Vehicle Active Noise Control for Low-Frequency Speaker Limits
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Solution Overview
Problem
Conventional audio systems in vehicles struggle to efficiently eliminate noise, particularly low-frequency components, due to speaker limitations, leading to distortion and deterioration of active noise control performance.
Innovation Solution
A method and device for controlling a sound control system in vehicles, which involves obtaining input signals from accelerometers or microphones, adjusting low-frequency components based on their magnitudes and a preset reference magnitude, generating a noise control signal, and transmitting it for speaker output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the audio system controls the speaker to output the noise control signal with low frequency components, then the noise control signal can eliminate noise, but the low frequency components may be distorted due to speaker non-linearity or saturation
Solution Approach 1:
The patent applies preliminary action by adjusting the magnitude of low frequency components in the noise control signal before it is output to the speaker. The controller identifies when low frequency components exceed a reference magnitude and reduces them in advance, preventing speaker saturation and distortion before they occur. This proactive adjustment ensures the speaker operates within its linear range while maintaining effective noise control performance.
2Reliability
If the noise control signal includes low frequency components with high magnitude, then noise cancellation effectiveness is improved, but speaker output capability is exceeded causing non-linearity
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the magnitude parameter of low frequency components in the noise control signal. The controller monitors the magnitude of low frequency components and selectively reduces them when they exceed a reference threshold, thereby changing the signal parameters to match the speaker's output capabilities while preserving noise control effectiveness within the speaker's operational range.
3Device complexity
If the audio system outputs noise control signal without adjusting low frequency magnitude, then noise control is simplified, but noise control performance deteriorates due to speaker limitations
Solution Approach 1:
The patent applies feedback by using a microphone to detect the actual noise level and speaker output, then feeding this information back to the controller. The controller compares the detected noise level with the output noise control signal and adjusts the magnitude of low frequency components accordingly, creating a closed-loop system that optimizes noise control performance while accounting for speaker limitations.
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 improves the performance of active noise control by ensuring that the noise control signal's low-frequency components are within the speaker's output range, preventing distortion and maintaining effective noise cancellation.
Implementation Method 1
obtaining an input signal including at least one of a reference signal of an accelerometer
Implementation Method 2
an error signal obtained from a sound signal of a microphone
Implementation Method 3
transmitting the noise control signal so that a speaker outputs the noise control signal
Data Source
AI summary
A sound control device and a method for controlling the sound control device provided in a vehicle. The method comprises obtaining an input signal including at least one of a reference signal of an accelerometer or an error signal obtained from a sound signal of a microphone; adjusting low frequency components of the input signal based on magnitudes of the low frequency components of the input signal and a preset reference magnitude; generating a noise control signal based on the adjusted input signal; and transmitting the noise control signal so that a speaker outputs the noise control signal.