Vehicle Speaker Displacement Limits for Active Noise Control
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Solution Overview
Problem
Conventional active noise control systems in vehicles face challenges in efficiently eliminating noise while maintaining audio quality, as the noise control signal can cause excessive speaker displacement, leading to distorted audio output due to the mixing of noise control and audio signals without considering the limitations of the speaker's displacement range.
Innovation Solution
A sound control device and method that determine the maximum limit value for speaker displacement based on whether the audio function is ON or OFF, adjusting the noise control signal to prevent distortion and ensure efficient noise cancellation while maintaining audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the noise control signal is output to eliminate internal noise, then the noise cancellation performance is improved, but the speaker displacement exceeds the permissible range causing audio quality deterioration
Solution Approach 1:
The system dynamically adjusts the maximum limit value for speaker displacement based on whether the audio function is active. When audio is playing, a conservative limit is applied to prevent distortion, while when no audio is present, a higher limit allows more aggressive noise cancellation. This dynamic adaptation resolves the contradiction by changing the operational parameters based on system state.
Solution Approach 2:
The patent changes the displacement limit parameter according to the audio function state. By switching between different limit values (first limit value when audio is ON, second limit value when audio is OFF), the system optimizes both noise cancellation effectiveness and audio quality without requiring complex real-time monitoring of speaker displacement.
2Productivity
If the noise control signal amplitude is increased to improve noise elimination, then the noise reduction effectiveness is improved, but the speaker displacement increases causing distortion
Solution Approach 1:
The system employs dynamic control of the noise control signal amplitude by adjusting the displacement limit based on audio function state. This allows the noise reduction effectiveness to be maximized when audio is not playing, while preventing distortion when audio is active, thus resolving the contradiction between productivity and reliability.
3Manufacturing precision
If the speaker displacement limit is set conservatively to maintain audio quality, then audio output quality is preserved, but the noise cancellation performance is reduced
Solution Approach 1:
The system resolves this contradiction by making the displacement limit dynamic rather than fixed. A conservative first limit value is applied when audio function is active to preserve quality, while a more aggressive second limit value is used when audio is OFF to enhance noise cancellation. This temporal separation of constraints optimizes both competing objectives.
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 effectively improves the performance of active noise control by accurately managing speaker displacement, allowing for enhanced noise reduction without compromising audio quality, especially when the audio function is ON, and increasing noise control output when the audio function is OFF.
Implementation Method 1
the audio system of the vehicle generates a noise control signal which has the same amplitude as an internal noise of the vehicle and has a phase opposite to the phase of the internal noise, and outputs the noise control signal to the interior of the vehicle
Data Source
AI summary
A sound control device mounted in a vehicle and control method thereof includes obtaining whether an audio function is ON or OFF, and determining a maximum limit value for a displacement of a speaker due to a noise control signal according to whether the audio function is ON or OFF.