Active Hearing Protection With Ear-Canal Feedback for Audio Fidelity
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Solution Overview
Problem
Conventional hearing protection devices fail to maintain audio fidelity while reducing exposure to unsafe sound pressure levels, leading to potential hearing damage and other health issues.
Innovation Solution
A user-specific active sound-reduction system with a wearable earpiece and digital signal processing module that includes external and internal microphones, a driver, and a DSP module to monitor and control sound exposure, applying short-term and long-term sound reductions to maintain safe sound pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional hearing protection devices are used to reduce sound pressure levels, then hearing damage is prevented, but audio fidelity is compromised
Solution Approach 1:
The system dynamically adjusts the degree of sound reduction in real-time based on the type of sound (music, speech, ambient noise) and the user's listening history. The DSP module continuously monitors acoustic feedback and modifies attenuation levels to maintain audio quality while ensuring safety, transitioning between different protection modes as needed
Solution Approach 2:
The system changes multiple parameters including frequency-dependent attenuation, compression ratios, and noise floor thresholds based on the detected sound characteristics and user profile. Different compression curves and equalization settings are applied to preserve audio fidelity while maintaining safe exposure levels
2Object-affected harmful factors
If active sound reduction is applied to maintain safe sound levels, then hearing protection is achieved, but device complexity increases
Solution Approach 1:
The earpiece serves multiple functions: it acts as a hearing protection device, an audio player, an environmental sound monitor, and a user feedback system. The same hardware components (microphones, driver, DSP) are used for both protection and audio reproduction, reducing overall system complexity
Solution Approach 2:
The system uses acoustic feedback from the ear canal to continuously monitor the actual sound levels reaching the user's ear drum. This feedback loop allows the DSP to automatically adjust processing parameters without requiring complex external monitoring equipment or manual calibration
3Loss of information
If high frequency reproduction is maintained while reducing low frequency attenuation, then audio fidelity is preserved, but sound pressure level control becomes difficult
Solution Approach 1:
The system divides the audio spectrum into multiple frequency bands (low frequencies, mid frequencies, high frequencies) and applies different processing parameters to each band independently. This allows high frequencies to be reproduced accurately while low frequencies are attenuated more aggressively to control overall sound pressure levels
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces sound pressure levels to audiologist-recognized safe levels while preserving audio fidelity, mitigating hearing loss and associated health risks.
Implementation Method 1
an output transducer (e.g., a driver) configured to be acoustically coupled to an inner volume of the user's ear canal when the earpiece is worn to receive an output audio signal and generate playback output sounds based on the output audio signal
Implementation Method 2
a first microphone on the outside (exposed to the ambient environment) and sealed within the ear canal a driver (as often used in conventional IEMs or earbuds) and mounted in very close proximity to that driver there's a second microphone positioned within the ear canal to sensing sound leakage
Data Source
AI summary
An active hearing protection system can generate audio signals adapted in real time for a specific user is provided with internal (e.g., within the ear canal) and external microphones, along with methods of making and using the hearing protection system. The System and method can be configured to Continually monitor Total SPL by internal transducer or microphone; and if user-specific safe SPL level is exceeded, the system can reduce a long-term threshold for the subject user. The method includes recording said subject user's Total SPL exposure data; and in response to said user's Total SPL exposure data, automatically determining updated user-specific or personalized optimal sound characteristics for said user to cater to the user's then-extant unique hearing.