Segmented Loudspeaker Voice Coil for Lower Heating at High Excursion
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Solution Overview
Problem
Conventional loudspeakers face inefficiencies and heating issues due to voice coil windings outside the air gap being powered, which do not contribute significantly to electromotive force but contribute to heating, limiting power handling and performance.
Innovation Solution
A segmented voice coil design with a main voice coil section and auxiliary voice coil sections, where the auxiliary sections are selectively driven based on excursion demand, minimizing power consumption and heating by only activating them when necessary for high-amplitude signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If all voice coil windings are powered continuously, then the voice coil can produce sufficient electromotive force for low-amplitude signals, but windings outside the air gap generate excessive heat without contributing to force generation
Solution Approach 1:
The voice coil is divided into multiple independent segments (first voice coil segment, second voice coil segment, third voice coil segment) arranged along the traveling axis. Each segment can be independently controlled by separate driving signals, allowing selective activation of only those segments positioned within the air gap during operation, thereby eliminating heat generation from segments outside the air gap while maintaining sufficient electromotive force for the required power handling.
2Power
If auxiliary voice coil sections are always activated, then power handling capability is maximized, but power consumption increases unnecessarily for low-amplitude signals
Solution Approach 1:
The system dynamically adjusts which voice coil segments are active based on the instantaneous signal amplitude and excursion demands. For low-amplitude signals, only the main voice coil segment within the air gap is activated, minimizing power consumption. For high-amplitude signals requiring greater excursion, auxiliary voice coil segments are selectively activated to provide additional electromotive force, thereby maximizing power handling capability only when necessary.
Solution Approach 2:
Different segments of the voice coil are assigned different functions based on their position along the traveling axis. The main segment positioned within the air gap handles low-amplitude signals continuously, while auxiliary segments positioned outside the air gap are activated only when high-amplitude signals require additional force, optimizing both power consumption and power handling capability through localized functional differentiation.
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 approach enhances power handling and reduces voice coil heating by optimizing energy use and minimizing unnecessary power consumption, while maintaining acoustic performance.
Implementation Method 1
When the coil windings are powered, they interact with the magnetic field of the magnetic circuit 2 to produce an electromotive force for translating the voice coil 1
Data Source
AI summary
A method for driving a voice coil of a loudspeaker may include providing a magnetic circuit having an air gap, providing a voice coil suspended in the air gap, and applying an audio signal to the voice coil to move it along a travelling axis. The voice coil comprises a main voice coil section, and a pair of auxiliary voice coil sections arranged along the travelling axis with auxiliary voice coil sections arranged respectively on either side of the main voice coil section. Applying an audio signal comprises continuously coupling a main driving signal based on the audio signal to the main voice coil and selectively coupling an auxiliary driving signal based on the audio signal to the pair of auxiliary voice coil sections. The disclosed embodiments further relate to a voice coil driving system and a loudspeaker comprising a voice coil driving system.