Hearing protection device and method and processing unit for hearing protection device

Abstract

A method for providing improved fidelity of speech in a hearing protection device is provided. The method includes receiving a sound signal from a sound source. The method further includes processing the sound signal using a sound filter to obtain a processed sound. The processing includes filtering the received sound signal into a plurality of frequency bands, and for a frequency band from the plurality of frequency bands, the processing further includes detecting a frequency strength. For the frequency band, the processing further includes computing a band gain. The computed band gain is based on an adjustable band setting. For the frequency band, the processing further includes applying a non-constant target control across the frequency band based on the computed band gain. The processing further includes reconstructing the processed frequency bands into the processed sound. The method further includes broadcasting the processed sound.

Description

PA102360W002HEARING PROTECTION DEVICE AND METHOD AND PROCESSING UNIT FOR HEARING PROTECTION DEVICETechnical Field

[0001] The present disclosure relates to a hearing protection device. The present disclosure further relates to a processing unit for a hearing protection device. The present disclosure further relates to a method for providing improved fidelity of speech in a hearing protection device.Background

[0002] Hearing protection devices may be worn by users when they are in loud or noisy environments. Hearing protection devices can reduce the amount of noise the users are exposed to. Some hearing protection devices may include microphones and speakers to allow communication among users. However, different users may produce a different balance of spectral energy in their speech. For some users, certain frequencies may exhibit unnatural resonance or attenuation, for example, due to an improper fit of the hearing protection devices. Further, some users may have speech that naturally contains an unusual and non-flat frequency spectrum, which can reduce the intelligibility of their speech.Summary

[0003] In a first aspect, a method for providing improved fidelity of speech in a hearing protection device is presented. The method includes receiving a sound signal from a sound source. The method further includes processing the sound signal using a sound filter to obtain a processed sound. The processing includes filtering the received sound into a plurality of frequency bands. For at least one frequency band from the plurality of frequency bands, the processing further includes detecting a frequency strength. For the at least one frequency band, the processing further includes computing a band gain. The computed band gain is based on an adjustable band setting. For the at least one frequency band, the processing further includes applying a non-constant target control across the at least one frequency band based on the computed band gain. The processing further includes reconstructing the processed frequency bands into the processed sound. The method further includes broadcasting the processed sound.

[0004] In a second aspect, a processing unit for a hearing protection device is presented. The processing unit includes a sound signal receiver configured to receive a sound signal. The processing unit further includes a filter configured to filter the received sound signal into a first plurality of frequency bands. The processing unit further includes a frequency strength detector configured to detect a frequency strength for each of the first plurality of frequency bands. The processing unit further includes a gain calculator configured to calculate a gain for each of the first plurality of frequency bands. The processing unit further includes a target controller configured to apply a non-constant target control, based on the calculated gain, across at least one of the first plurality of frequency bands to generate a second set of frequency bands. The processing unit further includes a reconstructor configured togenerate a processed sound by combining the second set of frequency bands. The processing unit further includes a communication component configured to communicate the processed sound to a speaker.

[0005] In a third aspect, a hearing protection device is presented. The hearing protection device includes a pair of in-ear buds. Each in-ear bud from the pair of in-ear buds includes a speaker configured to broadcast a processed sound. Each in-ear bud further includes a flange configured to engage an ear canal of a wearer of the pair of in-ear buds. The flange is configured to seal the speaker on an ear-canal side of the in-ear bud. The hearing protection device further includes a microphone configured to capture a sound signal. The hearing protection device further includes a processing unit. The processing unit includes a filter configured to filter the captured sound signal into a first plurality of frequency bands. The processing unit further includes a frequency strength detector configured to detect a frequency strength for each of the first plurality of frequency bands. The processing unit further includes a gain calculator configured to calculate a gain for each of the first plurality of frequency bands. The processing unit further a target controller configured to apply a non-constant target control, based on the calculated gain, across at least one of the first plurality of frequency bands to generate a second set of frequency bands. The processing unit further includes a reconstructor configured to generate the processed sound by combining the second set of frequency bands.

[0006] The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.Brief Description of the Drawings

[0007] Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

[0008] FIG. 1 is a block diagram of an example processing unit, according to embodiments of the present disclosure;

[0009] FIG. 2A illustrates a graph depicting an example sound signal;

[0010] FIG. 2B illustrates a graph depicting a first plurality of frequency bands generated by filtering the example sound signal of FIG. 2A, according to embodiments of the present disclosure;

[0011] FIG. 2C illustrates a graph depicting a first frequency band of the first plurality of frequency bands with a non-constant target control applied, according to embodiments of the present disclosure;

[0012] FIG. 2D illustrates a graph depicting a second frequency band of the first plurality of frequency bands with a non-constant target control applied, according to embodiments of the present disclosure;

[0013] FIG. 3 illustrates a block diagram of an example hearing protection device, according to embodiments of the present disclosure;

[0014] FIG. 4 illustrates a block diagram of an example hearing protection device, according to embodiments of the present disclosure;

[0015] FIG. 5 illustrates an example hearing protection device that may be used according to some embodiments of the present disclosure;

[0016] FIG. 6 illustrates a flowchart of a method for providing improved fidelity of speech in a hearing protection device, according to embodiments of the present disclosure;

[0017] FIGS. 7-8 show examples of mobile devices that can be used in the embodiments shown in previous Figures; and

[0018] FIG. 9 is a block diagram illustrating an example computing environment that can be used in embodiments shown in previous Figures.Detailed Description

[0019] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0020] In the following disclosure, the following definitions are adopted.

[0021] As used herein, all numbers should be considered modified by the term “about.” As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.

[0022] As used herein as a modifier to a property or attribute, the term “generally,” unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0023] The term “substantially,” unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0024] The term “about,” unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0025] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0026] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B.”

[0027] As used herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0028] As used herein, the term “coupled” generally means either a direct connection between two or more elements that are connected or an indirect connection through one or more passive or active intermediary devices.

[0029] As used herein, the term “frequency strength” refers to the amplitude of a particular frequency. For example, stronger frequencies are louder (i.e., have a greater amplitude) than weaker frequencies. The term “frequency strength” may also be referred to as the magnitude of a particular frequency. The terms “amplitude” and “magnitude” are interchangeably used herein.

[0030] As used herein, the term “noise” refers to an unwanted disturbance in an original sound signal which interferes with the original sound signal and corrupts the parameters of the original sound signal.

[0031] As used herein, the term “hearing protection device” generally refers to an ear protection device worn in or over the ears while exposed to hazardous noise and provides hearing protection to help prevent noise-induced hearing loss.

[0032] As used herein, “target curve” means a user- or manufacturer-defined desired spectral amplitude profile for the processed sound across a defined frequency range. It specifies, per frequency or per band, the intended amplitude / gain characteristics (e.g., flat, rising / treble-heavy, falling / bass-heavy, or arbitrary / custom shape) and is used by the gain calculator and target controller to compute and apply band gains that drive measured frequency strengths toward the target. A target curve may be represented as a continuous function or discrete per-band values, may include presets, may use a pivot frequency (e.g., about 1 kHz for speech), and may incorporate constraints such as maximum per-band boost limits.

[0033] As used herein, “non-constant target control” means a control function that applies gain which varies across frequency within a band (and optionally over time), rather than a uniform (constant) gain, to drive the measured spectrum toward a desired target curve. Examples include linearly increasing or decreasing gain, step-wise gain, piece-wise or arbitrary non-linear gain profiles, or per-bin gain maps. The non-constant target control is derived from the adjustable band setting (target curve) and the computed band gains, and may differ between bands.

[0034] As used herein, “adjustable band setting” means a configurable parameter set that specifies, for one or more frequency bands, the desired spectral amplitude / gain profde and related limits to be used by the gain calculator and target controller. It may encode a target curve (e.g., flat, rising / treble-heavy, falling / bass-heavy, or custom), per-band target levels or slopes, a pivot frequency (e.g., about 1 kHz for speech), presets, and per-band maximum boost / attenuation constraints. The adjustable band setting can be selected or updated by a user or set by a manufacturer, represented as discrete per-band values or a continuous function, stored in memory, and applied in real time.

[0035] As used herein, “gain calculator” means a hardware-, firmware-, or software-implemented module configured to determine, for each of a plurality of frequency bands (and optionally sub-bins within a band), a gain factor to move the measured frequency strength toward the desired target curve specified by the adjustable band setting. The gain may be computed, for example, as a ratio or difference between target and measured levels (e.g., target amplitude divided by measured amplitude), updated in real time on a frame basis, and constrained by limits such as a maximum band gain and / or a per-band maximum boost table. The gain calculator outputs per-band gain values to the target controller to effect a non-constant target control across frequency.

[0036] The present disclosure relates to a hearing protection device. The present disclosure further relates to a processing unit for a hearing protection device. The present disclosure further relates to a method for providing improved fidelity of speech in a hearing protection device.

[0037] The hearing protection device, in one embodiment, includes a pair of in-ear buds or independent ear cups. Each in-ear bud from the pair of in-ear buds includes a speaker configured to broadcast a processed sound. Each in-ear bud further includes a flange configured to engage an ear canal of a wearer of the pair of in-ear buds. The flange is configured to seal the speaker on an ear-canal side of the in-ear bud. The hearing protection device further includes a microphone configured to capture a sound signal. The hearing protection device further includes a processing unit. The processing unit includes a filter configured to filter the captured sound signal into a first plurality of frequency bands. The processing unit further includes a frequency strength detector configured to detect a frequency strength for each of the first plurality of frequency bands. The processing unit further includes a gain calculator configured to calculate a gain for each of the first plurality of frequency bands. The processing unit further a target controller configured to apply a non-constant target control, based on the calculated gain, across at least one of the first plurality of frequency bands to generate a second set of frequency bands. The processing unit further includes a reconstructor configured to generate the processed sound by combining the second set of frequency bands.

[0038] The hearing protection device may output the processed sound having improved speech fidelity and speech intelligibility to the user of the hearing protection device via the speaker.Specifically, the processing unit may process the sound signal to improve the speech fidelity and speech intelligibility of the speech in the sound signal. That is, the processed sound generated by the processing unit may have improved speech characteristics as compared to the sound signal. For example, the processed sound may have a balanced spectrum (i.e., about equal frequency strength of each frequency band), which may improve speech fidelity and intelligibility.

[0039] The non-constant target control applied by the target controller may adjust the first plurality of frequency bands in a non-constant (or non-consistent) manner. Therefore, each frequency band may have a non-constant gain applied to it. In contrast to conventional techniques that employ a consistent gain across a frequency band, the non-constant target control may provide greater control over each frequency band.

[0040] In some cases, the hearing protection device may improve fidelity and intelligibility of speech which naturally has an unusually non-flat frequency spectrum. Further, the processing unit may be suitable for the pair of in-ear buds, as the pair of in-ear buds can inadvertently cause certain frequencies to exhibit unnatural resonance, for example, due to improper fit of the pair of in-ear buds.

[0041] Referring now to the Figures, FIG. 1 is a block diagram of a processing unit 100 for a hearing protection device, according to embodiments of the present disclosure.

[0042] The hearing protection device, for which the processing unit 100 may be suitable, can be of any type. In some embodiments, the hearing protection device may include a pair of in-ear buds including speakers that provide received sound to a user’s ear. In some other embodiments, the hearing protection device may include a pair of earmuffs that enclose the user’s ear and provide a barrier to ambient sound. The pair of earmuffs may include speakers to provide received communication. The hearing protection device may include a microphone capable of picking up speech from users, or a user may wear a different device with a microphone, such as a comms unit, a headset with a boom microphone, a VOX unit, etc.

[0043] The processing unit 100 includes a sound signal receiver 102 configured to receive a sound signal 104. The sound signal 104 may be from a sound source. The sound signal 104 may be captured by an internal microphone of the hearing protection device or an external microphone communicably coupled to the hearing protection device. The sound signal receiver 102 may receive the sound signal 104 from the microphone. The sound signal 104 may include speech. As will be discussed in greater detail below, the processing unit 100 may process the sound signal 104 to improve intelligibility of the speech in the sound signal 104.

[0044] The processing unit 100 further includes a filter 106 configured to fdter the received sound signal 104 into a first plurality of frequency bands 108. The filter 106 may include a filter bank. Additionally, or alternatively, fast Fourier transform (FFT) may be employed to filter the received sound signal 104 into the first plurality of frequency bands 108. A number of frequency bands into which the filter 106 filters the sound signal 104 may be selected based on desired application attributes. In some cases, a greater number of frequency bands may be desired (e.g., for improved processing), while in some other cases, a smaller number of frequency bands may be desired (e.g., for reduced computational power requirement).

[0045] The processing unit 100 further includes a frequency strength detector 112 configured to detect a frequency strength for each of the first plurality of frequency bands 108. In other words, the frequency strength detector 112 may detect the amplitude for each of the first plurality of frequency bands 108. The frequency strength of a frequency band 108 may correspond to the loudness level of that frequency band 108.

[0046] The processing unit 100 further includes a gain calculator 114 configured to calculate a gain for each of the first plurality of frequency bands 108. The gain calculator 114 may calculate the gain for each of the first plurality of frequency bands 108 based on an adjustable band setting. In some embodiments, the adjustable band setting may be adjustable by the user of the hearing protection device.The adjustable band setting may be set, in some cases, to produce a balanced sound spectrum to improve speech fidelity and speech intelligibility.

[0047] The processing unit 100 further includes a target controller 116 configured to apply a nonconstant target control, based on the calculated gain, across at least one of the first plurality of frequency bands 108 to generate a second set of frequency bands 122.

[0048] For many applications, a gain is applied across a frequency band. Generally, the applied gain is applied consistently across the frequency band. However, in some embodiments herein, a non-constant gain is applied across a frequency band, e.g., a different gain is applied for different frequencies within the frequency band. The applied gain may have a linear slope, such that a higher frequency within the frequency band has a larger applied gain than a lower frequency within the frequency band. The slope may be positive or negative. In some embodiments, the applied gain has a non-linear pattern, for example with a gain increasing or decreasing in a stepwise manner across the frequency band, or according to a different gain curve.

[0049] Specifically, in some embodiments, the non-constant target control includes a non-linear control. That is, the target controller 116 may apply a non-linear control across a frequency band 108 based on the gain calculated by the gain calculator 114 for the frequency band 108.

[0050] In some embodiments, the non-constant target control includes a linearly increasing or linearly decreasing target control. That is, the target controller 116 may apply a linearly increasing or linearly decreasing target control across a frequency band 108 based on the gain calculated by the gain calculator 114 for the frequency band 108.

[0051] In some embodiments, the non-constant target control includes a step-wise increasing or a step-wise decreasing target control. That is, the target controller 116 may apply a step-wise increasing or a step-wise decreasing target control across a frequency band 108 based on the gain calculated by the gain calculator 114 for the frequency band 108.

[0052] In some examples, the target controller 116 may apply the non-constant target control, based on the calculated gain, across multiple frequency bands from the first plurality of frequency bands 108 to generate the second set of frequency bands 122. In an embodiment, the target controller 116 applies the non-constant target control across each of the first plurality of frequency bands 108.

[0053] In some embodiments, the target controller 116 may apply different non-constant target controls across different frequency bands of the first plurality of frequency bands 108. Specifically, in some embodiments, the target controller 116 may apply a first non-constant target control to a first frequency band from the first plurality of frequency bands 108 and a second non-constant target control to a second frequency band from the first plurality of frequency bands 108. The first and second nonconstant target controls may be different. For example, the target controller 116 may apply a linearly increasing target control across the first frequency band and a step- wise decreasing target control across the second frequency band.

[0054] The non-constant target control may be based on an adjustable band setting, which is based on a manufacturer-set band setting. In other words, the non-constant target control may be set by the manufacturer during production.

[0055] Alternatively, in some embodiments, the non-constant target control may be based on an adjustable band setting, which is based on a received user input from the user of the hearing protection device. That is, the user of the hearing protection device may adjust the non-constant target control. Since microphones of in-ear buds may tend to be biased toward lower frequencies, the user may adjust the spectral balance in favor of treble or bass as desired.

[0056] In some embodiments, the adjustable band setting includes a pivot (fulcrum) frequency within the speech band (e.g., about 1 kHz) about which the target curve is tilted. The gain calculator computes per-band gains relative to the pivot (e.g., approximately 0 dB at the pivot), and the target controller applies a non-constant target control that progressively increases or decreases gain above and below the pivot according to the selected slope or custom profile (flat, rising, falling, or arbitrary). The pivot may be user- or manufacturer-selectable, stored in memory, and used together with per-band limits (e.g., a maximum boost table) to improve speech intelligibility while maintaining natural timbre.

[0057] In some embodiments, the adjustable band setting defines a target curve selected to optimize speech intelligibility rather than provide a generic equalization. The target curve may emphasize frequency regions that contribute strongly to consonant clarity (e.g., approximately 1-4 kHz), de-emphasize excessive low-frequency energy (e.g., below about 300 Hz) that masks speech, and anchor the response near a pivot frequency (e.g., about 1 kHz) to preserve natural timbre. The gain calculator can apply intelligibility weighting across bands and compute gains to reduce an intelligibility -weighted error between the measured spectrum and the target curve, subject to constraints such as a maximum band gain and a per-band maximum boost table. The target controller then applies a non-constant target control that preferentially increases gain in bands important for speech while limiting boost where noise or distortion may be introduced.

[0058] In some embodiments, the processing unit performs filtering, frequency-strength detection, gain calculation, non-constant target control, and reconstruction in real time with low algorithmic latency. For example, a frame-based implementation (e.g., about 256 samples at 16 kHz with overlap / add) yields an end-to-end processing delay of about 16 ms or less. In communication use cases, total system latency (algorithmic plus transport) is maintained below about 150 ms. Frame length, filter-bank design, and smoothing constants are selected to satisfy these latency bounds while preserving intelligibility improvements.

[0059] In some embodiments, the system is configured for outgoing speech transmission and operates in mono by design. When the device includes two microphones, the processing unit selects one microphone signal (e.g., based on signal quality or noise) and applies the spectral balancing to that mono signal prior to transmission to a remote user. Alternatively, a standard pre-combining / summing stage may be used to form a single mono talker signal before applying the processing, thereby avoidingphase-combination issues. The processed mono speech is then communicated by the communication component to the external link (e.g., radio or Bluetooth).

[0060] In some embodiments, the processing unit includes a per-band maximum boost table that constrains the positive gain applied to each frequency band. The table stores, for each band, a maximum allowable boost (e.g., in dB). After the gain calculator determines a raw per-band gain to move the measured spectrum toward the target curve, the raw gain for each band is compared to the corresponding table entry and limited to that maximum before the target controller applies the gain. The table is typically monotonic with frequency such that higher-frequency bands are permitted less boost than low and mid bands to avoid over-amplifying high-frequency hiss or noise; for example, allowable boost may taper progressively above about 2-4 kHz.

[0061] The maximum boost table can be manufacturer-defined, user-selectable via presets, or updated per device profile and stored in non-volatile memory. In some embodiments, different tables are selected based on headset model, flange / fit, or regulatory constraints. The table may be static or adaptively adjusted based on estimated noise floor or input level. The per-band maximum boost table operates in addition to any global maximum band gain limiter, providing finer control that preserves speech intelligibility (by allowing moderate boosts in mid bands) while limiting artifacts, pumping, and distortion in high-frequency regions.

[0062] The processing unit 100 further includes a reconstructor 124 configured to generate a processed sound 126 by combining the second set of frequency bands 122. The reconstructor 124 may “reconstruct” the second set of frequency bands 122 to generate the processed sound 126. The processed sound 126 may be suitable for being output by a speaker. The processed sound 126 may include speech with improved fidelity and intelligibility as compared to the speech in the sound signal 104.

[0063] The processing unit 100 further includes a communication component 128 configured to communicate the processed sound 126 to a speaker 132. The communication component 128 may be communicably coupled with the reconstructor 124 and the speaker 132. The speaker 132 may be of the hearing protection device or other hearing protection devices.

[0064] The processing unit 100 may process the sound signal 104 to improve the speech fidelity and speech intelligibility of the speech in the sound signal 104. That is, the processed sound 126 generated by the processing unit 100 may have improved speech characteristics as compared to the sound signal 104. For example, the processed sound 126 may have a balanced spectrum (i.e., about equal frequency strength of each frequency band), which may improve speech fidelity and intelligibility.

[0065] The non-constant target control applied by the target controller 116 may adjust the first plurality of frequency bands 108 in a non-constant (or non-consistent) manner. Therefore, each frequency band 108 may have a non-constant gain applied to it. In contrast to conventional techniques that employ a consistent gain across a frequency band, the non-constant target control may provide greater control over each frequency band.

[0066] In some cases, the processing unit 100 may improve fidelity and intelligibility of speech which naturally has an unusually non-flat frequency spectrum. Further, the processing unit 100 may besuitable for in-ear buds, as the in-ear buds can inadvertently cause certain frequencies to exhibit unnatural resonance, for example, due to improper fit of the in-earbuds.

[0067] In some embodiments, the processing unit 100 may further include a maximum band gain limiter 134 configured to compare the calculated band gain for each of the first plurality of frequency bands 108 to a maximum allowed band gain. For any frequency band from the first plurality of frequency bands 108 having the calculated band gain greater than the maximum allowed band gain, the maximum band gain limiter 134 may be configured to limit the calculated band gain to the maximum allowed band gain. The maximum band gain limiter 134 may thus limit the calculated band gain so as to avoid setting excessively high gains that can lead to increased noise, distortion, clipping, or an overdriven sound.

[0068] In some embodiments, the processing unit 100 may further include a smoothing module 146. In some embodiments, the smoothing module 146 may be configured to calculate a square factor for at least one frequency band 108, and then apply the calculated square factor to the at least one frequency band 108. Applying the calculated square factor may provide extra gain adjustment to non-flat frequency bands and less gain adjustment on any frequency bands which are already mostly flat. This may facilitate achieving a flatter sound spectmm, and consequently may improve the speech fidelity and speech intelligibility.

[0069] In some embodiments, the smoothing module 146 may be configured to apply a smoothing function to the second set of frequency bands 122. The smoothing function may employ time-based smoothing factor applied to improve naturalness of the speech.

[0070] In one example, the smoothing factor may be calculated according to Equation 1 below:New Gain = (Old Gain * (Smoothing Factor)) + (New Gain * (1 - Smoothing Factor))Equation 1

[0071] In this example, the smoothing function may be defined in terms of frames. A frame is defined as a group of samples that are processed together. One frame may include arbitrary ‘x’ number of samples. In an embodiment, each frame may include a group of 256 samples. The smoothing factor may range from 0 to 1.

[0072] In some embodiments, the processing unit 100 may further include a level-dependent module 148 configured to apply a level-dependent function to the second set of frequency bands 122. The leveldependent module 148 may adapt the sound pressure level of the second set of frequency bands 122. The level-dependent module 148 may help to filter out impulse noises, such as gunshots from surrounding noises, and / or continuously adapt all ambient sound received to an appropriate level before it is reproduced to a user. The level-dependent module 148 may facilitate communication in noisy environments, or environments where noise levels can vary significantly, or where high impulse sounds may cause hearing damage.

[0073] FIG. 2A illustrates a graph 201 depicting an example sound signal 204. The graph 201 includes a curve 202 representing the variation frequency strength with respect to frequency of the sound signal 204. The sound signal 204 may be captured by a microphone of a hearing protection device. The sound signal 204 may include speech of an individual communicating with the user of the hearing protection device.

[0074] FIG. 2B illustrates a graph 203 depicting a first plurality of frequency bands 208 obtained by filtering the sound signal 204 of FIG. 2A according to the present disclosure. For example, the filter 106 of the processing unit 100 of FIG. 1 may filter the sound signal 204 into the first plurality of frequency bands 208. The first plurality of frequency bands 208 may include a first frequency band 206 and a second frequency band 207 different from the first frequency band 206.

[0075] FIG. 2C illustrates a graph 210 depicting the first frequency band 206 of FIG. 2B after application of a non-constant target control according to the present disclosure. Further, FIG. 2D illustrates a graph 211 depicting the second frequency band 207 of FIG. 2B after application of a nonconstant target control according to the present disclosure.

[0076] In FIG. 2C, a first non-constant target control 212 (depicted by a dashed line) is applied across the first frequency band 206. The first non-constant target control 212 is depicted as a linearly increasing target control in FIG. 2C. The first non-constant target control 212 may be applied across the first frequency band 206, for example, by the target controller 116 of FIG. 1.

[0077] In FIG. 2D, a second non-constant target control 214 (depicted by a dashed line) is applied across the second frequency band 207. The second non-constant target control 214 is depicted as a step- wise increasing target control in FIG. 2D. The second non-constant target control 214 may be applied across the second frequency band 207, for example, by the target controller 116 of FIG. 1. It may be noted that the first non-constant target control 212 of FIG. 2C and the second non-constant target control 214 of FIG. 2D are different.

[0078] FIG. 3 illustrates a block diagram of an example hearing protection device 300, according to embodiments of the present disclosure.

[0079] The hearing protection device 300 includes a pair of in-ear buds 310. Only one in-ear bud 310 is shown in FIG. 3 as a block for illustrative purposes. Each in-ear bud 310 from the pair of in-ear buds 310 includes a speaker 352 configured to broadcast a processed sound 346. Each in-ear bud 310 further includes a flange (not shown in FIG. 3) configured to engage an ear canal of a wearer of the pair of in-ear buds 310. The flange is configured to seal the speaker 352 on an ear-canal side of the in-ear bud 310.

[0080] The hearing protection device 300 further includes a microphone 330 configured to capture a sound signal 325. The hearing protection device 300 further includes a processing unit 320. The processing unit 320 may be similar in design and functionality to the processing unit 100 of FIG. 1 described above.

[0081] The processing unit 320 may include a sound signal receiver 322 configured to receive the sound signal 325 captured by the microphone 330. The sound signal 325 may include speech of an individual communicating with the wearer of the hearing protection device 300.

[0082] The processing unit 320 further includes a filter 326 configured to filter the captured sound signal 325 into a first plurality of frequency bands 328. The filter 326 may include a filter bank.Additionally, or alternatively, fast Fourier transform (FFT) may be employed to fdter the received sound signal 325 into the first plurality of frequency bands 328. A number of frequency bands into which the filter 326 filters the sound signal 325 may be selected based on desired application attributes. In some cases, a greater number of frequency bands may be desired (e.g., for improved processing), while in some other cases, a smaller number of frequency bands may be desired (e.g., for reduced computational power requirement).

[0083] The processing unit 320 further includes a frequency strength detector 332 configured to detect a frequency strength for each of the first plurality of frequency bands 328. In other words, the frequency strength detector 332 may detect the amplitude for each of the first plurality of frequency bands 328. The frequency strength of a frequency band 328 may correspond to the loudness level of the frequency band 328.

[0084] The processing unit 320 further includes a gain calculator 334 configured to calculate a gain for each of the first plurality of frequency bands 328. The gain calculator 334 may calculate the gain for each of the first plurality of frequency bands 328 based on an adjustable band setting. In some embodiments, the adjustable band setting may be adjustable by the user of the hearing protection device. The adjustable band setting may be set, in some cases, to produce a balanced sound spectrum to improve speech fidelity and speech intelligibility.

[0085] The processing unit 320 further incudes a target controller 336 configured to apply a nonconstant target control, based on the calculated gain, across at least one of the first plurality of frequency bands 328 to generate a second set of frequency bands 342.

[0086] For many applications, a gain is applied across a frequency band. Generally, the applied gain is applied consistently across the frequency band. However, in some embodiments herein, a non-constant gain is applied across a frequency band, e.g., a different gain is applied for different frequencies within the frequency band. The applied gain may have a linear slope, such that a higher frequency within the frequency band has a larger applied gain than a lower frequency within the frequency band. The slope may be positive or negative. In some embodiments, the applied gain has a non-linear pattern, for example with a gain increasing or decreasing in a stepwise manner across the frequency band, or according to a different gain curve.

[0087] Specifically, in some embodiments, the non-constant target control includes a non-linear control. That is, the target controller 336 may apply a non-linear control across a frequency band 328 based on the gain calculated by the gain calculator 334 for the frequency band 328.

[0088] In some embodiments, the non-constant target control includes a linearly increasing or linearly decreasing target control. That is, the target controller 336 may apply a linearly increasing or linearly decreasing target control across a frequency band 328 based on the gain calculated by the gain calculator 334 for the frequency band 328.

[0089] In some embodiments, the non-constant target control includes a step-wise increasing or a step-wise decreasing target control. That is, the target controller 336 may apply a step-wise increasing or a step-wise decreasing target control across a frequency band 328 based on the gain calculated by the gain calculator 334 for the frequency band 328.

[0090] In some examples, the target controller 336 may apply the non-constant target control, based on the calculated gain, across multiple frequency bands from the first plurality of frequency bands 328 to generate the second set of frequency bands 342. In an embodiment, the target controller 336 applies the non-constant target control across each of the first plurality of frequency bands 328.

[0091] In some embodiments, the target controller 336 may apply different non-constant target controls across different frequency bands of the first plurality of frequency bands 328. Specifically, in some embodiments, the target controller 336 may apply a first non-constant target control to a first frequency band from the first plurality of frequency bands 328 and a second non-constant target control to a second frequency band from the first plurality of frequency bands 328. The first and second nonconstant target controls may be different. For example, the target controller 336 may apply a linearly increasing target control across the first frequency band and a step- wise decreasing target control across the second frequency band.

[0092] The non-constant target control may be based on an adjustable band setting, which is based on a manufacturer-set band setting. In other words, the non-constant target control may be set by the manufacturer during production.

[0093] Alternatively, in some embodiments, the non-constant target control may be based on an adjustable band setting, which is based on a received user input from a user of the hearing protection device. That is, the user of the hearing protection device may adjust the non-constant target control. Since microphones of in-ear buds may tend to be biased toward lower frequencies, the user may adjust the spectral balance in favor of treble or bass as desired. The user input may be received using any suitable input / output (I / O) device located on the hearing protection device, or located remotely from the hearing protection device. For example, a user may enter a preferred adjustable band setting using an application accessed on a mobile computing device, which may then transmit the user input to the processing unit of the hearing protection device. However, it is expressly contemplated that, in some embodiments, the term “user-selected adjustable band setting” may refer to a preset band setting selected, for example, by a manufacturer or by a site manager for a worksite, and not be user-selectable.

[0094] The processing unit 320 further includes a reconstructor 344 configured to generate the processed sound 346 by combining the second set of frequency bands 342. The reconstructor 344 may “reconstruct” the second set of frequency bands 342 to generate the processed sound 346. The processedsound 346 may be suitable for being output by a speaker. The processed sound 346 may include speech with improved fidelity and intelligibility as compared to the speech in the sound signal 325.

[0095] In some embodiments, the processing unit 320 may further include a communication component 348 configured to communicate the processed sound 346 to the speaker 352. The communication component 348 may be communicably coupled with the reconstructor 124 and the speaker 352.

[0096] The hearing protection device 300 may output the processed sound 346 having improved speech fidelity and speech intelligibility to the user of the hearing protection device 300 via the speaker 352. Specifically, the processing unit 320 may process the sound signal 325 to improve the speech fidelity and speech intelligibility of the speech in the sound signal 325. That is, the processed sound 346 generated by the processing unit 320 may have improved speech characteristics as compared to the sound signal 325. For example, the processed sound 346 may have a more balanced spectrum (i.e. , about equal frequency strength of each frequency band), which may improve speech fidelity and intelligibility.

[0097] The non-constant target control applied by the target controller 336 may adjust the first plurality of frequency bands 328 in a non-constant (or non-consistent) manner. Therefore, each frequency band 328 may have a non-constant gain applied to it. In contrast to conventional techniques that employ a consistent gain across a frequency band, the non-constant target control may provide greater control over each frequency band.

[0098] In some cases, the hearing protection device 300 may improve fidelity and intelligibility of speech which naturally has an unusually non-flat frequency spectrum. Further, the processing unit 320 may be suitable for the pair of in-ear buds 310, as the pair of in-ear buds 310 can inadvertently cause certain frequencies to exhibit unnatural resonance, for example, due to improper fit of the pair of in-ear buds 310.

[0099] In some embodiments, the processing unit 320 may further include a maximum band gain limiter 354 configured to compare the calculated band gain for each of the first plurality of frequency bands 328 to a maximum allowed band gain. For any frequency band from the first plurality of frequency bands 328 having the calculated band gain greater than the maximum allowed band gain, the maximum band gain limiter 354 may be configured to limit the calculated band gain to the maximum allowed band gain. The maximum band gain limiter 354 may thus limit the calculated band gain so as to avoid setting excessively high gains that can lead to increased noise, distortion, clipping, or an overdriven sound.

[0100] In some embodiments, the processing unit 320 may further include a smoothing module 366. In some embodiments, the smoothing module 366 may be configured to calculate a square factor for at least one frequency band 328, and apply the calculated square factor to the at least one frequency band 328. Applying the calculated square factor may provide extra gain adjustment to non-flat frequency bands and less gain adjustment on any frequency bands which are already mostly flat. This may facilitate achieving a flatter sound spectmm, and consequently may improve the speech fidelity and speech intelligibility.

[0101] In some embodiments, the smoothing module 366 may be configured to apply a smoothing function to the second set of frequency bands 342. The smoothing function may employ time-based smoothing factor applied to improve naturalness of the speech, as described above with reference to FIG. 1.

[0102] In some embodiments, the processing unit 320 may further include a level-dependent module 368 configured to apply a level-dependent function to the second set of frequency bands 342. The leveldependent module 368 may adapt the sound pressure level of the second set of frequency bands 342. The level-dependent module 368 may help to filter out impulse noises, such as gunshots from surrounding noises, and / or continuously adapt all ambient sound received to an appropriate level before it is reproduced to a user. The level-dependent module 368 may facilitate communication in noisy environments, or environments where noise levels can vary significantly, or where high impulse sounds may cause hearing damage.

[0103] FIG. 4 illustrates an example hearing protection device 400, according to embodiments of the present disclosure. The hearing protection device 400 may be similar to the hearing protection device 300 discussed above with reference to FIG. 3.

[0104] The hearing protection device 400 includes a microphone 410 configured to capture a sound signal 402. The hearing protection device 400 further includes a processing unit 420. The processing unit 420 may be similar in design and functionality to the processing unit 320 of FIG. 3 described above. That is, the processing unit 420 may process the sound signal 402 to generate a processed sound 422 and communicate the processed sound 422 to one or more speakers.

[0105] In the illustrated embodiment of FIG. 4, the hearing protection device 400 further includes a first in-ear bud 430 and a second in-ear bud 440. The hearing protection device 400 further includes a first speaker 432 associated with the first in-ear bud 430 and a second speaker 442 associated with the second in-ear bud 440. In an embodiment, the processed sound 422 may be broadcast only by the first in-ear bud 430. In other words, the processing unit 420 may communicate the processed sound 422 to only the first speaker 432 associated with the first in-earbud 430. However, it is expressly contemplated that, in some embodiments, the processed sound 422 is broadcast through both the first and second speakers 432, 442.

[0106] FIG. 5 illustrates an example hearing protection device 500 that may be used according to some embodiments of the present disclosure.

[0107] The hearing protection device 500 includes a pair of in-ear buds 510. The hearing protection device 500 further includes a microphone 530 (schematically depicted by a circle in FIG. 5) configured to capture a sound signal. Each in-ear bud 510 from the pair of in-ear buds 510 includes a speaker configured to broadcast a processed sound. Each in-ear bud 510 further includes a flange 520 configured to engage an ear canal of a wearer of the pair of in-ear buds 510. The flange 520 is configured to seal the speaker on an ear-canal side of the in-ear bud 510. In FIG. 5, the flange 520 is shown as having a triple flange design. However, the flange 520 may have other designs, such as a single flange design or a double flange design.

[0108] FIG. 6 illustrates a flowchart of a method for providing improved fidelity of speech in a hearing protection device, according to embodiments of the present disclosure. The method 600 may be performed by a processing unit (such as the processing unit 100 of FIG. 1) of a hearing protection device.

[0109] At block 602, a sound signal is received from a sound source. The sound signal may be captured by a microphone and received from the microphone. The sound signal may include speech.

[0110] At block 604, the sound signal is processed using a sound filter to obtain a processed sound. Any suitable processing circuitry or processing unit may be employed to carry out the processing.

[0111] At block 606, the received sound signal is filtered into a plurality of frequency bands. The received sound signal may be filtered using a filter bank. Additionally, or alternatively, fast Fourier transform (FFT) may be employed to filter the received sound signal into the first plurality of frequency bands. A number of frequency bands into which the sound signal is filtered may be selected based on desired application attributes. In some cases, a greater number of frequency bands may be desired (e.g., for improved processing), while in some other cases, a smaller number of frequency bands may be desired (e.g., for reduced computational power requirement).

[0112] At block 608, a frequency strength for at least one frequency band from the plurality of frequency bands is detected. In other words, the amplitude for the at least one frequency band may be determined. The frequency strength of the at least one frequency band may correspond to the loudness level of the at least one frequency band.

[0113] At block 610, a band gain for the at least one frequency band is computed. The computed band gain is based on an adjustable band setting. In some embodiments, the adjustable band setting may be based on a manufacturer-set band setting. In some embodiments, the adjustable band setting may be based on a received user input from a user of the hearing protection device. The user may adjust the adjustable band setting according to their preference (e.g., favoring treble instead of bass).

[0114] At block 612, a non-constant target control is applied across the at least one frequency band based on the computed band gain.

[0115] For many applications, a gain is applied across a frequency band. Generally, the applied gain is applied consistently across the frequency band. However, in some embodiments herein, a non-constant gain is applied across a frequency band, e.g., a different gain is applied for different frequencies within the frequency band. The applied gain may have a linear slope, such that a higher frequency within the frequency band has a larger applied gain than a lower frequency within the frequency band. The slope may be positive or negative. In some embodiments, the applied gain has a non-linear pattern, for example with a gain increasing or decreasing in a stepwise manner across the frequency band, or according to a different gain curve.

[0116] In some embodiments, the non-constant target control includes a non-linear control. That is, a non-linear control may be applied across the at least one frequency band.

[0117] In some embodiments, the non-constant target control includes a linearly increasing or linearly decreasing target control. That is, a linearly increasing or linearly decreasing target control may be applied across the at least one frequency.

[0118] In some embodiments, the non-constant target control includes a step-wise increasing or a step-wise decreasing target control. That is, a step-wise increasing or a step-wise decreasing target control may be applied across the at least one frequency.

[0119] At block 614, the processed frequency bands are reconstructed into the processed sound. The processed frequency bands (and unprocessed frequency bands, if any) may be combined together to construct the processed sound. The processed sound may include speech with improved fidelity and intelligibility as compared to the speech in the sound signal received at block 602.

[0120] At block 616, the processed sound is broadcasted. For example, the processed sound may be broadcast to one or more speakers of the hearing protection device. As a result, the processed sound may be output to the user of the hearing protection device via the speaker of the hearing protection device. In some embodiments, the processed sound is broadcasted through only one speaker, e.g., to only the user’s left or only the user’s right ear. In some embodiments, the processed sound is broadcast to both the left and right speakers.

[0121] Using method 600, a hearing protection device may broadcast a processed sound having improved speech fidelity and speech intelligibility to the user of the hearing protection device. The processed sound generated using the method 600 may have improved speech characteristics as compared to the original sound signal. For example, the processed sound may have a balanced spectrum (i.e., about equal frequency strength of each frequency band), which may improve speech fidelity and intelligibility.

[0122] The non-constant target control may adjust the at least one frequency band in a non-constant (or non-consistent) manner. Therefore, the at least one frequency band may have a non-constant gain applied to it. In contrast to conventional techniques that employ a consistent gain across a frequency band, the non-constant target control may provide greater control over the at least one frequency band.

[0123] In some cases, the method 600 may improve fidelity and intelligibility of speech, which naturally has an unusually non-flat frequency spectrum. Further, the method 600 may be suitable for implementation within in-ear buds, as in-ear buds can inadvertently cause certain frequencies to exhibit unnatural resonance, for example, due to improper fit of the in-ear buds.

[0124] In some embodiments, the method 600 further includes detecting that the computed band gain exceeds a maximum allowed band gain, and limiting the computed band gain to the maximum allowed band gain. This may limit the computed band gain for the at least one frequency band so as to avoid setting excessively high gains that can lead to increased noise, distortion, clipping, or an overdriven sound.

[0125] In some embodiments, the method 600 further includes computing a square factor and applying the square factor to the at least one frequency band. Applying the computed square factor may provide extra gain adjustment if the at least one frequency band is a non-flat frequency band and less gainadjustment if the at least one frequency band is already mostly flat. This may facilitate achieving a flatter sound spectrum, and consequently may improve the speech fidelity and speech intelligibility.

[0126] In some embodiments, the method 600 further includes smoothing the processed frequency bands. For example, a smoothing function may be applied to the processed frequency bands. The smoothing function may employ a time-based smoothing factor applied to improve naturalness of the speech, for example, as described above with reference to FIG. 1.

[0127] In some embodiments, the steps of detecting, computing, and applying are taken for each of the plurality of frequency bands. Consequently, the method 600 may facilitate achieving a balanced sound spectrum across the plurality of frequency bands, thereby improving speech fidelity and speech intelligibility for the hearing protection device.

[0128] FIG. 7 is a simplified block diagram of one illustrative example of a handheld or mobile computing device that can be used as a user's or client's handheld device 816, in which the present system (or parts of it) can be deployed. For instance, a mobile device can be used to connect to a hearing protection device via a wireless channel and adjust the adjustable band setting according to the present disclosure. FIG. 8 is another example of a handheld or mobile device.

[0129] FIG. 7 provides a general block diagram of the components of a client device 816 that can run some components shown and described herein. Client device 816 interacts with them or runs some and interacts with some. In the device 816, a communications link 813 is provided that allows the handheld device to communicate with other computing devices and under some embodiments provides a channel for receiving information automatically, such as by scanning. Examples of communications link 813 include allowing communication though one or more communication protocols, such as wireless services used to provide cellular access to a network, as well as protocols that provide local wireless connections to networks.

[0130] In other examples, applications can be received on a removable Secure Digital (SD) card that is connected to an interface 815. Interface 815 and communication links 813 communicate with a processor 817 (which can also embody a processor) along a bus 819 that is also connected to memory 821 and input / output (I / O) components 823, as well as clock 825 and location system 827.

[0131] I / O components 823, in one embodiment, are provided to facilitate input and output operations and the device 816 can include input components such as buttons, touch sensors, optical sensors, microphones, touch screens, proximity sensors, accelerometers, orientation sensors and output components such as a display device, a speaker, and or a printer port. Other I / O components 823 can be used as well.

[0132] Clock 825 illustratively comprises a real time clock component that outputs a time and date. It can also provide timing functions for processor 817.

[0133] Illustratively, location system 827 includes a component that outputs a current geographical location of device 816. This can include, for instance, a global positioning system (GPS) receiver, a LORAN system, a dead reckoning system, a cellular triangulation system, or other positioning system. Itcan also include, for example, mapping software or navigation software that generates desired maps, navigation routes and other geographic functions.

[0134] Memory 821 stores operating system 829, network settings 831, applications 833, application configuration settings 835, contact or phone book application 843, client system 824, data store 837, communication drivers 839, and communication configuration settings 841. Memory 821 can include all types of tangible volatile and non-volatile computer-readable memory devices. It can also include computer storage media (described below). Memory 821 stores computer readable instructions that, when executed by processor 817, cause the processor to perform computer-implemented steps or functions according to the instructions. Processor 817 can be activated by other components to facilitate their functionality as well.

[0135] FIG. 8 shows that a device 900 can be a smart phone 971. Smart phone 971 has a touch sensitive display 973 that displays icons or tiles or other user input mechanisms 975. Mechanisms 975 can be used by a user to run applications, make calls, perform data transfer operations, etc. In general, smart phone 971 is built on a mobile operating system and offers more advanced computing capability and connectivity than a feature phone. Note that other forms of the devices 971 are possible.

[0136] FIG. 9 is a block diagram illustrating an example computing environment that can be used in embodiments shown in previous Figures.

[0137] FIG. 9 is one example of a computing environment 1000 in which elements of systems and methods described herein, or parts of them (for example), can be deployed. With reference to FIG. 9, an example system for implementing some embodiments includes a general-purpose computing device in the form of a computer 1010. Components of computer 1010 may include, but are not limited to, a processing unit 1020 (which can include a processor), a system memory 1030, and a system bus 1021 that couples various system components including the system memory 1030 to the processing unit 1020. The system bus 1021 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. Memory and programs described with respect to systems and methods described herein can be deployed in corresponding portions of FIG. 9.

[0138] Computer 1010 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 1010 and includes both volatile / nonvolatile media and removable / non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media is different from and does not include a modulated data signal or carrier wave. It includes hardware storage media including both volatile / nonvolatile and removable / non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desiredinformation, and which can be accessed by computer 1010. Communication media may embody computer readable instructions, data structures, program modules or other data in a transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.

[0139] The system memory 1030 includes computer storage media in the form of volatile and / or nonvolatile memory such as read only memory (ROM) 1031 and random access memory (RAM) 1032. A basic input / output system 1033 (BIOS) containing the basic routines that help to transfer information between elements within computer 1010, such as during start-up, is typically stored in ROM 1031. RAM 1032 typically contains data and / or program modules that are immediately accessible to and / or presently being operated on by processing unit 1020. By way of example, and not limitation, FIG. 9 illustrates operating system 1034, application programs 1035, other program modules 1036, and program data 1037.

[0140] The computer 1010 may also include other removable / non-removable and volatile / nonvolatile computer storage media. By way of example only, FIG. 9 illustrates a hard disk drive 1041 that reads from or writes to non-removable, nonvolatile magnetic media, nonvolatile magnetic disk, an optical disk drive 1055, and nonvolatile optical disk 1056. The hard disk drive 1041 is typically connected to the system bus 1021 through a non-removable memory interface such as interface 1040, and optical disk drive 1055 is typically connected to the system bus 1021 by a removable memory interface, such as interface 1050.

[0141] Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (e.g., ASICs), Application-specific Standard Products (e.g., ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0142] The drives and their associated computer storage media discussed above and illustrated in FIG. 9, provide storage of computer readable instructions, data structures, program modules and other data for the computer 1010. In FIG. 9, for example, hard disk drive 1041 is illustrated as storing operating system 1044, application programs 1045, other program modules 1046, and program data 1047. Note that these components can either be the same as or different from operating system 1034, application programs 1035, other program modules 1036, and program data 1037.

[0143] A user may enter commands and information into the computer 1010 through input devices such as a keyboard 1062, a microphone 1063, and a pointing device 1061, such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite receiver, scanner, or the like. These and other input devices are often connected to the processing unit 1020 through a user input interface 1060 that is coupled to the system bus but may be connected by other interface and bus structures. A visual display 1091 or other type of display device is also connected to the system bus 1021 via an interface, such as a video interface 1090. In addition to the monitor, computers may also include other peripheral output devices such as speakers 1097 and printer 1096, which may be connected through an output peripheral interface 1095.

[0144] The computer 1010 is operated in a networked environment using logical connections, such as a Local Area Network (LAN) or Wide Area Network (WAN) to one or more remote computers, such as a remote computer 1080.

[0145] When used in a LAN networking environment, the computer 1010 is connected to the LAN 1071 through a network interface 1070 or adapter. When used in a WAN networking environment, the computer 1010 typically includes a modem 1072 or other means for establishing communications over the WAN 1073, such as the Internet. In a networked environment, program modules may be stored in a remote memory storage device. FIG. 9 illustrates, for example, that remote application programs 1085 can reside on remote computer 1080.

[0146] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0147] The techniques of this disclosure may be implemented in a wide variety of computer devices, such as servers, laptop computers, desktop computers, notebook computers, tablet computers, hand-held computers, smart phones, and the like. Any components, modules or units have been described to emphasize functional aspects and do not necessarily require realization by different hardware units. The techniques described herein may also be implemented in hardware, software, firmware, or any combination thereof. Any features described as modules, units or components may be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. In some cases, various features may be implemented as an integrated circuit device, such as an integrated circuit chip or chipset. Additionally, although a number of distinct modules have been described throughout this description, many of which perform unique functions, all the functions of all of the modules may be combined into a single module, or even split into further additional modules. The modules described herein are only exemplary and have been described as such for better ease of understanding.

[0148] If implemented in software, the techniques may be realized at least in part by a computer- readable medium comprising instructions that, when executed in a processor, performs one or more of the methods described above. The computer-readable medium may comprise a tangible computer-readable storage medium and may form part of a computer program product, which may include packaging materials. The computer-readable storage medium may comprise random access memory (RAM) such as synchronous dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, magnetic or optical data storage media, and the like. The computer-readable storage medium may also comprise a non-volatile storage device, such as a hard-disk, magnetic tape, a compact disk (CD), digital versatile disk (DVD), Blu-ray disk, holographic data storage media, or other nonvolatile storage device.

[0149] The term “processor,” as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, thefunctionality described herein may be provided within dedicated software modules or hardware modules configured for performing the techniques of this disclosure. Even if implemented in software, the techniques may use hardware such as a processor to execute the software, and a memory to store the software. In any such cases, the computers described herein may define a specific machine that is capable of executing the specific functions described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements, which could also be considered a processor.

[0150] It will be apparent to those skilled in the art that the specific exemplary embodiments, elements, structures, features, details, arrangements, configurations, etc., that are disclosed herein can be modified and / or combined in numerous ways. In summary, numerous variations and combinations are contemplated as being within the bounds of the conceived invention, not merely those representative designs that were chosen to serve as exemplary illustrations. Thus, the scope of the present invention should not be limited to the specific illustrative structures described herein, but rather extends at least to the structures described by the language of the claims, and the equivalents of those structures. Any of the elements that are positively recited in this specification as alternatives may be explicitly included in the claims or excluded from the claims, in any combination as desired. Any of the elements or combinations of elements that are recited in this specification in open-ended language (e.g., comprise and derivatives thereof), are considered to additionally be recited in closed-ended language (e.g., consist and derivatives thereof) and in partially closed-ended language (e.g., consist essentially, and derivatives thereof). Although various theories and possible mechanisms may have been discussed herein, in no event should such discussions serve to limit the claimable subject matter. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document that is incorporated by reference herein but to which no priority is claimed, this specification as written will control. In the present detailed description of the preferred embodiments, reference is made to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments according to the invention. It is to be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0151] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0152] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

CLAIMS:What is claimed is:

1. A method for providing improved fidelity of speech in a hearing protection device, the method comprising: receiving a sound signal from a sound source; processing the sound signal using a sound filter to obtain a processed sound, wherein the processing comprises: filtering the received sound signal into a plurality of frequency bands, and for at least one frequency band from the plurality of frequency bands: detecting a frequency strength; computing a band gain, wherein the computed band gain is based on an adjustable band setting; applying a non-constant target control across the at least one frequency band based on the computed band gain; and reconstructing the processed frequency bands into the processed sound; and broadcasting the processed sound.

2. The method of claim 1, and further comprising: detecting that the computed band gain exceeds a maximum allowed band gain; and limiting the computed band gain to the maximum allowed band gain.

3. The method of claims 1 or 2, wherein the non-constant target control is selected from the group consisting of: i) a linearly increasing or linearly decreasing target control, ii)a step-wise increasing or a step-wise decreasing target control, or iii) a non-linear control.

4. The method of any of claims 1-3, and further comprising computing a square factor and applying the square factor to the at least one frequency band.

5. A processing unit for a hearing protection device, the processing unit comprising: a sound signal receiver configured to receive a sound signal; a filter configured to filter the received sound signal into a first plurality of frequency bands; a frequency strength detector configured to detect a frequency strength for each of the first plurality of frequency bands; a gain calculator configured to calculate a gain for each of the first plurality of frequency bands; a target controller configured to apply a non-constant target control, based on the calculated gain, across at least one of the first plurality of frequency bands to generate a second set of frequency bands; a reconstructor configured to generate a processed sound by combining the second set of frequency bands; anda communication component configured to communicate the processed sound to a speaker.

6. The processing unit of claim 5, and further comprising a maximum band gain limiter configured to compare the calculated band gain for each of the first plurality of frequency bands to a maximum allowed band gain, and for any frequency band from the first plurality of frequency bands having the calculated band gain greater than the maximum allowed band gain, limit the calculated band gain to the maximum allowed band gain.

7. The processing unit of claim 5 or 6, wherein the target controller applies a first non-constant target control to a first frequency band from the first plurality of frequency bands and a second non-constant target control to a second frequency band from the first plurality of frequency bands, and wherein the first and second non-constant target controls are different.

8. The processing unit of any of claims 5-7, and further comprising a smoothing module, wherein the smoothing module is configured to calculate a square factor for at least one frequency band, and apply the calculated square factor to the at least one frequency band.

9. The processing unit of any of claims 5-8, and further comprising a smoothing module configured to apply a smoothing function to the second set of frequency bands.

10. A hearing protection device comprising: a pair of in-ear buds, each comprising: a speaker configured to broadcast a processed sound; and a flange configured to engage an ear canal of a wearer of the pair of in-earbuds, wherein the flange is configured to seal the speaker on an ear-canal side of the in-ear bud; a microphone configured to capture a sound signal; and a processing unit, the processing unit comprising: a filter configured to filter the captured sound signal into a first plurality of frequency bands; a frequency strength detector configured to detect a frequency strength for each of the first plurality of frequency bands; a gain calculator configured to calculate a gain for each of the first plurality of frequency bands; a target controller configured to apply a non-constant target control, based on the calculated gain, across at least one of the first plurality of frequency bands to generate a second set of frequency bands; and a reconstructor configured to generate the processed sound by combining the second set of frequency bands.

11. The hearing protection device of claim 10, wherein the hearing protection device comprises: a first speaker associated with a first in-ear bud; and a second speaker associated with a second in-ear bud; wherein the processed sound is broadcast only by the first in-ear bud.

12. The hearing protection device of claim 10 or 11, wherein the processing unit further comprises a maximum band gain limiter configured to compare the calculated band gain for each of the first plurality of frequency bands to a maximum allowed band gain, and for any frequency band from the first plurality of frequency bands having the calculated band gain greater than the maximum allowed band gain, limit the calculated band gain to the maximum allowed band gain.

13. The hearing protection device of any of claims 10 -12, wherein the target controller applies the nonconstant target control across each of the first plurality of frequency bands.

14. The hearing protection device of claim 13, wherein the target controller applies a first non-constant target control to a first frequency band from the first plurality of frequency bands and a second nonconstant target control to a second frequency band from the first plurality of frequency bands, and wherein the first and second non-constant target controls are different.

15. The hearing protection device of any of claims 10-14, wherein the processing unit further comprises a smoothing module, wherein the smoothing module is configured to calculate a square factor for at least one frequency band, and apply the calculated square factor to the at least one frequency band.

16. The hearing protection device of any of claims 10-15, wherein the processing unit further comprises a smoothing module configured to apply a smoothing function to the second set of frequency bands.

17. The hearing protection device of any of claims 10-16, wherein the non-constant target control is based on an adjustable band setting, which is based on a received user input from a user of the hearing protection device.

18. The hearing protection device of any of claims 10-18, wherein the non-constant target control is based on an adjustable band setting, which is based on a manufacturer-set band setting.

19. The hearing protection device of any of claims 10-19, wherein the processing unit further comprises a per-band maximum boost table stored in memory, the table specifying, for each of the first plurality of frequency bands, a maximum allowable positive gain, and wherein the target controller is configured to limit the applied gain in each frequency band to the corresponding maximum allowable positivegain, the table prescribing lower maximum boosts for higher-frequency bands than for low- and mid-frequency bands.

20. The hearing protection device of any of claims 10-19, wherein the adjustable band setting defines a pivot frequency of about 1 kHz within the speech band about which a target response is tilted, and wherein the gain calculator and target controller are configured to vary gain above and below the pivot according to a selected slope or profile.

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