Dual Compression Driver With Shared Magnet for Acoustic Phase Alignment

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Solution Overview

Problem

Dual compression drivers are costly due to the necessity of using two expensive neodymium magnets for two motor assemblies, and there is a need to minimize time delay and unwanted combing effects between diaphragms.

Innovation Solution

A dual compression driver design utilizing a single shared annular magnet between two driver assemblies, with specialized configurations of diaphragms and phasing plugs to minimize time delay and prevent combing effects, while maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If two separate motor assemblies with two neodymium magnets are used in a dual compression driver, then each diaphragm can be driven independently with sufficient force, but the cost of the driver increases significantly

Engineering Contradiction:

Improvedriving force for each diaphragmVSAvoidmanufacturing cost

Core Design Contradiction:

ForceVSEase of manufacture

Solution Approach 1:

The patent combines two separate motor assemblies into a single shared motor assembly where one neodymium magnet serves both diaphragms. The first and second voice coils are positioned on opposite sides of the shared magnet, allowing a single magnet to provide the necessary magnetic field for both diaphragms, thereby reducing material costs while maintaining independent driving capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared neodymium magnet performs multiple functions by serving as the magnetic source for both the first and second voice coils simultaneously. This multi-functional design allows one magnet to replace what would traditionally require two separate magnets, reducing overall component count and manufacturing cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Force

If two separate motor assemblies are used, then each diaphragm receives adequate magnetic field strength, but the device complexity and component count increase

Engineering Contradiction:

Improvemagnetic field strength for voice coilsVSAvoidnumber of motor assemblies

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent merges two separate motor assemblies into one unified assembly where the shared magnet and single coil assembly structure provide the magnetic field for both diaphragms. This integration reduces the number of discrete motor assembly components while ensuring adequate magnetic field strength is maintained for both voice coils through proper geometric positioning.

Inventive Principle:

Principle #5Merging (Combining)

3Loss of time

If the phasing plugs are positioned adjacent to each other with short acoustic pathways, then the time delay between diaphragm exits is minimized preventing combing effects, but the acoustic pathway length is reduced

Engineering Contradiction:

Improvetime delay between acoustic signalsVSAvoidacoustic pathway length

Core Design Contradiction:

Loss of timeVSLength of stationary object

Solution Approach 1:

The patent employs asymmetric acoustic pathway design where the first and second acoustic pathways are configured to converge at an offset location rather than meeting symmetrically at the center. This asymmetric convergence allows the pathways to be of different lengths while still achieving minimal time delay, as the shorter pathway compensates for the longer one, maintaining phase coherence without requiring equal path lengths.

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

Significantly reduces costs by using a single magnet and maintains high-frequency extension, lower moving mass, increased dynamic range, and reduced distortion, without sacrificing acoustic performance.

Implementation Method 1

a shared annular magnet disposed between the first driver assembly and the second driver assembly

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

dual compression driver includes two annular diaphragms... the diaphragms radiate through two acoustic chambers

Methodology Applied

Scientific EffectAcoustic compression: Compression

Data Source

PatentUS20250234134A1Dual compression driver with single magnet

Publication Date: 2025.07.17 HARMAN PROFESSIONAL INC

AI summary

A dual compression driver includes a first driver assembly having a first annular diaphragm disposed about a central axis and a first phasing plug disposed coaxially below the first annular diaphragm with a first plurality of apertures extending therethrough, and a second driver assembly having a second annular diaphragm disposed about the central axis and a second phasing plug disposed coaxially above the second annular diaphragm with a second plurality of apertures extending therethrough. A shared annular magnet is disposed between the first driver assembly and the second driver assembly. A back cover is mounted to the first phasing plug, and a front adapter is mounted to the second phasing plug and includes a hollow conduit formed therein defining a circular exit of the dual compression driver. Acoustic signals from the first and second pluralities of apertures merge and radiate through the hollow conduit to the circular exit.