Dipole Speaker Assembly Reducing Room Mode Excitation

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Solution Overview

Problem

Conventional low-frequency speaker designs struggle to accurately reproduce sound in enclosed spaces due to room resonance, uneven sound pressure levels, and excessive sound transmission to adjacent areas, leading to distorted bass and reduced emotional impact.

Innovation Solution

A speaker assembly based on an acoustic dipole design, utilizing a configuration of drivers to direct sound energy towards and away from the listener, reducing energy transmission to sidewalls, ceilings, and floors, while minimizing vibration and acoustic energy coupling to structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional monopole speaker designs are used to reproduce low-frequency sound, then sound energy is radiated uniformly in all directions, but this causes excessive transmission to adjacent spaces and excitation of room modes leading to uneven sound distribution

Engineering Contradiction:

Improvespeaker design simplicityVSAvoidlow-frequency sound transmission to adjacent spaces

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The monopole speaker is segmented into two separate radiating surfaces (front and rear) that function as independent acoustic sources. Each surface radiates sound in opposite directions, creating a dipole configuration that cancels omnidirectional radiation patterns and reduces unwanted sound transmission to adjacent spaces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The speaker design transitions from symmetric omnidirectional radiation (monopole) to asymmetric directional radiation (dipole). The front and rear radiating surfaces create an asymmetric sound field where sound energy is directed forward and backward rather than uniformly in all directions, reducing excitation of room modes and improving sound distribution.

Inventive Principle:

Principle #4Asymmetry

2Use of energy by moving object

If sound volume is increased to improve emotional impact and visceral quality of reproduced sound, then low-frequency sound transmission to adjacent spaces increases, causing disturbance and unpleasant effects

Engineering Contradiction:

Improvesound energy output for emotional impactVSAvoiddisturbance to adjacent property or living spaces

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The dipole configuration creates asymmetric directional radiation that confines low-frequency sound energy to the front and rear directions. This asymmetric sound field prevents uniform omnidirectional transmission, allowing higher volume levels to be achieved without proportionally increasing disturbance to adjacent spaces.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The design converts the potentially harmful omnidirectional radiation pattern into a beneficial directional pattern. The same sound energy that would otherwise transmit uniformly to adjacent spaces is now directed forward and backward, where it can be heard by listeners without causing disturbance to neighboring properties.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If room dimensions and geometry are allowed to naturally distribute low-frequency sound energy, then sound pressure levels vary widely depending on listener position, but this creates tonal unevenness and loss of emotional impact

Engineering Contradiction:

Improvenatural sound distribution in roomVSAvoidsound pressure level uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The dipole speaker creates a controlled asymmetric sound field that overrides the natural symmetric room mode patterns. By directing sound energy forward and backward with a specific radiation pattern, the speaker achieves more uniform sound pressure distribution across the listening area, reducing tonal unevenness caused by room geometry.

Inventive Principle:

Principle #4Asymmetry

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 dipole speaker design enhances sound quality by reducing room mode excitation, minimizing sound transmission to adjacent spaces, and providing faithful low-frequency reproduction, with improved acoustic efficiency and reduced size and weight compared to traditional designs.

Implementation Method 1

A speaker assembly based on an acoustic dipole design, utilizing a configuration of drivers to direct sound energy towards and away from the listener

Methodology Applied

Scientific EffectAcoustic dipole radiation: Sound

Implementation Method 2

direct sound energy towards and away from the listener, reducing energy transmission to sidewalls, ceilings, and floors

Methodology Applied

Scientific EffectPhase cancellation: Interference

Data Source

PatentUS9226061B2Speaker assembly

Publication Date: 2015.12.29 REESE JOHN THEODORE

AI summary

A speaker assembly provides a system for reproducing low frequency sound and for directing the sound generated both toward and away from a listener, or in any direction desired, by use of an acoustic dipole. The speaker assembly beneficially provides a significantly improved low frequency sound quality, while reducing sound and vibration transmitted to an adjacent space via an airborne or structure-borne pathway. The speaker assembly also beneficially provides for a suitable use in a plurality of environments, including, without limitation, an outdoor environment, a residential setting, or a professional application.