Directional Microphone Array for Hearing Protection
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Solution Overview
Problem
In noisy environments, existing hearing protection devices hinder communication by suppressing desired sounds, such as human voices, while failing to effectively filter out unwanted ambient noise.
Innovation Solution
A sound enhancement apparatus and method using a directional microphone array, processing means for signal enhancement, and sound suppression means, such as ear muffs or ear plugs, to isolate and amplify desired sounds while suppressing ambient noise by at least 15 dB, employing adaptive, spatial, and temporal processing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hearing protection devices are used to protect hearing in noisy environments, then hearing damage is mitigated, but the ability to hear and communicate is negatively impacted
Solution Approach 1:
The system extracts the desired sound signal from the ambient noise using a directional microphone array and signal processing. The microphone array captures sounds from multiple directions, and processing means selectively enhances the desired signal while suppressing unwanted ambient noise, allowing the user to hear specific sounds clearly even while wearing hearing protection.
Solution Approach 2:
The system introduces an intermediary processing chain between the ambient sound and the user's ear. The directional microphone array, processing means, and loudspeaker work together to create an intermediate enhanced signal that protects the ear from harmful noise while preserving desired communication signals.
2Object-affected harmful factors
If ambient noise is suppressed to protect hearing, then hearing safety is improved, but desired sounds become harder to hear
Solution Approach 1:
The system applies different processing qualities to different sound sources. The directional microphone array and processing means identify and enhance sounds from specific directions (where desired signals are located) while applying stronger suppression to sounds from other directions (ambient noise), creating local quality differences in noise suppression across the sound field.
Solution Approach 2:
The system dynamically adjusts the level of noise suppression based on the characteristics of the desired signal. When a desired sound is detected in a specific direction, the system reduces suppression for that direction while maintaining suppression for ambient noise from other directions, making the suppression adaptive rather than static.
3Loss of information
If directional microphone array and signal processing are used to enhance desired sounds, then sound intelligibility is improved, but device complexity increases
Solution Approach 1:
The system segments the sound processing task into distinct functional components: the directional microphone array for spatial signal capture, the processing means for enhancement and noise suppression, and the loudspeaker for output. This segmentation allows each component to be optimized independently while working together to improve sound intelligibility.
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
Effectively enhances desired sounds, like human voices, while reducing ambient noise by 15-50 dB, maintaining high intelligibility and protecting hearing in noisy conditions.
Implementation Method 1
at least two microphones providing a directional microphone array arranged to be pointed in the direction of a sound source to receive sound emitted by said sound source
Implementation Method 2
sound suppression means arranged to be located adjacent each ear of the user to suppress ambient sound reaching the ear drums of the user
Data Source
AI summary
An apparatus for sound enhancement has at least two microphones (9) that provide a directional microphone array which is arranged to be pointed in the direction of a sound source. The directional microphone array thereby receives sound emitted by the sound source and generates sound signals. A processor (20) processors the sound signals generated by the microphone array to enhance the sound received by the directional microphone array from the sound source relative to other sound received by the directional microphone array. The processor (20) generates a corresponding enhanced signal (ES). Loud speakers (22) reproduce the enhanced signal as audible sound. Furthermore, sound suppression devices (7, 7a) are provided to suppress ambient should from reaching the eardrums of the user. This sound suppression acts in conjunction with the directional microphone array and the processor (20) which enhance the SOI to provide a listening environment in which the SOI is enhanced.