Hemispherical Cup Loudspeaker Drivers for Low-Frequency Resonance Control
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Solution Overview
Problem
Traditional loudspeakers face challenges in reproducing low frequencies without causing enclosure resonances and mechanical vibrations, leading to distortion, as they require large volumes of air and suffer from resonance peaks in the 180 Hz-300 Hz range.
Innovation Solution
The design features a loudspeaker system with two opposed loudspeaker drivers housed in a resonance chamber, each enclosed by a substantially hemispherical cup with a layered construction and a frame structure that minimizes air volume and structural resonances, using cement-based syntactic foam for damping and an asymmetric port configuration to extend the low-frequency response beyond 370 Hz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a large volume enclosure is used to reproduce low frequencies, then the low frequency response is extended, but the enclosure becomes large and bulky and mechanical vibrations and resonances increase
Solution Approach 1:
The enclosure is divided into multiple sealed compartments (first sealed enclosure, second sealed enclosure, third sealed enclosure) rather than using a single large volume enclosure. This segmentation allows the system to achieve the necessary acoustic volume while keeping individual enclosure volumes small, thereby preventing mechanical vibrations and resonances while maintaining low frequency response capability.
2Duration of action of stationary object
If a large volume enclosure is used to reproduce low frequencies, then the low frequency response is extended, but the enclosure becomes large and bulky
Solution Approach 1:
The enclosure is divided into multiple sealed compartments (first sealed enclosure, second sealed enclosure, third sealed enclosure) rather than using a single large volume enclosure. This segmentation allows the system to achieve the necessary acoustic volume while keeping individual enclosure volumes small, thereby preventing mechanical vibrations and resonances while maintaining low frequency response capability.
3Ease of manufacture
If traditional enclosure designs are used, then manufacturing is simple, but resonance peaks of 10 dB-20 dB occur at 180 Hz-300 Hz
Solution Approach 1:
The enclosure is divided into multiple sealed compartments (first sealed enclosure, second sealed enclosure, third sealed enclosure) rather than using a single large volume enclosure. This segmentation allows the system to achieve the necessary acoustic volume while keeping individual enclosure volumes small, thereby preventing mechanical vibrations and resonances while maintaining low frequency response capability.
Solution Approach 2:
Different wall elements (first wall element, second wall element, third wall element, fourth wall element) are positioned at specific distances from each other to create the segmented enclosure structure. This local arrangement of walls at controlled distances eliminates resonances while maintaining ease of manufacture through modular construction.
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 configuration reduces distortion, allows for smaller physical size, faster diaphragm acceleration, and improved phase characteristics by eliminating non-linear distortion and mechanical vibrations, thereby extending the useful operating frequency range and minimizing unwanted sound pressure.
Implementation Method 1
cement-based syntactic foam for damping
Implementation Method 2
sound absorbing material
Implementation Method 3
a large volume of air must be moved precisely to reproduce the lowest frequencies
Implementation Method 4
arranging the cups with a substantially hemispherical design, creates the least surface area for a given internal volume and thereby also the least structural resonances in any given frequency band
Data Source
AI summary
An audio loudspeaker system for reproducing frequencies between 16 Hz and 700 Hz, comprising a loudspeaker housing defining an inner resonance chamber and at least two loudspeaker drivers arranged in the housing and having front faces arranged facing each other in an opposed manner. The housing comprises vertical wall elements arranged with a distance approximately defining a width of the resonance chamber, where each wall element comprises first and second side surfaces and a circumferential edge surface. A first side surface of the wall elements constitutes and inner surface of the housing and partly defines an enclosure of the resonance chamber, and a second side surface of the wall elements constitutes exterior side surfaces of the audio loudspeaker system. The loudspeaker drivers are arranged within substantially hemispherical cups arranged on the second side surfaces of the wall elements and enclosing the loudspeaker drivers in a close manner.