Acoustically Transparent Waveguide for Coaxial Loudspeakers
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Solution Overview
Problem
Coaxial loudspeakers face issues with uneven sound coverage and decreased intelligibility due to the obstruction caused by the high-frequency section, which disrupts the sound radiation from the low-frequency section, leading to inconsistent audio quality and echo problems.
Innovation Solution
A high-frequency acoustic waveguide design with a perforation layer that is acoustically transparent to low-frequency sound waves, minimizing obstruction while maintaining high-frequency performance by using a micro-perforation layer that covers openings in the mask layer, either on the inner or outer surface, or integrated into the mask layer, to allow low-frequency sound to pass through while minimizing high-frequency leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the high-frequency section is mounted coaxially within the low-frequency section, then the sound can be confined to a specific listening area, but the high-frequency section creates an obstruction that disrupts sound radiation from the low-frequency section
Solution Approach 1:
The high-frequency waveguide is constructed with a porous or perforated structure that allows low-frequency sound waves to pass through while containing high-frequency sound. This porous design eliminates the obstruction problem by making the waveguide partially transparent to low-frequency waves, enabling both frequency ranges to coexist without mutual interference.
Solution Approach 2:
The waveguide employs composite construction combining materials and structures with different acoustic properties - solid portions for high-frequency containment and porous/perforated portions for low-frequency transmission. This composite approach allows simultaneous optimization for both high-frequency directionality and low-frequency sound passage.
2Object-generated harmful factors
If large holes are created in the high-frequency waveguide to allow low-frequency sound passage, then the obstruction is reduced, but high-frequency sound leaks out of the waveguide
Solution Approach 1:
Different portions of the waveguide structure have different properties: solid walls in regions requiring high-frequency containment and porous/perforated regions allowing low-frequency passage. This local differentiation of structural quality enables selective frequency transmission - small perforations that are acoustically transparent to low frequencies while maintaining integrity for high-frequency containment.
Solution Approach 2:
The waveguide structure utilizes parameter changes in the size, distribution, and geometry of perforations to achieve frequency-selective transmission. By carefully controlling perforation parameters (size, spacing, pattern), the waveguide becomes transparent to low-frequency sound while maintaining opacity to high-frequency sound, resolving the leakage problem.
3Reliability
If the high-frequency waveguide is made solid to prevent high-frequency leakage, then high-frequency performance is maintained, but low-frequency sound radiation becomes uneven
Solution Approach 1:
The waveguide transitions from a solid structure to a porous or perforated structure, allowing low-frequency sound waves to pass through the high-frequency waveguide without significant obstruction. This porous design eliminates uneven sound coverage by enabling uniform low-frequency radiation while maintaining high-frequency containment through the carefully designed perforation pattern.
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 ensures consistent sound radiation patterns and improved intelligibility by making the high-frequency waveguide substantially transparent to low-frequency sound waves, reducing echoes and maintaining high-frequency performance.
Implementation Method 1
the mask layer includes a plurality of openings sized and shaped to make the mask layer acoustically transparent to sound waves below a crossover frequency
Implementation Method 2
the perforation layer has a plurality of micro-perforations sized and shaped to make the perforation layer acoustically opaque to sound waves above the crossover frequency
Data Source
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AI summary
The invention provides a high-frequency acoustic waveguide for use in coaxial loudspeaker systems. The waveguide is made up of a plurality of walls that define a conduit with an input end and an output end. Each of the walls includes a mask layer and a perforation layer. The mask layer has a plurality of holes sized and shaped to make the mask layer acoustically transparent to sound waves below a crossover frequency. The perforation layer has a plurality of micro-perforations sized and shaped to make the perforation layer acoustically opaque to sound waves above the crossover frequency. The waveguide directs sound waves above the crossover frequency, and is acoustically transparent to sound waves below the crossover frequency.