Acoustic Device Microperforated Absorption for High-Frequency Sound Leakage
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Solution Overview
Problem
Existing acoustic devices face challenges in effectively reducing sound leakage, particularly at high frequencies, due to phase differences and resonance issues, leading to chaotic sound field distributions and inadequate sound leakage reduction in the far field.
Innovation Solution
An acoustic device with a diaphragm, housing, and sound absorbing structure featuring a microperforated plate and cavity, which guides sound through different acoustic holes with controlled phase differences and absorbs sound in a target frequency range, while being positioned near the ear canal without blocking it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If two sound sources with opposite phases are used to reduce sound leakage, then sound leakage in the far field is reduced to a certain extent, but at high frequencies the wavelength is much shorter making the distance between sound sources non-negligible compared to wavelength, resulting in inability to cancel sound signals effectively
Solution Approach 1:
The sound generation component is divided into multiple independent sound sources (first sound source and second sound source) with different radiation characteristics. The first sound source has a first acoustic transmission structure while the second sound source has a second acoustic transmission structure, allowing each to be optimized for different frequency ranges to achieve effective sound leakage reduction across the full frequency spectrum
Solution Approach 2:
Different acoustic transmission structures are designed with different local characteristics - the first acoustic transmission structure is optimized for low-frequency sound transmission while the second acoustic transmission structure is optimized for high-frequency sound transmission. This local differentiation allows each structure to perform its function effectively without compromising the other frequency range
2Productivity
If an acoustic transmission structure is used to transmit sound, then sound is transmitted from the sound outlet, but when the structure resonates it adds a resonance peak to the transmitted sound wave, causing chaotic sound field distribution and reducing sound leakage reduction effect
Solution Approach 1:
The second sound source is designed to emit a sound signal with a phase opposite to that of the first sound source. This preliminary opposite-phase action creates destructive interference that cancels out the resonance peaks and chaotic sound field distribution caused by the acoustic transmission structures, thereby preventing the harmful effects before they propagate
Solution Approach 2:
The second sound source acts as an intermediary element that mediates the resonance problem. By introducing this additional sound source with opposite phase, it serves as a counterbalancing mechanism that neutralizes the resonance effects of the acoustic transmission structures without affecting the overall sound transmission efficiency
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 device enhances directional sound field control by minimizing sound leakage and improving sound distribution, especially at high frequencies, while maintaining comfort by not obstructing the ear canal.
Implementation Method 1
a sound absorbing structure coupled to the second acoustic cavity and is configured to absorb the sound transmitted from the second acoustic cavity to the second acoustic hole in a target frequency range
Implementation Method 2
when an acoustic transmission structure of the sound generation component resonates, the phase of the acoustic signal actually radiated by a sound outlet of the sound generation component has a certain phase difference from an original phase
Data Source
AI summary
An acoustic device is provided, including: a diaphragm; a housing configured to accommodate the diaphragm and form a first acoustic cavity and a second acoustic cavity corresponding to a front side and a rear side of the diaphragm. The diaphragm radiates sound into the first acoustic cavity and the second acoustic cavity, and the sound in the first acoustic cavity and the sound in the second acoustic cavity are guided out through a first acoustic hole coupled to the first acoustic cavity and a second acoustic hole coupled to the second acoustic cavity; a sound absorbing structure coupled to the second acoustic cavity and is configured to absorb the sound transmitted from the second acoustic cavity to the second acoustic hole in a target frequency range, the acoustic structure including a microperforated plate and a cavity, the microperforated plate including through holes.