Dual Passive Radiators for Loudspeaker Walking Reduction

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Solution Overview

Problem

Conventional loudspeaker systems with a single passive radiator often experience a 'walking' problem due to high momentum forces from internal air pressure fluctuations, leading to unwanted noise and potential safety issues.

Innovation Solution

A passive radiator assembly featuring a pair of passive radiators mounted on opposite sides of a structural frame with a predetermined distance between them, ensuring they do not touch and minimizing vibration, thereby reducing the 'walking' problem while maintaining improved bass performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single passive radiator is used to improve bass performance, then low frequency response is enhanced, but the loudspeaker experiences high momentum forces causing walking and unwanted noise

Engineering Contradiction:
Improvebass performanceVSAvoidwalking and unwanted noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs a second passive radiator as a counterweight to balance the momentum forces generated by the first passive radiator. This dual-radiator configuration creates opposing forces that cancel each other out, eliminating the walking effect and unwanted noise while preserving the bass enhancement benefits

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Object-generated harmful factors

If a second passive radiator is added to counteract walking, then walking is reduced, but the device complexity and space requirements increase

Engineering Contradiction:
Improvewalking reductionVSAvoidnumber of passive radiators
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the two passive radiators into a single integrated assembly where both radiators are mounted on the same structural frame in close proximity. This combining approach achieves the walking reduction benefit while minimizing the increase in device complexity and space occupation compared to using separate radiators

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If passive radiators are mounted close together to save space, then device size is reduced, but the radiators may touch and create unwanted vibrations

Engineering Contradiction:
Improveassembly sizeVSAvoidvibration stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by providing individual mounting structures for each passive radiator on the frame, with specific spacing and positioning designed to prevent contact between the radiators during operation. This localized structural design ensures vibration stability while maintaining a compact overall assembly size

Inventive Principle:
Principle #3Local quality

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 dual passive radiator design significantly reduces the loudspeaker's movement, eliminating the 'walking' issue and enhancing bass performance without increasing the speaker's size or exposing the radiators, while allowing for a more compact and aesthetically pleasing design.

Implementation Method 1

the internal air pressure fluctuations caused by the movement of the driving speaker causes the passive radiator to begin moving forward / backward as if it was also a driven speaker

Methodology Applied
Scientific EffectAcoustic radiation pressure: Acoustic Radiation Pressure

Implementation Method 2

When the passive radiator moves, it creates sound frequencies just as a normal driver does

Methodology Applied
Scientific EffectSound wave generation: Sound

Data Source

PatentEP3278569B1Passive radiator assembly
Publication Date: 2021.09.22 HARMAN INT IND INC
  • EP3278569B1 patent drawingFigure 1~2
  • EP3278569B1 patent drawingFigure 3~4
  • EP3278569B1 patent drawingFigure 5~6

AI summary

A passive radiator assembly for a loudspeaker system comprising: a pair of passive radiators including a first and a second passive radiator; a frame having a first, a second and a third opening wherein the first and second opening are located on parallel sides of the frame, respectively, wherein the first and the second passive radiator are mounted into the first and second opening of the parallel sides of the frame, respectively, so as to oppose each other at a predetermined distance.