Portable Audio Waveguide Transition Structure for Noise Reduction
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Solution Overview
Problem
Acoustic waveguides in portable audio systems face challenges in efficiently coupling subsections and reducing noise, particularly due to complex molding requirements and resonance issues.
Innovation Solution
A waveguide structure with subsections that bend around different axes, featuring a transition section with varying cross-sectional areas, and a split waveguide design with branch sections and a trunk waveguide, incorporating cavities and vents to reduce noise and resonance peaks, fabricated from multiple parts using injection molding techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex waveguide structure with multiple subsections is used to reduce noise and resonance, then acoustic performance is improved, but manufacturing complexity increases
Solution Approach 1:
The waveguide is divided into multiple subsections (first, second, third, and fourth subsections) that can be manufactured separately using injection molding and then assembled together. This segmentation allows each subsection to be optimized for its specific acoustic function while simplifying the manufacturing process compared to creating a single complex piece.
Solution Approach 2:
The waveguide subsections are designed to nest within each other in a hierarchical arrangement, with smaller subsections fitting within larger ones. This nested structure reduces the overall space required, simplifies assembly, and maintains the complex acoustic functionality through the nested configuration of chambers and passages.
2Reliability
If the waveguide uses subsections bending around different axes, then acoustic coupling is improved, but manufacturing precision requirements increase
Solution Approach 1:
Multiple waveguide subsections that would traditionally require precise alignment when bent around different axes are merged into a single integrated structure formed by injection molding. This combining of functions into one manufacturable unit eliminates the need for complex assembly and alignment procedures while maintaining the acoustic coupling benefits of multi-axis bending.
3Object-affected harmful factors
If cavities and vents are added to reduce resonance peaks, then noise reduction is improved, but device complexity increases
Solution Approach 1:
Cavities and vents are strategically positioned at specific locations within the waveguide structure where they most effectively reduce resonance peaks and noise. Rather than uniformly distributing these features throughout the entire waveguide, the local quality principle applies them only where acoustically necessary, minimizing structural complexity while maximizing noise reduction effectiveness.
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 solution effectively reduces noise and resonance peaks, simplifies the molding process, and enhances acoustic performance by optimizing the waveguide's geometry and structure.
Implementation Method 1
Acoustic waveguides have been used in audio systems such as the commercially available Bose® WAVE® radio, WAVE® Radio/CD, and ACOUSTIC WAVE® music systems manufactured by Bose Corporation
Implementation Method 2
A waveguide structure with subsections that bend around different axes, featuring a transition section with varying cross-sectional areas, and a split waveguide design with branch sections and a trunk waveguide, incorporating cavities and vents to reduce noise and resonance peaks
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An apparatus includes a housing. A waveguide is located within the housing. The waveguide includes a first subsection that bends around a first axis and has a first cross-sectional area with an aspect ratio that is substantially different from unity. A second subsection bends around a second axis that is non-parallel to the first axis and includes a second cross-sectional area with an aspect ratio that is substantially different from unity. A third subsection acoustically couples the first subsection to the second subsection. The third subsection includes a third cross-sectional area with an aspect ratio that varies between the first aspect ratio and the second aspect ratio.