Nomadic Audio Device Calibration via Component-Specific Digital Filters
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Solution Overview
Problem
Portable audio devices often suffer from degraded user experience due to variations in component frequency responses and assembly defects, leading to instability in closed-loop transfer functions and feedback issues.
Innovation Solution
A calibration method for portable audio devices involving a calibration system with a microphone, speaker, and electronic device that determines and implements specific digital filters for each component, adjusting for actual performance rather than nominal models, thereby improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If filters are designed based on nominal frequency response without considering component dispersion, then manufacturing complexity is reduced, but device performance and reliability deteriorate
Solution Approach 1:
The patent applies preliminary action by performing frequency response measurement and calibration filter determination during the manufacturing process before the device is delivered to the user. The system measures the actual frequency response of each component (speaker, microphones) and determines calibration filters that compensate for deviations from nominal values, ensuring each device is optimized for its specific components before leaving the factory.
Solution Approach 2:
The patent implements parameter changes by adjusting the filter characteristics (gain, frequency response) based on measured component parameters. The calibration filters modify the audio signal parameters to compensate for actual component variations, transforming the system from using fixed nominal parameters to using dynamically adjusted parameters based on actual measurements.
2Reliability
If calibration procedures are implemented for each device, then device performance and reliability improve, but manufacturing complexity and time increase
Solution Approach 1:
The patent applies self-service by enabling the device to perform its own calibration using built-in measurement capabilities. The portable audio device uses its own speaker and microphones to measure frequency response, and the processor automatically determines calibration filters without requiring external calibration equipment or manual intervention, making the calibration process self-contained and automatable.
Solution Approach 2:
The patent implements feedback by using the measured frequency response to automatically adjust filter parameters. The system measures the actual performance of components, compares it to nominal values, and uses this feedback information to determine calibration filters that compensate for deviations, creating a closed-loop calibration process.
3Manufacturing precision
If calibration is performed for each individual device, then manufacturing precision improves, but production time and productivity decrease
Solution Approach 1:
The patent replaces mechanical calibration methods with electronic/digital processing. Instead of physical adjustments to components, the system uses digital signal processing to apply calibration filters that compensate for component variations, enabling automated calibration that is faster and more precise than manual mechanical adjustment methods.
Solution Approach 2:
The patent implements periodic action by performing calibration measurements and filter determination automatically during the manufacturing process for each device. This systematic periodic calibration ensures consistent quality without requiring continuous manual intervention, balancing precision with production efficiency.
Data Source
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AI summary
The present invention relates to a method for calibrating a portable audio device 10 comprising at least one portable microphone 20, 25 and a portable loudspeaker 15, the portable audio device 10 being arranged in a housing 95 comprising a calibration system 75. The calibration system comprises a calibration microphone 80, a calibration loudspeaker 85, and an electronic calibration device 90. The method comprises: - a phase of transmitting an audio signal to the portable loudspeaker or the calibration loudspeaker for its transmission, - a calibration phase comprising: - receiving a signal resulting from the acquisition of the audio signal emitted by the portable microphone or the calibration microphone, - determining a calibration filter H_calib_SPK; H_calilb_FB; H_calib_FF, from the received signal, - an implementation phase, in the portable audio device, of the determined calibration filter.