Loudspeaker Control Device Using Electrical Parameter Estimation
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Solution Overview
Problem
Existing loudspeaker control systems fail to effectively account for the structure of unclosed enclosures, leading to incomplete correction of non-linearities and complexity in setup, especially when using open-loop control methods without mechanical sensors.
Innovation Solution
A device that calculates a loudspeaker excitation signal by incorporating differential flatness principles, structural adaptation, and dynamic reference quantities, taking into account the enclosure's structure and using bounded integration units to control low-frequency excursions, while estimating electromechanical parameters for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open-loop control methods are used without mechanical sensors, then device complexity and cost are reduced, but measurement precision and control accuracy deteriorate
Solution Approach 1:
The patent replaces mechanical sensors (microphones) with an electrical measurement system that uses voltage and current measurements across speaker terminals to characterize loudspeaker behavior. This substitution eliminates bulky mechanical components while maintaining control accuracy through electrical parameter measurements.
Solution Approach 2:
The patent introduces an intermediary measurement approach where voltage and current measurements serve as proxies for direct mechanical measurement. By measuring electrical parameters (voltage across terminals, current through voice coil) and using them to derive mechanical behavior through mathematical models, the system achieves accurate control without direct mechanical sensing.
2Device complexity
If standard open-loop control models are used, then device complexity is reduced, but adaptability to different enclosure structures deteriorates
Solution Approach 1:
The patent implements a dynamic control approach where the control algorithm adapts to different enclosure structures (closed, open, vented, bass reflex) by adjusting parameters based on the measured loudspeaker behavior. The system doesn't require different algorithms for different enclosures but rather dynamically adjusts to accommodate various structures through parameter optimization.
Solution Approach 2:
The patent changes control parameters based on the specific enclosure structure and loudspeaker configuration. By measuring actual voltage and current behavior and optimizing control parameters accordingly, the system adapts to different enclosure types without requiring complex structural modifications or multiple control algorithms.
3Manufacturing precision
If correction is calculated and added to input signal at each instant, then sound reproduction fidelity is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary characterization of the loudspeaker by measuring voltage and current behavior during normal operation. This preliminary measurement phase allows the system to build a model of the loudspeaker's non-linear behavior, which is then used to calculate and apply corrections in real-time without requiring complex calculations at every instant.
Solution Approach 2:
The patent implements continuous measurement and correction where voltage and current are measured continuously during operation, and corrections are applied continuously to the input signal. This continuous action ensures that non-linearities are compensated in real-time, maintaining high sound reproduction accuracy throughout the entire operating range.
Data Source
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AI summary
The invention relates to a device for controlling a loudspeaker (14) in a loudspeaker enclosure, comprising: - an input for an audio signal (S audio_ref ) to be reproduced; - an output for supplying an excitation signal from the loudspeaker; - means (26, 36, 38, 70, 80, 90) for calculating the excitation signal of the loudspeaker (14) at every moment in time according to the audio signal (S audio_ref ). Upstream, the device comprises means (26, 36, 38, 70, 80, 90) for calculating the excitation signal, means (24, 25) for calculating a desired dynamic value (A ref ) of the loudspeaker diaphragm according to the audio signal (S audio_ref ) to be reproduced and the structure of the enclosure, the means (25) for calculating the desired dynamic value (Aref) of the loudspeaker diaphragm being suitable for applying a correction that is different from the identity, and taking into account structural dynamic values (x o, v o ) of the enclosure that are different from the mere dynamic values relative to the loudspeaker diaphragm, and the means (26, 36, 38, 70, 80, 90) for calculating the excitation signal of the loudspeaker being suitable for calculating the excitation signal according to the desired dynamic value (A ref ) of the loudspeaker diaphragm.