Transmission Line Loudspeaker With Folded Waveguide
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Solution Overview
Problem
Conventional loudspeakers face challenges in optimizing sound energy transmission and radiation, leading to inefficiencies in low and high frequency outputs, and often require grilles for external sound emission, limiting form factor flexibility.
Innovation Solution
A loudspeaker design featuring a folded acoustic transmission line with internal transducers emitting energy at two locations along its length, a closed end tapering to a point, and an inverted taper for reduced high frequency harmonic peaks and improved low frequency output, allowing for a single outlet without grilles and adaptable form factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional waveguides are used to guide sound pressure waves, then sound radiation is achieved, but high frequency harmonic peaks occur and low frequency output is insufficient
Solution Approach 1:
The acoustic transmission line is divided into multiple sections with different cross-sectional areas, creating a segmented structure that progressively transforms sound waves. This segmentation allows different frequency ranges to be handled by different sections, reducing harmful high frequency peaks while maintaining efficient energy transmission through the gradual area changes.
Solution Approach 2:
The cross-sectional area parameter of the transmission line is continuously changed along its length, creating a tapered structure. This parameter change transforms the acoustic impedance progressively, allowing efficient transmission of low frequency energy while naturally attenuating high frequency harmonic peaks through the varying geometry.
2Power
If acoustic transducers are mounted on external walls, then sound radiation is achieved, but high frequency output is excessive and low frequency output is insufficient
Solution Approach 1:
The transducers are positioned inside the enclosure rather than on external walls, moving them to a different spatial dimension. This internal positioning allows the transducers to couple directly with the acoustic transmission line, efficiently transferring low frequency energy into the enclosed volume where it can be amplified by the resonant properties of the transmission line structure.
3Reliability
If multiple volumes and ports are used to achieve desired sound characteristics, then sound radiation is improved, but device complexity increases
Solution Approach 1:
The single acoustic transmission line structure performs multiple functions simultaneously: it acts as a resonant chamber for low frequency enhancement, a waveguide for sound radiation, and a filter for harmonic reduction. This multi-functional design eliminates the need for separate volumes and ports, achieving reliable sound radiation characteristics with reduced complexity.
Solution Approach 2:
Multiple acoustic functions that would traditionally require separate volumes and ports are merged into a single integrated transmission line structure. The transmission line combines resonance, waveguiding, and filtering functions in one continuous structure, simplifying the overall device while maintaining reliable sound radiation characteristics.
4Ease of operation
If grilles are used for external sound emission, then sound radiation is achieved, but form factor flexibility is limited
Solution Approach 1:
The grille component is completely removed from the design. The transmission line opens directly to the external environment, eliminating the need for grilles. This extraction of the grille element provides unobstructed access for placing objects on the loudspeaker surface while maintaining effective sound radiation through the open transmission line outlet.
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 design reduces high frequency harmonic peaks, enhances low frequency output, eliminates the need for grilles, and allows for varied form factors by optimizing sound energy transmission and radiation patterns.
Implementation Method 1
a certain portion of the energy present in the sound pressure waves is absorbed while traveling through the waveguide
Implementation Method 2
each acoustic transducer configured to emit acoustic energy directly into the acoustic transmission line
Data Source
AI summary
A loudspeaker including an acoustic waveguide includes an enclosure, an acoustic transmission line formed within the enclosure, and a plurality of acoustic transducers contained within the enclosure and disposed along a length of the acoustic transmission line. Each acoustic transducer is configured to emit acoustic energy directly into the acoustic transmission line at two separated locations along the length of the acoustic transmission line.