Dual-Speaker Earphone Cavity Layout for Better Sound Isolation

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Solution Overview

Problem

The small internal space and limited weight of earphones result in a small acoustic cavity volume for speaker assemblies, leading to unsatisfactory sound quality.

Innovation Solution

A speaker assembly design featuring a housing assembly with separate accommodating cavities for bone-conduction and air-conduction speakers, where the bone-conduction speaker blocks a communication hole to isolate cavities and includes pressure relief holes, enhancing the acoustic cavity volume and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the internal space of earphones is kept small to maintain portability, then the weight and size are reduced, but the volume of the acoustic cavity is limited which deteriorates sound quality

Engineering Contradiction:

Improveacoustic cavity volumeVSAvoidearphone weight

Core Design Contradiction:

Volume of moving objectVSWeight of moving object

Solution Approach 1:

The housing assembly is divided into multiple accommodating cavities (first accommodating cavity for bone-conduction speaker, second accommodating cavity for air-conduction speaker) separated by partition walls. This segmentation allows each cavity to be optimized for its specific speaker type while collectively maximizing the total acoustic volume within the constrained earphone housing, thereby improving sound quality without increasing overall device size or weight

Inventive Principle:

Principle #1Segmentation

2Volume of moving object

If bone-conduction speaker and air-conduction speaker share the same cavity, then space is utilized efficiently, but interference between the two speakers deteriorates sound quality

Engineering Contradiction:

Improvespace utilizationVSAvoidspeaker interference

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Stress or pressure

If communication hole is provided between cavities for pressure relief, then pressure buildup is reduced, but cavity isolation is compromised which affects bone conduction effectiveness

Engineering Contradiction:

Improvepressure reliefVSAvoidcavity isolation

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

A communication hole is provided in the partition wall between the first and second accommodating cavities. This intermediary structure allows controlled pressure equalization between the two cavities while maintaining their physical separation and acoustic isolation, thus preventing pressure buildup that would affect bone conduction effectiveness without compromising cavity isolation

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This design improves sound quality by enlarging the acoustic cavity volume, ensuring a closed environment for bone-conduction and reducing interference, while maintaining structural reliability and assembly convenience.

Implementation Method 1

The bone-conduction speaker has a first central axis and is configured to generate a vibration in a direction of the first central axis

Methodology Applied

Scientific EffectBone conduction: Vibration

Implementation Method 2

The air-conduction speaker has a second central axis and is configured to generate a vibration in a direction of the second central axis

Methodology Applied

Scientific EffectAir conduction: Sound

Data Source

PatentEP4704437A1Loudspeaker assembly and earphone

Publication Date: 2026.03.04 SHENZHEN SHOKZ CO LTD

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AI summary

Provided are a speaker assembly (10) and an earphone (1). The speaker assembly (10) includes a housing assembly (100), a bone-conduction speaker (200), and an air-conduction speaker (300). The housing assembly (100) is provided with a first accommodating cavity (111), a second accommodating cavity (112), and a communication hole (113) connecting the first accommodating cavity (111) and the second accommodating cavity (112). The bone-conduction speaker (200) is disposed in the first accommodating cavity (111) and blocks the communication hole (113) to isolate the first accommodating cavity (111) from the second accommodating cavity (112). The air-conduction speaker (300) is disposed in the second accommodating cavity (112). The present disclosure can simply and effectively enlarge a volume of an acoustic cavity formed in an internal space of the speaker assembly (10), thereby improving the sound quality effect of the speaker assembly (10).