Audio Signal Correction for Transducer Frequency Matching

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Solution Overview

Problem

Existing audio systems suffer from distortions due to the nonlinearity and internal resonances of electroacoustic transducers, particularly in loudspeakers, leading to discrepancies in amplitude-frequency characteristics between sound recording and reproduction, which affect the fidelity of acoustic signals.

Innovation Solution

A method of correcting audio signals using the formula CAS \( t = AS(t) + B \int AS(t) dt + C \frac{dAS(t)}{dt} \), where coefficients B and C are optimized to align the amplitude-frequency characteristics of the sound reproducing transducer with the original source, effectively correcting the audio signal before transmission to the electroacoustic transducer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional audio signal transmission is used without correction, then the system is simple and easy to implement, but the sonic fidelity is poor due to distortions from nonlinearity, internal resonances, and frequency variations

Engineering Contradiction:
Improvesonic fidelityVSAvoidsignal correction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-processing the audio signal with correction coefficients before transmission to the electroacoustic transducer. The correction formula CAS(t) = AS(t) + B ∫AS(t)dt + C dAS(t)/dt is applied in advance to compensate for anticipated distortions, allowing the system to achieve high sonic fidelity without adding complex correction hardware at the reproduction stage

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameters of the audio signal by applying mathematical operations (integration and differentiation) with optimized coefficients B and C. These parameter transformations modify the signal characteristics to counteract the nonlinearities and resonances of the transducer, improving sonic fidelity while maintaining system simplicity

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the audio signal is corrected using the formula CAS(t) = AS(t) + B ∫AS(t) dt + C dAS(t)/dt, then the amplitude-frequency characteristics are improved and sonic fidelity is enhanced, but the processing complexity increases

Engineering Contradiction:
Improveamplitude-frequency characteristic accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or hardware-based correction systems with mathematical signal processing. Instead of using additional physical components to correct amplitude-frequency characteristics, the invention uses digital or analog mathematical operations (integration and differentiation) to achieve the same effect with simpler implementation

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

Solution Approach 2:

The patent optimizes the parameters B and C in the correction formula to achieve accurate amplitude-frequency characteristics. By carefully selecting these parameters, the system achieves high manufacturing precision in signal correction while keeping the processing complexity manageable through a unified mathematical approach

Inventive Principle:
Principle #35Parameter changes

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 method significantly enhances the fidelity of acoustic signal reproduction across various types of electroacoustic transducers, including electromagnetic and magnetoelectric dynamic transducers, by aligning the amplitude-frequency characteristics, resulting in high-fidelity sound reproduction.

Implementation Method 1

an electric current of a current intensity I variable in a manner representing an acoustic signal (therefore the electric current constitutes an audio signal) is flowed through a coil of the total length L of its conductor wire, wherein the coil is fixedly coupled with the transducer membrane and located in a strong magnetic filed of magnetic induction B. The flow of the electric current I induces force F acting upon the coil (and thus also upon the membrane) and having the value defined by the formula: F = l x L x B

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 2

for a conversion of an acoustic pressure (a sound) into an electric signal (generated for example in a microphone and an electric guitar pickup and the like), electroacoustic transducers are used

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3890347B1A method of an audio signal correction
Publication Date: 2026.04.29 YAYUMA AUDIO
  • EP3890347B1 patent drawingFigure 1~3
  • EP3890347B1 patent drawingFigure 4~6
  • EP3890347B1 patent drawingFigure 7~9

AI summary

A method for modifying an audio signal (AS) for an audio system with an electroacoustic sound recording transducer (r) with a membrane, with an electroacoustic sound reproducing transducer (u) with a membrane, wherein the audio signal (AS) is modified by adding an integral part and a derivative part to the audio signal (AS), resulting in a corrected audio signal (CAS), the method comprising the steps of: - adapting coefficients B and C as such that the amplitude-frequency transmission characteristic (trans. u) of the membrane velocity of the sound reproducing transducer (u) subjected to the corrected audio signal (CAS) has a shape that is similar to or identical as the shape of the amplitude-frequency transmission characteristic (trans. r) of the membrane velocity of the sound recording transducer (r) subjected to the audio signal (AS), wherein coefficient B amounts from -10 to 0 and wherein coefficient C amounts from 0 to 0.04.