Isobaric Speaker Assembly for Vibration-Canceling Wearable Audio
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Solution Overview
Problem
Speakers mounted on wearable devices like VR or AR headsets generate vibrations that interfere with inertial measurement units, causing inaccurate motion tracking and audio leakage, which existing solutions either impair audio quality or introduce delays.
Innovation Solution
An audio device with a first and second membrane configuration, where the membranes move in opposite directions to maintain isobaric pressure in a shared back volume, canceling vibrations without affecting low-frequency performance or introducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single speaker is mounted on a wearable device to provide audio output, then audio functionality is achieved, but vibration is generated that interferes with IMU signals and causes inaccurate motion tracking
Solution Approach 1:
Two speakers are merged into a single isobaric speaker assembly where their membranes are coupled together and move in unison. This combination allows the back volumes of both speakers to be shared, creating a compact structure that reduces vibration while maintaining audio output functionality.
Solution Approach 2:
The isobaric speaker configuration uses two speakers with membranes moving in opposite directions to counterbalance each other's vibration forces. The shared back volume ensures that pressure changes from one membrane are compensated by the other, effectively canceling out vibration interference with the IMU.
2Power
If speakers with improved low-frequency performance are used, then bass quality is enhanced, but vibration from the speakers increases and audio leakage increases
Solution Approach 1:
The isobaric configuration merges two speakers into a unified system with a shared back volume. This merging allows the system to achieve improved low-frequency response through the combined displacement volume while the coupled membranes move in a way that reduces individual vibration amplitudes and minimizes audio leakage.
Solution Approach 2:
The speakers are configured with their front surfaces facing opposite directions, creating an asymmetric arrangement where the membranes move in opposite directions. This asymmetry in orientation allows the system to maintain strong low-frequency output while the opposing movements cancel out vibration and reduce audio leakage to the sides.
3Object-affected harmful factors
If vibration cancellation is attempted through existing methods, then vibration interference is reduced, but audio quality is impaired or delays are introduced into IMU signal generation
Solution Approach 1:
The isobaric speaker system achieves vibration cancellation through its own inherent design rather than requiring external correction systems. The coupled membranes and shared back volume create a self-balancing mechanism where the speakers naturally counteract each other's vibration, eliminating the need for post-processing that would impair audio quality or introduce delays.
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
Effectively mitigates vibrations that interfere with motion tracking while preserving audio quality and reducing audio leakage, ensuring accurate motion tracking and user privacy.
Implementation Method 1
a shared back volume that is formed in part by the first back surface and the second back surface, with pressure within the shared back volume configured to be isobaric
Implementation Method 2
the membranes move in opposite directions to maintain isobaric pressure in a shared back volume, canceling vibrations
Data Source
AI summary
An audio device includes a first speaker and a second speaker. A front surface of a membrane of the second speaker faces a rear surface of a membrane of the first speaker. The membrane of the first speaker moves in an opposite direction than the membrane of the second speaker when the audio device outputs audio content. This configuration maintains isobaric pressure for a back volume shared between the first speaker and the second speaker, reducing vibration of the audio device when outputting audio content.