Undulating Speaker Surround Geometry for Non-Pistonic Motion Control
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Solution Overview
Problem
Audio speakers experience issues with non-pistonic motion at certain resonant frequencies, leading to sound quality degradation and potential failure due to the voicecoil rubbing against the magnet, which existing suspension systems fail to adequately address.
Innovation Solution
An audio speaker design featuring a surround with an undulating film that supports the diaphragm, distributing stresses to control and limit non-pistonic motion by concentrating them along the outer rim sides rather than the corner regions, thereby maintaining axial motion participation at least one order of magnitude higher than non-axial motion participation at resonant frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional surround supports the diaphragm, then the diaphragm is centered relative to the frame, but non-pistonic motion occurs at resonant frequencies causing voicecoil rubbing and sound quality degradation
Solution Approach 1:
The patent applies local quality by creating undulations only in specific regions of the surround film - specifically along the outer rim sides while excluding corner regions. This localized undulation design concentrates stress control in areas where it most effectively prevents non-pistonic motion, while maintaining other beneficial properties of the surround in different regions.
Solution Approach 2:
The patent utilizes curvature by forming undulations in the surround film that create curved surfaces. These undulations have smooth surface curvatures that extend across surface boundaries, and the curved geometry helps distribute stresses to control non-pistonic motion while maintaining axial motion participation.
2Reliability
If the surround film is made undulating to control non-pistonic motion, then axial motion participation is maintained at least one order of magnitude higher than non-axial motion, but the manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the surround into distinct regions with different geometries - undulated regions along the outer rim sides and non-undulated corner regions. The undulation itself can be viewed as segmented into multiple surface boundaries defined by radial line segments, allowing stress distribution to be controlled in a segmented manner.
Solution Approach 2:
The patent utilizes parameter changes by modifying the geometric parameters of the surround film - specifically introducing undulations with specific surface curvatures in certain regions while maintaining flat geometry in others. This selective parameter modification allows control of non-pistonic motion without requiring complete redesign of the entire surround structure.
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 undulating film design effectively reduces non-pistonic motion, preventing rub and buzz issues, and speaker failure, while being a low-cost solution that maintains sound quality across resonant frequencies without the need for complex electronic compensation.
Implementation Method 1
The speaker surround may include a film, e.g., an elastic film, which undulates in a peripheral direction along the radial gap around the outer rim
Data Source
AI summary
An audio speaker having a suspension system including a surround to support a diaphragm within a frame and to reduce non-pistonic motion of the diaphragm at several resonant frequencies is disclosed. More particularly, embodiments of the surround include a film that undulates in a peripheral direction around the diaphragm and includes several undulations above and below a radial gap between the diaphragm and the frame. Other embodiments are also described and claimed.