Audio Signal Processing Device for Multi-Point Sound Localization
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Solution Overview
Problem
In sound reproduction systems with multiple speakers of different characteristics, achieving simultaneous alignment of sound arrival times and levels across various frequencies at multiple listening points is challenging, leading to unstable sound localization.
Innovation Solution
An audio signal processing device and method that sets identical amplitude-frequency and phase characteristics for left and right speakers, and corrects the center speaker's characteristics to match those of the left and right speakers using inverse filter processing and speaker characteristic adding units, ensuring all frequencies arrive simultaneously at listening points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time alignment adjustment is performed separately for each speaker, then the arrival time of sound can be aligned at one listening point, but the arrival time over the entire frequency range is not aligned and sound localization is unstable
Solution Approach 1:
The patent applies parameter changes by adjusting both the amplitude-frequency characteristics and phase characteristics of each speaker's output signal. Specifically, it modifies the phase parameters across different frequency ranges to compensate for the different propagation distances, ensuring that sound waves of all frequencies arrive simultaneously at multiple listening points, thereby resolving the contradiction between arrival time alignment and sound localization stability
Solution Approach 2:
The patent implements dynamic adjustment of speaker output characteristics based on the spatial configuration. The system dynamically calculates and applies different phase corrections for each speaker according to its position relative to the listening points, enabling adaptive optimization of sound field distribution across the entire frequency range
2Measurement precision
If IIR filter is used for sound quality adjustment, then amplitude-frequency characteristics can be corrected, but phase characteristics cannot be controlled and sound localization is not enhanced
Solution Approach 1:
The patent segments the frequency range into multiple bands and applies independent phase correction to each band. This segmentation allows the system to address both amplitude-frequency and phase characteristics separately across different frequency ranges, overcoming the limitation of IIR filters that can only adjust amplitude without controlling phase
Solution Approach 2:
The patent extends parameter changes to include both amplitude-frequency parameters and phase parameters. By independently adjusting phase parameters for each speaker across different frequency bands, the system achieves comprehensive control over both magnitude and phase characteristics, enabling enhanced sound localization that IIR filters cannot provide
3Adaptability or versatility
If multiple speakers with different characteristics are arranged in a space, then sound can be output from multiple positions, but the arrival time and level of different frequencies vary and sound localization becomes unstable
Solution Approach 1:
The patent applies local quality by optimizing the output characteristics of each speaker individually according to its specific position and role in the sound field. Each speaker's amplitude-frequency and phase characteristics are adjusted locally to compensate for its distance and orientation relative to listening points, ensuring that all speakers contribute coherently to stable sound localization despite their different positions
Solution Approach 2:
The patent implements dynamic coordination between multiple speakers by calculating and applying position-dependent phase corrections. The system dynamically adjusts the output characteristics of each speaker based on its spatial configuration, enabling coherent sound field formation across multiple listening points and frequencies, thereby achieving stable sound localization
Data Source
AI summary
There is provided an audio signal processing device for setting, upon outputting audio signals from a left speaker and a right speaker each having an identical amplitude-frequency characteristic and a phase characteristic, and from one center speaker arranged between the left speaker and the right speaker, listening points between the left speaker and the center speaker and between the right speaker and the center speaker, the audio signal processing device including an inverse filter processing unit configured to provide inverse characteristics of an amplitude-frequency characteristic and a phase characteristic of the center speaker, and a speaker characteristic adding processing unit configured to correct the amplitude-frequency characteristic and the phase characteristic of an audio signal of the center speaker that have been processed by the inverse filter processing unit in a manner that they correspond to characteristics of the left speaker and the right speaker.