Acoustic Output Device Diaphragm Interference Directivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional audio devices with monopole radiation suffer from insufficient sound directionality due to high far-field sound leakage, and attempts to improve directivity through quasi-dipole configurations are compromised by inconsistencies in dimensions and reliability issues such as waterproofing.
Innovation Solution
An acoustic output device featuring a first diaphragm and a second diaphragm, where the vibration phases of the diaphragms are opposite in a target frequency range, with the second diaphragm disposed around the first, to produce a directional acoustic field by interfering sounds, and utilizing a Helmholtz resonator or array to adjust boundary impedance for improved directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If monopole radiation configuration is used, then near-field radiation efficiency is improved, but far-field sound directionality deteriorates due to large sound leakage
Solution Approach 1:
The audio device is divided into multiple independent acoustic units (first acoustic unit and second acoustic unit), each with its own diaphragm and acoustic cavity. This segmentation allows each unit to function as an independent sound source, enabling precise control of sound radiation patterns and reducing unwanted sound leakage while maintaining radiation efficiency.
2Object-generated harmful factors
If quasi-dipole configuration with holes is used, then sound directionality is improved, but product reliability deteriorates due to waterproofing issues
Solution Approach 1:
The acoustic cavity is enclosed by a flexible diaphragm that acts as both the sound radiation surface and a waterproof barrier. This eliminates the need for holes in the device housing, maintaining waterproofing integrity while still achieving directional sound control through the controlled vibration of the diaphragm and acoustic resonance within the sealed cavity.
3Object-generated harmful factors
If quasi-dipole configuration is used, then sound directionality is improved, but radiation efficiency deteriorates due to dimensional inconsistencies
Solution Approach 1:
The first and second acoustic units are designed with matched acoustic impedances and vibration characteristics, creating a balanced dipole configuration. The diaphragms are positioned and dimensioned to ensure equal and opposite sound pressure generation, optimizing the dipole radiation pattern and minimizing energy loss while achieving superior sound directionality.
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
Enhances sound directionality while maintaining near-field radiation efficiency and ensuring reliability by reducing far-field sound leakage and improving waterproofing performance.
Implementation Method 1
a vibration phase of the first diaphragm may be opposite to a vibration phase of the second diaphragm, and the second sound may interfere with the first sound to produce a directional acoustic field
Implementation Method 2
utilizing a Helmholtz resonator or array to adjust boundary impedance for improved directivity
Data Source
AI summary
The present disclosure provides an acoustic output device. The acoustic output device includes a first acoustic assembly and a second acoustic assembly. The first acoustic assembly may comprise a first diaphragm, and the first diaphragm vibrates to produce a first sound. The second acoustic assembly may comprise a second diaphragm, the second diaphragm vibrates to produce a second sound, wherein at least a portion of the second diaphragm may be disposed around the first diaphragm. Vibrational phases of the first diaphragm and the second diaphragm may be opposite in a target frequency range, and the second sound may interfere with the first sound to produce a directional acoustic field pointing to a target direction.