Headphone Equalization Using Impedance Detection and Auto Matching

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Solution Overview

Problem

Existing audio signal processing technologies fail to effectively improve audio quality for a wide variety of sound transducers, such as headphones, due to poor matching between devices and headphones, leading to suboptimal frequency responses and user dissatisfaction.

Innovation Solution

An apparatus and method for processing audio signals that includes an equalization parameter determinator to identify sound transducers using image recognition or impedance measurement, selecting appropriate equalization parameters, and applying them through an equalizer to enhance audio quality, with the option to share settings via a global database for user collaboration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sound transducers are bought separately by customers, then customers have freedom to choose their own equipment, but audio quality degrades due to poor matching between devices and headphones

Engineering Contradiction:

Improvecustomer choice freedomVSAvoidaudio quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system changes the electrical parameters (gain, frequency response) of the audio signal to match the acoustic characteristics of different headphones. By dynamically adjusting signal parameters based on detected headphone impedance characteristics, the system maintains audio quality across various headphone models while preserving customer freedom to choose their own equipment.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from impedance measurements to automatically adjust equalization parameters. The audio device detects headphone characteristics through electrical impedance measurement and uses this feedback to select appropriate equalization settings, creating a closed-loop system that adapts to different headphones without requiring manual customer configuration.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If professional measurement equipment and procedures are used to identify frequency response, then measurement accuracy is high, but complexity and cost increase significantly

Engineering Contradiction:

Improvefrequency response measurement accuracyVSAvoidmeasurement equipment complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical/acoustic measurement equipment (dummy heads, acoustic couplers) with electrical impedance measurement. By substituting electrical measurement for acoustic measurement, the system achieves sufficient measurement precision using simple electrical circuits already present in the audio device, eliminating the need for expensive professional measurement equipment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The audio device performs its own self-characterization by measuring the impedance of connected headphones through its existing audio output circuitry. The device uses its own built-in resources (power amplifier, output circuit) to automatically detect headphone characteristics without requiring external measurement equipment, making the process simple and self-contained.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If equalization parameters are manually selected and adjusted, then user control is maintained, but time and effort are consumed for optimization

Engineering Contradiction:

Improveuser controlVSAvoidtime for parameter optimization

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary automatic equalization by detecting headphone impedance characteristics and pre-selecting appropriate equalization parameters before the user begins listening. This preliminary automatic configuration eliminates the time-consuming manual optimization process while preserving user ability to override or adjust settings if desired.

Inventive Principle:

Principle #10Preliminary action

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 allows for automatic and user-friendly adjustment of audio signals to match the specific characteristics of various sound transducers, significantly improving audio quality and user satisfaction by providing tailored equalization settings.

Implementation Method 1

a sound transducer identification configured to identify a sound transducer using an image recognition

Methodology Applied

Scientific EffectImage recognition: Image Processing

Implementation Method 2

an equalization parameter determinator configured to acquire a set of equalization parameters using a measurement of an impedance of the sound transducer over frequency

Methodology Applied

Scientific EffectImpedance measurement: Electrical Resistance

Data Source

PatentUS11039243B2Apparatus for providing an audio signal for reproduction by a sound transducer, system, method and computer program

Publication Date: 2021.06.15 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An apparatus for processing an audio signal for reproduction by a sound transducer includes 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 include 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.