Hearing Instrument Self-Calibration Using Built-In Microphone
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Solution Overview
Problem
Current methods for determining real ear acoustic coupling in hearing instruments are inaccurate due to lack of consideration for individual anatomical parameters and require laborious probe measurements, leading to systematic fitting errors and inefficiencies.
Innovation Solution
A method using a hearing instrument with an outer microphone and receiver to obtain a transfer function, allowing for computation of real ear acoustic coupling quantities like RECD, which can be used to set fitting parameters without a separate probe, leveraging the relationship between feedback threshold and acoustic coupling quantities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RECD direct measurements are performed using a separate microphone probe, then individual RECD differences can be measured, but the measurement process becomes very time consuming and requires special equipment
Solution Approach 1:
The hearing instrument uses its own built-in microphone to perform self-measurement of the acoustic coupling characteristics. The microphone in the hearing instrument itself is used as the measurement microphone, eliminating the need for separate probe equipment and reducing measurement time while maintaining accuracy
Solution Approach 2:
The built-in microphone of the hearing instrument serves dual purposes: it functions as both the operational microphone for hearing assistance and as the measurement microphone for RECD determination. This multi-functionality eliminates the need for separate measurement equipment
2Ease of operation
If conventional 2 cc coupler measurements are used, then the measurement process is simplified, but individual anatomical differences are not considered leading to fitting errors
Solution Approach 1:
The hearing instrument performs self-measurement in the user's actual ear, automatically capturing individual anatomical characteristics without requiring external measurement equipment or complex procedures. The built-in microphone records the actual acoustic coupling in the user's ear canal
Solution Approach 2:
The measurement transitions from using a standardized artificial ear canal model (2 cc coupler) to measuring in the actual user's ear canal, capturing individual anatomical parameters such as ear canal volume, shape, and resonance characteristics that vary between users
3Measurement precision
If a separate microphone probe is introduced into the user's ear for measurement, then direct RECD measurement is possible, but additional leakage is produced and artifacts are caused
Solution Approach 1:
The hearing instrument uses its own built-in microphone that is already positioned in the ear canal during normal operation. This eliminates the need to introduce additional foreign objects (separate probe microphones) that would cause leakage and artifacts
Solution Approach 2:
The measurement function extracts and utilizes the existing built-in microphone of the hearing instrument rather than introducing an external measurement device. The built-in microphone is already optimally positioned and integrated into the hearing instrument system
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 enables precise estimation of individual RECD and other acoustic coupling quantities, reducing fitting errors and measurement time, and allowing for self-adjusting hearing instruments with improved sound delivery.
Implementation Method 1
at least one outer microphone operable to obtain an input signal from an acoustic signal incident on the user's ear
Implementation Method 2
at least one receiver operable to produce an output acoustic signal for impinging on the user's eardrum
Implementation Method 3
obtaining a transfer function representative of an acoustic transfer from the receiver to the outer microphone
Data Source
AI summary
According to the invention, a real ear acoustic coupling quantity representative of the acoustic coupling of a hearing instrument to the user's ear or an anatomical transfer quantity—for example the Real-Ear-to-Coupler-Difference (RECD), the Microphone Location Effect (MLE), the Coupler Response for Flat Insertion Gain (CORFIG), and/or the Real Ear Open Gain (REOG)—is obtained from a transfer function representative of an acoustic transfer from the receiver to the outer microphone such as a signal feedback threshold gain. The obtained quantity may be used for setting a fitting parameter of the hearing instrument, for example a gain correction.