Microphone Port Mesh and Cavity for Wind and Ultrasonic Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Portable listening devices, such as earbuds, are susceptible to picking up undesirable ambient noises and ultrasonic frequencies, which interfere with device performance, particularly in amplified microphone signals.
Innovation Solution
A microphone port configuration featuring a mesh and cavity with sloping surfaces and a blocking member to suppress ultrasonic frequencies and wind noise, utilizing a porous mesh with a blocking member to acoustically close a portion of the mesh, thereby attenuating undesirable sounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the microphone is exposed to the ambient environment to pick up sounds, then the microphone can capture user voice and ambient noise for noise cancellation, but the microphone also picks up undesirable sounds such as wind noise and ultrasonic frequencies that interfere with device performance
Solution Approach 1:
The patent applies local quality by creating a non-uniform acoustic environment within the cavity. The sloped surface and strategically positioned blocking member generate spatial variations in acoustic impedance and pressure distribution, allowing different regions of the cavity to selectively attenuate different frequency components. This localized acoustic treatment enables the microphone to capture desired sounds while suppressing harmful frequencies without requiring a complete acoustic seal.
Solution Approach 2:
The patent employs a porous acoustic mesh as a filter medium in the acoustic port. This porous material allows passage of audible frequencies while providing acoustic impedance to ultrasonic frequencies and wind noise. The mesh structure creates tortuous flow paths that dissipate high-frequency energy and reduce wind-induced turbulence, thereby filtering harmful factors while maintaining microphone functionality.
2Object-affected harmful factors
If a mesh is added to the microphone port to block ultrasonic frequencies, then ultrasonic suppression is improved, but the mesh may also attenuate desirable sound frequencies
Solution Approach 1:
The patent utilizes parameter changes by varying the acoustic impedance profile throughout the cavity. The sloped surface and blocking member create a gradient in acoustic mass and compliance, forming a low-pass acoustic filter characteristic. This gradual impedance transition allows audible frequencies to pass through with minimal attenuation while progressively blocking higher ultrasonic frequencies, achieving frequency-selective suppression without compromising desirable sound pickup.
3Ease of operation
If the acoustic port is opened to the ambient environment for sound pickup, then the microphone can function properly, but wind noise can enter and interfere with the microphone signal
Solution Approach 1:
The patent introduces an intermediary acoustic chamber between the ambient environment and the microphone. This cavity acts as a buffer zone that decouples the microphone from direct exposure to wind noise while still allowing acoustic coupling for desired sound pickup. The sloped surface and blocking member within the cavity further modify wind flow patterns, reducing turbulence and pressure fluctuations that cause wind noise, thereby protecting the microphone signal.
4Object-affected harmful factors
If a blocking member is added to acoustically close portions of the mesh, then wind noise suppression is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the acoustic port into functional zones: an open mesh region for sound pickup, a sloped surface region for acoustic mass control, and a blocked region for wind noise suppression. The blocking member is strategically positioned to cover only the portions of the mesh most susceptible to wind noise, rather than completely sealing the port. This selective segmentation achieves effective wind noise attenuation while minimizing the added structural complexity.
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 reduces the impact of ultrasonic frequencies and wind noise on microphone performance, enhancing sound pickup quality and noise cancellation.
Implementation Method 1
a mesh and a cavity dimensioned to suppress ultrasonic frequencies may be coupled to, or form a portion of, the microphone port
Implementation Method 2
the combination of the sloped cavity and the acoustically closed mesh may be used to mitigate or otherwise suppress ultrasonic frequencies and/or undesirable noises from reaching the microphone
Implementation Method 3
the cavity may be formed around the microphone port and define a sloped surface from an outer edge of the cavity to the microphone port that ensures the pressure contributions from the outer parts of the mesh area covering the cavity have a lower impedance by lowering the acoustic mass
Data Source
AI summary
A transducer port assembly comprising: a frame defining an acoustic chamber having an opening to an ambient environment and one or more interior sloping surfaces coupled to an acoustic port of a transducer; an acoustic mesh coupled to the opening to the ambient environment; and a blocking member coupled to the acoustic mesh to acoustically close a portion of the acoustic mesh.