Earbud Acoustic Path Layout for Echo-Resistant Audio Capture
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Solution Overview
Problem
Wearable devices with integrated speakers and microphones suffer from poor sound performance and excessive echo due to conventional arrangements that fail to manage sound waves effectively, particularly when worn on the ear.
Innovation Solution
A wearable device design featuring a housing with a protrusion insertable into the ear, including a first sound path for the speaker and a second sound path for the microphone, where the microphone is spaced further away from the surface than the speaker, and the paths are asymmetrical and of varying lengths, with the second path having a resonance point in the 1kHz to 4kHz bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a speaker and microphone are arranged in parallel in a compact housing, then the device can be manufactured in compact size, but sound performance deteriorates and echo increases
Solution Approach 1:
The housing is divided into multiple sound paths (first sound path for speaker, second sound path for microphone) with different lengths and configurations. This segmentation allows each component to have its own optimized acoustic path, improving sound performance while maintaining compact overall device size.
Solution Approach 2:
The patent employs asymmetric sound path design where the first sound path and second sound path have different lengths and geometries. The protrusion structure creates asymmetric acoustic chambers that optimize sound wave propagation for each component, preventing echo and improving audio quality in the compact form factor.
2Device complexity
If sound components are arranged simply in parallel, then device complexity is reduced and manufacturing is easier, but sound wave management becomes ineffective causing poor sound performance
Solution Approach 1:
Instead of a simple parallel arrangement, the patent segments the acoustic space into distinct first and second sound paths with different lengths. The protrusion structure further divides the housing into separate acoustic chambers, creating an effective sound wave management system that maintains reasonable manufacturing complexity.
Solution Approach 2:
The patent introduces a third dimension by creating a protrusion that extends from the housing surface. This dimensional addition creates separate acoustic paths without significantly increasing overall device complexity, allowing effective sound wave management through spatial differentiation.
3Device complexity
If the microphone is placed close to the housing surface, then the device structure is simplified, but reflected sound waves are excessively collected causing echo and voice deterioration
Solution Approach 1:
The housing structure is segmented to create a second sound path that is physically separated from the first sound path. The protrusion structure divides the acoustic space, preventing reflected sound waves from the speaker from being excessively collected by the microphone, thereby reducing echo while maintaining structural simplicity.
Solution Approach 2:
The protrusion structure acts as an intermediary acoustic element that separates the speaker and microphone paths. It creates distinct acoustic chambers that prevent direct coupling of reflected sound waves between the two components, reducing echo without requiring complex additional structures.
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
Enhances sound performance by managing sound waves more effectively, reducing echo, and improving mass-producibility and usability of the device.
Implementation Method 1
the second sound path including a third opening formed through another area of the surface of the protrusion, extending from the third opening in a second length larger than the first length, and including a fourth opening facing the microphone, wherein the first opening is projected externally in a first direction from a top surface of the protrusion in order to form a step with respect to the third opening
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
Certain embodiments of the disclosure relate to microphone-equipped wearable devices, and more particularly, to wearable devices worn on users' ear. According to certain embodiments of the disclosure, a wearable device comprises a speaker, a microphone, and a housing, the housing includes a protrusion configured to be insertable into a user's ear, a first sound path including a first opening formed through an area of a surface of the protrusion, extending from the first opening in a first length, and including a second opening facing the speaker, and a second sound path including a third opening formed through another area of the surface of the protrusion, extending from the third opening in a second length larger than the first length, and including a fourth opening facing the microphone. Other certain embodiments are also possible.