Speaker Output Correction with Vibration Feedback for Low-Frequency Sound

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Solution Overview

Problem

Existing speaker technologies face challenges in accurately correcting output characteristics without physical enlargement, especially for low-frequency reproduction, and fail to adapt to aging-related changes in transfer characteristics.

Innovation Solution

A speaker output characteristic correction system that includes a filter, a transfer characteristic setting unit, and a displacement detection unit to dynamically adjust and update the filter transfer characteristic based on speaker vibration displacement and impedance, ensuring accurate alignment with target acoustic signal characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the diameter of the speaker is increased to increase the fundamental sound pressure level of low-frequency output, then the low-frequency sound pressure level is improved, but the size, weight, and cost of the speaker increase

Engineering Contradiction:

Improvelow-frequency sound pressure levelVSAvoidspeaker weight

Core Design Contradiction:

Stress or pressureVSWeight of moving object

Solution Approach 1:

The patent applies parameter changes by using digital signal processing to modify the electrical parameters (filter transfer characteristics) rather than physical parameters (speaker diameter). The system calculates inverse transfer characteristics and convolutes them with audio signals to achieve the desired sound pressure level increase without physically enlarging the speaker components.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical approach (enlarging speaker diameter) with an electrical/digital approach (applying filter transfer characteristics to audio signals). By substituting mechanical modification with signal processing, the system achieves the same acoustic effect without increasing physical size or weight.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stress or pressure

Engineering Contradiction:

Improvelow-frequency sound pressure levelVSAvoidspeaker cost

Core Design Contradiction:

Stress or pressureVSEase of manufacture

Solution Approach 1:

The patent changes the approach from physical parameter modification (larger components) to digital parameter modification (filter characteristics). This allows achieving the desired acoustic performance through software-based signal processing rather than expensive hardware upgrades, thereby reducing manufacturing cost.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes mechanical/hardware solutions with electrical/software solutions. Instead of manufacturing larger, more expensive speaker components, the system uses digital signal processing to achieve the same effect, significantly reducing production costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If inverse characteristics are calculated using pre-experiment methods with microphones, then the transfer characteristics can be corrected, but the accuracy for each speaker with different characteristics or errors cannot be achieved and aging-related changes cannot be coped with

Engineering Contradiction:

Improvetransfer characteristic accuracyVSAvoidadaptability to individual speaker variations and aging

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by continuously monitoring the actual speaker response and using this information to calculate and update the filter transfer characteristics. The system measures the actual transfer characteristic of each speaker and adjusts the correction parameters accordingly, ensuring high accuracy for individual speakers and adapting to aging-related changes over time.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making the filter transfer characteristics adjustable and updateable rather than fixed. The system can dynamically recalculate the inverse transfer characteristics based on actual speaker performance, allowing it to adapt to individual speaker variations and aging-related changes without requiring physical reconfiguration.

Inventive Principle:

Principle #15Dynamics

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 system enables precise correction of speaker output characteristics to match actual transfer characteristics, enhancing low-frequency sound pressure without physical enlargement and adapting to age-related changes, ensuring high accuracy and improved performance.

Implementation Method 1

a voice coil 205 and a magnetic flux generating unit 221 configured to generate the magnetic flux. The displacement detection unit 7 is configured to detect a displacement of a vibration of the speaker 2

Methodology Applied

Scientific EffectElectromagnetic interaction: Lorentz Force

Data Source

PatentEP4586642A1Speaker output characteristic correction system and acoustic system

Publication Date: 2025.07.16 ALPS ALPINE CO LTD

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Figure 2A~2B
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AI summary

A speaker output characteristic correction system for correcting an output characteristic of a speaker with respect to an audio signal output from a sound source device, includes a filter configured to supply to the speaker an output obtained by applying a set filter transfer characteristic to the audio signal output from the sound source device, a transfer characteristic setting unit configured to set a filter transfer characteristic of the filter, and a displacement detection unit configured to detect a displacement of a vibration of the speaker.