Array Speaker Sound Focusing Using Pre-calculated Correction Filters
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Solution Overview
Problem
Array speaker systems face challenges in focusing sound effectively due to variations in sound radiation patterns caused by speaker positions and geometric arrangements, leading to deviations in delay and gain values between channels, which degrade focusing performance.
Innovation Solution
A method and apparatus that process input signals using a focusing filter corrected with sound characteristic information, including magnitude and phase, and compensate for delay and gain deviations using a compensation filter, calculated through least-square error methods and correlation analysis, to improve sound focusing in array speaker systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If filter values are calculated in advance to obtain a target frequency beam pattern, then the device complexity is reduced, but the manufacturing precision deteriorates due to unaccounted sound characteristic variations
Solution Approach 1:
The patent applies preliminary action by pre-calculating correction values for sound characteristics (magnitude and phase per channel) and storing them in lookup tables. During operation, the system retrieves these pre-computed correction values based on measured sound characteristics, avoiding real-time complex calculations while maintaining high precision sound focusing.
Solution Approach 2:
The system implements feedback by measuring actual sound characteristics (magnitude and phase) from the array speaker system output, using these measurements to select appropriate correction values from lookup tables, and applying corrections to achieve accurate beam forming. This closed-loop approach ensures high manufacturing precision.
2Manufacturing precision
If delay and gain values are adjusted to match target beam pattern, then the sound radiation pattern accuracy is improved, but the device complexity increases due to additional compensation filters
Solution Approach 1:
The patent segments the filtering process into two independent functional blocks: a focusing filter for beam forming and a compensation filter for delay/gain correction. Each filter handles specific correction tasks, allowing independent optimization and simplifying the overall system design while maintaining high beam pattern accuracy.
Solution Approach 2:
Delay and gain compensation values are pre-calculated and stored in lookup tables based on channel characteristics. The compensation filter retrieves these pre-computed values rather than calculating them in real-time, reducing computational complexity while maintaining accurate beam pattern formation.
3Productivity
If sound characteristic information is measured and corrected, then the sound focusing performance is improved, but the measurement precision requirements increase
Solution Approach 1:
The system measures sound characteristics at specific discrete positions and frequencies to build lookup tables, rather than attempting to measure all possible conditions continuously. This partial measurement approach provides sufficient correction data for practical applications while reducing measurement complexity and precision requirements compared to exhaustive measurement.
Data Source
AI summary
Provided are apparatus and method for focusing sound so that a sound radiation pattern output from an array speaker system composed of a plurality of speakers may approach a target sound radiation pattern. The sound focusing apparatus uses a focusing filter formed in consideration of sound characteristics of the array speaker system. In addition, the sound focusing apparatus may compensate for delay and gain values of each channel generated when an input signal is replicated to a plurality of channels and output through an array speaker in the array speaker system.