Hearing Amplifier Howling Detection With Dynamic Range Control
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Solution Overview
Problem
Hearing aids often suffer from acoustic feedback, known as howling, which is exacerbated by high amplification gain and can cause discomfort or hearing damage, and existing solutions inadequately address the issue of residual feedback after amplification gain recovery.
Innovation Solution
A hearing device system incorporating a Dynamic Range Controller (DRC) and howling detector, which constrains output signal amplitude and alerts the user to howling, allowing for user interaction to correct the issue and reset the system, combined with a filter bank for enhanced detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amplification gain is increased to make quiet sounds audible, then hearing sensitivity is improved, but acoustic feedback (howling) occurs and can damage the inner ear
Solution Approach 1:
The patent divides the audio signal into multiple frequency bands using a filter bank, allowing independent processing of each band. This segmentation enables targeted amplification and feedback control for specific frequencies, resolving the contradiction by permitting high gain in quiet frequency regions while suppressing feedback in problematic frequency regions through band-specific notching.
Solution Approach 2:
The system dynamically changes amplification parameters based on detected feedback conditions. When howling is detected in a specific frequency band, the system adjusts the gain parameter for that band while maintaining normal gain in other bands, thus preserving hearing sensitivity overall while eliminating the harmful feedback effect.
2Object-affected harmful factors
If feedback cancellation algorithms are applied to suppress howling, then acoustic feedback is reduced, but residual feedback remains after amplification gain recovery
Solution Approach 1:
The system performs preliminary detection of feedback conditions across multiple frequency bands before full amplification recovery occurs. By maintaining surveillance in each band and preparing suppression mechanisms in advance, the system can quickly respond to residual feedback attempts, preventing them from developing into full howling events during gain recovery.
Solution Approach 2:
The patent implements a feedback monitoring system that continuously detects acoustic feedback conditions and triggers appropriate suppression actions. This closed-loop feedback mechanism ensures that residual feedback is detected and corrected, maintaining reliable suppression even after initial feedback cancellation has occurred.
Data Source
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AI summary
With regards to a hearing assistive device, a user's speech can be picked up by the microphone and feed through the speaker causing an acoustic feedback effect. The user may have to constantly adjust the volume of the hearing assistive device to achieve a more comfortable volume based on where the speech is coming from. Furthermore, the when the hearing assistive device experiences feedback, the amplification of the feedback can cause damage to the user's hearing. Therefore, mitigating the acoustic feedback effect of assistive hearing devices can generate a more efficient and comfortable hearing device. The acoustic feedback can be mitigated by leveraging a dynamic range controller and a howling detector which comprises a user interface and a status indicator.