Acoustic Waveguide Equal Expansion Rate Symmetric Transformer
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Solution Overview
Problem
Existing audio speaker systems face limitations in tailoring the radiation angle of sound from a loudspeaker driver exit, struggling to achieve desired coverage patterns, especially when the angle is neither wide nor narrow, and often require brute force methods or assumptions about wavefront shapes.
Innovation Solution
The use of an acoustic waveguide with divided input and output sections, such as a circular divided input transforming into a divided annular ring or rectangular output, allows for precise control of energy distribution and radiation angles, accommodating various excitation waves and pressure gradients, without relying on normal pressure gradients at the entrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rectangular slot is used to transform the round driver exit, then the radiation angle is widened in one direction, but the radiation angle remains narrow in the other direction where the slot dimension is larger than the driver exit
Solution Approach 1:
The waveguide divides the acoustic path into multiple segments with different transformation functions. The first waveguide transforms the round driver exit to an intermediate shape, while the second waveguide transforms the intermediate shape to the final rectangular slot, allowing independent optimization of each transformation stage to achieve uniform radiation in all directions
Solution Approach 2:
The patent uses asymmetric geometric transitions within the waveguides to compensate for the anisotropic radiation characteristics. By carefully designing the asymmetric path lengths and cross-sectional area changes in each segment, the system balances the radiation pattern to achieve uniform omnidirectional coverage despite the rectangular output geometry
2Adaptability or versatility
If horn walls are used to control radiation angle, then the radiation pattern is confined, but the horn becomes very long for narrow coverage angles
Solution Approach 1:
The patent replaces the traditional long horn mechanical structure with acoustic waveguides that use controlled geometric transformations and path length variations to achieve the same radiation pattern control in a much more compact form factor
Solution Approach 2:
The waveguides achieve narrow radiation patterns by dynamically changing acoustic parameters along the path, including cross-sectional area, path length, and transformation rate, allowing compact design while maintaining control over radiation angle without requiring long horn structures
3Adaptability or versatility
If vanes are applied in the throat to spread acoustic energy, then the radiation angle is widened, but the approach is brute force and lacks precision
Solution Approach 1:
Instead of using brute force vanes throughout the throat, the patent applies localized geometric transformations in specific segments of the waveguides. Each segment has tailored cross-sectional area changes and path length variations that precisely control the acoustic energy distribution, achieving the desired radiation angle with targeted local modifications rather than global brute force approaches
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
This approach enables flexible control of radiation angles, achieving wider or narrower patterns as needed, with equal power distribution and impedance across paths, enhancing the versatility and efficiency of sound wave transformation.
Implementation Method 1
acoustic waveguides that transform wavefronts of one shape from primary waveguides into another shape
Data Source
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AI summary
An acoustic transformer includes at least one outer boundary wall. A plurality of inner walls are disposed within the outer boundary wall. The outer boundary wall and the inner walls define a substantially annular input opening divided by at least some of the inner walls into a plurality of circumferentially-spaced input sections. Each of the input sections has an inner circumferential side and an outer circumferential side. A substantially rectangular output opening is divided by at least some of the inner walls into a plurality of output sections. Each of a plurality of acoustic paths interconnects a respective one of the input sections with a respective one of the output sections. Each of the paths has a substantially equal path length and a substantially equal expansion rate.