Acoustic Perforated Sheet for Microphone Frequency Response Control
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Solution Overview
Problem
Microphones in electronic devices, such as laptops and mobile phones, often have irregular frequency response due to long sound-guiding tubes, leading to suboptimal recording and voice call quality, necessitating a solution to improve sound quality and reduce costs.
Innovation Solution
A sound-receiving system featuring a sound-guiding tube with a winding path and an acoustic perforated sheet that filters specific frequency ranges, reducing frequency response peaks and enhancing sound quality by attenuating frequencies between 100 Hz to 8000 Hz, thereby flattening the frequency response curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sound-guiding tube is made long to fit device configuration requirements, then the microphone can be integrated into compact electronic devices, but the frequency response generates irregular amplification in the voice band affecting recording and voice call quality
Solution Approach 1:
The patent introduces an acoustic perforated sheet with specific mesh openings (0.03mm to 0.08mm) placed at the sound-receiving hole of the microphone. This porous structure filters specific frequency ranges (100Hz to 8000Hz) to reduce irregular amplification while allowing the sound-guiding tube to maintain its long winding path for compact device integration. The perforated sheet reduces frequency response by 15dB to 40dB in the voice band, resolving the contradiction between compactness and frequency response quality.
2Reliability
If the sound-guiding tube length is reduced to improve frequency response, then voice band amplification irregularity decreases, but the microphone cannot be properly integrated into compact electronic devices
Solution Approach 1:
The patent changes the physical parameters of the acoustic system by introducing a perforated sheet with specific mesh sizes (0.03mm to 0.08mm) and opening rates (1% to 10%). This parameter modification allows the sound-guiding tube to maintain its long length (3mm to 4mm or greater) for compact device integration while the perforated sheet compensates for the frequency response issues by filtering specific frequency ranges, thus resolving the contradiction between tube length and frequency response quality.
3Reliability
If complex frequency response correction methods are used to improve sound quality, then recording and voice call quality improve, but manufacturing cost increases
Solution Approach 1:
The patent employs a simple acoustic perforated sheet made of inexpensive materials with basic mesh structures to achieve frequency response correction. This low-cost component replaces complex and expensive frequency correction systems, providing effective sound quality improvement (reducing frequency response by 15dB to 40dB) while maintaining ease of manufacture and low production cost.
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 frequency response peaks by 15-40 dB, improving sound quality and shifting peak frequencies out of the speech range, thus enhancing recording and voice call reliability while potentially lowering manufacturing costs.
Implementation Method 1
The acoustic perforated sheet is disposed adjacent to the sound-receiving hole and is a distance away from the sound-receiving hole. The acoustic perforated sheet reduces and filters the frequency response of a specific frequency range of the microphone.
Implementation Method 2
The acoustic perforated sheet reduces the frequency response of the specific frequency range of the microphone by between 15 dB and 40 dB
Data Source
AI summary
A sound-receiving system is provided, including: a sound-guiding tube, a microphone, and an acoustic perforated sheet. The sound-guiding tube has a winding path, including a first end, a second end, and a sound-receiving hole. The second end is opposite the first end. The sound-receiving hole is disposed at the first end. The microphone is abutted against the second end. The acoustic perforated sheet is disposed adjacent to the sound-receiving hole and is a distance away from the sound-receiving hole. The sound-receiving hole is offset from the microphone. The acoustic perforated sheet reduces and filters the frequency response of a specific frequency range of the microphone.