Earphone Acoustic Feedback Loop for Sound Quality Consistency
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Solution Overview
Problem
Conventional acoustic signal apparatus, such as earphones, face challenges in providing consistent performance due to variations in individual ear characteristics, leading to inconsistent sound quality and noise leakage.
Innovation Solution
An apparatus comprising a housing with a loudspeaker and a microphone positioned between the loudspeaker and the eardrum, along with a controller that uses detected acoustic signals to provide a control signal for filtering, enabling personalized sound delivery and active noise cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional earphones are used without personalization, then the device complexity is low, but the sound quality consistency across different users deteriorates
Solution Approach 1:
The system performs preliminary measurement of the user's ear canal characteristics using the microphone before actual audio playback. The controller stores these measurements and uses them to pre-adjust the filter settings, ensuring consistent sound quality from the start without requiring real-time adjustments during music playback.
Solution Approach 2:
The microphone captures acoustic signals from the ear canal and feeds them back to the controller. The controller analyzes these feedback signals to determine ear characteristics and automatically adjusts the filter parameters accordingly, creating a closed-loop system that ensures consistent sound quality across different users.
2Measurement precision
If the microphone is positioned between the loudspeaker and eardrum, then the measurement precision of ear characteristics improves, but the device complexity increases due to additional components
Solution Approach 1:
The microphone serves dual purposes: it functions as both a measurement device for capturing ear canal acoustic characteristics and as part of the noise cancellation system. This merging of functions reduces the need for separate dedicated measurement microphones, thereby limiting the increase in device complexity while maintaining high measurement precision.
Solution Approach 2:
The acoustic signal detected by the microphone is used for multiple purposes including determining ear characteristics, active noise cancellation, and potentially speech enhancement. This multi-functionality maximizes the utility of the added microphone component, justifying the increased device complexity by delivering multiple benefits from a single addition.
3Adaptability or versatility
If filtering is applied to adapt to individual ear characteristics, then the adaptability improves, but the processing time increases
Solution Approach 1:
The filter characteristics are determined in advance based on the user's ear measurements taken during initial setup. This preliminary determination allows the system to apply pre-calculated filter settings during actual audio playback, minimizing real-time processing requirements and reducing the perceived time loss while maintaining high adaptability.
Solution Approach 2:
The system adjusts filter parameters based on detected ear characteristics, but these adjustments are made efficiently by modifying only the necessary filter coefficients rather than reprocessing the entire audio signal. This selective parameter change approach maintains adaptability while minimizing processing time and computational overhead.
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 ensures consistent and personalized sound quality by adapting to individual ear characteristics, reducing noise leakage and enhancing user experience through targeted output optimization.
Implementation Method 1
the microphone may be configured to convert the detected acoustic signal into an electrical signal and provide the electrical signal to the controller
Data Source
AI summary
An apparatus, method and computer program, the apparatus including includes a housing configured to be positioned in a user's external ear, a loudspeaker located at a first position within the housing and configured to provide an acoustic signal, a microphone configured to detect an acoustic signal located at a second position within the housing, a filter configured to filter an input signal provided to the loudspeaker; and a controller configured to enable the acoustic signal detected by the microphone to be used to provide a control signal to the filter.