Loudspeaker Surround with Non-Axisymmetric Corrugations
Solution Overview
Problem
Traditional loudspeaker driver surrounds tend to buckle and deform uncontrollably under back pressure, leading to geometric buckling and distortion, especially in small enclosures, which affects sound quality and frequency response.
Innovation Solution
A loudspeaker driver surround with a smoothly rounded corrugated roll surface of non-axisymmetric design, featuring a high order of rotational symmetry, which allows controlled deformation and resistance to back pressure without buckling, maintaining minimal mass and sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surround is made thicker to resist back pressure, then the resistance to back pressure improves, but the mass increases and frequency response deteriorates
Solution Approach 1:
The patent employs a thin surround (0.7mm) with a corrugated roll surface design that provides structural rigidity through geometric shaping rather than material thickness. The corrugations create a series of radial folds that resist compression from back pressure while maintaining minimal mass, demonstrating the principle of using flexible thin structures with optimized geometry to achieve both lightness and pressure resistance.
2Ease of operation
If the surround deforms under back pressure, then the diaphragm can move, but the surround buckles and sound quality deteriorates
Solution Approach 1:
The patent utilizes a corrugated roll surface with smoothly rounded folds rather than sharp edges or flat surfaces. This curved geometric structure allows the surround to deform in a controlled manner during diaphragm movement while preventing sudden buckling. The rounded corrugations distribute stress evenly and maintain structural integrity, ensuring reliable sound quality throughout the full range of diaphragm motion.
3Weight of moving object
If the surround is made lighter to improve frequency response, then the mass decreases, but the resistance to back pressure reduces
Solution Approach 1:
The patent divides the roll surface into multiple radial corrugations or folds that segment the continuous surface into discrete structural elements. This segmentation creates a series of rigid radial beams that collectively resist back pressure while using minimal material. Each corrugation acts as an independent structural element, and their combined effect provides superior pressure resistance compared to a smooth surface of the same mass.
4Stability of the object's composition
If the surround deforms controllably to avoid buckling, then the geometric stability improves, but the mass increases
Solution Approach 1:
The patent employs a corrugated roll surface with asymmetric folding patterns that provide enhanced geometric stability. The corrugations create a non-uniform geometric structure that resists deformation more effectively than a symmetric smooth surface, while the asymmetric design allows for optimized material distribution that minimizes mass. The geometric asymmetry provides inherent stability against buckling under back pressure.
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 corrugated design prevents geometric buckling and uncontrolled deformation, maintaining sound quality and frequency response while minimizing mass, allowing the surround to deform predictably and resist back pressure effectively.
Implementation Method 1
a generally annular element of flexible and suitably resilient material... the roll surface being provided with a plurality of smoothly rounded corrugations or folds... the corrugations giving the projecting roll surface an order of rotational symmetry of at least 30
Data Source
AI summary
A loudspeaker driver surround 2 comprises a flexible, generally annular element having a central axis 8 along which in use a diaphragm is driven, an outer edge 6 for fitment to an enclosure and an inner edge 4 for fitment to the diaphragm, with a roll surface which extends between the edges and which projects in the direction of the axis, wherein the roll surface has a shape formed by a plurality of axial corrugations 10 extending generally radially with respect to the annular element between the outer and inner edges thereof, the corrugations being shaped and configured such that the roll surface is non-axisymmetric about the axis, and the arrangement being such that cross-sections of the roll surface which extend radially with respect to the annular element between the outer and inner edges thereof have a substantially constant length at all circumferential positions around the annular element and so that the shape of the said cross-section varies continuously between circumferential positions around the annular element, the corrugations giving the projecting roll surface an order of rotational symmetry of at least 30.