with compensation according to one or more embodiments.|0024| FIGURE 4 is a block diagram illustrating operation of a representative embodiment of an HPD with compensation including talk-thru speech-isolation augmentation.|0025| FIGURE 5 is a system block diagram of a representative embodiment of an HPD with compensation including active noise cancellation (ANC) and communications capabilities.

[0026] FIGURE 6 is a flowchart illustrating operation of an HPD with compensation and related method for compensation of audio signals in an HPD.DETAILED DESCRIPTION

[0027] As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary and may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the teachings and representative embodiments of the disclosure.

[0028] According to one aspect, a system or method according to the disclosure includes one or more computers or controllers having a programmed processor that executes instructions stored in a non-transitory computer readable storage medium to perform one or more steps of the method. In general, the processes, methods, or algorithms disclosed herein can be performed by a processing device, general-purpose microprocessor, controller, or computer, which can include any existing programmable electronic control unit or dedicated electronic control unit or controller. Similarly, the processes, methods, or algorithms can be stored as data and instructions in a non-transitory storage medium executable by a controller or computer in many forms including, but not limited to, information permanently stored on non-writable storage media such as ROM devices and information alterably stored on writeable storage media including solid-state, electronic, magnetic, and / or optical storage devices. Certain processes, methods, or algorithms may also be implemented in a software executable object. Alternatively, the processes, methods, or algorithms can be embodied in whole orin part using suitable dedicated or custom hardware components, such as Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), state machines, controllers, or any other hardware components or devices, or a combination of hardware, software and firmware components. Processing of sound / noise signals may be performed by a programmed commercially available digital signal processor (DSP) in one or more embodiments.

[0029] Illustration or description of a process, algorithm or function in a particular sequence or order or by a particular processor, computer, or controller may not be required to perform the described operation or achieve the described result. Some processes, functions, algorithms, or portions thereof may be repeatedly performed, performed in a different sequence, or omitted for particular applications whether or not explicitly illustrated or described as such. In addition, references to processes, functions, algorithms, or portions thereof performed by at least one controller or computer do not imply or require that the same controller or computer perform all of the indicated steps where two or more controllers or computers are provided regardless of how the representative embodiment is illustrated in this disclosure as being performed by a single controller or two or more cooperating controllers in communication by a wired or wireless connection. Various processes, functions, algorithms, or portions thereof may be performed by a local on-board controller or processor and / or by a remote computer, controller, or processor and communicated to one or more other computers, processors or controllers, to implement various types of processing strategies including interrupt- driven, sequential, parallel, multi-threading, etc.

[0030] The HPD and audio system described herein may be incorporated into various types of wearable devices such as a headset having a headband connecting OTE ear cups and may also be incorporated into a helmet or similar head-worn wearable device that accommodates secondary HPDs such as earplugs, for example.|0031| For best hearing protection, proper sizing and insertion techniques should be used for the specific type of earplugs being used. For foam earplugs, this may involve rolling or molding the earplugs to fit comfortably in the ear canal and holding in place while the foam expands to ensure a secure seal. In some cases, custom-molded earplugs that are individually tailored to the wearer's ear canal can provide the most effective and comfortable protection, although these have various disadvantages with respect to cost and availability, particularly for occasional use. Poor fitmentassociated with a particular insertion may introduce noise leak paths and reduce the effectiveness of the ITE HPDs resulting in temporary or permanent noise-induce hearing loss (NIHL). Poor fitment may also decrease speech intelligibility associated with lowering the signal-to-noise ratio (SNR). Different earplugs may have different sound attenuation characteristics.

[0032] As described in greater detail herein, the present inventors have developed an HPD and method that provide compensation to enhance speech intelligibility and may reduce mental fatigue using generalized or customized hearing frequency profiles that may be associated with a particular earplug type or manufacturer, a particular user, a particular application, and / or a particular use / fitment. The hearing frequency profiles may be determined by a third-party for a particular earplug, application, etc. or may be customized by the user on-demand by selecting one of a plurality of previously stored profiles and / or via a self-administered “hearing test” using the HPD either alone or in combination with ITE earplugs after insertion similar to that described in detail in commonly owned and co-pending US2024 / 0148557A1, the disclosure of which is hereby incorporated by reference in its entirety. In various embodiments, an onboard or linked application controls generation of a tone at different test frequencies (in sequence) to determine a user hearing threshold at each frequency. The corresponding sound pressure levels (SPL) measured during the test may be used by the application to generate the hearing frequency profiles to personalize the headset equalization, compensating for hearing deficiencies and increasing speech intelligibility of pass-through ambient speech and / or electronic communications to enhance situational awareness and mission effectiveness.

[0033] To measure insertion loss for a particular ITE HPD, users wear the testing headset / HPD prior to insertion of the ITE HPDs to take a test establishing a baseline hearing threshold. The headset is then removed and the user inserts the ITE HPDs and dons the headset again to initiate a second test that establishes the attenuation the earplugs provide. The change in measured attenuation represents the specific plug attenuation for the particular insertion. The measurement results may be compared to reference values to provide an indication of the effectiveness for the particular insertion to the user so that any deficiencies may be addressed prior to any potential hearing harm associated with ineffective hearing protection. An audible indication of effective occlusion (“Good”, “Adequate”, or “Poor”) may be provided to allow the user to adjust specific ITE insertions for proper attenuation / protection. The frequency-specific attenuation information, which also incorporates characteristics of any existing user hearing profile, may also be stored for subsequent use as the hearingfrequency profiles to provide audio compensation to talk-through speech signals as well as wired or wirelessly received communication signals as described herein.10034] Figure 1 illustrates a representative OTE HPD system with compensation for use alone or in combination with in-the-ear (ITE) hearing protection devices after insertion into ear canals of a user according to various embodiments of the disclosure. System 100 includes a muff-type OTE headset 110 having a headband 112 configured to extend around the head of a user. Left and right OTE earcups 114, 116 are connected to respective end portions of the headband 112 and configured for positioning over an associated ear of the user. Each earcup 114, 116 includes a respective OTE foam cushion / seal 118, 120. Headset 112 includes left and right ambient microphones 122, 124 associated with respective earcups 114, 116, and configured to generate signals in response to ambient sound. Signals from ambient microphones 122, 124 may be used as feedforward signals for active noise cancellation (ANC) and / or for talk-through speech-isolation augmentation as described in greater detail herein. Feedforward signals representing ambient sound may also be used to adjust or control volume compensation applied to the talk-through signals or to wired or wirelessly received communication signals. Volume compensation may increase in response to increased ambient noise, or may decrease in response to increased ambient noise depending upon the particular application and implementation.|0035| Headset 110 includes left and right internal microphones 126, 128 associated with respective earcups 114, 116 and configured to generate signals in response to sound within the respective earcups. Internal microphones 126, 128 may be used to provide feedback signals for embodiments having active noise cancellation. Left and right drivers or speakers 140, 142 are positioned within respective earcups 114, 116 and configured to generate sound in response to at least one of a communication signal (such as from a linked external radio, smartphone, music player, or similar device as described below) and the signal from a respective one of the ambient microphones 122, 124 to provide selective pass-through of ambient sounds or speech talk-thru for situational awareness.

[0036] As also illustrated in Figure 1, system 100 includes at least one processor 150 in communication with the left and right ambient microphones 122, 124, the left and right internal microphones 126, 128, and the left and right drivers / speakers 140, 142. The at least one processor 150is programmed or otherwise configured to control the speakers 140, 142 to provide compensation based on respective previously stored hearing frequency profiles. In some embodiments, the hearing frequency profiles are generated by third parties and associated with a particular ITE earplug type, style, size, material, etc. or associated with a particular application, such as a shooting range, airport or aircraft support, etc. The frequency profiles may also be associated with a particular location or area, such as a manufacturing facility or a machining area within a manufacturing facility, for example. Generalized hearing frequency profiles may be generated and stored for subsequent local or remote access by the HPD 110 for a wide variety of classes or types of applications, uses, etc. In one embodiment, hearing frequency profiles are wirelessly transmitted via transceiver 170 to HPD 110 and stored in local memory 152.

[0037] In some embodiments, HPD 110 may be used to generate the hearing frequency profdes. In these embodiments, the at least one processor 150 is programmed to control the speakers 140, 142 to sequentially generate sound at each of a plurality of predetermined frequencies (in sequence), the sound increasing in sound pressure level (SPL) at each of the plurality of frequencies until receiving a signal responsive to user input, such as from a user-operable input device, such as keypad 160, volume control 162, or linked smartphone 180. Processor 150 then stores an SPL value for each of the plurality of frequencies associated with the signal from the user operable input in a memory 152 accessible by the at least one processor 150. Memory 152 may be implemented using onboard non-volatile memory and / or by removable non-transitory computer readable storage media, such as a flash drive / card, or similar device, and / or by a remotely located non-volatile memory or storage device such as contained within linked smartphone 180 or a similar device, for example. The data may be stored in any convenient format, such as Comma-Separated Values (CSV) or machine- readable JSON formats, for example, whether stored locally on-board the headset 110 or remotely on a linked mobile device 180 for subsequent retrieval, use, and historical storage.

[0038] The at least one processor 150 then compares each stored SPL value to a corresponding reference value to determine associated difference values that may be applied to communication signals received via transceiver 170 or via ambient microphones 122, 124 to compensate the output sent to speakers 140, 142. The corresponding reference values may represent average hearing ability for a designated cohort or general population, for example, and may be provided as default values or customized for a particular application.

[0039] In one or more embodiments, headset 110 may include a transceiver 170, such as a Bluetooth transceiver, to wirelessly communicate with a linked device, such as smartphone 180, for example. A linking / pairing button 172 may be used to initiate a connection as known by those of ordinary skill in the art. Headset 110 may also include an integrated communication microphone, such as boom microphone 174 connected to and extending from one of the earcups 114, 116 and configured to generate signals in response to user speech. Boom microphone 174 may be in communication with at least one of the speakers 140, 142, and in communication with processor 150. Alternatively, or in combination, boom microphone 174 may be directly or indirectly coupled to an input / output jack 176 for wired connection to an external device, such as a radio, smartphone 180, computer (not shown), etc. Similarly, alternatively or in combination, boom microphone may be directly or indirectly coupled to wireless transceiver 170 to transmit signals associated with user speech to a wirelessly connected external device, such as a radio, smartphone 180, computer (not shown), etc. HPD 110 also includes a battery compartment configured to provide power from an associated single-use or rechargeable battery to various system components.

[0040] For purposes of illustration and brevity of description, system 100 includes various components or features that are redundant and may be omitted in various embodiments. For example, embodiments including transceiver 170 may omit wired input / output jack 176. Similarly, embodiments that include transceiver 170 and / or input / output jack 176 to connect to an external device 180 having a user interface with one or more user-operable inputs may omit a keypad 160 and / or volume control 162. Likewise, boom microphone 174 and removable computer readable storage media 152 may be omitted in some embodiments. Those of ordinary skill in the art may recognize various other configurations and combinations of the illustrated and described components suitable for particular applications and implementations that are within the scope of the claimed subject matter but not explicitly illustrated or described.

[0041] In the representative embodiment of Figure 1, system 100 includes a hearing protection device 110 including a headband 112 configured to extend around the head of a user. Left and right OTE earcups 114, 116 are each connected to a respective end portion of the headband 112 and configured for positioning over respective ears of the user. Left and right ambient microphones 122, 124 each associated with a respective one of the earcups 114, 116 are configured to generate signals responsive to ambient sound. Left and right internal microphones 126, 128 each positioned within arespective one of the earcups 114, 116 are configured to generate signals responsive to sound within the respective earcup. Left and right speakers 140, 142 are each positioned within a respective one of the earcups 114, 116 and configured to generate sound responsive to at least one of a communication signal received via transceiver 170 or via a wired input and the signal from a respective one of the ambient microphones after processing. At least one processor 150 is in communication with the ambient microphones 122, 124 the internal microphones 126, 128 and the speakers 140, 142. The at least one processor 150 is programmed to: retrieve left and right hearing frequency profiles previously stored in memory 152 accessible by the at least one processor 150; apply a speech isolation filter to signals from the ambient microphones 122, 124 to generate respective left and right filtered speech signals; apply the retrieved left and right hearing frequency profiles to the left and right filtered speech signals to generate respective left and right audio signals; and output the left and right audio signals to the left and right speakers 140, 142, respectively.|0042| Figure 2 is a flowchart illustrating operation of a system or method for generating hearing frequency profiles for use in an HPD with compensation according to one or more embodiments. The algorithm, process, or software represented in Figure 2 includes various steps, tasks, or functions that may be performed by one or more programmed microprocessors or controllers as previously described, such as processor(s) 150 (Fig. 1) and / or processor(s) of a remote computer or device, such as smartphone 180 (Fig. 1) in cooperation with associated components and hardware of a testing system, such as HPD system 100 (Fig. 1).

[0043] Process or control strategy 200 generally represents a high-level description of a method for generating hearing frequency profiles to be accessible by an HPD processor for use in generating compensated audio signals when used alone or in combination with ITE earplugs or similar devices. Step 210 generally represents controlling speakers to sequentially emit a sound or tone at each of a plurality of predetermined frequencies from OTE earcups of the headset. The sound or tone at each of the predetermined frequencies is increased from a lower sound pressure level to a higher sound pressure level. In various embodiments, step 210 may be performed automatically by the processor. Alternatively, step 210 may be performed in response to a signal from a user operable volume control. For example, the processor may generate a sound at a first frequency with near zero SPL and the user may operate a volume control or other input to increase volume of the sound until the user hears the sound as noted by the volume control remaining at a particular volume for a predetermined period oftime, or by reversing from increasing volume control to decreasing volume control (and possibly reversing again as the user identifies the hearing threshold volume). In other embodiments, the processor may automatically increase the SPL until the user activates an input, such as a touch screen on a linked smartphone, or a button on the headset, for example.

[0044] Responsive to receiving a signal indicative of the user hearing the sound at each of the plurality of predetermined testing frequencies, step 212 represents storing a frequency-associated sound pressure level value in fixed or removable non-transitory computer readable storage media, which may include wirelessly transmitting the sound pressure level values to a remotely located memory or storage media, such as a smartphone memory (for example), in some embodiments. The processor(s) then compare the frequency-associated sound pressure level value for each of the plurality of frequencies to corresponding predetermined frequency-associated reference values as represented at step 214 to generate the hearing frequency profile for subsequent use in compensating the sounds delivered by the HPD.

[0045] In one or more embodiments, the process may further include the processor(s) compensating an input audio signal received by at least one microphone of the headset based on the hearing frequency profiles for the plurality of frequencies as represented at 216, and generating an audio output signal applied to at least one speaker of the headset based on the compensated input audio signal as represented at 218. In various embodiments, compensating the input audio signal may include determining an equalization function based on the hearing frequency profiles as represented at 230, and applying the equalization function to sound received by at least one microphone of the headset and / or received via a wired or wireless communication signal as represented at 232. Block 218 may include generating an equalized sound signal for at least one speaker of the headset as represented at 234.]0046| Figure 3 illustrates a representative user interface for a smartphone app displaying representative hearing frequency profiles. User interface 300 may be implemented by a touch screen and / or may include one or more physical buttons, sliders, switches, etc. configured as user-operable inputs. User interface 300 may be used to display user-generated hearing frequency profiles or to display a hearing frequency profile provided by a third party. Similarly, user interface 300 may be used to select one of a plurality of available hearing frequency profiles for a particular ITE earplug,application, location, etc. as described herein. As illustrated in the representative embodiment of Figure 3, user interface 300 provides bar graphs illustrating results of testing for a left ear 310 with bar 312 representing the SPL hearing threshold without earplugs (or alternatively another previously stored baseline reference value) and bar 314 representing the SPL hearing threshold with earplugs inserted. In the embodiment illustrated, the difference between the values represented by bars 312, 314 corresponds to the attenuation or protection provided at each of the test frequencies 316. In one embodiment, five (5) test frequencies are used (such as 500Hz, 1kHz, 2kHz, 4kHz, and 8kHz). In another embodiment using five (5) test frequencies, frequencies of 250Hz, 500Hz, 1kHz, 2kHz, and 4kHz are used. In other embodiments, up to twelve (12) frequencies may be used, such as 125Hz, 250Hz, 500Hz, 750Hz, 1kHz, 1.5kHz, 2kHz, 3kHz, 4kHz, 6kHz, 8kHz, and 12kHz, for example. The number of test frequencies and the selected frequencies may vary based on the particular application and implementation. User interface 300 may also include one or more control inputs to control test administration, interface configuration, etc. as generally represented at 340. When the user-generated hearing frequency profiles have been determined, or third-party or other previously obtained profiles have been identified for use, the active profiles are stored in the memory 152 of the HPD or other remote storage accessible by the one or more processors for use in generating the compensated audio signals.

[0047] Figure 4 is a block diagram illustrating operation of a representative embodiment of an HPD with compensation including talk-through speech-isolation augmentation. System 400 receives signals from an ambient or feed-forward microphone 410 representative of ambient sounds including speech and ambient noise. Speech frequency isolation block 420 increases the signal-to-noise ratio of speech signals using a bandpass filter 416 and / or additional processing. Previously stored hearing frequency profiles are retrieved and applied to provide programmatically or dynamically changed audio compensation for ITE earplugs as generally represented at 432 with volume level compensation providing an adjustment to signal levels of the compensated audio signal as represented at 430. One or more adjustable thresholds (X) may be applied as represented at 517 based on ambient sound detected by ambient microphone 410 and / or a noise dosing subsystem as described in greater detail herein. The applied audio compensation may be a generalized or fixed hearing frequency profile for a particular application, location, earplug type, etc. that is applied for all users (programmatically changed), or dynamically changed or reset each time a user generates a new hearing frequency profile.(0048] Volume level compensation may change based on the ambient sound level or based on accumulated noise dosing relative to one or more thresholds that may vary based on the particular application or mission. For example, the signal gain or volume compensation may increase with higher ambient noise to improve speech intelligibility, i.e. when ambient noise exceeds a corresponding threshold, such as 65db for example, volume compensation may be increased in stepwise or continuous fashion based on increasing ambient noise up to a second threshold of, for example, 75db. Ambient noise level may also be used to decrease or cutoff volume level compensation when instantaneous or accumulated noise levels (noise dosing) exceed an associated threshold. For example, volume compensation or amplification may be reduced in response to ambient noise exceeding a corresponding threshold such as 85dB. Volume compensation or amplification may be cutoff or reduced to zero in response to ambient noise exceeding an associated threshold such as lOOdB or noise dosing or exposure exceeding an associated threshold such as 100% of 8-hour sound exposure for example. In one embodiment, a noise dosing threshold is configured to measure accumulated sound energy exceeding a threshold of 85 dB by integrating sound levels exceeding the threshold over time. Signal gain or volume amplification is cutoff when the sound energy exceeds a the corresponding dosing level, such as exceeding 85 dB for two hours within an eight-hour measurement window. Integration of the sound energy assures that total noise exposure ((measured sound - threshold level sound) x duration) is within recognized limits for an exposure period so that the HPD does not exacerbate continued noise exposure by amplifying pass-thru sound or talk-thru speech. Once pass- thru sound signals from ambient microphone 410 are cutoff based on the ambient noise and / or noise dosing thresholds, an audio or visual alert may be triggered to notify the user so the user does not misconstrue the reduced pass-thru sound / speech as a malfunction of the HPD. The accumulated noise dosing level may be reset after a predetermined time period (such as 16 hours, 24 hours, etc.) or in response to a wired or wirelessly received override signal, or entry of a passcode or similar security control so that the user cannot defeat the hearing protection feature without authorization.

[0049] Speech tuning is applied to the audio and / or volume compensated signal as represented at 434 with the resulting output combined with any other audio signals 436 at block 438 with the combined signal sent to the speakers as represented at 440. Other audio signals 436 may include radio, intercom, or various external audio signals. While Figure 4 illustrates a single channel (left or right),similar processing is applied to each channel using a respective microphone, hearing frequency profile, and speaker for each channel.|0050| Figure 5 is a system block diagram of a representative embodiment of an HPD with audio and volume compensation including active noise cancellation (ANC), sound and speech talk- thru, and external communications capabilities. System 500 receives signals from an ambient or feedforward microphone 510 that are provided to speech frequency isolation block 512, which may isolate speech signals by applying a bandpass filter 511 or other digital signal processing. The speech signal is compensated using previously stored hearing frequency profiles and volume compensated at block 514 subject to corresponding thresholds 517 (X) as previously described. The audio compensation using the hearing frequency profiles may be programmatically or dynamically changed as previously described with respect to the talk-through system block diagram in the representative embodiment of Figure 4. Volume compensation applied to the audio compensated signal may be changed based on instantaneous, averaged, or accumulated ambient noise or noise dosing input from a noise dosing subsystem as represented at 516. Speech tuning is applied as represented at 518 with the resulting signal combined at 520 with feed-forward ANC signal 522, feedback ANC signal 544, and any communication speech signals after speech tuning at 560 and 580. The combined signals are provided to the output speakers as represented at 530.[00511 Signals from internal feedback microphone 540 and optionally from ambient feedforward microphone 510 are provided to noise dosing subsystem 542, which integrates or otherwise accumulates noise exposure information based on noise inside the earcups reaching the tympanic membrane for noise exceeding a corresponding threshold for some time duration, such as duration of noise exceeding 85 dB within a measurement time window such as eight (8) hours. Dosing subsystem 542 may determine accumulated noise / sound exposure over time by any suitable method, such as integration of the sound signal, averaging, or other more complex algorithms that may weight sound pressure level differently for different frequencies, for example. Noise dosing represents the combined noise from ambient noise, communication audio, talk-thru speech, etc. that is not cancelled by ANC and reaches the ear canal or tympanic membrane of the user. Dosing subsystem 542 may also determine whether instantaneous or average noise measured by ambient feed-forward microphone 510 exceeds a corresponding threshold and may select or adjust threshold levels based on various factors, such as application, mission, currently accumulated noise dosing level, average noise, etc. Noise ornoise dosing that exceeds a corresponding threshold may be used to adjust volume compensation stepwise, proportionately, and / or as a cutoff threshold, for example. Signals from feedback microphone 540 are also used to generate a feedback ANC signal as represented at 544 that is combined with the feed-forward ANC signal 522 to perform active noise cancellation using ANC control strategies well understood by those of ordinary skill in the art.

[0052] In one representative application for an HPD with compensation according to the disclosure, an amplified muff application of the audio system (such as a gun range or other shooter muff with talk-thru functionality), the level of amplification may be automatically adjusted based on the ambient noise levels and / or noise dosing. An individual wearing this HPD could move from an 80 dB environment into a >90 dB environment and (for example) a 10 second average measure of noise from ambient microphone could adjust the amplification of the talk-through signal (corresponding to particular frequencies, such as 500 Hz to 3500 Hz, for example as selected by the speech isolation filter) automatically. This provides an application of volume feedback to control the HPD to provide effective hearing protection while also allowing desired or wanted sounds (that may be passed through as detected, amplified, or attenuated) to reach the user.

[0053] Wireless or wired communication signals may be provided by an intercom or radio as represented at 550, 552 with associated audio tuning as represented at 554. Speech frequency isolation and ambient noise reduction is applied as represented at 556 to improve the SNR of the speech signal as previously described. The speech signal is then compensated using the hearing frequency profiles and volume compensated at 558 subject to corresponding thresholds associated with ambient noise or noise dosing (X) as previously described. Speech tuning is applied to the resulting signal at 560 before being combined with other audio signals at 520 and being output to the speakers at 530.

[0054] In a similar fashion, secondary or auxiliary signals 570, 572 may be received from a wired or wireless connection as represented at 550, 552 with associated audio tuning as represented at 574. Speech frequency isolation and ambient noise reduction is applied as represented at 576 to improve the SNR of the speech signal as previously described. The speech signal is then compensated using the hearing frequency profiles and volume compensated at 578 subject to corresponding thresholds associated with ambient noise or noise dosing (X) as previously described. Speech tuningis applied to the resulting signal at 580 before being combined with other audio signals at 520 and being output to the speakers at 530.|0055| Figure 6 is a flowchart illustrating operation of an HPD with compensation and related method for audio and volume compensation of signals in an HPD. Control strategy or algorithm 600 includes generating left and right hearing frequency profiles and storing the left and right hearing frequency profiles in a memory accessible by at least one processor as represented at 610 and described in greater detail with respect to Figures 2 and 3. The generated or otherwise selected left and right hearing frequency profiles previously stored in memory are retrieved as represented at 620. A speech isolation filter or algorithm is applied to signals from left and right ambient (feed-forward) microphones positioned to receive ambient sound to generate respective left and right filtered speech signals as represented at 630. The retrieved left and right hearing frequency profiles are applied to the left and right filtered speech signals, respectively, to generate respective left and right audio signals as represented at 640. Ambient noise level is determined based on signals from the ambient feedforward microphones and noise dosing level is detected by left and right internal (feedback) microphones over a measurement period as represented at 650. Volume compensation is applied to the left and right audio signals subject to one or more noise thresholds as represented at 660. As previously described, the volume compensation may vary based on the ambient noise level or based on the noise dosing level relative to associated thresholds. Volume may be increased in response to the noise level being less than an associated threshold, and not increased (i.e. maintained or decreased) otherwise.

[0056] As also illustrated in Figure 6, the method may include audio and volume compensating communication signals received via a wireless or wired connection using the hearing frequency profiles and volume compensation as represented at 664. Active noise cancellation using feedback and / or feed-forward signals may be performed as represented at 666. The resulting audio signals are combined as represented at 670 and output to corresponding speakers within the earcups of the HPD as represented at 680.

[0057] While the best mode has been described in detail, those familiar with the art will recognize various alternative designs and embodiments within the scope of the following claims. While various embodiments may have been described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, as one skilled in the art isaware, one or more characteristics may be compromised to achieve desired system attributes, which depend on the specific application and implementation. These attributes include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. The embodiments discussed herein that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.

Claims

WHAT IS CLAIMED IS:

1. An over-the-ears (OTE) hearing protection device, comprising: a headband configured to extend around the head of a user; left and right earcups each connected to a respective end portion of the headband and configured for positioning over respective ears of the user; left and right ambient microphones each associated with a respective one of the earcups and configured to generate signals responsive to ambient sound; left and right internal microphones each positioned within a respective one of the earcups and configured to generate signals responsive to sound within the earcups; left and right speakers each positioned within a respective one of the earcups and configured to generate sound responsive to at least one of a communication signal and the signal from a respective one of the ambient microphones; and at least one processor in communication with the ambient microphones, the internal microphones, and the speakers, the at least one processor programmed to: retrieve left and right hearing frequency profiles previously stored in memory accessible by the at least one processor; apply a speech isolation filter to signals from the ambient microphones to generate respective left and right filtered speech signals; apply the retrieved left and right hearing frequency profiles to the left and right filtered speech signals to generate respective left and right audio signals; and output the left and right audio signals to the left and right speakers, respectively.

2. The hearing protection device of claim 1 wherein the at least one processor is further programmed to generate the left and right hearing frequency profiles.

3. The hearing protection device of claim 2 wherein the at least one processor is further programmed to: control the left and right speakers to sequentially generate sound at each of a plurality of frequencies, the sound increasing in sound pressure level (SPL) at eachof the plurality of frequencies for each speaker until receiving a signal responsive to user input; store an SPL value in the memory accessible by the at least one processor for each of the plurality of frequencies in response to the user input; compare each stored SPL value to a corresponding reference value to determine associated difference values; and store the difference values in the memory as the left and right hearing frequency profiles.

4. The hearing protection device of claim 3 wherein the user input comprises a signal from a volume control positioned on one of the earcups.

5. The hearing protection device of claim 3 wherein the user input comprises a signal from a wirelessly connected smartphone.

6. The hearing protection device of claim 1 wherein the left and right hearing frequency profiles are associated with one of a plurality of commercially available ear plugs.

7. The hearing protection device of claim 1 wherein the at least one processor is further programmed to adjust volume of the left and right audio signals in response to amplitudes of respective signals from the left and right ambient microphones.

8. The hearing protection device of claim 7 wherein the at least one processor is further programmed to: determine a noise dosing level based on amplitudes of signals from the left and right internal microphones over a measurement period.

9. The hearing protection device of claim 8 wherein the at least one processor is further programmed to adjust volume of the left and right audio signals in response to the noise dosing level.

10. The hearing protection device of claim 9 wherein the at least one processor is further programmed to increase volume of the left and right audio signals in response to the noise dosing levelbeing less than an associated threshold, and to reduce volume of the left and right audio signals otherwise.

11. The hearing protection device of claim 1 further comprising a transceiver in communication with the at least one processor and configured to transmit and receive communication signals, wherein the at least one processor is further programmed to: apply the retrieved left and right hearing frequency profiles to received communication signals to generate respective left and right compensated communication signals; and output the left and right compensated communication signals to the left and right speakers, respectively.

12. The hearing protection device of claim 11 further comprising a communications microphone configured to generate signals in response to user speech, the communications microphone in communication with the at least one processor.

13. The hearing protection device of claim 12 wherein the communications microphone comprises a boom microphone extending from one of the left and right earcups.

14. The hearing protection device of claim 1 wherein the at least one processor is further programmed to perform active noise cancellation (ANC) using input signals from the left and right internal microphones to generate respective left and right feedback ANC signals, and signals from the left and right ambient microphones to generate respective left and right feedforward ANC signals, the at least one processor combining the left and right feedforward ANC signals with the left and right feedback ANC signals to generate respective left and right combined ANC signals, and applying the left and right combined ANC signals to the left and right speakers, respectively.

15. A method for compensating audio signals provided by an over-the-ears (OTE)hearing protection device, the method performed by at least one processor executing instructions to: retrieve left and right hearing frequency profiles previously stored in memory accessible by the at least one processor;apply a speech isolation filter to signals from left and right ambient microphones positioned to receive ambient sound to generate respective left and right filtered speech signals; apply the retrieved left and right hearing frequency profiles to the left and right filtered speech signals to generate respective left and right audio signals; and output the left and right audio signals to left and right speakers, respectively, of the hearing protection device.

16. The method of claim 15 further comprising generating the left and right hearing frequency profiles and storing the left and right hearing frequency profiles in the memory accessible by the at least one processor.

17. The method of claim 16 wherein generating the left and right hearing frequency profiles comprises: controlling the left and right speakers to sequentially generate sound at each of a plurality of frequencies, the sound increasing in sound pressure level (SPL) at each of the plurality of frequencies for each speaker until receiving a signal responsive to user input; storing an SPL value in the memory accessible by the at least one processor for each of the plurality of frequencies in response to a signal from a user operable input; comparing each stored SPL value to a corresponding reference value to determine associated difference values; and storing the difference values in the memory as the left and right hearing frequency profiles.

18. The method of claim 17 further comprising: determining a noise dosing level based on amplitudes of signals from the left and right internal microphones over a measurement period.

19. The method of claim 18 further comprising adjusting volume of the left and right audio signals in response to the noise dosing level.

20. The method of claim 18 further comprising:increasing volume of the left and right audio signals in response to increasing ambient noise unless: the ambient noise exceeds a corresponding ambient noise threshold or the noise dosing level exceeds a noise dosing threshold.

21. The method of claim 15 further comprising: applying the retrieved left and right hearing frequency profiles to received communication signals to generate respective left and right compensated communication signals; and outputting the left and right compensated communication signals to the left and right speakers, respectively.

22. The method of claim 15 further comprising: performing active noise cancellation (ANC) using input signals from left and right internal microphones to generate respective left and right feedback ANC signals, and signals from the left and right ambient microphones to generate respective left and right feedforward ANC signals.

23. The method of claim 22 further comprising: combining the left and right feedforward ANC signals with the left and right feedback ANC signals to generate respective left and right combined ANC signals; and applying the left and right combined ANC signals to the left and right speakers, respectively.

24. The method of claim 15 further comprising: automatically increasing volume of the left and right audio signals in response to increasing ambient noise unless: the ambient noise exceeds a corresponding ambient noise threshold or a noise dosing level exceeds a noise dosing threshold.

Images