Hearing devices and methods for implementing an adaptively adjusted cut-off frequency

1. A hearing device comprising:

a memory storing instructions; and

a processor communicatively coupled to the memory and configured to execute the instructions to:

receive an input audio signal having a range of input frequencies;

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; and

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.

2. The hearing device of claim 1 , wherein 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.

3. The hearing device of claim 2 , wherein, when the instantaneous input bandwidth of the input audio signal is less than the predefined minimum cut-off frequency value, no frequency compression is applied to the input audio signal during the mapping.

4. The hearing device of claim 2 , wherein 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.

5. The hearing device of claim 2 , wherein 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.

6. The hearing device of claim 2 , wherein, 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, the adaptively adjusted cut-off frequency decreases as the instantaneous input bandwidth increases.

7. The hearing device of claim 2 , wherein, when the instantaneous input bandwidth is above the predefined maximum cut-off frequency value, the cut-off frequency is set to the predefined minimum cut-off frequency value.

8. The hearing device of claim 2 , wherein 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.

9. The hearing device of claim 8 , wherein 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.

10. The hearing device of claim 1 , wherein 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.

11. The hearing device of claim 1 , wherein 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.

12. The hearing device of claim 1 , wherein 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.

13. 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.

14. The method of claim 13 , wherein 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.

15. The method of claim 14 , further comprising 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.

16. The method of claim 14 , further comprising 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.

17. The method of claim 14 , wherein 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.

18. The hearing device of claim 17 , wherein 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.

19. The method of claim 13 , further comprising 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.

20. A non-transitory computer readable storage medium storing instructions that, when executed, direct a processor of a hearing device to:

receive an input audio signal having a range of input frequencies;

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; and

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.