Detachable Ear Canal Simulator for High-Frequency Impedance
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Solution Overview
Problem
Existing ear simulators, such as the 711 type, are inaccurate in representing the average acoustic impedance of human ears beyond 7 kHz and fail to accurately model ear drum impedance, leading to errors in sound amplification and pressure predictions in hearing instrument fitting procedures.
Innovation Solution
An ear simulator assembly is developed, comprising an ear drum simulator that models the average acoustic ear drum impedance and a detachable ear canal simulator, which accurately represents the acoustic impedance of human ear canals and drums across a broader frequency range, including frequencies above 10 kHz, by decoupling the acoustic properties of the ear canal and drum simulators and mimicking the natural acoustic load on the eardrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a 711 type ear simulator is used to represent average acoustic ear drum impedance, then the acoustic parameters can be reproduced accurately up to about 7 kHz, but the accuracy deteriorates above this frequency due to half-wave resonance and inability to verify transfer impedance
Solution Approach 1:
The ear simulator is divided into separate functional modules: a detachable ear canal simulator and an ear drum simulator. This segmentation allows each component to be optimized independently for its specific frequency range, with the ear drum simulator focusing on accurate impedance representation above 7 kHz without being constrained by the resonant limitations of the integrated 711 design.
Solution Approach 2:
The invention introduces a detachable ear canal simulator that can be connected or disconnected from the ear drum simulator. This dynamic configuration allows the system to operate in different modes: with the ear canal simulator attached for comprehensive acoustic simulation, or disconnected for direct ear drum impedance measurement, thereby extending reliable operation across broader frequency ranges.
2Ease of manufacture
If the measurement plane is oriented parallel to the sound termination plane in a 711 type ear simulator, then the construction is simplified, but the orientation does not accurately mimic the tilted human ear drum relative to the ear canal
Solution Approach 1:
By separating the ear canal simulator from the ear drum simulator, the invention allows the ear drum simulator to be designed with the correct tilted orientation relative to the ear canal axis, accurately mimicking human anatomy. The detachable connection enables this precise angular relationship without complicating the overall construction, as each component can be manufactured independently with its optimal geometry.
3Device complexity
If a single integrated ear simulator design is used, then the device structure is simple, but it cannot accurately represent both ear canal and ear drum impedance separately across extended frequency ranges
Solution Approach 1:
The invention divides the ear simulator into a detachable ear canal simulator and an ear drum simulator, allowing each component to be optimized for its specific acoustic function. The ear canal simulator handles low-frequency acoustic coupling, while the ear drum simulator provides accurate high-frequency impedance representation, thereby extending the overall frequency range and accuracy without creating a monolithic complex structure.
Solution Approach 2:
The detachable connection between the ear canal and ear drum simulators provides dynamic configurability. Users can attach the ear canal simulator for comprehensive acoustic simulation or disconnect it for direct ear drum impedance measurements, enabling the system to adapt to different measurement requirements and extend its operational versatility across frequency ranges.
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 ear simulator assembly provides accurate prediction of sound amplification and ear drum sound pressure, enabling precise evaluation of portable communication equipment and hearing instrument fitting, with improved accuracy in representing the acoustic properties of human ears up to 20 kHz.
Implementation Method 1
an ear simulator representing an average acoustic ear drum impedance of ears of a population of humans
Implementation Method 2
A measurement microphone is arranged at a sound termination plane of the ear simulator
Data Source
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AI summary
The present invention relates to an ear simulator representing an average acoustic ear drum impedance of ears of a population of humans. Another aspect of the invention relates to an ear simulator assembly comprising an ear simulator representing average acoustic ear drum impedance and a detachable ear canal simulator to provide an ear simulator assembly representing an acoustic impedance of a human ear canal or average human canals of the population.