Low Profile Loudspeaker Segmented Magnet and Suspension Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Smaller loudspeakers face challenges in achieving low frequency response due to limited diaphragm size and stiffness, leading to restricted vibrational excursion and spurious vibrations that degrade high-frequency performance, making them unsuitable for low-profile devices like laptops and tablets.
Innovation Solution
A low-profile loudspeaker transducer design featuring a magnet assembly with segmented annular magnets and a surround suspension system that allows maximum vibrational amplitude while constraining unwanted movements, enhancing excursion and reducing spurious vibrations, thus improving low-frequency response and high-frequency performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diaphragm size is reduced for smaller loudspeakers, then the device can be used in low-profile applications, but the low-frequency response deteriorates due to limited vibrational excursion
Solution Approach 1:
The magnet assembly is divided into multiple segments (first magnet assembly with outer and inner magnets, second magnet assembly) that can be independently positioned and optimized. This segmentation allows the magnetic circuit to be reconfigured for maximum efficiency in a compact space, enabling small diaphragm size while maintaining adequate low-frequency response through optimized magnetic field distribution across the segmented structure.
Solution Approach 2:
The patent transitions from a conventional planar magnet arrangement to a multi-layer stacked configuration with magnets positioned at different vertical levels (first magnet assembly above top plate, second magnet assembly below top plate). This three-dimensional arrangement allows the magnetic circuit to achieve sufficient magnetic flux density and voice coil interaction in a reduced horizontal footprint, enabling compact diaphragm size while preserving low-frequency performance through vertical space utilization.
2Speed
If the suspension stiffness is increased to support smaller diaphragm mass, then high-frequency response improves, but spurious vibrations occur that degrade performance
Solution Approach 1:
The suspension system employs different stiffness characteristics at different locations: the surround provides primary support with optimized stiffness for the diaphragm perimeter, while the spider assembly provides localized center support with tailored compliance. This local differentiation allows the suspension to support the lightweight small diaphragm for high-frequency response while the distributed support points minimize spurious vibrations by preventing localized resonances and maintaining controlled motion throughout the diaphragm structure.
Solution Approach 2:
The suspension system is designed with dynamic compliance that adapts to different operating conditions. The surround and spider assembly work together to provide the necessary stiffness for high-frequency response while allowing controlled compliance that prevents the buildup of spurious vibrations. The dynamic interaction between the suspension elements allows the system to maintain stability across the frequency range despite the reduced mass of the small diaphragm.
3Length of stationary object
If the magnet assembly is compacted for low-profile design, then the device thickness is reduced, but the magnetic flux density may be insufficient for adequate voice coil force
Solution Approach 1:
The magnetic circuit utilizes a stacked three-dimensional configuration with the top plate separating first and second magnet assemblies positioned at different vertical levels. This arrangement compresses the magnetic path in the vertical dimension while maintaining adequate magnetic flux density through the concentrated gap region where the voice coil interacts with the combined magnetic fields from both assemblies, achieving compact thickness without sacrificing voice coil force.
Solution Approach 2:
The first and second magnet assemblies are magnetically combined through the top plate to create a unified magnetic circuit that delivers concentrated flux density in the voice coil gap. The outer and inner magnets of the first assembly work together with the second assembly to generate sufficient combined magnetic force, merging multiple magnetic sources into a compact structure that maintains adequate force output despite reduced overall thickness.
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 achieves increased vibrational excursion and improved low-frequency response, reducing spurious vibrations and enabling the loudspeaker to be used in low-profile devices such as laptops and tablets without compromising high-frequency performance.
Implementation Method 1
The variations of electric energy are converted into corresponding variations of acoustic energy (i.e., sound waves) by rapidly vibrating a flexible diaphragm within the transducer
Implementation Method 2
The surround suspension member includes an outer edge that is attached to the top surface of the annular outer magnet, and an inner edge that is attached to the upper end of the former
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A surround suspension system for a low profile loudspeaker transducer having a former (218), diaphragm (202), and loudspeaker magnet assembly (220, 224) is described, wherein the former (218) is connected to a voice coil (214). The loudspeaker magnet assembly (220, 224) includes an annular outer magnet (224) having a top surface and the surround suspension system may include a surround suspension member (212). The surround suspension member (212) includes an outer edge (618) that is attached to the top surface of the annular outer magnet (224), and an inner edge (614) that is attached to the upper end of the former (218).