Multi-Port Wind Noise Protection via Asymmetric Aperture Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wind noise significantly reduces the intelligibility of desired sounds in microphones, as existing solutions like wind screens are inadequate and software processing can degrade machine recognition, and wind noise mechanically interferes with microphone detection.
Innovation Solution
A multi-port wind noise protection system is implemented, where multiple apertures on a microphone housing receive sound, with wind noise being uncorrelated and attenuated while speech remains correlated, improving the signal-to-noise ratio by mixing sound waves at the microphone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If wind screens are used to protect the microphone, then wind noise protection is provided, but they are inadequate and do not sufficiently reduce wind noise
Solution Approach 1:
The single aperture is divided into multiple apertures (first aperture, second aperture, third aperture, fourth aperture) arranged in a specific pattern. Each aperture receives sound independently, and the multiple received signals are combined through signal processing to achieve wind noise cancellation while preserving speech signals.
Solution Approach 2:
A processor acts as an intermediary that receives multiple sound signals from the apertures, applies signal processing algorithms to separate wind noise from speech, and generates an output signal with reduced wind noise. The processor mediates between the raw microphone inputs and the final cleaned audio output.
2Object-affected harmful factors
If software processing is used to reduce wind noise, then noise reduction is achieved, but machine recognition is degraded
Solution Approach 1:
The system performs preliminary spatial filtering by arranging multiple apertures in a specific geometric pattern before the sound signals are fully processed. This pre-arranged spatial configuration begins the separation of wind noise from speech signals early in the signal chain, preserving speech integrity for subsequent recognition processing.
Solution Approach 2:
The system changes the spatial parameter configuration by using multiple apertures at specific distances from the microphone (e.g., 0.5 inches, 1.0 inches, 1.5 inches) rather than a single aperture. This parameter change in spatial arrangement enables the system to differentiate between correlated speech signals and uncorrelated wind noise through signal combination.
3Object-affected harmful factors
If multiple apertures are used to receive sound, then wind noise is attenuated through uncorrelated mixing, but device complexity increases
Solution Approach 1:
The apertures are arranged in an asymmetric pattern with different distances from the microphone (0.5 inches, 1.0 inches, 1.5 inches) rather than a symmetric configuration. This asymmetric arrangement creates unique spatial filtering characteristics that enhance wind noise attenuation while maintaining a relatively simple physical structure.
Solution Approach 2:
The multiple apertures serve multiple functions simultaneously: they receive speech signals, receive wind noise, and through their specific spatial arrangement, provide spatial filtering and wind noise cancellation. This multi-functionality reduces the need for additional dedicated wind noise protection components.
4Measurement precision
If multiple apertures are used to improve signal-to-noise ratio, then wind noise is reduced by 3 dB per doubling of apertures, but manufacturing complexity increases
Solution Approach 1:
The multiple apertures are integrated into the housing structure in a nested or embedded manner, where the apertures are formed as part of the housing itself rather than as separate components. This integration simplifies manufacturing by combining the housing formation and aperture creation into a single manufacturing process.
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
This approach effectively increases the signal-to-noise ratio by 3 dB for each doubling of apertures, achieving up to 6 dB attenuation of wind noise relative to speech, enhancing power efficiency and reducing processing burdens in audio devices.
Implementation Method 1
Multiple apertures on a housing receive a sound and conduct it to a microphone
Implementation Method 2
The undesired component such as wind is uncorrelated at the apertures and mixes at the microphone, attenuating in amplitude
Data Source
AI summary
A system method provides for multi-port wind noise protection. A sound may include a desired component such as speech and an undesired component such as wind. Multiple apertures on a housing receive the sound and conduct it to a microphone. The undesired component such as wind is uncorrelated at the apertures and mixes at the microphone, attenuating in amplitude while the desired component such as speech is correlated at the apertures. In this manner, the signal to noise ratio between the desired component and undesired component is improved at the microphone.