Headphone Equalization Using Ear-Cavity Sound Pressure Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing headphones fail to provide personalized equalization that adapts to the unique characteristics of individual users' ears, leading to variability in sound quality due to differences in ear shape, size, and positioning.
Innovation Solution
A headphone system that includes a microphone to measure sound pressure levels inside the cavity formed by the headphone and the user's ear, using real-time digital signal processing to apply personalized equalization based on a pre-determined target frequency response, compensating for electro-acoustic system resonances and acoustical leakages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard headphone equalization is used, then device complexity is minimized, but sound quality varies due to individual ear characteristics
Solution Approach 1:
The system performs preliminary measurements of the user's ear canal acoustics before audio playback using test signals. This preliminary characterization of individual ear characteristics allows the equalization filter to be customized in advance, ensuring consistent sound quality from the first use without requiring complex real-time adjustments during playback.
Solution Approach 2:
The system uses a microphone to measure the actual sound pressure levels in the user's ear canal and compares these measurements against target frequency responses. This feedback loop enables the system to automatically adjust and optimize the equalization filter parameters to match the user's specific ear anatomy, achieving personalized sound quality.
2Manufacturing precision
If personalized equalization measurements are implemented, then sound quality is improved, but measurement precision requirements increase
Solution Approach 1:
The system introduces a microphone as an intermediary measurement device placed within the ear canal to directly capture sound pressure levels. This intermediary sensor enables precise measurement of the actual acoustic environment in the user's ear, providing accurate data for equalization optimization without requiring complex external measurement equipment.
Solution Approach 2:
The system replaces complex mechanical measurement setups with electronic sound pressure level measurements using a microphone and digital signal processing. This substitution allows for precise, automated measurements of frequency response characteristics without requiring manual calibration or complex mechanical reference standards.
3Adaptability or versatility
If real-time signal processing is applied, then adaptability to individual ears is improved, but processing time and computational requirements increase
Solution Approach 1:
The system performs the computationally intensive measurement and analysis operations in advance during an initialization phase. By completing the ear characterization and filter design before regular audio playback, the system minimizes processing time during actual use while still achieving personalized equalization.
Solution Approach 2:
The system implements a dynamic equalization approach where the full measurement and optimization process occurs during an initial setup phase, and then the finalized filter is applied continuously during normal playback. This dynamic strategy allows for comprehensive adaptation when needed while maintaining efficient operation during standard use.
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 sound quality by providing customized equalization that enhances bass reproduction and sound balance, while reducing acoustical leakages and resonances, resulting in a tailored audio experience for each user.
Implementation Method 1
obtain a measurement of sound pressure level at a microphone mounted in a near field of a headphone driver of the headphone and inside a cavity formed by the headphone and a user's ear
Implementation Method 2
compensating for electro-acoustic system resonances and acoustical leakages
Implementation Method 3
using real-time digital signal processing to apply personalized equalization based on a pre-determined target frequency response
Data Source
Figure 1
Figure 2
Figure 3
AI summary
One embodiment provides a method of personalized headphone equalization system for a headphone. The method comprises obtaining a measurement of sound pressure level at a microphone mounted in a near field of a headphone driver of the headphone and inside a cavity formed by the headphone and a user's ear. The method further comprises providing personalized equalization (EQ) of output reproduced via a headphone driver by performing EQ correction of the output based on the measurement of sound pressure level and a pre-determined target frequency response for the headphone, resulting in an equalized output that is adapted to individual characteristics of the user's ear.