Patent Description:
Users of hearing devices typically have a hearing loss shape where the hearing loss becomes stronger with increasing frequency. As a result, while low-frequency sounds may still be perceivable, high-frequency sounds may be difficult or impossible for a user to perceive. In addition, due to, for example, physical limitations of a receiver of a hearing device, open fitting configurations, and/or potential feedback, it may not be possible to provide the required amplification to represent such high-frequency sounds to a user. To overcome these problems, one approach is to implement frequency lowering algorithms in which high input audio frequencies are remapped to relatively lower output frequencies where users of hearing devices typically have better residual hearing. <CIT> describes a method for fitting a hearing device to the needs of a user which includes setting a cut-off frequency for a frequency lowering algorithm within a cut-off frequency range. <NPL>) describes an adaptive frequency-lowering algorithm which switches between a lower and a higher predefined cut-off frequency. However, such frequency lowering algorithms may unnecessarily reserve a portion of available output bandwidth to receive high-frequency compressed content, which may result in significantly compressing original harmonics in an input audio signal and undesired artifacts in an output audio signal.

Hearing devices and methods for implementing an adaptively adjusted cut-off frequency are described herein. The invention provides a hearing device according to claim <NUM> and a method according to claim <NUM>. As will be described in more detail below, the invention concerns a hearing device which comprises a memory storing instructions and a processor communicatively coupled to the memory. The behind an ear of a user. In some examples, a hearing device may be implemented by an in-the-ear ("ITE") component configured to at least partially be inserted within an ear canal of a user. In some examples, a hearing device may include a combination of an ITE component, a BTE component, and/or any other suitable component. According to the invention, the adaptively adjusting of the cut-off frequency as the continuous function of the input audio signal includes adaptively adjusting the cut-off frequency as a continuous function of an instantaneous input bandwidth of the input audio signal.

In an embodiment of the hearing device, no frequency compression is applied to the input audio signal during the mapping, when the instantaneous input bandwidth of the input audio signal is less than the predefined minimum cut-off frequency value.

In another embodiment of the hearing device, the processor is further configured to execute the instructions to apply, when the instantaneous input bandwidth of the input audio signal is between the predefined minimum cut-off frequency value and the predefined maximum cut-off frequency value, a fixed frequency compression ratio to modify the range of frequencies of the input audio signal, wherein the generating of the output audio signal includes mapping the range of input frequencies, as modified based on the fixed frequency compression ratio, to the range of output frequencies.

In another embodiment of the hearing device, the processor is further configured to execute the instructions to apply, when the instantaneous input bandwidth of the input audio signal is between the predefined minimum cut-off frequency value and the predefined maximum cut-off frequency value, an input bandwidth-dependent frequency compression ratio to modify the range of frequencies of the input audio signal, wherein the generating of the output audio signal includes mapping the range of input frequencies, as modified based on the input bandwidth-dependent frequency compression ratio, to the range of output frequencies.

In another embodiment of the hearing device, the adaptively adjusted cut-off frequency decreases as the instantaneous input bandwidth increases, when the instantaneous input bandwidth of the input audio signal is between the predefined minimum cut-off frequency value and the predefined maximum cut-off frequency value.

In another embodiment of the hearing device, the cut-off frequency is set to the predefined minimum cut-off frequency value, when the instantaneous input bandwidth is above the predefined maximum cut-off frequency value.

In another embodiment of the hearing device, the instantaneous input bandwidth of the input audio signal is defined as a frequency associated with a first bin index of a particular input frame of the input audio signal that reaches a predefined percentage of a total energy of the particular input frame of the input audio signal.

In another embodiment of the hearing device, the predefined percentage is equal to or greater than ninety percent of the total energy of the particular input frame of the input audio signal.

In an example of the hearing device, which does not form part of the present invention, but which is described here for illustrative purposes, the adaptively adjusting of the cut-off frequency as the continuous function of the input audio signal includes adaptively adjusting the cut-off frequency as a continuous function of an instantaneous input level of the input audio signal.

In another embodiment of the hearing device, the processor is further configured to execute the instructions to apply a pre-compensation filter to the input audio signal to mitigate low frequency masking of the output audio signal. In another embodiment of the hearing device, the processor is further configured to execute the instructions to provide the output audio signal to a receiver configured to represent the output audio signal to a user of the hearing device.

The invention also concerns a method comprising: receiving, by a processor of a hearing device, an input audio signal having a range of input frequencies; adaptively adjusting, by the processor of the hearing device, a cut-off frequency for the input audio signal such that a value of the cut-off frequency varies between a predefined minimum cut-off frequency value and a predefined maximum cut-off frequency value as a continuous function of the input audio signal; and generating, by the processor of the hearing device, an output audio signal by mapping the range of input frequencies to a range of output frequencies determined based on the adaptively adjusted cut-off frequency.

According to the invention, the adaptively adjusting of the cut-off frequency as the continuous function of the input audio signal includes adaptively adjusting the cut-off frequency as a continuous function of an instantaneous input bandwidth of the input audio signal.

In another implementation, the method further comprises applying, by the processor of the hearing device when the instantaneous input bandwidth of the input audio signal is between the predefined minimum cut-off frequency value and the predefined maximum cut-off frequency value, a fixed frequency compression ratio to modify the range of frequencies of the input audio signal, wherein the generating of the output audio signal includes mapping the range of input frequencies, as modified based on the fixed frequency compression ratio, to the range of output frequencies.

In another implementation, the method further comprises applying, by the processor of the hearing device when the instantaneous input bandwidth of the input audio signal is between the predefined minimum cut-off frequency value and the predefined maximum cut-off frequency value, an input bandwidth-dependent frequency compression ratio to modify the range of frequencies of the input audio signal, wherein the generating of the output audio signal includes mapping the range of input frequencies, as modified based on the input bandwidth-dependent frequency compression ratio, to the range of output frequencies.

In another implementation of the method, the instantaneous input bandwidth of the input audio signal is defined as a frequency associated with a first bin index of a particular input frame of the input audio signal that reaches a predefined percentage of a total energy of the particular input frame of the input audio signal.

In another implementation of the method, the predefined percentage is equal to or greater than ninety percent of the total energy of the particular input frame of the input audio signal.

In another implementation, the method further comprises applying, by the processor of the hearing device, a pre-compensation filter to the input audio signal to mitigate low frequency masking of the output audio signal.

The invention also concerns a non-transitory computer readable storage medium storing instructions that, when executed, direct a processor to perform the method of the invention as described herein.

<FIG> illustrates an exemplary hearing device <NUM> that may be implemented according to principles described herein. As shown, hearing device <NUM> may include, without limitation, a memory <NUM> and a processor <NUM> selectively and communicatively coupled to one another. Memory <NUM> and processor <NUM> may each include or be implemented by hardware and/or software components (e.g., processors, memories, communication interfaces, instructions stored in memory for execution by the processors, etc.).

Memory <NUM> may maintain (e.g., store) executable data used by processor <NUM> to perform any of the operations associated with implementing an adaptively adjusted cut-off frequency. For example, memory <NUM> may store instructions <NUM> that may be executed by processor <NUM> to perform any of the operations associated with hearing device <NUM> described herein. Instructions <NUM> may be implemented by any suitable application, software, code, and/or other executable data instance.

Memory <NUM> may also maintain any data received, generated, managed, used, and/or transmitted by processor <NUM>. For example, memory <NUM> may maintain hearing loss data <NUM> that may be representative of any information associated with a hearing loss profile of a user of hearing device <NUM>, predefined maximum cut-off frequency values, predefined minimum cut-off frequency values, and/or any other suitable information. In addition, memory <NUM> may maintain any data suitable to facilitate communications (e.g., wired and/or wireless communications) between hearing device <NUM> and one or more additional computing devices, such as those described herein. Memory <NUM> may maintain additional or alternative data in other implementations.

Processor <NUM> is configured to perform any suitable processing operation that may be associated with hearing device <NUM> such as by representing audio content to a user of hearing device <NUM>. For example, when hearing device <NUM> corresponds to a hearing aid device, such processing operations may include monitoring ambient sound and/or representing sound to a user via an in-ear receiver. In examples where hearing device <NUM> is included as part of a cochlear implant system, such processing operations may include directing a cochlear implant to generate and apply electrical stimulation representative of one or more audio signals (e.g., one or more audio signals detected by a microphone, input by way of an auxiliary audio input port, etc.) to one or more stimulation sites associated with an auditory pathway (e.g., the auditory nerve) of a user.

Processor <NUM> may be configured to perform (e.g., execute instructions <NUM> stored in memory <NUM> to perform) various processing operations associated with implementing an adaptively adjusted cut-off frequency. Such processing operations may include receiving an input audio signal having a range of input frequencies, adaptively adjusting a cut-off frequency for the input audio signal such that a value of the cut-off frequency varies between a predefined minimum cut-off frequency value and a predefined maximum cut-off frequency value as a continuous function of the input audio signal, and generating an output audio signal by mapping the range of input frequencies to a range of output frequencies determined based on the adaptively adjusted cut-off frequency. These and other operations that may be performed by hearing device <NUM> are described herein.

<FIG> shows an exemplary flowchart <NUM> that depicts operations that may be performed by hearing device <NUM> (e.g., processor <NUM>) according to principles described herein. As shown in <FIG>, hearing device <NUM> may receive an input audio signal at operation <NUM>. Hearing device <NUM> may receive the input audio signal in any suitable manner. For example, hearing device <NUM> may receive the input audio signal as ambient sound captured by a microphone included as part of or otherwise communicatively connected to hearing device <NUM>. In certain alternative implementations, hearing device <NUM> may receive the input audio signal from an external computing device (e.g., a smartphone, a tablet computer, a desktop computer, etc.) by way of any suitable wired or wireless communication protocol (e.g., Bluetooth, Wi-Fi, etc.).

At operation <NUM>, hearing device <NUM> may perform an input audio signal computation to process the input audio signal to facilitate adaptively adjusting a cut-off frequency of the input audio signal. Hearing device may perform any suitable processing operation or combination of processing operations as may serve a particular implementation. For example, in certain implementations, hearing device <NUM> may transform the input audio signal from a time domain to a frequency domain by applying a transformation function to obtain an input spectrum having a range of input frequencies.

At operation <NUM>, hearing device <NUM> may perform a computation to adaptively adjust a cut-off frequency for the input audio signal. This may be accomplished in any suitable manner. For example, hearing device <NUM> may adaptively adjust a cut-off frequency for the input audio signal such that a value of the cut-off frequency varies between a predefined minimum cut-off frequency value and a predefined maximum cut-off frequency value as a continuous function of the input audio signal. The predefined minimum cut-off frequency value may correspond to any suitable fixed value that is sufficient to preserve low frequency vowel structures of the input audio signal. The predefined maximum cut-off frequency value may correspond to any suitable fixed maximum output frequency value that represents an upper limit of the remaining hearing bandwidth of a particular user of hearing device <NUM>. No output audio content may be provided above the predefined maximum cut-off frequency value because the particular user of hearing device <NUM> may have no ability to perceive the output audio content and/or the gain required to provide output audio content may be excessively high. In certain examples, the particular values for the predefined minimum cut-off frequency value and the predefined maximum cut-off frequency value may be user specific and may be determined in any suitable manner (e.g., based on hearing loss data <NUM> stored by memory <NUM>).

<FIG> shows an exemplary graph <NUM> that depicts a range in which an adaptively adjusted cut-off frequency may vary. As shown in <FIG>, a frequency range of an input audio signal is represented on the x-axis and a frequency range of an output audio signal is represented on the y-axis. As shown in <FIG>, the input audio signal includes a range of frequencies from <NUM> to an upper frequency value <NUM>. The input audio signal shown in <FIG> includes predefined minimum cut-off frequency value <NUM> and a predefined maximum cut-off frequency value <NUM>. Hearing device <NUM> is configured to adaptively adjust the cut-off frequency within a frequency range <NUM> such that the cut-off frequency may have a value corresponding to predefined minimum cut-off frequency value <NUM>, predefined maximum cut-off frequency value <NUM>, or any value therebetween depending on the input audio signal.

The output audio signal along the y-axis in <FIG> has a frequency range from <NUM> to a maximum output frequency <NUM>. As shown in <FIG>, a minimum output frequency <NUM> is provided along the frequency range of the output audio signal. Minimum output frequency <NUM> may be associated with an output frequency at which frequency compression may occur.

Returning to <FIG>, in certain examples, hearing device <NUM> may, based on the adaptively adjusted cut-off frequency, apply frequency compression to the input audio signal at operation <NUM>. This may be accomplished in any suitable manner. For example, in certain implementations, hearing device <NUM> may apply a fixed frequency compression ratio to modify the range of input frequencies of the input audio signal. Hearing device <NUM> may calculate the fixed compression ratio in any suitable manner. For example, hearing device <NUM> may calculate the fixed compression ratio by calculating a point A and a point B shown in <FIG>. Point A has the coordinates of predefined minimum cut-off frequency value <NUM> and minimum output frequency <NUM>. Point B has the coordinates of upper frequency value <NUM> and maximum output frequency <NUM>. In such an example, the fixed compression ratio may correspond to the inverse value of the slope of the line extending from point A to point B (i.e., compression ratio = <NUM>/(slope of A to B)).

At operation <NUM>, hearing device <NUM> may generate an output audio signal by mapping the range of input frequencies to a range of output frequencies determined based on the adaptively adjusted cut-off frequency. Hearing device <NUM> may map the range of input frequencies to the range of output frequencies in any suitable manner. For example, hearing device <NUM> may replace at least some of the frequency components in the range of output frequencies with at least some of the frequency components in the range of input frequencies. Additionally or alternatively, hearing device <NUM> may combine at least some of the frequency components in the range of output frequencies with at least some of the frequency components in the range of input frequencies. In examples in which hearing device <NUM> applies a fixed frequency compression ratio, operation <NUM> may include mapping the range of input frequencies, as modified based on the fixed compression ratio, to the range of output frequencies. In certain examples, the mapping of the range of input frequencies to the range of output frequencies may include nonlinear frequency compression where lower frequencies may be unprocessed while higher frequencies may be compressed in greater amounts.

The output audio signal generated at operation <NUM> may be represented to a user of hearing device <NUM> in any suitable manner. For example, hearing device <NUM> may provide the output audio signal to a receiver (e.g., a speaker) placed in the user's ear canal or at any other suitable location.

In certain examples, hearing device <NUM> may adaptively adjust the cut-off frequency as a continuous function of an instantaneous input bandwidth of the input audio signal. The instantaneous input bandwidth of the input audio signal may be defined in any suitable manner. For example, the instantaneous input bandwidth of the input audio signal may be defined as a frequency associated with a first bin index of a particular input frame of the input audio signal that reaches a predefined percentage of a total energy of the particular input frame of the input audio signal. In certain examples, the predefined percentage may be equal to or greater than ninety percent of the total energy of the particular input frame.

<FIG> shows an exemplary graph <NUM> that depicts how a value of an adaptively adjusted cut-off frequency may change within a plurality of different frequency ranges <NUM>, <NUM>, and <NUM> as a function of the instantaneous input bandwidth. As shown in <FIG>, frequency range <NUM> corresponds to a region where the instantaneous input bandwidth of the input audio signal is less than or equal to a predefined minimum cut-off frequency value <NUM>. This may occur when most of the energy of the input audio signal is in low frequencies (e.g., by having vowel sounds). While the instantaneous input bandwidth is within frequency range <NUM>, hearing device <NUM> may be configured to set the cut-off frequency to a predefined maximum cut-off frequency value <NUM>. In so doing, in frequency range <NUM>, no frequency compression is applied to the input audio signal during the mapping of the range of input frequencies to the range of output frequencies.

Frequency range <NUM> corresponds to a region where the instantaneous input bandwidth is between predefined minimum cut-off frequency value <NUM> and a predefined maximum cut-off frequency value <NUM>. As shown in <FIG>, while the instantaneous input bandwidth is within frequency range <NUM>, hearing device <NUM> is configured to decrease the adaptively adjusted cut-off frequency as the instantaneous input bandwidth increases. In so doing, the adaptively adjusted cut-off frequency may vary within frequency range <NUM> depending on the instantaneous input bandwidth of the input audio signal.

Frequency range <NUM> corresponds to a region where the instantaneous input bandwidth is greater than predefined maximum cut-off frequency value <NUM>. In such examples in which the instantaneous input bandwidth is above predefined maximum cut-off frequency value <NUM>, hearing device <NUM> is configured to set the adaptively adjusted cut-off frequency to predefined minimum cut-off frequency value <NUM>.

<FIG> show exemplary graphs that depict the adaptively adjusted cut-off frequency while the instantaneous input bandwidth is within each of the frequency ranges <NUM>, <NUM>, and <NUM> shown in <FIG>. In the graph shown in <FIG>, the instantaneous input bandwidth is within frequency range <NUM> shown in <FIG>. In view of this, hearing device <NUM> sets an adaptively adjusted cut-off frequency <NUM> to a value that corresponds to a predefined maximum frequency value <NUM> and the input audio content between <NUM> and adaptively adjusted cut-off frequency <NUM> is mapped to the output audio signal with no modification (e.g., fully linear). In so doing, it is possible to prevent artifacts from being introduced into the output audio signal and maximize sound quality.

In the graph shown in <FIG>, the instantaneous input bandwidth is within frequency range <NUM> shown in <FIG>. In view of this, adaptively adjusted cut-off frequency <NUM> is between predefined maximum frequency value <NUM> and a predefined minimum frequency value <NUM>. In such an example, the input audio signal is broadband and adaptively adjusted cut-off frequency <NUM> linearly decreases with increasing bandwidth of the instantaneous input bandwidth. In so doing, a relatively larger area of the range of frequencies of the output audio signal may be devoted to receive high-frequency compressed content.

In the graph shown in <FIG>, the instantaneous input bandwidth is within frequency range <NUM> shown in <FIG>. In such an example, a significant part of the energy of the input audio signal may be located in the high frequencies due to, for example, fricative consonants being present in the input audio signal. As such, adaptively adjusted cut-off frequency <NUM> is set in <FIG> to predefined minimum frequency value <NUM>. With such a configuration, a relatively larger amount of output frequency (e.g., between the minimum output frequency and the maximum output frequency) is devoted to receive high-frequency compressed content.

In certain implementations, hearing device <NUM> may implement an adaptive frequency compression ratio instead of a fixed frequency compression ratio. For example, hearing device <NUM> may implement an input bandwidth-dependent frequency compression ratio to modify the range of frequencies of the input audio signal. In such examples, the compression ratio may operate in a manner similar to that shown in <FIG> if the instantaneous input bandwidth is less than or equal to predefined minimum frequency value <NUM> shown in <FIG>. That is, in such an example, no frequency compression may be applied to the input audio signal while mapping the range of frequencies of the input audio signal to the range of output frequencies of the output audio signal. However, if the instantaneous input bandwidth is between predefined minimum frequency value <NUM> and predefined maximum cut-off frequency value <NUM>, the adaptively adjusted cut-off frequency may be computed as shown in <FIG> and an adaptive frequency compression ratio may be implemented that decreases as the instantaneous input bandwidth increases. If, on the other hand, the instantaneous input bandwidth is greater than predefined maximum cut-off frequency value <NUM> shown in <FIG>, then the frequency compression ratio may be fixed and may be determined in any suitable manner. For example, the fixed frequency compression ratio (CR) in such an example may equal: <MAT> Where Fs = the upper frequency of the input audio signal; Fmin = the predefined minimum cut-off frequency value; and FOutMax = the maximum output frequency of the output audio signal.

In examples in which hearing device <NUM> applies an adaptive frequency compression ratio (e.g., an input bandwidth-dependent frequency compression ratio), hearing device <NUM> may map the range of input frequencies of an input audio signal, as modified based on the adaptive frequency compression ratio, to the range of output frequencies of the output audio signal.

In an example of the hearing device, which does not form part of the present invention, but which is described here for illustrative purposes, hearing device <NUM> may adaptively adjust the cut-off frequency as a continuous function of an instantaneous input level of the input audio signal. Hearing device <NUM> may use the instantaneous input level of the input audio signal in any suitable manner to adaptively adjust the cut-off frequency. For example, hearing device <NUM> may use the instantaneous input level in a manner similar to the instantaneous input bandwidth such as described herein.

In certain examples, hearing device <NUM> may implement a pre-compensation filter to mitigate low-frequency masking of an output audio signal. The spread of masking by low frequencies to high frequencies becomes larger at relatively higher input levels. For example, high frequencies that would not be masked by a low-frequency sound at a level of <NUM> dB sound pressure level (SPL) may be masked by the same masker at <NUM> dB SPL. To mitigate this, hearing device <NUM> may determine and apply a pre-compensation filter to an input audio signal. Such a pre-compensation filter may correspond to an adaptive pre-compensation filter that takes into account an overall SPL in an environment surrounding hearing device <NUM> as well as a balance between low-frequency and high-frequency energies of the input audio signal. Hearing device <NUM> may determine the pre-compensation filter in any suitable manner. To illustrate an example, a pre-compensation filter may take as input the SPL derived in bark bands Ebark, which is a 20x1 vector. The broadband SPL EBB may be defined as: <MAT> which corresponds to the maximum SPL between <NUM> and <NUM>.

If EBB > Emax (where Emax is typically 80dB SPL), EBB may be set to Emax. If EBB < Emin (where Emin is typically 50dB SPL), no pre-compensation filter is applied.

If EBB ≥ Emin, three slopes δi are computed as: <MAT>.

In the above expression, δ<NUM> may be associated with a frequency range of <NUM>-<NUM>, δ<NUM> may be associated with a frequency range of <NUM>-<NUM>, and δ<NUM> may be associated with a frequency range of <NUM>-<NUM>.

Three intercepts βi may be computed as: <MAT>.

Three coefficients γi may be computed as: <MAT>.

A 64x1 vector C containing frequency domain gains of the pre-compensation filter expressed in dB may be initialized with zeros. The coefficients associated to the frequency bins between <NUM> (bin index # <NUM>) and <NUM> (bin index # <NUM>) may be derived as: <MAT>.

The above expressions associated with determining a pre-compensation filter are provided for illustrative purposes only. It is understood that a pre-compensation filter may be determined in any other suitable manner as may serve a particular implementation.

<FIG> illustrates an exemplary flowchart <NUM> in which a pre-compensation filter may be applied to an input audio signal. As shown in <FIG>, hearing device <NUM> may receive an input audio signal at operation <NUM>. This may be accomplished in any suitable manner such as described herein.

At operation <NUM>, hearing device <NUM> may perform a pre-compensation filter computation. This may be accomplished in any suitable manner such as described herein.

In certain examples, prior to performing operation <NUM>, hearing device <NUM> may perform one or more additional processing operations on the input audio signal. For example, hearing device <NUM> may perform a bin to bark conversion, a computation of the SPL in bark, and/or any other suitable processing operation.

At operation <NUM>, hearing device <NUM> may apply the computed pre-compensation filter to the input audio signal. This may be accomplished in any suitable manner.

At operation <NUM>, hearing device <NUM> may perform an input bandwidth computation on the input audio signal as adjusted by the pre-compensation filter. This may be accomplished in any suitable manner such as described herein.

At operation <NUM>, hearing device <NUM> may perform an adaptively adjusted cut-off frequency computation. This may be accomplished in any suitable manner such as described herein.

At operation <NUM>, hearing device <NUM> may perform a frequency compression operation. As described herein, whether hearing device <NUM> performs frequency compression may depend on the input audio signal. For example, if the instantaneous input bandwidth of the input audio signal is equal to or less than a predefined minimum frequency value, hearing device <NUM> may not perform operation <NUM> on the input audio signal.

At operation <NUM>, hearing device <NUM> may generate an output audio signal based on the audio signals and/or data received, generated, etc. at operations <NUM>-<NUM>.

<FIG> illustrates an exemplary method <NUM> for implementing an adaptively adjusted cut-off frequency. While <FIG> illustrates exemplary operations according to one embodiment, other embodiments may omit, add to, reorder, and/or modify any of the operations shown in <FIG>. One or more of the operations shown in <FIG> may be performed by a hearing device such as hearing device <NUM>, any components included therein, and/or any implementation thereof.

At operation <NUM>, a processor (e.g., processor <NUM>) may determine, while a hearing device (e.g., hearing device <NUM>) is configured to receive an input audio signal having a range of input frequencies. Operation <NUM> may be performed in any of the ways described herein.

At operation <NUM>, the processor may adaptively adjust a cut-off frequency for the input audio signal such that a value of the cut-off frequency varies between a predefined minimum cut-off frequency value and a predefined maximum cut-off frequency value as a continuous function of the input audio signal. Operation <NUM> may be performed in any of the ways described herein.

At operation <NUM>, the processor may generate an output audio signal by mapping the range of input frequencies to a range of output frequencies determined based on the adaptively adjusted cut-off frequency. Operation <NUM> may be performed in any of the ways described herein.

<FIG> illustrates an exemplary computing device <NUM> that may be specifically configured to perform one or more of the processes described herein. As shown in <FIG>, computing device <NUM> may include a communication interface <NUM>, a processor <NUM>, a storage device <NUM>, and an input/output ("I/O") module <NUM> communicatively connected one to another via a communication infrastructure <NUM>. While an exemplary computing device <NUM> is shown in <FIG>, the components illustrated in <FIG> are not intended to be limiting. Additional or alternative components may be used in other embodiments. Components of computing device <NUM> shown in <FIG> will now be described in additional detail.

In some examples, any of the systems, hearing devices, and/or other components described herein may be implemented by computing device <NUM>. For example, memory <NUM> may be implemented by storage device <NUM>, and processor <NUM> may be implemented by processor <NUM>.

Claim 1:
A hearing device (<NUM>) comprising:
a memory (<NUM>) storing instructions; and
a processor (<NUM>) communicatively coupled to the memory (<NUM>) and configured to execute the instructions to:
receive (<NUM>) an input audio signal having a range of input frequencies;
adaptively adjust (<NUM>) a cut-off frequency for the input audio signal such that the value of the cut-off frequency varies between a predefined minimum cut-off frequency value and a predefined maximum cut-off frequency value as a continuous function of the input audio signal; and
generate (<NUM>) an output audio signal by mapping the range of input frequencies to a range of output frequencies determined based on the adaptively adjusted cut-off frequency,
characterized in that
the adaptively adjusting of the cut-off frequency as the continuous function of the input audio signal includes adaptively adjusting the cut-off frequency as a continuous function of an instantaneous input bandwidth of the input audio signal.