Hearing Aid Vent Acoustic Measurement System
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Solution Overview
Problem
The acoustic properties of hearing aid vents are difficult to model accurately due to insufficient parametric description, leading to errors in hearing aid fitting and potential positive feedback loops, which can result in poor fitting and unstable operation.
Innovation Solution
A system and method for measuring the acoustic properties of the vent using a microphone, signal processing unit, and determining means that generate and analyze tone signals to correlate the actual acoustic response with expected properties, providing a warning for discrepancies and allowing for adjustments during fitting sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a vent is introduced in the ear-mould to equalize sound pressure and prevent occlusion, then the user comfort and pressure equalization are improved, but low frequency energy leakage increases and positive feedback loops are established
Solution Approach 1:
The patent implements feedback cancellation means that includes estimating a physical feedback signal generated by the vent, modeling a signal processing feedback signal to compensate for the estimated physical feedback signal, and subtracting the signal processing feedback signal from the audio signal. This active feedback cancellation approach allows the vent to remain open for user comfort while electronically compensating for the resulting low frequency energy leakage and positive feedback loops.
2Ease of operation
If hearing aid fitting software uses data tables and physical models of the vent for estimating acoustic properties, then the fitting process is simplified, but the accuracy of vent acoustic property estimation deteriorates due to insufficient parametric description
Solution Approach 1:
The patent replaces the mechanical modeling approach (data tables and physical models) with an acoustic measurement system that uses a microphone, signal generator, and analysis means to directly measure the acoustic properties of the actual vent in the actual ear-mould. This substitution of direct acoustic measurement for theoretical modeling eliminates the accuracy problems associated with insufficient parametric description while maintaining ease of operation through automated measurement.
3Measurement precision
If Real-Ear-Measurement (REM) is performed by inserting a microphone in the residual space, then acoustic properties can be measured, but the probe causes change of residual space and creates leakage leading to incorrect results
Solution Approach 1:
The patent performs the acoustic measurement of vent properties before the hearing aid is inserted into the user's ear, using the hearing aid itself as the measurement device. The signal generator generates test signals that travel through the vent and are captured by the microphone, allowing measurement of vent acoustic properties without inserting any additional probes into the residual space that would alter the acoustic environment or create leakage.
4Productivity
If manufacturers store acoustic properties of the vent in the hearing aid, then the hearing aid can operate with preset parameters, but large errors in prescription and simulation occur when stored properties do not correspond to the physical vent
Solution Approach 1:
The patent enables the hearing aid to automatically measure its own vent acoustic properties using its built-in microphone and signal generator during the fitting process. The hearing aid generates test signals, captures the acoustic response through its own microphone, and uses the determining means to calculate the actual vent properties. This self-measurement capability ensures that the stored acoustic properties always correspond to the actual physical vent, eliminating prescription and simulation errors while maintaining operational efficiency.
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 approach improves the fitting of hearing aids by accurately identifying and correcting vent-related issues, reducing operational quality problems and ensuring better sound pressure equalization.
Implementation Method 1
a speaker for converting said processed electric sound signal to a processed sound pressure
Implementation Method 2
a microphone converting ambient sound pressure to an electric sound signal
Implementation Method 3
The vent ensures that the enclosed pressure changes may be equalised with ambient pressure
Data Source
AI summary
This invention relates to a system (300) for measuring acoustic properties of a vent (126) in a hearing aid. The system (300) comprises: a microphone (202) converting ambient sound pressure to an electric sound signal; a signal processing unit (302) connected to the microphone (202) and generating a processed electric sound signal; and a speaker (204) converting the processed electric sound signal to a processed sound pressure. In addition, the system comprises a determining means, which is adapted to determine the acoustic properties by measuring the acoustic feedback from the speaker 204 to the microphone (202).