Headphone Equalization Using Automatic Impedance Identification

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Solution Overview

Problem

Existing audio signal processing technologies fail to consistently improve audio quality across a wide variety of sound transducers, such as headphones, due to limitations in identifying and adapting to specific headphone models, leading to suboptimal frequency responses and user dissatisfaction.

Innovation Solution

An apparatus and method that uses image recognition, impedance measurement, and spread spectrum identification to automatically determine equalization parameters for sound transducers, allowing for user-friendly adjustment and improved audio quality without requiring manual selection from a long list of headphone models.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual selection of equalization parameters from a long list of headphone models is used, then precise equalization can be achieved, but user operation becomes complex and time-consuming

Engineering Contradiction:
Improveequalization precisionVSAvoiduser operation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs automatic headphone identification and equalization parameter selection without requiring user intervention. The apparatus autonomously detects headphone impedance characteristics, matches them with stored reference data, and applies appropriate equalization filters, eliminating the need for manual model selection while maintaining precise equalization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes equalization parameters dynamically based on detected headphone characteristics. By measuring impedance across different frequencies and comparing with reference data, the system automatically adjusts equalization parameters to match the specific headphone model, achieving precise equalization without manual input.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If automatic headphone identification is implemented, then ease of operation is improved, but device complexity increases due to additional identification components

Engineering Contradiction:
Improveautomatic identificationVSAvoidapparatus complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The audio output apparatus performs multiple functions using existing components: it outputs audio signals, measures impedance characteristics, identifies headphone models, and applies equalization. By making the apparatus multi-functional, no additional dedicated identification hardware is needed, reducing overall device complexity while enabling automatic identification.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses impedance measurement as an intermediary to identify headphone models. Instead of requiring direct communication protocols or complex identification circuits in the headphones, the apparatus measures electrical impedance characteristics that naturally differ between headphone models, using this intermediate physical property for identification.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If impedance measurement over frequency is used for identification, then identification accuracy is improved, but measurement time and energy consumption increase

Engineering Contradiction:
Improveidentification accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Reference impedance data for multiple headphone models is pre-measured and stored in the apparatus before actual use. During operation, the system only needs to measure the current headphone's impedance and compare it against the pre-existing reference data, significantly reducing measurement time while maintaining high identification accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system replaces complex mechanical or optical identification methods with electrical impedance measurement. By substituting physical identification mechanisms with electrical property analysis, the system achieves accurate identification more quickly and with lower energy consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If equalization parameters are optimized for specific headphone models, then audio quality is improved, but adaptability to different headphone types decreases

Engineering Contradiction:
Improveaudio qualityVSAvoidheadphone compatibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts equalization parameters based on the detected headphone model. Instead of using fixed equalization settings, the apparatus measures impedance characteristics, identifies the specific headphone model, and then applies model-specific equalization parameters, achieving both high audio quality and broad adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system segments the equalization process into distinct steps: impedance measurement, model identification, and parameter selection. By dividing the equalization into segments tailored to each headphone model, the system provides optimized audio quality for each specific type while maintaining versatility across different models.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2817977B1Apparatus for providing an audio signal for reproduction by a sound transducer, system, method and computer program
Publication Date: 2019.12.18 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2817977B1 patent drawingFigure 1
  • EP2817977B1 patent drawingFigure 2
  • EP2817977B1 patent drawingFigure 3

AI summary

An apparatus for processing an audio signal for reproduction by a sound transducer comprises an equalization parameter determinator for determining a set of equalization parameters and an equalizer configured to equalize an input audio signal, to obtain an equalized audio signal. Different concepts for the determination of the set of equalization parameters comprise an image recognition, an evaluation of an identification signal which is provided by the sound transducer via an audio connection, and a measurement of the impedance of the sound transducer over frequency. Also, an upload functionality and a download functionality are provided.