Low-Profile Loudspeaker Bi-Conical Support Structure
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Solution Overview
Problem
Conventional loudspeakers with shallow depth designs face challenges in maintaining stiffness and preventing rocking vibrations, which can lead to voice coil misalignment and damage, especially when the suspension is close to the surround plane, and existing solutions like double cone or flat diaphragms with stiffening ribs may compromise acoustic volume or require complex attachment points.
Innovation Solution
A loudspeaker design featuring a largely flat or mildly convex/concave diaphragm with a bi-conical support structure that attaches the suspension away from the diaphragm plane, providing a free surface for adhesive connection and reducing rocking vibrations, while maintaining acoustic volume and allowing for flexible positioning to optimize excursion clearances, and incorporating conical portions and apertures for increased stiffness and reduced acoustic impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a simple flat shallow diaphragm is used to minimize loudspeaker depth, then the overall depth is reduced, but the diaphragm stiffness is insufficient leading to rocking vibrations
Solution Approach 1:
The patent applies curvature to the diaphragm surface, transforming it from a flat plane to a convex or concave shape. This curvature inherently increases the diaphragm's stiffness without adding significant depth, as the curved surface distributes stress more effectively and resists deformation. The diaphragm may be convex towards the front or concave towards the rear, maintaining a shallow profile while achieving the required structural rigidity to prevent rocking vibrations.
2Length of stationary object
If the suspension is arranged in a plane close to the surround plane to minimize depth, then the loudspeaker depth is reduced, but the rocking vibration resistance is insufficient
Solution Approach 1:
The patent positions the suspension in a plane that is offset from the surround plane along the loudspeaker axis, creating a dimensional separation. This offset arrangement increases the moment arm for the restoring forces, thereby enhancing the system's resistance to rocking vibrations. The suspension plane is positioned at a distance from the surround plane, creating a lever arm that amplifies the stabilizing moment without significantly increasing the overall loudspeaker depth.
3Strength
If a double cone diaphragm shape is used to increase stiffness, then the diaphragm stiffness is improved, but the acoustic volume behind the diaphragm is reduced
Solution Approach 1:
The patent applies curvature selectively to specific regions of the diaphragm rather than uniformly throughout. The diaphragm may have a convex front surface or a concave rear surface, but the curvature is localized to achieve stiffness where needed while preserving the acoustic volume behind the diaphragm. This localized application of curvature allows the diaphragm to maintain structural rigidity without the volumetric penalty of a full double-cone shape.
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 design achieves higher stiffness and elevated breakup frequency, minimizing rocking motions and maintaining acoustic volume, thus reducing the likelihood of voice coil misalignment and damage, while allowing for conventional manufacturing processes and flexible assembly.
Implementation Method 1
a voice coil comprising a conductor through which a current may be passed, placed within a magnet assembly so that when current is passed through the voice coil an electromagnetic driving force is produced
Implementation Method 2
a suspension is attached to a rear face of the cone, and comprises a structure with a gentle elastic response in order to provide a restoring force to the diaphragm
Implementation Method 3
The movement of the diaphragm creates a pressure wave in the surrounding air, which propagates as a sound wave
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to a loudspeaker (10) which can be arranged to minimise its overall depth while also increasing the breakup frequency and reducing potential rocking vibrations. Accordingly, the present invention is directed to a loudspeaker (10), comprising a magnet structure (12), and a voice coil (15) lying within a magnetic field established by the magnet structure (12) and responsive to electrical signals to undergo excursions from a rest position along an axis of motion; a driven body (16), connected to the voice coil (15) and moveable to project acoustic waves from a front of the loudspeaker (10); and a suspension (18) for providing a restoring force to the driven body towards the rest position, the suspension (18) extending from an attachment point (20) on the driven body (16) to an attachment point on a fixed portion of the loudspeaker (22); wherein the driven body (16) comprises a diaphragm (24) and a support structure (26) extending rearwardly from a connection point (28) with the voice coil (15) to a connection point (20) with the suspension (18) located rearward of the frontal part of the magnet structure (12).