Microphone Apparatus Wind Noise Reduction Closed Space
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Solution Overview
Problem
Conventional microphone apparatuses struggle to reduce wind noise effectively without significantly lowering the microphone's sensitivity, especially in strong winds during two-wheel vehicle use, and often require costly and complex configurations with acoustic resistance materials that compromise speech signal quality.
Innovation Solution
A microphone apparatus featuring a first vibration plate, a support member, and a second vibration plate fixed at a predetermined distance, with an armoring body that forms a closed space with air, allowing the second vibration plate to reduce noise transmission through its stiffness and enabling sound wave transmission via air, thus maintaining sensitivity and reducing wind noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a porous windshield made of urethane foam is used to reduce wind noise, then wind noise is reduced, but acoustic resistance increases and microphone sensitivity decreases
Solution Approach 1:
The windshield is divided into multiple layers with different functions: an outer porous wind noise reducing layer and an inner acoustic resistance layer. This segmentation allows each layer to perform its specific function optimally without compromising the other, reducing wind noise while maintaining microphone sensitivity.
Solution Approach 2:
The windshield uses a composite structure combining porous material (for wind noise reduction) and acoustic resistance material (for maintaining sensitivity). This composite approach enables simultaneous achievement of wind noise reduction and sensitivity maintenance that cannot be obtained with a single material.
2Object-affected harmful factors
If acoustic resistance material is used to reduce wind noise, then wind noise is reduced, but the speech signal to noise ratio remains unchanged
Solution Approach 1:
The windshield is segmented into functional layers: the outer porous layer handles wind noise reduction through physical barrier effects, while the inner acoustic resistance layer manages acoustic impedance. This segmentation allows independent optimization of each function, improving wind noise reduction while preserving speech signal quality.
Solution Approach 2:
The invention changes the physical parameters of the windshield structure by using multiple layers with different porosity, density, and acoustic impedance values. These parameter changes enable the windshield to reduce wind noise while maintaining appropriate acoustic resistance levels that preserve speech signal transmission.
3Object-affected harmful factors
If two microphone units are used in electrically reversed phase to reduce noise, then noise reduction is achieved theoretically, but manufacturing cost increases due to the need for homogeneous microphone units
Solution Approach 1:
The invention extracts the noise reduction function from the microphone unit itself and transfers it to the windshield structure. By implementing noise reduction mechanisms in the windshield (porous material and acoustic resistance layers), the system can use a single microphone unit without requiring pairs of homogeneous units, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
The windshield acts as an intermediary element between the environment and the microphone unit. It mediates the acoustic field by reducing wind noise and managing acoustic impedance, allowing a single microphone unit to achieve noise reduction effects that would otherwise require complex multi-unit configurations.
4Object-affected harmful factors
If the microphone unit is placed closer to the sound source to prevent noise, then noise is reduced, but the volume of sound becomes excessive and distortion occurs
Solution Approach 1:
The windshield serves as an intermediary that manages the acoustic field between the sound source and the microphone unit. It selectively transmits acoustic energy while managing the acoustic impedance to prevent excessive sound volume and distortion, allowing the microphone to be positioned optimally without compromising output quality.
Solution Approach 2:
The invention changes the acoustic parameters of the environment around the microphone unit by introducing the windshield with specific acoustic resistance and porosity values. These parameter changes allow the microphone to operate at optimal distances from the sound source while preventing noise and distortion through controlled acoustic field management.
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 solution effectively reduces wind noise by up to 20dB in strong winds while maintaining the microphone's sensitivity, improving the signal-to-noise ratio and protecting the microphone unit from external forces, and allows for a more cost-effective and simpler design compared to existing solutions.
Implementation Method 1
the second vibration plate different from the first vibration plate of the microphone unit is provided and a closed space with a gas kept therein is formed between the first vibration plate and the second vibration plate, it is possible to reduce noise (wind noise) to be transmitted to the vibration plate of the microphone unit by the stiffness or the like of the second vibration plate
Implementation Method 2
the vibration of the second vibration plate by receiving a sound wave from outside is transmitted to the first vibration plate within the microphone unit through the gas (air) within the closed space
Data Source
Figure 1(A)~2
Figure 3~5
Figure 6
AI summary
A microphone unit (1) has a first vibration plate. A support member (6) supports the microphone unit (1). A second vibration plate (5) is fixed to the support member (6) at a predetermined distance from the first vibration plate. An armoring body (2) covers the microphone unit (1), the support member (6) and the second vibration plate (5). A space surrounded by the support member (6), the first vibration plate and the second vibration plate (5) is a closed space (S1) with air kept therein.