Noise-Cancelling Headphone Vent Hole Microphone Placement
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Solution Overview
Problem
Noise-cancelling headphones with feedforward noise-cancelling technology face sound quality degradation due to sounds leaking through vent holes, which are necessary for adjusting sound quality, as these sounds are incorrectly picked up by the microphone and processed as noise-cancelling signals.
Innovation Solution
The design includes a housing unit with a microphone positioned externally and a vent hole that is strategically located to prevent emitted sounds from being collected, using an accommodating portion and sound collecting hole placement to ensure that only external noises are detected, thereby preventing sound quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a vent hole is provided to adjust air pressure in the air chamber, then sound quality is improved, but external sounds leak through the vent hole and are collected by the microphone, degrading noise-cancelling performance
Solution Approach 1:
A sound hole is introduced as an intermediary structure between the vent hole and the microphone. The sound hole allows external sounds to reach the microphone while the vent hole remains open for air pressure adjustment. This mediator structure enables both functions to coexist without interference.
Solution Approach 2:
The patent segments the sound collection path from the vent hole by introducing a separate sound hole. This segmentation allows the vent hole to serve its air pressure adjustment function while the sound hole specifically handles sound collection, preventing degradation of noise-cancelling performance.
2Volume of moving object
If the microphone is disposed at the exterior of the housing unit for feedforward noise-cancelling, then the headphone structure can be downsized and sound quality is maintained, but the microphone may collect sounds leaking through vent holes, causing noise-cancelling degradation
Solution Approach 1:
The sound hole acts as an intermediary that guides external sounds to the microphone without allowing the microphone to collect sounds leaking from the vent hole. This maintains the external microphone placement benefits while preventing noise-cancelling degradation.
3Reliability
If the ear piece is sealed to enhance noise-cancelling effect, then noise-cancelling performance is improved, but reproduced sounds become muffled and sound quality degrades
Solution Approach 1:
The patent extracts the sound collection function from the sealed ear piece structure by providing a dedicated sound hole. This allows the ear piece to remain sealed for noise-cancelling enhancement while the sound hole enables reproduced sounds to be heard clearly without muffling.
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 solution effectively prevents sound quality degradation by ensuring that only external noises are processed for noise-cancelling, maintaining sound quality and reducing user discomfort caused by directionality issues and wind influence.
Implementation Method 1
The microphone collects external sounds (hereinafter referred to as 'noises') around the headphone
Implementation Method 2
a driver unit attached to the housing unit... outputs the combined sound waves from a driver unit
Implementation Method 3
the air pressure in an air chamber disposed behind the driver unit... vent holes to adjust the air pressure in the air chamber
Data Source
AI summary
A noise-cancelling headphone is provided that prevents degradation in the sound quality of the sound output from the driver unit caused by the sounds leaking through the vent hole for adjusting the sound quality. The noise-cancelling headphone includes a housing unit having an interior and an exterior, a driver unit attached to the housing unit, and a microphone collecting sound at the exterior of the housing unit. The housing unit includes an accommodating portion accommodating the microphone and a vent hole establishing communication between an air chamber behind the driver unit and the exterior of the housing unit. The housing unit is constructed such that emitted sounds from the vent hole are prevented from being collected by the microphone.