Magnetic Negative Spring Loudspeaker Radial Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Loudspeakers with magnetic negative spring (MNS) drivers, such as repel-attract drivers (RAD) and permanent magnet crown (PMC) drivers, face issues like radial instability, non-linear force vs displacement curves, and instability at high altitudes, leading to audible distortions and mechanical failures.
Innovation Solution
The design incorporates a magnetic negative spring with a first portion connected to a moveable armature and a second stationary portion, arranged for radial stability and linear forces. Additionally, a variable air volume or variable reluctance device is used to adjust the resonance frequency, and a moveable ferromagnetic plunger adjusts magnetic stiffness in response to atmospheric pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a magnetic negative spring (MNS) driver is used in a loudspeaker, then large pressure forces on the sound panel can be cancelled, but radial instability occurs leading to mechanical failures
Solution Approach 1:
The MNS is divided into multiple discrete magnets arranged in a specific pattern around the voice coil. This segmentation allows each magnet to contribute to both the pressure force cancellation and the radial stability, with the distributed arrangement creating balanced magnetic fields that prevent radial instability while maintaining force cancellation capability.
Solution Approach 2:
The MNS magnets are positioned asymmetrically relative to the voice coil, with specific spacing and angular arrangements that create a magnetic field configuration optimized for both pressure cancellation and radial stability. The asymmetric placement ensures that the magnetic forces are distributed to provide restoring forces against radial displacement while maintaining the pressure balance.
2Force
If a magnetic negative spring (MNS) driver is used in a loudspeaker, then pressure forces can be cancelled, but the force vs displacement curve becomes non-linear causing audible distortions
Solution Approach 1:
Different regions of the MNS are designed with varying magnetic properties and geometries to optimize the local magnetic field distribution. By adjusting the strength, size, and position of individual magnets in different angular positions, the overall force-displacement characteristic is tuned to be more linear across the operating range while maintaining pressure cancellation.
Solution Approach 2:
The MNS configuration allows the magnetic field distribution to dynamically adapt to the voice coil position. As the voice coil moves, the relative positions of the MNS magnets create a magnetic field that automatically adjusts to maintain a more linear force response, reducing distortion across the speaker's operating range.
3Force
If a magnetic negative spring (MNS) driver is used in a loudspeaker, then pressure forces can be cancelled, but instability occurs at high altitudes
Solution Approach 1:
The MNS design incorporates parameters such as magnet spacing, size, and magnetic strength that are optimized to compensate for changes in atmospheric pressure at different altitudes. The magnetic field configuration is designed to maintain stable operation across a range of environmental conditions, with the magnetic forces providing consistent pressure cancellation regardless of external atmospheric pressure variations.
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 enhances radial stability, linearizes the force curve, and maintains speaker stability across varying altitudes, reducing audible distortions and mechanical failures while allowing for precise control of resonance frequency.
Implementation Method 1
a magnetic negative spring that has a first magnetic negative spring portion that is mechanically connected to the moveable armature and a second magnetic negative spring portion that is stationary relative to the enclosure. The magnetic negative spring is operable to provide a first magnetic negative spring force when the sound panel is moving toward the enclosure and a second magnetic negative spring force when the sound panel is moving away from the enclosure.
Implementation Method 2
a moveable armature mechanically connected to the sound panel including an actuator operable to convert electrical energy into mechanical energy
Implementation Method 3
The magnets of the MNS are arranged for radial stability and/or to provide for linear forces
Implementation Method 4
a moveable ferromagnetic plunger adjusts magnetic stiffness in response to atmospheric pressure changes
Data Source
AI summary
Electroacoustic drivers that can be utilized in loudspeaker systems that utilize drivers having a magnetic negative spring (MNS). The magnets of the MNS can be arranged for radial stability and/or to provide for linear magnetic forces. A variable reluctance device can be used to vary the resonant frequency of electroacoustic driver in response to a feedback signal.