ANC Earphone Feedback Calibration for User-Specific Noise Reduction
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Solution Overview
Problem
Existing noise reduction earphones fail to meet the individual noise reduction requirements of different users due to varying ear canal feedback, affecting the noise reduction experience.
Innovation Solution
A noise reduction earphone equipped with a memory, speaker, feedback microphone, and processor that performs a calibration process to adjust the low-frequency gain of the feedback microphone based on feedback frequency response differences, ensuring the feedback noise reduction performance matches the target frequency response curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active noise reduction technology is used to emit anti-phase audio signals, then noise reduction effect is improved, but feedback noise reduction performance cannot meet requirements of different users due to varying ear canal feedback
Solution Approach 1:
The system performs preliminary calibration by playing calibration audio signals through the speaker and measuring the actual frequency response curve via the feedback microphone before normal use. This preliminary measurement of the user's specific ear canal characteristics allows the system to pre-adjust the anti-phase signal parameters, ensuring both effective noise reduction and adaptability to that specific user's ear canal feedback characteristics.
Solution Approach 2:
The system dynamically adjusts parameters of the anti-phase noise reduction signal based on the measured actual frequency response curve. By comparing the actual curve with the target frequency response curve, the system modifies signal parameters such as gain and frequency characteristics to match the specific user's ear canal properties, thereby resolving the contradiction between maintaining reliable noise reduction and adapting to different users.
2Device complexity
If fixed frequency response curve is used for noise reduction, then device complexity is reduced, but noise reduction performance varies across different wearing environments and users
Solution Approach 1:
The system automatically performs frequency response calibration by utilizing its own speaker to play calibration signals and its feedback microphone to measure the actual frequency response curve. This self-calibration mechanism eliminates the need for external calibration equipment or complex manual adjustment procedures, maintaining device simplicity while achieving adaptive performance for different users and wearing environments through automated parameter adjustment.
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
Improves feedback noise reduction performance across different wearing environments by adjusting the low-frequency gain to match individual ear canal feedback, enhancing the noise reduction experience for various users.
Implementation Method 1
the feedback microphone is configured to collect a feedback signal corresponding to the sound signal
Implementation Method 2
The method adopted by active noise reduction technology is to emit an audio signal with a similar amplitude and opposite phase to the noise through the speaker in the earphone, thereby reducing the noise heard by a user
Data Source
AI summary
Disclosed is a noise reduction earphone including a memory, a speaker, a feedback microphone and a processor. The memory stores a target frequency response curve and a target frequency response difference corresponding to a sound signal. The feedback microphone collects a feedback signal corresponding to the sound signal. The processor receives a start signal and then performs a calibration process including (a) controlling the speaker to play the sound signal; (b) receiving the feedback signal; (c) generating a feedback frequency response curve based on the feedback signal, and obtaining a feedback frequency response difference between the target frequency response curve and the feedback frequency response curve; (d) adjusting a low-frequency gain of the feedback microphone when the feedback frequency response difference is less than or greater than the target frequency response difference, and returning to (a) until the feedback frequency response difference is equal to the target frequency response difference.