Blended Waveguide and Reflector for Loudspeaker Acoustic Control
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Solution Overview
Problem
Existing loudspeaker systems face challenges in achieving high fidelity and high intensity sound reproduction across a broad frequency range while maintaining a compact, energy-efficient design, particularly when using a single transducer, as folded horns restrict higher frequency sound transmission due to standing waves and sharp turns, limiting their effectiveness above 300 Hz.
Innovation Solution
A blended folded horn and reflector system is introduced, featuring a parabolic region within the horn to focus higher frequency sound and a reflector that guides the radiation through the horn, allowing a single transducer to cover a wide frequency range without the limitations of conventional folded horns, by using a parabolic reflector to maintain impedance matching and reduce distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a folded horn is used to reduce package size, then the horn can be made more compact, but higher frequency sound transmission is restricted due to standing waves and sharp turns
Solution Approach 1:
The horn is divided into distinct frequency zones: a folded section for low frequencies (below 300 Hz) and a straight section for mid and high frequencies (above 300 Hz). This segmentation allows each section to be optimized for its specific frequency range, resolving the contradiction between compactness and high-frequency transmission.
Solution Approach 2:
The horn transitions from a two-dimensional folded path to a three-dimensional structure with both folded and straight sections. The fold angle and transition geometry are carefully designed to maintain acoustic continuity while enabling the horn to serve multiple frequency ranges simultaneously.
2Volume of moving object
If the degree of folding is increased to make the horn more compact, then the package size is reduced, but the cut off frequency for sound transmission decreases
Solution Approach 1:
The horn is divided into distinct low-frequency folded section and high-frequency straight section, allowing the folded portion to be compact while the straight portion maintains adequate acoustic length for higher frequencies.
Solution Approach 2:
Different sections of the horn have different geometric properties optimized for their specific frequency ranges. The folded section uses appropriate fold angles for low frequencies, while the straight section provides the necessary acoustic path length for mid and high frequencies.
3Ease of manufacture
If flat surfaces are used in the folded horn to simplify construction, then manufacturing is easier, but sharp turns are created that affect higher frequency transmission
Solution Approach 1:
The horn is divided into a folded section with flat surfaces for low frequencies and a straight section for mid and high frequencies. This segmentation allows the use of simple flat surfaces where they are acceptable while maintaining proper acoustic geometry where needed.
Solution Approach 2:
Different sections of the horn have different surface characteristics: the folded section uses flat surfaces for manufacturing simplicity, while the straight section provides the necessary acoustic continuity for high-frequency transmission.
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 enables a compact loudspeaker system to efficiently transmit sound across the entire audible frequency spectrum, from 70 to 6000 Hz, without the cut-off issues associated with conventional folded horns, ensuring consistent sound quality and throughput.
Implementation Method 1
The parabolic region operates to focus sound in the upper portion of the operational frequency range of the loudspeaker and to reflect the resulting focused sound beam along a second radiant axis through the mouth of the folded horn
Implementation Method 2
The parabolic region operates to focus sound in the upper portion of the operational frequency range of the loudspeaker
Data Source
AI summary
A blended acoustic folded horn and reflector provides for throughput of higher frequency bands without giving rise to standing waves. The horn includes a parabolic region intersected by a first direct radiant axis centered on the throat. The parabolic region is shaped and oriented to define a reflected radiant axis through the mouth for frequency components of the acoustic input above a cut-off frequency. The parabolic region operates to focus sound in the upper portion of the operational frequency range of the loudspeaker and to reflect the resulting focused sound beam along a second radiant axis through the mouth of the folded horn.