Ear Canal Response Correction for Personalized Earbud Sound
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Solution Overview
Problem
Conventional earbuds use a one-size-fits-all approach to sound calibration, failing to account for the unique ear anatomy and eardrum acoustic impedances of individual users, leading to unsuitable sound characteristics.
Innovation Solution
A computer-implemented method that uses internal microphones of the earbud to measure and characterize the user's ear canal behavior, predicting the acoustic response at the eardrum without direct measurement, and applying ear canal response correction to tailor sound quality based on individual ear properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a one-size-fits-all calibration approach using an ear simulator is used, then manufacturing complexity is reduced and production is simplified, but sound quality and acoustic performance become unsuitable for individual users with varying ear characteristics
Solution Approach 1:
The system performs preliminary measurement of the user's ear canal characteristics during initial use or setup. The microphone captures the acoustic response of the user's ear canal to test signals, and the processor stores these characteristics for later use in personalizing audio output, eliminating the need for complex per-user manual calibration.
Solution Approach 2:
The system uses feedback from the microphone measurement to dynamically adjust the audio output. The processor compares the measured ear canal response against reference data and applies compensation filters to personalize the sound, creating a closed-loop system that adapts to individual user characteristics.
2Measurement precision
If direct measurement of eardrum response is implemented, then measurement precision of acoustic response is improved, but device complexity increases due to additional sensors and measurement requirements
Solution Approach 1:
The system uses the ear canal acoustic response as an intermediary measurement to infer eardrum characteristics. Instead of directly measuring eardrum response, the microphone captures the acoustic field in the ear canal, and the processor uses transfer function modeling to predict eardrum behavior from these indirect measurements.
Solution Approach 2:
The system creates a computational model (copy) of the eardrum response based on ear canal measurements. The processor uses the measured ear canal transfer function to simulate and predict what the eardrum response would be, avoiding the need for direct eardrum sensing while maintaining measurement accuracy.
3Measurement precision
If additional microphones or sensors are placed on the eardrum for measurement, then measurement precision is improved, but ease of operation and user comfort deteriorate due to invasive placement requirements
Solution Approach 1:
The system uses the existing internal microphone, which serves multiple functions including active noise cancellation and acoustic measurement, to also measure ear canal characteristics for personalization. This multi-functional use of the microphone eliminates the need for additional dedicated measurement sensors that would compromise comfort.
4Adaptability or versatility
If individualized ear canal characterization is implemented, then sound quality and acoustic performance are improved, but processing complexity increases due to custom calculations for each user
Solution Approach 1:
The system characterizes individual ear canals by measuring changes in acoustic parameters (transfer function, impedance) and uses these parameter variations to personalize the audio output. The processor adjusts equalization parameters and compensation filters based on the measured deviations from reference ear characteristics.
Solution Approach 2:
The system extracts the essential ear canal characteristics (transfer function, resonant frequencies, impedance profile) from the full acoustic measurement and uses only these extracted parameters for personalization calculations, reducing processing complexity while maintaining personalization accuracy.
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
Customizes sound output to match individual ear anatomy, improving timbre, spatial audio quality, and active noise cancellation performance without requiring direct eardrum measurement or additional sensors.
Implementation Method 1
driving an audio output device to reproduce a stimulus signal when a wearable device is placed along an ear canal of a user
Implementation Method 2
receiving a sound signal from a microphone based on the stimulus signal
Data Source
AI summary
Various embodiments disclose a computer-implemented method that can include driving an audio output device to reproduce a stimulus signal when a wearable device is placed along an ear canal of a user, receiving a sound signal from a microphone based on the stimulus signal, and determining, based on the sound signal and a calculated response of the microphone retrieved from a memory, one or more characteristics of the ear canal of the user, wherein the one or more characteristics of the ear canal comprises an ear canal impedance, and applying, based on the one or more characteristics of the ear canal, an ear canal response correction to an output signal played back by the audio output device.