Speaker Supply Circuit Resonance Filtering for Current Drive

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Solution Overview

Problem

Current loudspeaker current driving methods suffer from uncorrected resonance peaks and increased acoustic levels in high frequencies, which are not effectively addressed by existing solutions, particularly in current control systems where voltage control provides natural damping but requires specific adaptations.

Innovation Solution

A circuit with a device for filtering resonance peaks using a dead resistor associated with a parallel RLC impedance in the instrumentation ground circuit or feedback loop, allowing for electronic correction of resonance peaks without altering the current control mechanism, and incorporating virtual inductors for adaptive impedance adjustment to compensate for temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If current control is used to drive the loudspeaker, then the advantages of current control are maintained, but resonance peaks are not corrected and high-frequency acoustic levels increase

Engineering Contradiction:
Improvecurrent control operationVSAvoidresonance peaks and high-frequency acoustic levels
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

A filtering device is introduced as an intermediary element in the electrical circuit between the power supply and the loudspeaker. This device includes a resistor connected in series with a parallel RLC circuit (comprising inductor Lb, capacitor Cb, and resistor Rb), which acts as a mediator to selectively attenuate resonance frequencies while allowing the current control system to operate without modification

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The filtering device changes the electrical parameters (impedance, resistance, inductance, capacitance) at specific frequency ranges to suppress resonance peaks. By adjusting the parameters of Lb, Cb, Rb, and the series resistor, the system modifies the electrical characteristics to counteract the mechanical resonance of the loudspeaker without affecting the overall current control mechanism

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If voltage control is used, then resonance peaks are naturally damped, but specific adaptations are required that complicate the system

Engineering Contradiction:
Improveresonance peak dampingVSAvoidsystem complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

Instead of using voltage control to damp resonance (which requires complex adaptations), the invention inverts the approach by using a passive filtering device in the power supply circuit that naturally suppresses resonance through its RLC configuration, achieving voltage-control-like damping benefits while maintaining simple current control architecture

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The filtering device automatically suppresses resonance peaks through its inherent RLC circuit characteristics without requiring active control, feedback mechanisms, or complex adaptations. The parallel RLC circuit self-adjusts to attenuate resonance frequencies based on its natural resonant properties, eliminating the need for additional control complexity

Inventive Principle:
Principle #25Self-service

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

Enables current control with improved sound quality by filtering resonance peaks and reducing high-frequency acoustic levels, maintaining the advantages of current control while avoiding the drawbacks of uncorrected resonance and increased directivity, and allowing for precise correction across varying temperatures.

Implementation Method 1

filtering device for the resonance peak of said at least one loudspeaker HP occurring at a certain frequency

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

impedance incorporated either in said first instrumentation ground circuit or in said feedback loop, the impedance parameters being predetermined according to the resonance peak

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Impedance Tomography

Implementation Method 3

a filtering device for the resonance peak... in the form of an impedance... comprising at least a first resistor

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

parallel RLC impedance comprising at least a first resistor, at least a first inductor and at least a first capacitor

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 5

parallel RLC impedance comprising at least a first resistor, at least a first inductor and at least a first capacitor arranged in parallel

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3249949B1Device and method for filtering the resonance peak in the power supply circuit of at least one speaker
Publication Date: 2019.09.04 UNIVERSITE DU MAINE
  • EP3249949B1 patent drawingFigure 1~2
  • EP3249949B1 patent drawingFigure 3~4
  • EP3249949B1 patent drawingFigure 5~5a

AI summary

The present invention relates to a circuit for supplying acoustic signals to at least one loudspeaker (HP) incorporating a device for filtering the resonance peak of said at least one loudspeaker (HP) occurring at a given frequency, characterized in that the device for filtering the resonance peak of said at least one loudspeaker (HP) is incorporated either in the first instrumentation ground circuit or either in the return loop, this filtering device being purely electrical under the form of an impedance incorporated in the first instrumentation ground circuit or in the return loop, the parameters of the impedance being predetermined according to the resonance peak to be filtered from said at least one loudspeaker (HP).