Array Speaker Low-Frequency Sound Focusing via Sub-Array Segmentation
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Solution Overview
Problem
Array speaker systems face challenges in focusing low-frequency sound signals effectively due to their fixed size, leading to poor sound reproduction when users are positioned at a distance from the system, resulting in inadequate directivity and increased beam width.
Innovation Solution
The method involves generating delayed signals, filtering low-frequency signals, and adjusting their gain to divide them into two groups, which are then applied to speaker units on either side of the array speaker system's center, improving sound focusing by enhancing directivity and reducing side lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the array speaker system uses a fixed size configuration, then the device structure is simple and compact, but the low-frequency sound signal cannot be properly focused and the beam width becomes too wide
Solution Approach 1:
The patent segments the array speaker system into multiple sub-arrays, with each sub-array responsible for specific frequency ranges. The low-frequency sub-arrays are positioned at the ends of the array while high-frequency sub-arrays are positioned at the center, allowing independent optimization of focusing characteristics for different frequencies without changing the overall fixed size structure.
Solution Approach 2:
The patent applies different focusing characteristics to different regions of the array speaker system. The end portions of the array are configured with characteristics suitable for low-frequency sound focusing, while the center portion is configured for high-frequency sound reproduction, creating local optimization of sound focusing precision within the fixed overall structure.
2Power
If the array speaker system reproduces low-frequency sound signals, then the sound output is sufficient, but the directivity is poor and sound cannot be focused to a specific position
Solution Approach 1:
The patent divides the audio signal into different frequency bands and directs them to different sub-arrays. Low-frequency signals are routed to end sub-arrays that are specifically configured for directional low-frequency reproduction, while high-frequency signals go to center sub-arrays, enabling both sufficient sound output and effective directionality control.
Solution Approach 2:
The patent introduces a frequency-based dimensional separation where different spatial regions of the array handle different frequency dimensions. This allows low-frequency sounds to be focused in the horizontal direction while maintaining adequate output power, and high-frequency sounds to be reproduced with appropriate directivity in the vertical direction.
3Length of moving object
If the user listens to sound at a position located a predetermined distance from the array speaker system, then the listening distance is extended, but the low-frequency sound signal becomes unclear and difficult to hear
Solution Approach 1:
The end portions of the array speaker system are configured with specific local characteristics optimized for low-frequency sound focusing at extended distances. These end sub-arrays have different acoustic impedance and radiation characteristics compared to the center sub-arrays, enabling clear low-frequency sound delivery to distant listeners while maintaining overall system functionality.
4Device complexity
If the array speaker system uses conventional sound reproduction methods, then the implementation is simple, but the beam width is wide and side lobes are high causing poor sound focusing
Solution Approach 1:
The patent segments the array into multiple sub-arrays with different focusing characteristics. By controlling the phase and amplitude distributions in each sub-array independently, the system achieves narrow beam width and suppressed side lobes for low-frequency sounds, while maintaining simple overall system implementation through modular sub-array configuration.
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 enhances sound focusing performance for low-frequency signals, allowing users to clearly hear sound from a desired direction without degrading sound quality, even when receiving broadband frequencies.
Implementation Method 1
The principle of sound transmission, generally called directivity, is to make a plurality of sound source signals overlap each other using phase differences between the sound source signals in order to increase signal strength along a specific direction
Implementation Method 2
filtering a low-frequency signal having a frequency that is lower than a reference frequency from the delayed signals
Implementation Method 3
The principle of sound transmission, generally called directivity, is to make a plurality of sound source signals overlap each other using phase differences between the sound source signals in order to increase signal strength along a specific direction
Data Source
AI summary
Provided is a method and apparatus for focusing sound using an array speaker system. The method includes generating a plurality of delayed signals to be focused to a predetermined position from an input signal, filtering a low-frequency signal having a frequency that is lower than a reference frequency from the delayed signals, generating low-frequency focusing signals divided into 2 groups by adjusting a gain of the filtered low-frequency signal, and applying the low-frequency focusing signals divided into the 2 groups to speaker units of the array speaker system at both sides with respect to a center portion of the array speaker system and outputting the low-frequency focusing signals through the speaker units. In this way, the performance of sound focusing for the low-frequency signal can be improved and thus a listener located a predetermined distance from and in a predetermined direction relative to the array speaker system can clearly listen to the low-frequency focusing signals.