Audio Control Device Dynamic High-Frequency Gain Limiting
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Solution Overview
Problem
Conventional audio power amplifiers limit the level of super high-frequency components to prevent voice coil damage, but this limits the acoustic effect and can lead to overheating, as they do not effectively handle frequencies beyond the audible band.
Innovation Solution
An audio control device that includes a first fixed filter allowing sound signals above a certain frequency to pass, a level integrator to calculate integrated values, and a control unit that limits high-frequency bands only when necessary, ensuring that high-frequency signals are not excessively applied to the speaker, thereby maintaining acoustic effect and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-pass filter is used to attenuate super high-frequency components, then voice coil damage is prevented, but acoustic effect is lowered and music sources with high-frequency components cannot be properly handled
Solution Approach 1:
The patent applies dynamic control by continuously monitoring the integrated level of super high-frequency components and adjusting the gain of the high-pass filter section in real-time. When the integrated level exceeds a threshold, the gain is reduced to prevent voice coil damage; when it is below the threshold, the gain is increased to enhance acoustic effect. This dynamic adjustment resolves the contradiction between protection and performance.
Solution Approach 2:
The patent changes the parameter of filter gain dynamically based on the integrated level of super high-frequency components. By adjusting the gain parameter of the high-pass filter section according to the actual signal conditions, the system can adapt between protection mode (lower gain) and performance mode (higher gain), resolving the fixed trade-off between reliability and acoustic effect.
2Reliability
If the level of super high-frequency component is limited, then voice coil breakdown is prevented, but heat accumulation still occurs when voice coil cannot follow the frequency
Solution Approach 1:
The patent implements feedback control by using a level integrator to continuously accumulate the level information of super high-frequency components and feeding this information back to the gain control of the high-pass filter section. This feedback mechanism allows the system to respond to actual signal conditions and adjust accordingly, preventing both breakdown and excessive heat accumulation by maintaining appropriate gain levels.
Solution Approach 2:
The system performs self-regulation by automatically adjusting the filter gain based on its own monitoring of the super high-frequency component levels. The level integrator and gain control work together to self-correct potential overheating conditions without external intervention, ensuring the voice coil operates within safe temperature ranges while maximizing acoustic output.
3Adaptability or versatility
If low-pass filter is removed to handle music sources, then super high-frequency components can be input, but heat accumulates and voice coil breaks down when frequency exceeds voice coil capability
Solution Approach 1:
The patent segments the frequency spectrum by using a high-pass filter section to extract super high-frequency components separately from the main audio signal. This segmentation allows the system to process and control these components independently through separate gain adjustment, enabling music source compatibility while maintaining voice coil safety through targeted control of problematic frequency ranges.
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 solution allows for enhanced acoustic performance by utilizing higher frequency sound signals while preventing voice coil overheating and breakdown, by dynamically controlling the frequency bands based on integrated signal levels, ensuring efficient heat dissipation and maintaining sound quality.
Implementation Method 1
a level integrator that obtains a first integrated value by integrating levels of sound signals that have passed through the first fixed filter
Implementation Method 2
the control unit limits a sound signal in a frequency band higher than at least the first frequency when the first integrated value exceeds a predetermined value
Implementation Method 3
generates a speaker drive signal by processing a sound signal from a sound source input unit
Data Source
AI summary
A first fixed filter extracts high-frequency and low-frequency sound signals outside the audible band, and a level integrator integrates levels of the sound signals to obtain a first integrated value. With a second fixed filter, the level integrator integrates levels of sound signals in a low frequency band within the audible band to obtain a second integrated value. A control unit determines whether the high-frequency sound signals are dominant by comparing the first integrated value with the second integrated value. When the high-frequency sound signals are dominant, the control unit attenuates high-frequency speaker drive signals using a variable filter.