Earplug with Dual Resonance Cavities for Occlusion Reduction
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Solution Overview
Problem
Conventional earplugs with acoustic dampening meshes often cause an undesirable occlusion effect due to excessive sound attenuation at high frequencies, and achieving a desired resonance frequency requires a long canal, which complicates construction and limits adaptability.
Innovation Solution
A compact earplug design featuring a straight acoustic canal with a mesh separating two resonance volumes, allowing for ventilation and sound attenuation, where the resonance frequency is tuned by adjusting the volume rather than extending the canal length, providing minimal occlusion over an extended frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mesh is used for sound attenuation, then ventilation and air equilibration are improved, but high frequency sound attenuation increases causing occlusion effect
Solution Approach 1:
A resonance tube is introduced as an intermediary element between the mesh and the ear canal. This resonance tube creates a resonance peak that compensates for the mesh's high-frequency attenuation, acting as a mediator to restore the attenuated frequencies while maintaining the mesh's ventilation function.
Solution Approach 2:
The resonance frequency of the resonance tube is specifically tuned to match the attenuation characteristics of the mesh. By adjusting the length and diameter parameters of the resonance tube, the resonance peak is positioned to compensate exactly where the mesh causes excessive attenuation, balancing the frequency response.
2Reliability
If a long canal is used to provide resonance at desired frequency, then resonance compensation is improved, but device complexity and construction difficulty increase
Solution Approach 1:
Instead of extending the canal length in one dimension, the invention uses a resonance tube with specific cross-sectional dimensions. The resonance frequency is achieved through the tube's diameter and length ratio, allowing compact construction while maintaining the required resonance compensation.
Solution Approach 2:
The resonance characteristics are achieved by optimizing the dimensional parameters of a compact tube structure rather than using a long canal. The specific diameter-to-length ratio creates the desired resonance peak in a space-efficient manner, simplifying the overall earplug construction.
3Object-affected harmful factors
If resonance is tuned to specific frequency range, then occlusion effect is reduced, but sound levels at adjacent frequencies are further lowered
Solution Approach 1:
The resonance tube provides targeted compensation only in the frequency range where the mesh causes excessive attenuation. By concentrating the resonance peak specifically where needed rather than broadly boosting all frequencies, the solution reduces occlusion effect without causing excessive sound levels across the entire spectrum.
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
The design achieves balanced sound attenuation with minimal occlusion across a wide frequency range, improving ventilation and adaptability while maintaining a simple construction, by utilizing a mesh between resonance volumes to compensate for mesh attenuation above one kilohertz.
Implementation Method 1
The resonance cavities provide resonance peaks that (partially) compensate attenuation of the mesh in a resonance frequencies range above one kilohertz
Implementation Method 2
A mesh has a desired property that it can allow ventilation or equilibration of air and water there through
Data Source
AI summary
An earplug and method for attenuating sound. An acoustic canal extends straight through a housing to guide the sound inside an ear canal. The acoustic canal comprises a canal section dimensioned to fit at least partially inside the ear canal. The canal section ends at one side in a first exterior opening to let the sound into the ear canal. Another side of the canal section transitions into a first resonance volume with a relatively wide diameter. A second resonance volume ends at one side in a second exterior opening and, the other side being separated from the first resonance volume by a sound attenuating mesh. This provides resonance cavities that compensate attenuation of the mesh over a wide range of high frequencies.