Mass Loaded Earbud Vent Chamber Acoustic Isolation

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Solution Overview

Problem

Intra-concha earphones face sound leakage and inconsistent acoustic performance due to not sealing within the ear canal, allowing external sound to interfere with the audio experience and reducing the effectiveness of sound delivery.

Innovation Solution

The design incorporates a housing with a rear space divided into a back volume, a bass duct, and a vent chamber, where the vent chamber is acoustically coupled with both the back volume and the bass duct, and vents to the surrounding environment through a single rear port, utilizing acoustic ports and meshes to control acoustic impedance and enhance sound propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If intra-concha earphones are designed without sealing within the ear canal, then ease of operation and comfort are improved, but sound leakage and acoustic performance consistency deteriorate

Engineering Contradiction:

Improveease of useVSAvoidacoustic performance consistency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The rear space is segmented into multiple functional chambers (back volume, vent chamber, bass duct) separated by chamber partitions. This segmentation allows independent optimization of acoustic pathways while maintaining the non-sealing design for ease of use.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Acoustic meshes are introduced as intermediary elements covering the ports and apertures. These meshes mediate between the need for open design and the requirement for acoustic isolation, providing frequency-dependent filtering while maintaining breathability and comfort.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple ports are used in the rear wall, then acoustic performance is improved, but protection against foreign material intrusion deteriorates

Engineering Contradiction:

Improveacoustic performanceVSAvoidforeign material intrusion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Multiple acoustic pathways (acoustic port, bass duct, vent chamber) are merged into a single rear port opening. This consolidation maintains acoustic performance by allowing sound to travel through different internal pathways while presenting only one external opening, thereby reducing foreign material intrusion risks.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Acoustic meshes serve as intermediary protective elements covering the ports. These meshes allow acoustic energy to pass through while blocking foreign materials, enabling multiple acoustic pathways to coexist with enhanced protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If acoustic impedance is increased at the acoustic port, then sound isolation is improved, but sound propagation effectiveness deteriorates

Engineering Contradiction:

Improvesound isolationVSAvoidsound propagation loss

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Different acoustic impedances are assigned to different ports and apertures based on their specific functional requirements. The acoustic port has higher impedance for isolation, while the vent port maintains lower impedance for effective sound discharge, optimizing both isolation and propagation locally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Acoustic impedance parameters are carefully controlled and optimized for each pathway. By adjusting port dimensions, mesh densities, and chamber volumes, the system achieves appropriate impedance characteristics to balance sound isolation with effective sound propagation through the vent chamber.

Inventive Principle:

Principle #35Parameter changes

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 configuration improves sound isolation and consistency by directing sound through specific acoustic pathways, reducing external interference and allowing for compact packaging while maintaining effective sound delivery and noise control.

Implementation Method 1

a driver that converts an electrical audio signal into a sound

Methodology Applied

Scientific EffectElectromagnetic transduction: Electromagnetic Induction

Implementation Method 2

a first portion of a sound emitted by the driver may propagate through the acoustic port and a second portion of the sound may propagate through the bass duct such that the sound portions meet in the vent chamber

Methodology Applied

Scientific EffectAcoustic propagation: Sound

Data Source

PatentUS11575985B2Mass loaded earbud with vent chamber

Publication Date: 2023.02.07 APPLE INC

AI summary

Intra-concha earphones are disclosed. In an embodiment, an intra-concha earphone includes a housing having a rear space divided into a back volume, a bass duct, and a vent chamber between a driver and a rear wall. The vent chamber may be acoustically coupled with the back volume through both an acoustic port and the bass duct. Furthermore, the vent chamber may be acoustically coupled with a surrounding environment through a vent port, which may be a sole acoustic opening in the rear wall. Thus, sound emitted by the driver may propagate through the acoustic port and the bass duct to meet in the vent chamber before being discharged through the vent port to the surrounding environment. Other embodiments are also described and claimed.