Bidirectional Pressure Port for In-Ear Audio Impedance Management
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Solution Overview
Problem
Conventional in-ear audio devices cause ear fatigue and potential hearing damage due to increased tympanic membrane excursions and impedance mismatch, which are not effectively addressed by existing pressure relief methods such as external vents or additional pressure management materials, and often result in sound degradation and frequency response distortions.
Innovation Solution
An in-ear audio device design featuring a bidirectional pressure channel that allows indirect fluid communication between the speaker's front and back sides, reducing pneumatic pressure without external vents or additional materials, and utilizing multiple sound channels to modify frequency response without introducing phase or distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ear canal is sealed with an earphone to reduce ambient sounds, then ambient noise reduction is improved, but impedance mismatch and audio degradation occur
Solution Approach 1:
The patent divides the sealed ear canal system into multiple independent acoustic channels: a first acoustic channel for delivering audio signals from the speaker to the ear drum, and a second acoustic channel for pressure equalization between the speaker front and back sides. This segmentation allows the audio signal path to remain sealed for noise reduction while providing a separate path for pressure management, thereby maintaining audio quality without compromising ambient noise reduction.
2Object-affected harmful factors
If a sealed design is used to reduce ambient sounds, then ambient noise reduction is improved, but pneumatic pressure on the speaker increases
Solution Approach 1:
The patent introduces a second acoustic channel as an intermediary path that connects the front and back sides of the speaker. This intermediary channel allows pneumatic pressure to be equalized between the two sides of the speaker diaphragm, reducing the net pneumatic pressure stress on the speaker while maintaining the sealed design for ambient noise reduction. The second channel acts as a pressure relief pathway without interfering with the primary audio signal transmission.
3Stress or pressure
If a pressure port is opened to the external environment to relieve pneumatic pressure, then pneumatic pressure reduction is improved, but sound quality and resonance are affected
Solution Approach 1:
The patent creates a localized pressure equalization pathway through the second acoustic channel that is spatially distinct from the primary audio signal path. The second channel is positioned and configured to provide pressure relief specifically at the speaker level, allowing pneumatic pressure reduction without opening the main ear canal seal. This localized approach maintains sound quality by keeping the primary audio channel sealed while providing pressure management in a specific local region around the speaker.
4Reliability
If elastic membranes are used to modify earphone impedance, then impedance matching is improved, but latency problems and material degradation occur
Solution Approach 1:
The patent replaces the mechanical elastic membrane system with an acoustic channel-based impedance management system. Instead of relying on the elastic properties of materials that can degrade and cause latency, the invention uses the acoustic impedance characteristics of the second channel to provide impedance matching. This substitution eliminates material degradation issues and reduces latency by using a passive acoustic pathway rather than a mechanical elastic element.
Data Source
AI summary
An audio device comprises an acoustic transducer or speaker with a bidirectional vent coordinating between the front and back of the speaker. The bidirectional vent provides a balanced impedance in both the push/pull conditions of the speaker excursions while minimizing listener fatigue, without the need for a separate external vent or separate pressure management material. The audio device may include dual sound ports which have different dimensions, that may be selected to tune the response curve of the audio device, and to create smooth transitions of pneumatic pressure between the ear canal and the speaker.