Adaptive Equalization for Earbud Acoustic Barrier Compensation
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Solution Overview
Problem
Audio devices, such as earbuds and headphones, face challenges in maintaining audio quality due to imperfect acoustic barriers that allow environmental noise to penetrate and output audio to leak, affecting both noise cancellation and sound output.
Innovation Solution
An adaptive filter using a least-mean-squares algorithm is employed to minimize error signals between microphone and playback data, generating a transfer function to process audio and compensate for barrier effects, combined with active noise cancellation techniques to enhance sound quality and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an acoustic barrier is used to block environmental noise, then noise cancellation is improved, but sound leakage and degradation of output audio quality occur
Solution Approach 1:
The system uses a microphone to capture the actual audio output and feeds it back to an adaptive filter. The filter compares this feedback with the original playback data and continuously adjusts its transfer function to minimize the difference, thereby compensating for sound leakage and barrier effects in real-time
Solution Approach 2:
The adaptive filter dynamically changes its transfer function parameters based on the captured audio environment. By continuously updating the filter coefficients to minimize the error signal, the system adapts to varying acoustic conditions and compensates for barrier-induced audio degradation
2Object-affected harmful factors
If an acoustic barrier is used to block environmental noise, then noise cancellation is improved, but clarity of incoming audio is degraded
Solution Approach 1:
The microphone captures the composite signal containing both environmental noise and speech. The adaptive filter uses feedback from this captured signal to learn and cancel the barrier-induced noise components, preserving the clarity of the speech component through continuous error minimization
Solution Approach 2:
The adaptive filter extracts and removes the unwanted noise components from the captured audio signal by generating an estimate of the barrier effects and subtracting it from the original signal, thereby isolating and preserving the speech component
3Reliability
If adaptive filtering is used to compensate for barrier effects, then audio quality is improved, but device complexity increases
Solution Approach 1:
The adaptive filter is self-adjusting and automatically updates its transfer function based on real-time feedback from the microphone. The system serves itself by continuously learning the acoustic environment and adapting without external intervention, reducing the need for manual calibration or complex external control systems
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 effectively improves sound quality by reducing noise interference and enhancing the clarity of both incoming and outgoing audio, allowing users to better distinguish speech and hear environmental sounds while using audio devices.
Implementation Method 1
an adaptive filter of an automatic-echo cancellation system is adapted, using an algorithm such as a least-mean-squares ('LMS') algorithm to minimize an error signal that corresponds to a difference between microphone data and playback data
Implementation Method 2
an acoustic barrier when it is in contact with an ear (or other body part) of a user. This barrier may, however, be imperfect; it may, for example, permit sound to penetrate it
Implementation Method 3
combined with active noise cancellation techniques to enhance sound quality and noise reduction
Data Source
AI summary
A system and method includes an audio device, such as an earbud or headphones, that includes one or more loudspeakers for outputting audio. The audio device further in includes one or more microphones that are positioned near an ear of a user. An acoustic barrier may be formed between a surface of the device and the ear of the user; properties of this barrier may, however, vary from user to user. The system determines these properties on a per-user basis and compensates for any differences therein.