Ultrathin Acoustic Diffuser Using Spiral Propagation Paths
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Solution Overview
Problem
Schroeder diffusers, widely used in sound engineering, face limitations in thickness due to their design principle, making them unsuitable for effectively diffusing low-frequency sound waves, as the thickness required is excessively large.
Innovation Solution
A broadband ultrathin acoustic wave diffusion structure utilizing a combination of acoustic wave propagation and focused sections with variable-section cavities filled with isotropic or anisotropic materials, where the propagation passages are designed in a monolayer or multilayer spiral form to accommodate long lengths, allowing for efficient diffusion of low-frequency sound waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Schroeder diffuser design principle is used, then sound diffusion capability is improved, but thickness size becomes excessively large for low-frequency sound waves
Solution Approach 1:
The patent transforms the traditional one-dimensional depth-based diffusion approach into a multi-dimensional structure by folding the acoustic propagation passage into spiral, helical, or meandering paths. This allows the passage length to extend significantly beyond the physical thickness of the diffuser panel, enabling effective low-frequency diffusion while maintaining a thin profile. The acoustic path length can be dozens of times greater than the panel thickness through this dimensional transformation.
Solution Approach 2:
The patent embeds the acoustic propagation passage within itself by folding it into nested spiral or helical configurations. The passage is contained within a compact volume, with inner loops nested within outer loops, maximizing the acoustic path length within a minimal thickness. This nesting strategy allows the diffuser to achieve the required acoustic path length for low-frequency diffusion without requiring proportional increases in physical thickness.
2Reliability
If acoustic propagation passage length is increased to diffuse low-frequency sound waves, then diffusion effectiveness is improved, but available space becomes insufficient
Solution Approach 1:
The patent resolves the space limitation by transitioning from a straight linear passage to a three-dimensional folded configuration. The passage is arranged in spiral, helical, or stacked layers that utilize the third dimension (depth/thickness) to extend the acoustic path length without proportionally increasing the footprint area. This allows the passage length to be dozens of times greater than the panel thickness while occupying minimal planar space.
Solution Approach 2:
The patent employs curved and spiral geometries for the acoustic propagation passage instead of straight linear paths. The spiral and helical configurations allow the passage to coil back on itself multiple times within a compact volume, maximizing the path length within limited space. The curved paths enable the acoustic wave to travel a much longer distance through the diffuser material without requiring a proportionally larger overall structure.
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 structure achieves significant reduction in size while maintaining effective sound diffusion capabilities, allowing for dozens to hundreds of times the thickness of traditional diffusers, effectively addressing the challenge of low-frequency sound wave diffusion.
Implementation Method 1
The through cavity has variable section, and isotropic or anisotropic acoustic material is filled in the variable-section cavity
Implementation Method 2
The anisotropic acoustic material is formed by embedding membranes or string nets into the isotropic acoustic material
Implementation Method 3
the acoustic wave propagation section is formed by a simply connected acoustic wave propagation passage with a close end
Data Source
AI summary
A broadband ultrathin acoustic wave diffusion structure has a plurality of acoustic wave diffusion units. Each acoustic wave diffusion unit has at least one acoustic wave propagation section, and an acoustic wave focused section communicating with the acoustic wave propagation section is arranged according to needs. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused cavity is a variable-section cavity. The acoustic wave propagation section is formed by a simply connected acoustic wave propagation passage with a close end. Different acoustic wave diffusion units have different lengths of the simply connected acoustic wave propagation passages. The maximum length of the simply connected acoustic wave propagation passage may be dozens or even hundreds of times of the thickness of the acoustic wave diffusion structure, which can meet the diffusion requirements for low frequency acoustic waves to the maximum extent.